esphome / espasyncwebserver

Async Web Server for ESP8266 and ESP32

ESPAsyncWebServer

A fork of the ESPAsyncWebServer library by @me-no-dev for ESPHome.

For help and support

Async HTTP and WebSocket Server for ESP8266 Arduino

For ESP8266 it requires ESPAsyncTCP To use this library you might need to have the latest git versions of ESP8266 Arduino Core

For ESP32 it requires AsyncTCP to work To use this library you might need to have the latest git versions of ESP32 Arduino Core

Table of contents

• ESPAsyncWebServer
  • Table of contents
  • Installation
    • Using PlatformIO
  • Why should you care
  • Important things to remember
  • Principles of operation
    • The Async Web server
    • Request Life Cycle
    • Rewrites and how do they work
    • Handlers and how do they work
    • Responses and how do they work
    • Template processing
  • Libraries and projects that use AsyncWebServer
  • Request Variables
    • Common Variables
    • Headers
    • GET, POST and FILE parameters
    • FILE Upload handling
    • Body data handling
    • JSON body handling with ArduinoJson
  • Responses
    • Redirect to another URL
    • Basic response with HTTP Code
    • Basic response with HTTP Code and extra headers
    • Basic response with string content
    • Basic response with string content and extra headers
    • Send large webpage from PROGMEM
    • Send large webpage from PROGMEM and extra headers
    • Send large webpage from PROGMEM containing templates
    • Send large webpage from PROGMEM containing templates and extra headers
    • Send binary content from PROGMEM
    • Respond with content coming from a Stream
    • Respond with content coming from a Stream and extra headers
    • Respond with content coming from a Stream containing templates
    • Respond with content coming from a Stream containing templates and extra headers
    • Respond with content coming from a File
    • Respond with content coming from a File and extra headers
    • Respond with content coming from a File containing templates
    • Respond with content using a callback
    • Respond with content using a callback and extra headers
    • Respond with content using a callback containing templates
    • Respond with content using a callback containing templates and extra headers
    • Chunked Response
    • Chunked Response containing templates
    • Print to response
    • ArduinoJson Basic Response
    • ArduinoJson Advanced Response
  • Serving static files
    • Serving specific file by name
    • Serving files in directory
    • Serving static files with authentication
    • Specifying Cache-Control header
    • Specifying Date-Modified header
    • Specifying Template Processor callback
  • Param Rewrite With Matching
  • Using filters
    • Serve different site files in AP mode
    • Rewrite to different index on AP
    • Serving different hosts
    • Determine interface inside callbacks
  • Bad Responses
    • Respond with content using a callback without content length to HTTP/1.0 clients
  • Async WebSocket Plugin
    • Async WebSocket Event
    • Methods for sending data to a socket client
    • Direct access to web socket message buffer
    • Limiting the number of web socket clients
  • Async Event Source Plugin
    • Setup Event Source on the server
    • Setup Event Source in the browser
  • Scanning for available WiFi Networks
  • Remove handlers and rewrites
  • Setting up the server
    • Setup global and class functions as request handlers
    • Methods for controlling websocket connections
    • Adding Default Headers
    • Path variable

Installation

Using PlatformIO

PlatformIO is an open source ecosystem for IoT development with cross platform build system, library manager and full support for Espressif ESP8266/ESP32 development. It works on the popular host OS: Mac OS X, Windows, Linux 32/64, Linux ARM (like Raspberry Pi, BeagleBone, CubieBoard).

1. Install PlatformIO IDE
2. Create new project using "PlatformIO Home > New Project"
3. Update dev/platform to staging version:
   • Instruction for Espressif 8266
   • Instruction for Espressif 32
4. Add "ESP Async WebServer" to project using Project Configuration File platformio.ini and lib_deps option:

[env:myboard]
platform = espressif...
board = ...
framework = arduino

# using the latest stable version
lib_deps = ESP Async WebServer

# or using GIT Url (the latest development version)
lib_deps = https://github.com/me-no-dev/ESPAsyncWebServer.git

5. Happy coding with PlatformIO!

Why should you care

• Using asynchronous network means that you can handle more than one connection at the same time
• You are called once the request is ready and parsed
• When you send the response, you are immediately ready to handle other connections while the server is taking care of sending the response in the background
• Speed is OMG
• Easy to use API, HTTP Basic and Digest MD5 Authentication (default), ChunkedResponse
• Easily extendible to handle any type of content
• Supports Continue 100
• Async WebSocket plugin offering different locations without extra servers or ports
• Async EventSource (Server-Sent Events) plugin to send events to the browser
• URL Rewrite plugin for conditional and permanent url rewrites
• ServeStatic plugin that supports cache, Last-Modified, default index and more
• Simple template processing engine to handle templates

Important things to remember

• This is fully asynchronous server and as such does not run on the loop thread.
• You can not use yield or delay or any function that uses them inside the callbacks
• The server is smart enough to know when to close the connection and free resources
• You can not send more than one response to a single request

Principles of operation

The Async Web server

• Listens for connections
• Wraps the new clients into Request
• Keeps track of clients and cleans memory
• Manages Rewrites and apply them on the request url
• Manages Handlers and attaches them to Requests

Request Life Cycle

• TCP connection is received by the server
• The connection is wrapped inside Request object
• When the request head is received (type, url, get params, http version and host), the server goes through all Rewrites (in the order they were added) to rewrite the url and inject query parameters, next, it goes through all attached Handlers(in the order they were added) trying to find one that canHandle the given request. If none are found, the default(catch-all) handler is attached.
• The rest of the request is received, calling the handleUpload or handleBody methods of the Handler if they are needed (POST+File/Body)
• When the whole request is parsed, the result is given to the handleRequest method of the Handler and is ready to be responded to
• In the handleRequest method, to the Request is attached a Response object (see below) that will serve the response data back to the client
• When the Response is sent, the client is closed and freed from the memory

Rewrites and how do they work

• The Rewrites are used to rewrite the request url and/or inject get parameters for a specific request url path.
• All Rewrites are evaluated on the request in the order they have been added to the server.
• The Rewrite will change the request url only if the request url (excluding get parameters) is fully match the rewrite url, and when the optional Filter callback return true.
• Setting a Filter to the Rewrite enables to control when to apply the rewrite, decision can be based on request url, http version, request host/port/target host, get parameters or the request client's localIP or remoteIP.
• Two filter callbacks are provided: ON_AP_FILTER to execute the rewrite when request is made to the AP interface, ON_STA_FILTER to execute the rewrite when request is made to the STA interface.
• The Rewrite can specify a target url with optional get parameters, e.g. /to-url?with=params

Handlers and how do they work

• The Handlers are used for executing specific actions to particular requests
• One Handler instance can be attached to any request and lives together with the server
• Setting a Filter to the Handler enables to control when to apply the handler, decision can be based on request url, http version, request host/port/target host, get parameters or the request client's localIP or remoteIP.
• Two filter callbacks are provided: ON_AP_FILTER to execute the rewrite when request is made to the AP interface, ON_STA_FILTER to execute the rewrite when request is made to the STA interface.
• The canHandle method is used for handler specific control on whether the requests can be handled and for declaring any interesting headers that the Request should parse. Decision can be based on request method, request url, http version, request host/port/target host and get parameters
• Once a Handler is attached to given Request (canHandle returned true) that Handler takes care to receive any file/data upload and attach a Response once the Request has been fully parsed
• Handlers are evaluated in the order they are attached to the server. The canHandle is called only if the Filter that was set to the Handler return true.
• The first Handler that can handle the request is selected, not further Filter and canHandle are called.

Responses and how do they work

• The Response objects are used to send the response data back to the client
• The Response object lives with the Request and is freed on end or disconnect
• Different techniques are used depending on the response type to send the data in packets returning back almost immediately and sending the next packet when this one is received. Any time in between is spent to run the user loop and handle other network packets
• Responding asynchronously is probably the most difficult thing for most to understand
• Many different options exist for the user to make responding a background task

Template processing

• ESPAsyncWebserver contains simple template processing engine.
• Template processing can be added to most response types.
• Currently it supports only replacing template placeholders with actual values. No conditional processing, cycles, etc.
• Placeholders are delimited with % symbols. Like this: %TEMPLATE_PLACEHOLDER%.
• It works by extracting placeholder name from response text and passing it to user provided function which should return actual value to be used instead of placeholder.
• Since it's user provided function, it is possible for library users to implement conditional processing and cycles themselves.
• Since it's impossible to know the actual response size after template processing step in advance (and, therefore, to include it in response headers), the response becomes chunked.

Libraries and projects that use AsyncWebServer

• WebSocketToSerial - Debug serial devices through the web browser
• Sattrack - Track the ISS with ESP8266
• ESP Radio - Icecast radio based on ESP8266 and VS1053
• VZero - the Wireless zero-config controller for volkszaehler.org
• ESPurna - ESPurna ("spark" in Catalan) is a custom C firmware for ESP8266 based smart switches. It was originally developed with the ITead Sonoff in mind.
• fauxmoESP - Belkin WeMo emulator library for ESP8266.
• ESP-RFID - MFRC522 RFID Access Control Management project for ESP8266.

Request Variables

Common Variables

request->version();       // uint8_t: 0 = HTTP/1.0, 1 = HTTP/1.1
request->method();        // enum:    HTTP_GET, HTTP_POST, HTTP_DELETE, HTTP_PUT, HTTP_PATCH, HTTP_HEAD, HTTP_OPTIONS
request->url();           // String:  URL of the request (not including host, port or GET parameters)
request->host();          // String:  The requested host (can be used for virtual hosting)
request->contentType();   // String:  ContentType of the request (not avaiable in Handler::canHandle)
request->contentLength(); // size_t:  ContentLength of the request (not avaiable in Handler::canHandle)
request->multipart();     // bool:    True if the request has content type "multipart"

Headers

//List all collected headers
int headers = request->headers();
int i;
for(i=0;i<headers;i++){
  AsyncWebHeader* h = request->getHeader(i);
  Serial.printf("HEADER[%s]: %s\n", h->name().c_str(), h->value().c_str());
}

//get specific header by name
if(request->hasHeader("MyHeader")){
  AsyncWebHeader* h = request->getHeader("MyHeader");
  Serial.printf("MyHeader: %s\n", h->value().c_str());
}

//List all collected headers (Compatibility)
int headers = request->headers();
int i;
for(i=0;i<headers;i++){
  Serial.printf("HEADER[%s]: %s\n", request->headerName(i).c_str(), request->header(i).c_str());
}

//get specific header by name (Compatibility)
if(request->hasHeader("MyHeader")){
  Serial.printf("MyHeader: %s\n", request->header("MyHeader").c_str());
}

GET, POST and FILE parameters

//List all parameters
int params = request->params();
for(int i=0;i<params;i++){
  AsyncWebParameter* p = request->getParam(i);
  if(p->isFile()){ //p->isPost() is also true
    Serial.printf("FILE[%s]: %s, size: %u\n", p->name().c_str(), p->value().c_str(), p->size());
  } else if(p->isPost()){
    Serial.printf("POST[%s]: %s\n", p->name().c_str(), p->value().c_str());
  } else {
    Serial.printf("GET[%s]: %s\n", p->name().c_str(), p->value().c_str());
  }
}

//Check if GET parameter exists
if(request->hasParam("download"))
  AsyncWebParameter* p = request->getParam("download");

//Check if POST (but not File) parameter exists
if(request->hasParam("download", true))
  AsyncWebParameter* p = request->getParam("download", true);

//Check if FILE was uploaded
if(request->hasParam("download", true, true))
  AsyncWebParameter* p = request->getParam("download", true, true);

//List all parameters (Compatibility)
int args = request->args();
for(int i=0;i<args;i++){
  Serial.printf("ARG[%s]: %s\n", request->argName(i).c_str(), request->arg(i).c_str());
}

//Check if parameter exists (Compatibility)
if(request->hasArg("download"))
  String arg = request->arg("download");

FILE Upload handling

void handleUpload(AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final){
  if(!index){
    Serial.printf("UploadStart: %s\n", filename.c_str());
  }
  for(size_t i=0; i<len; i++){
    Serial.write(data[i]);
  }
  if(final){
    Serial.printf("UploadEnd: %s, %u B\n", filename.c_str(), index+len);
  }
}

Body data handling

void handleBody(AsyncWebServerRequest *request, uint8_t *data, size_t len, size_t index, size_t total){
  if(!index){
    Serial.printf("BodyStart: %u B\n", total);
  }
  for(size_t i=0; i<len; i++){
    Serial.write(data[i]);
  }
  if(index + len == total){
    Serial.printf("BodyEnd: %u B\n", total);
  }
}

If needed, the _tempObject field on the request can be used to store a pointer to temporary data (e.g. from the body) associated with the request. If assigned, the pointer will automatically be freed along with the request.

JSON body handling with ArduinoJson

Endpoints which consume JSON can use a special handler to get ready to use JSON data in the request callback:

#include "AsyncJson.h"
#include "ArduinoJson.h"

AsyncCallbackJsonWebHandler* handler = new AsyncCallbackJsonWebHandler("/rest/endpoint", [](AsyncWebServerRequest *request, JsonVariant &json) {
  JsonObject& jsonObj = json.as<JsonObject>();
  // ...
});
server.addHandler(handler);

Responses

Redirect to another URL

//to local url
request->redirect("/login");

//to external url
request->redirect("http://esp8266.com");

Basic response with HTTP Code

request->send(404); //Sends 404 File Not Found

Basic response with HTTP Code and extra headers

AsyncWebServerResponse *response = request->beginResponse(404); //Sends 404 File Not Found
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Basic response with string content

request->send(200, "text/plain", "Hello World!");

Basic response with string content and extra headers

AsyncWebServerResponse *response = request->beginResponse(200, "text/plain", "Hello World!");
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Send large webpage from PROGMEM

const char index_html[] PROGMEM = "..."; // large char array, tested with 14k
request->send_P(200, "text/html", index_html);

Send large webpage from PROGMEM and extra headers

const char index_html[] PROGMEM = "..."; // large char array, tested with 14k
AsyncWebServerResponse *response = request->beginResponse_P(200, "text/html", index_html);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Send large webpage from PROGMEM containing templates

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

const char index_html[] PROGMEM = "..."; // large char array, tested with 14k
request->send_P(200, "text/html", index_html, processor);

Send large webpage from PROGMEM containing templates and extra headers

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

const char index_html[] PROGMEM = "..."; // large char array, tested with 14k
AsyncWebServerResponse *response = request->beginResponse_P(200, "text/html", index_html, processor);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Send binary content from PROGMEM

//File: favicon.ico.gz, Size: 726
#define favicon_ico_gz_len 726
const uint8_t favicon_ico_gz[] PROGMEM = {
 0x1F, 0x8B, 0x08, 0x08, 0x0B, 0x87, 0x90, 0x57, 0x00, 0x03, 0x66, 0x61, 0x76, 0x69, 0x63, 0x6F,
 0x6E, 0x2E, 0x69, 0x63, 0x6F, 0x00, 0xCD, 0x53, 0x5F, 0x48, 0x9A, 0x51, 0x14, 0xBF, 0x62, 0x6D,
 0x86, 0x96, 0xA9, 0x64, 0xD3, 0xFE, 0xA8, 0x99, 0x65, 0x1A, 0xB4, 0x8A, 0xA8, 0x51, 0x54, 0x23,
 0xA8, 0x11, 0x49, 0x51, 0x8A, 0x34, 0x62, 0x93, 0x85, 0x31, 0x58, 0x44, 0x12, 0x45, 0x2D, 0x58,
 0xF5, 0x52, 0x41, 0x10, 0x23, 0x82, 0xA0, 0x20, 0x98, 0x2F, 0xC1, 0x26, 0xED, 0xA1, 0x20, 0x89,
 0x04, 0xD7, 0x83, 0x58, 0x20, 0x28, 0x04, 0xAB, 0xD1, 0x9B, 0x8C, 0xE5, 0xC3, 0x60, 0x32, 0x64,
 0x0E, 0x56, 0xBF, 0x9D, 0xEF, 0xF6, 0x30, 0x82, 0xED, 0xAD, 0x87, 0xDD, 0x8F, 0xF3, 0xDD, 0x8F,
 0x73, 0xCF, 0xEF, 0x9C, 0xDF, 0x39, 0xBF, 0xFB, 0x31, 0x26, 0xA2, 0x27, 0x37, 0x97, 0xD1, 0x5B,
 0xCF, 0x9E, 0x67, 0x30, 0xA6, 0x66, 0x8C, 0x99, 0xC9, 0xC8, 0x45, 0x9E, 0x6B, 0x3F, 0x5F, 0x74,
 0xA6, 0x94, 0x5E, 0xDB, 0xFF, 0xB2, 0xE6, 0xE7, 0xE7, 0xF9, 0xDE, 0xD6, 0xD6, 0x96, 0xDB, 0xD8,
 0xD8, 0x78, 0xBF, 0xA1, 0xA1, 0xC1, 0xDA, 0xDC, 0xDC, 0x2C, 0xEB, 0xED, 0xED, 0x15, 0x9B, 0xCD,
 0xE6, 0x4A, 0x83, 0xC1, 0xE0, 0x2E, 0x29, 0x29, 0x99, 0xD6, 0x6A, 0xB5, 0x4F, 0x75, 0x3A, 0x9D,
 0x61, 0x75, 0x75, 0x95, 0xB5, 0xB7, 0xB7, 0xDF, 0xC8, 0xD1, 0xD4, 0xD4, 0xF4, 0xB0, 0xBA, 0xBA,
 0xFA, 0x83, 0xD5, 0x6A, 0xFD, 0x5A, 0x5E, 0x5E, 0x9E, 0x28, 0x2D, 0x2D, 0x0D, 0x10, 0xC6, 0x4B,
 0x98, 0x78, 0x5E, 0x5E, 0xDE, 0x95, 0x42, 0xA1, 0x40, 0x4E, 0x4E, 0xCE, 0x65, 0x76, 0x76, 0xF6,
 0x47, 0xB5, 0x5A, 0x6D, 0x4F, 0x26, 0x93, 0xA2, 0xD6, 0xD6, 0x56, 0x8E, 0x6D, 0x69, 0x69, 0xD1,
 0x11, 0x36, 0x62, 0xB1, 0x58, 0x60, 0x32, 0x99, 0xA0, 0xD7, 0xEB, 0x51, 0x58, 0x58, 0x88, 0xFC,
 0xFC, 0x7C, 0x10, 0x16, 0x02, 0x56, 0x2E, 0x97, 0x43, 0x2A, 0x95, 0x42, 0x2C, 0x16, 0x23, 0x33,
 0x33, 0x33, 0xAE, 0x52, 0xA9, 0x1E, 0x64, 0x65, 0x65, 0x71, 0x7C, 0x7D, 0x7D, 0xBD, 0x93, 0xEA,
 0xFE, 0x30, 0x1A, 0x8D, 0xE8, 0xEC, 0xEC, 0xC4, 0xE2, 0xE2, 0x22, 0x6A, 0x6A, 0x6A, 0x40, 0x39,
 0x41, 0xB5, 0x38, 0x4E, 0xC8, 0x33, 0x3C, 0x3C, 0x0C, 0x87, 0xC3, 0xC1, 0x6B, 0x54, 0x54, 0x54,
 0xBC, 0xE9, 0xEB, 0xEB, 0x93, 0x5F, 0x5C, 0x5C, 0x30, 0x8A, 0x9D, 0x2E, 0x2B, 0x2B, 0xBB, 0xA2,
 0x3E, 0x41, 0xBD, 0x21, 0x1E, 0x8F, 0x63, 0x6A, 0x6A, 0x0A, 0x81, 0x40, 0x00, 0x94, 0x1B, 0x3D,
 0x3D, 0x3D, 0x42, 0x3C, 0x96, 0x96, 0x96, 0x70, 0x7E, 0x7E, 0x8E, 0xE3, 0xE3, 0x63, 0xF8, 0xFD,
 0xFE, 0xB4, 0xD7, 0xEB, 0xF5, 0x8F, 0x8F, 0x8F, 0x5B, 0x68, 0x5E, 0x6F, 0x05, 0xCE, 0xB4, 0xE3,
 0xE8, 0xE8, 0x08, 0x27, 0x27, 0x27, 0xD8, 0xDF, 0xDF, 0xC7, 0xD9, 0xD9, 0x19, 0x6C, 0x36, 0x1B,
 0x36, 0x36, 0x36, 0x38, 0x9F, 0x85, 0x85, 0x05, 0xAC, 0xAF, 0xAF, 0x23, 0x1A, 0x8D, 0x22, 0x91,
 0x48, 0x20, 0x16, 0x8B, 0xFD, 0xDA, 0xDA, 0xDA, 0x7A, 0x41, 0x33, 0x7E, 0x57, 0x50, 0x50, 0x80,
 0x89, 0x89, 0x09, 0x84, 0xC3, 0x61, 0x6C, 0x6F, 0x6F, 0x23, 0x12, 0x89, 0xE0, 0xE0, 0xE0, 0x00,
 0x43, 0x43, 0x43, 0x58, 0x5E, 0x5E, 0xE6, 0x9C, 0x7D, 0x3E, 0x1F, 0x46, 0x47, 0x47, 0x79, 0xBE,
 0xBD, 0xBD, 0x3D, 0xE1, 0x3C, 0x1D, 0x0C, 0x06, 0x9F, 0x10, 0xB7, 0xC7, 0x84, 0x4F, 0xF6, 0xF7,
 0xF7, 0x63, 0x60, 0x60, 0x00, 0x83, 0x83, 0x83, 0x18, 0x19, 0x19, 0xC1, 0xDC, 0xDC, 0x1C, 0x8F,
 0x17, 0x7C, 0xA4, 0x27, 0xE7, 0x34, 0x39, 0x39, 0x89, 0x9D, 0x9D, 0x1D, 0x6E, 0x54, 0xE3, 0x13,
 0xE5, 0x34, 0x11, 0x37, 0x49, 0x51, 0x51, 0xD1, 0x4B, 0xA5, 0x52, 0xF9, 0x45, 0x26, 0x93, 0x5D,
 0x0A, 0xF3, 0x92, 0x48, 0x24, 0xA0, 0x6F, 0x14, 0x17, 0x17, 0xA3, 0xB6, 0xB6, 0x16, 0x5D, 0x5D,
 0x5D, 0x7C, 0x1E, 0xBB, 0xBB, 0xBB, 0x9C, 0xD7, 0xE1, 0xE1, 0x21, 0x42, 0xA1, 0xD0, 0x6B, 0xD2,
 0x45, 0x4C, 0x33, 0x12, 0x34, 0xCC, 0xA0, 0x19, 0x54, 0x92, 0x56, 0x0E, 0xD2, 0xD9, 0x43, 0xF8,
 0xCF, 0x82, 0x56, 0xC2, 0xDC, 0xEB, 0xEA, 0xEA, 0x38, 0x7E, 0x6C, 0x6C, 0x4C, 0xE0, 0xFE, 0x9D,
 0xB8, 0xBF, 0xA7, 0xFA, 0xAF, 0x56, 0x56, 0x56, 0xEE, 0x6D, 0x6E, 0x6E, 0xDE, 0xB8, 0x47, 0x55,
 0x55, 0x55, 0x6C, 0x66, 0x66, 0x46, 0x44, 0xDA, 0x3B, 0x34, 0x1A, 0x4D, 0x94, 0xB0, 0x3F, 0x09,
 0x7B, 0x45, 0xBD, 0xA5, 0x5D, 0x2E, 0x57, 0x8C, 0x7A, 0x73, 0xD9, 0xED, 0xF6, 0x3B, 0x84, 0xFF,
 0xE7, 0x7D, 0xA6, 0x3A, 0x2C, 0x95, 0x4A, 0xB1, 0x8E, 0x8E, 0x0E, 0x6D, 0x77, 0x77, 0xB7, 0xCD,
 0xE9, 0x74, 0x3E, 0x73, 0xBB, 0xDD, 0x8F, 0x3C, 0x1E, 0x8F, 0xE6, 0xF4, 0xF4, 0x94, 0xAD, 0xAD,
 0xAD, 0xDD, 0xDE, 0xCF, 0x73, 0x0B, 0x0B, 0xB8, 0xB6, 0xE0, 0x5D, 0xC6, 0x66, 0xC5, 0xE4, 0x10,
 0x4C, 0xF4, 0xF7, 0xD8, 0x59, 0xF2, 0x7F, 0xA3, 0xB8, 0xB4, 0xFC, 0x0F, 0xEE, 0x37, 0x70, 0xEC,
 0x16, 0x4A, 0x7E, 0x04, 0x00, 0x00
};

AsyncWebServerResponse *response = request->beginResponse_P(200, "image/x-icon", favicon_ico_gz, favicon_ico_gz_len);
response->addHeader("Content-Encoding", "gzip");
request->send(response);

Respond with content coming from a Stream

//read 12 bytes from Serial and send them as Content Type text/plain
request->send(Serial, "text/plain", 12);

Respond with content coming from a Stream and extra headers

//read 12 bytes from Serial and send them as Content Type text/plain
AsyncWebServerResponse *response = request->beginResponse(Serial, "text/plain", 12);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Respond with content coming from a Stream containing templates

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//read 12 bytes from Serial and send them as Content Type text/plain
request->send(Serial, "text/plain", 12, processor);

Respond with content coming from a Stream containing templates and extra headers

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//read 12 bytes from Serial and send them as Content Type text/plain
AsyncWebServerResponse *response = request->beginResponse(Serial, "text/plain", 12, processor);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Respond with content using a callback

//send 128 bytes as plain text
request->send("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
});

Respond with content using a callback and extra headers

//send 128 bytes as plain text
AsyncWebServerResponse *response = request->beginResponse("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
});
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Respond with content using a callback containing templates

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//send 128 bytes as plain text
request->send("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
}, processor);

Respond with content using a callback containing templates and extra headers

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//send 128 bytes as plain text
AsyncWebServerResponse *response = request->beginResponse("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
}, processor);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Chunked Response

Used when content length is unknown. Works best if the client supports HTTP/1.1

AsyncWebServerResponse *response = request->beginChunkedResponse("text/plain", [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
});
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Chunked Response containing templates

Used when content length is unknown. Works best if the client supports HTTP/1.1

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

AsyncWebServerResponse *response = request->beginChunkedResponse("text/plain", [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
}, processor);
response->addHeader("Server","ESP Async Web Server");
request->send(response);

Print to response

AsyncResponseStream *response = request->beginResponseStream("text/html");
response->addHeader("Server","ESP Async Web Server");
response->printf("<!DOCTYPE html><html><head><title>Webpage at %s</title></head><body>", request->url().c_str());

response->print("<h2>Hello ");
response->print(request->client()->remoteIP());
response->print("</h2>");

response->print("<h3>General</h3>");
response->print("<ul>");
response->printf("<li>Version: HTTP/1.%u</li>", request->version());
response->printf("<li>Method: %s</li>", request->methodToString());
response->printf("<li>URL: %s</li>", request->url().c_str());
response->printf("<li>Host: %s</li>", request->host().c_str());
response->printf("<li>ContentType: %s</li>", request->contentType().c_str());
response->printf("<li>ContentLength: %u</li>", request->contentLength());
response->printf("<li>Multipart: %s</li>", request->multipart()?"true":"false");
response->print("</ul>");

response->print("<h3>Headers</h3>");
response->print("<ul>");
int headers = request->headers();
for(int i=0;i<headers;i++){
  AsyncWebHeader* h = request->getHeader(i);
  response->printf("<li>%s: %s</li>", h->name().c_str(), h->value().c_str());
}
response->print("</ul>");

response->print("<h3>Parameters</h3>");
response->print("<ul>");
int params = request->params();
for(int i=0;i<params;i++){
  AsyncWebParameter* p = request->getParam(i);
  if(p->isFile()){
    response->printf("<li>FILE[%s]: %s, size: %u</li>", p->name().c_str(), p->value().c_str(), p->size());
  } else if(p->isPost()){
    response->printf("<li>POST[%s]: %s</li>", p->name().c_str(), p->value().c_str());
  } else {
    response->printf("<li>GET[%s]: %s</li>", p->name().c_str(), p->value().c_str());
  }
}
response->print("</ul>");

response->print("</body></html>");
//send the response last
request->send(response);

ArduinoJson Basic Response

This way of sending Json is great for when the result is below 4KB

#include "AsyncJson.h"
#include "ArduinoJson.h"


AsyncResponseStream *response = request->beginResponseStream("application/json");
DynamicJsonBuffer jsonBuffer;
JsonObject &root = jsonBuffer.createObject();
root["heap"] = ESP.getFreeHeap();
root["ssid"] = WiFi.SSID();
root.printTo(*response);
request->send(response);

ArduinoJson Advanced Response

This response can handle really large Json objects (tested to 40KB) There isn't any noticeable speed decrease for small results with the method above Since ArduinoJson does not allow reading parts of the string, the whole Json has to be passed every time a chunks needs to be sent, which shows speed decrease proportional to the resulting json packets

#include "AsyncJson.h"
#include "ArduinoJson.h"


AsyncJsonResponse * response = new AsyncJsonResponse();
response->addHeader("Server","ESP Async Web Server");
JsonObject& root = response->getRoot();
root["heap"] = ESP.getFreeHeap();
root["ssid"] = WiFi.SSID();
response->setLength();
request->send(response);

Specifying Cache-Control header

It is possible to specify Cache-Control header value to reduce the number of calls to the server once the client loaded the files. For more information on Cache-Control values see Cache-Control

// Cache responses for 10 minutes (600 seconds)
server.serveStatic("/", SPIFFS, "/www/").setCacheControl("max-age=600");

//*** Change Cache-Control after server setup ***

// During setup - keep a pointer to the handler
AsyncStaticWebHandler* handler = &server.serveStatic("/", SPIFFS, "/www/").setCacheControl("max-age=600");

// At a later event - change Cache-Control
handler->setCacheControl("max-age=30");

Specifying Date-Modified header

It is possible to specify Date-Modified header to enable the server to return Not-Modified (304) response for requests with "If-Modified-Since" header with the same value, instead of responding with the actual file content.

// Update the date modified string every time files are updated
server.serveStatic("/", SPIFFS, "/www/").setLastModified("Mon, 20 Jun 2016 14:00:00 GMT");

//*** Chage last modified value at a later stage ***

// During setup - read last modified value from config or EEPROM
String date_modified = loadDateModified();
AsyncStaticWebHandler* handler = &server.serveStatic("/", SPIFFS, "/www/");
handler->setLastModified(date_modified);

// At a later event when files are updated
String date_modified = getNewDateModfied();
saveDateModified(date_modified); // Save for next reset
handler->setLastModified(date_modified);

Specifying Template Processor callback

It is possible to specify template processor for static files. For information on template processor see Respond with content coming from a File containing templates.

String processor(const String& var)
{
  if(var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

server.serveStatic("/", SPIFFS, "/www/").setTemplateProcessor(processor);

Param Rewrite With Matching

It is possible to rewrite the request url with parameter matchg. Here is an example with one parameter: Rewrite for example "/radio/{frequence}" -> "/radio?f={frequence}"

class OneParamRewrite : public AsyncWebRewrite
{
  protected:
    String _urlPrefix;
    int _paramIndex;
    String _paramsBackup;

  public:
  OneParamRewrite(const char* from, const char* to)
    : AsyncWebRewrite(from, to) {

      _paramIndex = _from.indexOf('{');

      if( _paramIndex >=0 && _from.endsWith("}")) {
        _urlPrefix = _from.substring(0, _paramIndex);
        int index = _params.indexOf('{');
        if(index >= 0) {
          _params = _params.substring(0, index);
        }
      } else {
        _urlPrefix = _from;
      }
      _paramsBackup = _params;
  }

  bool match(AsyncWebServerRequest *request) override {
    if(request->url().startsWith(_urlPrefix)) {
      if(_paramIndex >= 0) {
        _params = _paramsBackup + request->url().substring(_paramIndex);
      } else {
        _params = _paramsBackup;
      }
    return true;

    } else {
      return false;
    }
  }
};

Usage:

  server.addRewrite( new OneParamRewrite("/radio/{frequence}", "/radio?f={frequence}") );

Using filters

Filters can be set to Rewrite or Handler in order to control when to apply the rewrite and consider the handler. A filter is a callback function that evaluates the request and return a boolean true to include the item or false to exclude it. Two filter callback are provided for convince:

• ON_STA_FILTER - return true when requests are made to the STA (station mode) interface.
• ON_AP_FILTER - return true when requests are made to the AP (access point) interface.

Serving different hosts

// Filter callback using request host
bool filterOnHost1(AsyncWebServerRequest *request) { return request->host() == "host1"; }

// Server setup: server files in "/host1/" to requests for "host1", and files in "/www/" otherwise.
server.serveStatic("/", SPIFFS, "/host1/").setFilter(filterOnHost1);
server.serveStatic("/", SPIFFS, "/www/");

Determine interface inside callbacks

  String RedirectUrl = "http://";
  if (ON_STA_FILTER(request)) {
    RedirectUrl += WiFi.localIP().toString();
  } else {
    RedirectUrl += WiFi.softAPIP().toString();
  }
  RedirectUrl += "/index.htm";
  request->redirect(RedirectUrl);

Bad Responses

Some responses are implemented, but you should not use them, because they do not conform to HTTP. The following example will lead to unclean close of the connection and more time wasted than providing the length of the content

Respond with content using a callback without content length to HTTP/1.0 clients

//This is used as fallback for chunked responses to HTTP/1.0 Clients
request->send("text/plain", 0, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
});

Async WebSocket Plugin

The server includes a web socket plugin which lets you define different WebSocket locations to connect to without starting another listening service or using different port

Async WebSocket Event

void onEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventType type, void * arg, uint8_t *data, size_t len){
  if(type == WS_EVT_CONNECT){
    //client connected
    os_printf("ws[%s][%u] connect\n", server->url(), client->id());
    client->printf("Hello Client %u :)", client->id());
    client->ping();
  } else if(type == WS_EVT_DISCONNECT){
    //client disconnected
    os_printf("ws[%s][%u] disconnect: %u\n", server->url(), client->id());
  } else if(type == WS_EVT_ERROR){
    //error was received from the other end
    os_printf("ws[%s][%u] error(%u): %s\n", server->url(), client->id(), *((uint16_t*)arg), (char*)data);
  } else if(type == WS_EVT_PONG){
    //pong message was received (in response to a ping request maybe)
    os_printf("ws[%s][%u] pong[%u]: %s\n", server->url(), client->id(), len, (len)?(char*)data:"");
  } else if(type == WS_EVT_DATA){
    //data packet
    AwsFrameInfo * info = (AwsFrameInfo*)arg;
    if(info->final && info->index == 0 && info->len == len){
      //the whole message is in a single frame and we got all of it's data
      os_printf("ws[%s][%u] %s-message[%llu]: ", server->url(), client->id(), (info->opcode == WS_TEXT)?"text":"binary", info->len);
      if(info->opcode == WS_TEXT){
        data[len] = 0;
        os_printf("%s\n", (char*)data);
      } else {
        for(size_t i=0; i < info->len; i++){
          os_printf("%02x ", data[i]);
        }
        os_printf("\n");
      }
      if(info->opcode == WS_TEXT)
        client->text("I got your text message");
      else
        client->binary("I got your binary message");
    } else {
      //message is comprised of multiple frames or the frame is split into multiple packets
      if(info->index == 0){
        if(info->num == 0)
          os_printf("ws[%s][%u] %s-message start\n", server->url(), client->id(), (info->message_opcode == WS_TEXT)?"text":"binary");
        os_printf("ws[%s][%u] frame[%u] start[%llu]\n", server->url(), client->id(), info->num, info->len);
      }

      os_printf("ws[%s][%u] frame[%u] %s[%llu - %llu]: ", server->url(), client->id(), info->num, (info->message_opcode == WS_TEXT)?"text":"binary", info->index, info->index + len);
      if(info->message_opcode == WS_TEXT){
        data[len] = 0;
        os_printf("%s\n", (char*)data);
      } else {
        for(size_t i=0; i < len; i++){
          os_printf("%02x ", data[i]);
        }
        os_printf("\n");
      }

      if((info->index + len) == info->len){
        os_printf("ws[%s][%u] frame[%u] end[%llu]\n", server->url(), client->id(), info->num, info->len);
        if(info->final){
          os_printf("ws[%s][%u] %s-message end\n", server->url(), client->id(), (info->message_opcode == WS_TEXT)?"text":"binary");
          if(info->message_opcode == WS_TEXT)
            client->text("I got your text message");
          else
            client->binary("I got your binary message");
        }
      }
    }
  }
}

Methods for sending data to a socket client

//Server methods
AsyncWebSocket ws("/ws");
//printf to a client
ws.printf((uint32_t)client_id, arguments...);
//printf to all clients
ws.printfAll(arguments...);
//printf_P to a client
ws.printf_P((uint32_t)client_id, PSTR(format), arguments...);
//printfAll_P to all clients
ws.printfAll_P(PSTR(format), arguments...);
//send text to a client
ws.text((uint32_t)client_id, (char*)text);
ws.text((uint32_t)client_id, (uint8_t*)text, (size_t)len);
//send text from PROGMEM to a client
ws.text((uint32_t)client_id, PSTR("text"));
const char flash_text[] PROGMEM = "Text to send"
ws.text((uint32_t)client_id, FPSTR(flash_text));
//send text to all clients
ws.textAll((char*)text);
ws.textAll((uint8_t*)text, (size_t)len);
//send binary to a client
ws.binary((uint32_t)client_id, (char*)binary);
ws.binary((uint32_t)client_id, (uint8_t*)binary, (size_t)len);
//send binary from PROGMEM to a client
const uint8_t flash_binary[] PROGMEM = { 0x01, 0x02, 0x03, 0x04 };
ws.binary((uint32_t)client_id, flash_binary, 4);
//send binary to all clients
ws.binaryAll((char*)binary);
ws.binaryAll((uint8_t*)binary, (size_t)len);
//HTTP Authenticate before switch to Websocket protocol
ws.setAuthentication("user", "pass");

//client methods
AsyncWebSocketClient * client;
//printf
client->printf(arguments...);
//printf_P
client->printf_P(PSTR(format), arguments...);
//send text
client->text((char*)text);
client->text((uint8_t*)text, (size_t)len);
//send text from PROGMEM
client->text(PSTR("text"));
const char flash_text[] PROGMEM = "Text to send";
client->text(FPSTR(flash_text));
//send binary
client->binary((char*)binary);
client->binary((uint8_t*)binary, (size_t)len);
//send binary from PROGMEM
const uint8_t flash_binary[] PROGMEM = { 0x01, 0x02, 0x03, 0x04 };
client->binary(flash_binary, 4);

Direct access to web socket message buffer

When sending a web socket message using the above methods a buffer is created. Under certain circumstances you might want to manipulate or populate this buffer directly from your application, for example to prevent unnecessary duplications of the data. This example below shows how to create a buffer and print data to it from an ArduinoJson object then send it.

void sendDataWs(AsyncWebSocketClient * client)
{
    DynamicJsonBuffer jsonBuffer;
    JsonObject& root = jsonBuffer.createObject();
    root["a"] = "abc";
    root["b"] = "abcd";
    root["c"] = "abcde";
    root["d"] = "abcdef";
    root["e"] = "abcdefg";
    size_t len = root.measureLength();
    AsyncWebSocketMessageBuffer * buffer = ws.makeBuffer(len); //  creates a buffer (len + 1) for you.
    if (buffer) {
        root.printTo((char *)buffer->get(), len + 1);
        if (client) {
            client->text(buffer);
        } else {
            ws.textAll(buffer);
        }
    }
}

Limiting the number of web socket clients

Browsers sometimes do not correctly close the websocket connection, even when the close() function is called in javascript. This will eventually exhaust the web server's resources and will cause the server to crash. Periodically calling the cleanClients() function from the main loop() function limits the number of clients by closing the oldest client when the maximum number of clients has been exceeded. This can called be every cycle, however, if you wish to use less power, then calling as infrequently as once per second is sufficient.

void loop(){
  ws.cleanupClients();
}

Async Event Source Plugin

The server includes EventSource (Server-Sent Events) plugin which can be used to send short text events to the browser. Difference between EventSource and WebSockets is that EventSource is single direction, text-only protocol.

Setup Event Source on the server

AsyncWebServer server(80);
AsyncEventSource events("/events");

void setup(){
  // setup ......
  events.onConnect([](AsyncEventSourceClient *client){
    if(client->lastId()){
      Serial.printf("Client reconnected! Last message ID that it gat is: %u\n", client->lastId());
    }
    //send event with message "hello!", id current millis
    // and set reconnect delay to 1 second
    client->send("hello!",NULL,millis(),1000);
  });
  //HTTP Basic authentication
  events.setAuthentication("user", "pass");
  server.addHandler(&events);
  // setup ......
}

void loop(){
  if(eventTriggered){ // your logic here
    //send event "myevent"
    events.send("my event content","myevent",millis());
  }
}

Setup Event Source in the browser

if (!!window.EventSource) {
  var source = new EventSource('/events');

  source.addEventListener('open', function(e) {
    console.log("Events Connected");
  }, false);

  source.addEventListener('error', function(e) {
    if (e.target.readyState != EventSource.OPEN) {
      console.log("Events Disconnected");
    }
  }, false);

  source.addEventListener('message', function(e) {
    console.log("message", e.data);
  }, false);

  source.addEventListener('myevent', function(e) {
    console.log("myevent", e.data);
  }, false);
}

Scanning for available WiFi Networks

//First request will return 0 results unless you start scan from somewhere else (loop/setup)
//Do not request more often than 3-5 seconds
server.on("/scan", HTTP_GET, [](AsyncWebServerRequest *request){
  String json = "[";
  int n = WiFi.scanComplete();
  if(n == -2){
    WiFi.scanNetworks(true);
  } else if(n){
    for (int i = 0; i < n; ++i){
      if(i) json += ",";
      json += "{";
      json += "\"rssi\":"+String(WiFi.RSSI(i));
      json += ",\"ssid\":\""+WiFi.SSID(i)+"\"";
      json += ",\"bssid\":\""+WiFi.BSSIDstr(i)+"\"";
      json += ",\"channel\":"+String(WiFi.channel(i));
      json += ",\"secure\":"+String(WiFi.encryptionType(i));
      json += ",\"hidden\":"+String(WiFi.isHidden(i)?"true":"false");
      json += "}";
    }
    WiFi.scanDelete();
    if(WiFi.scanComplete() == -2){
      WiFi.scanNetworks(true);
    }
  }
  json += "]";
  request->send(200, "application/json", json);
  json = String();
});

Remove handlers and rewrites

Server goes through handlers in same order as they were added. You can't simple add handler with same path to override them. To remove handler:

// save callback for particular URL path
auto handler = server.on("/some/path", [](AsyncWebServerRequest *request){
  //do something useful
});
// when you don't need handler anymore remove it
server.removeHandler(&handler);

// same with rewrites
server.removeRewrite(&someRewrite);

server.onNotFound([](AsyncWebServerRequest *request){
  request->send(404);
});

// remove server.onNotFound handler
server.onNotFound(NULL);

// remove all rewrites, handlers and onNotFound/onFileUpload/onRequestBody callbacks
server.reset();

Setting up the server

#include "ESPAsyncTCP.h"
#include "ESPAsyncWebServer.h"

AsyncWebServer server(80);
AsyncWebSocket ws("/ws"); // access at ws://[esp ip]/ws
AsyncEventSource events("/events"); // event source (Server-Sent events)

const char* ssid = "your-ssid";
const char* password = "your-pass";
const char* http_username = "admin";
const char* http_password = "admin";

//flag to use from web update to reboot the ESP
bool shouldReboot = false;

void onRequest(AsyncWebServerRequest *request){
  //Handle Unknown Request
  request->send(404);
}

void onBody(AsyncWebServerRequest *request, uint8_t *data, size_t len, size_t index, size_t total){
  //Handle body
}

void onUpload(AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final){
  //Handle upload
}

void onEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventType type, void * arg, uint8_t *data, size_t len){
  //Handle WebSocket event
}

void setup(){
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  if (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.printf("WiFi Failed!\n");
    return;
  }

  // attach AsyncWebSocket
  ws.onEvent(onEvent);
  server.addHandler(&ws);

  // attach AsyncEventSource
  server.addHandler(&events);

  // respond to GET requests on URL /heap
  server.on("/heap", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send(200, "text/plain", String(ESP.getFreeHeap()));
  });

  // upload a file to /upload
  server.on("/upload", HTTP_POST, [](AsyncWebServerRequest *request){
    request->send(200);
  }, onUpload);

  // send a file when /index is requested
  server.on("/index", HTTP_ANY, [](AsyncWebServerRequest *request){
    request->send(SPIFFS, "/index.htm");
  });

  // HTTP basic authentication
  server.on("/login", HTTP_GET, [](AsyncWebServerRequest *request){
    if(!request->authenticate(http_username, http_password))
        return request->requestAuthentication();
    request->send(200, "text/plain", "Login Success!");
  });

  // Simple Firmware Update Form
  server.on("/update", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send(200, "text/html", "<form method='POST' action='/update' enctype='multipart/form-data'><input type='file' name='update'><input type='submit' value='Update'></form>");
  });
  server.on("/update", HTTP_POST, [](AsyncWebServerRequest *request){
    shouldReboot = !Update.hasError();
    AsyncWebServerResponse *response = request->beginResponse(200, "text/plain", shouldReboot?"OK":"FAIL");
    response->addHeader("Connection", "close");
    request->send(response);
  },[](AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final){
    if(!index){
      Serial.printf("Update Start: %s\n", filename.c_str());
      Update.runAsync(true);
      if(!Update.begin((ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000)){
        Update.printError(Serial);
      }
    }
    if(!Update.hasError()){
      if(Update.write(data, len) != len){
        Update.printError(Serial);
      }
    }
    if(final){
      if(Update.end(true)){
        Serial.printf("Update Success: %uB\n", index+len);
      } else {
        Update.printError(Serial);
      }
    }
  });

  // Catch-All Handlers
  // Any request that can not find a Handler that canHandle it
  // ends in the callbacks below.
  server.onNotFound(onRequest);
  server.onFileUpload(onUpload);
  server.onRequestBody(onBody);

  server.begin();
}

void loop(){
  if(shouldReboot){
    Serial.println("Rebooting...");
    delay(100);
    ESP.restart();
  }
  static char temp[128];
  sprintf(temp, "Seconds since boot: %u", millis()/1000);
  events.send(temp, "time"); //send event "time"
}

Setup global and class functions as request handlers

#include <Arduino.h>
#include <ESPAsyncWebserver.h>
#include <Hash.h>
#include <functional>

void handleRequest(AsyncWebServerRequest *request){}

class WebClass {
public :
  AsyncWebServer classWebServer = AsyncWebServer(81);

  WebClass(){};

  void classRequest (AsyncWebServerRequest *request){}

  void begin(){
    // attach global request handler
    classWebServer.on("/example", HTTP_ANY, handleRequest);

    // attach class request handler
    classWebServer.on("/example", HTTP_ANY, std::bind(&WebClass::classRequest, this, std::placeholders::_1));
  }
};

AsyncWebServer globalWebServer(80);
WebClass webClassInstance;

void setup() {
  // attach global request handler
  globalWebServer.on("/example", HTTP_ANY, handleRequest);

  // attach class request handler
  globalWebServer.on("/example", HTTP_ANY, std::bind(&WebClass::classRequest, webClassInstance, std::placeholders::_1));
}

void loop() {

}

Methods for controlling websocket connections

  // Disable client connections if it was activated
  if ( ws.enabled() )
    ws.enable(false);

  // enable client connections if it was disabled
  if ( !ws.enabled() )
    ws.enable(true);

Example of OTA code

  // OTA callbacks
  ArduinoOTA.onStart([]() {
    // Disable client connections    
    ws.enable(false);

    // Advertise connected clients what's going on
    ws.textAll("OTA Update Started");

    // Close them
    ws.closeAll();

  });

Adding Default Headers

In some cases, such as when working with CORS, or with some sort of custom authentication system, you might need to define a header that should get added to all responses (including static, websocket and EventSource). The DefaultHeaders singleton allows you to do this.

Example:

DefaultHeaders::Instance().addHeader("Access-Control-Allow-Origin", "*");
webServer.begin();

NOTE: You will still need to respond to the OPTIONS method for CORS pre-flight in most cases. (unless you are only using GET)

This is one option:

webServer.onNotFound([](AsyncWebServerRequest *request) {
  if (request->method() == HTTP_OPTIONS) {
    request->send(200);
  } else {
    request->send(404);
  }
});

Path variable

With path variable you can create a custom regex rule for a specific parameter in a route. For example we want a sensorId parameter in a route rule to match only a integer.

  server.on("^\\/sensor\\/([0-9]+)$", HTTP_GET, [] (AsyncWebServerRequest *request) {
      String sensorId = request->pathArg(0);
  });

NOTE: All regex patterns starts with ^ and ends with $

To enable the Path variable support, you have to define the buildflag -DASYNCWEBSERVER_REGEX.

For Arduino IDE create/update platform.local.txt:

Windows: C:\Users(username)\AppData\Local\Arduino15\packages\{espxxxx}\hardware\espxxxx\{version}\platform.local.txt

Linux: ~/.arduino15/packages/{espxxxx}/hardware/{espxxxx}/{version}/platform.local.txt

Add/Update the following line:

  compiler.cpp.extra_flags=-DDASYNCWEBSERVER_REGEX

For platformio modify platformio.ini:

[env:myboard]
build_flags = 
  -DASYNCWEBSERVER_REGEX

NOTE: By enabling ASYNCWEBSERVER_REGEX, <regex> will be included. This will add an 100k to your binary.

espasyncwebserver's Issues

TEMPLATE_PLACEHOLDER define problem

Hello,
i try to redefine the template placeholder with

#ifdef  TEMPLATE_PLACEHOLDER
   #undef  TEMPLATE_PLACEHOLDER
#endif
#define TEMPLATE_PLACEHOLDER '`' 

#include <ESPAsyncWebServer.h>
.....

but it was ignored, so when i change the line 63 in webResponseImpl.h to the new character it work.
so what can i do to overwrite the default template placeholder without modify the library direct?

Can't reach the server on my local network

Could any of you help me?

I can't make this library work on ESP32 CYD. I get no errors, however I can't reach my board at {LOCAL_NETWORK_IP}/mfa. I can also ping the {LOCAL_NETWORK_IP} from any of the devices connected to the same router. I also tried {LOCAL_NETWORK_IP}:80/mfa and had no success as well

Here is the code

#include <Arduino.h>
#include <ESPAsyncWebServer.h>
#include <SPIFFS.h>
#include "constants.h"

bool checkFileExists(const char *path)
{
	if (SPIFFS.exists(path))
	{
		Serial.printf("File %s exists.\n", path);
		return true;
	}
	else
	{
		Serial.printf("File %s does not exist!\n", path);
		return false;
	}
}

void init_manager()
{
	Serial.println("Initializing manager server.");
	AsyncWebServer server(80);

	if (!SPIFFS.begin(true))
	{
		Serial.println("something went wrong while mounting SPIFFS");
		return;
	}

	if (
		!checkFileExists("/index.html") ||
		!checkFileExists("/404.html") ||
		!checkFileExists("/favicon.ico"))
	{
		Serial.println("One or more required files are missing. Initialization aborted.");
		return;
	}

	Serial.println("Configuring routes.");

	server.on(
		"/",
		HTTP_GET,
		[](AsyncWebServerRequest *request)
		{
			request->send(200, "text/plain", "Hello, world!");
		});

	server.on(
		"/mfa",
		HTTP_GET,
		[](AsyncWebServerRequest *request)
		{
			request->send(SPIFFS, "/index.html", "text/html");
		});

	server.onNotFound(
		[](AsyncWebServerRequest *request)
		{
			request->send(SPIFFS, "/404.html", "text/html");
		});

	server.serveStatic("/_nuxt/", SPIFFS, "/_nuxt/");

	server.on(
		"/favicon.ico",
		HTTP_GET,
		[](AsyncWebServerRequest *request)
		{
			request->send(SPIFFS, "/favicon.ico", "image/x-icon");
		});

	Serial.println("Routes configured.");

	server.begin();
	Serial.println("Server initialized.");
}

Solved compile error ESP32 platform ESP32 V3.0

When installing the ESP32 V3.0.0 new some function are removed and or changed
changing the following will resolve compile error with the libraries major version V2 and V3.

          Changed in Arduino\libraries\ESPAsyncWebServer\src\WebAuthentic
           at line 75,76,77   

                #ifdef ESP_ARDUINO_VERSION_MAJOR
                   #if ESP_ARDUINO_VERSION >= ESP_ARDUINO_VERSION_VAL(3, 0, 0)
                     // Code for version 3.x
                   mbedtls_md5_init(&_ctx);
                   mbedtls_md5_starts(&_ctx);
                   mbedtls_md5_update(&_ctx, data, len);
                   mbedtls_md5_finish(&_ctx, _buf);
                   #else
                    // Code for version 2.x
                   #ifdef ESP32
                      mbedtls_md5_init(&_ctx);
                      mbedtls_md5_starts_ret(&_ctx);
                      mbedtls_md5_update_ret(&_ctx, data, len);
                      mbedtls_md5_finish_ret(&_ctx, _buf);
                   #else
                      MD5Init(&_ctx);
                      MD5Update(&_ctx, data, len);
                      MD5Final(_buf, &_ctx);
                    #endif
                 #endif
                #endif

           in AsyncEventSource.cpp changed at line 189 ets_printf --> log_e for V3
     and in AsyncWebSocket.cpp changed at line 549 ets_printf --> log_e  for V3

                 #ifdef ESP_ARDUINO_VERSION_MAJOR
                   #if ESP_ARDUINO_VERSION >= ESP_ARDUINO_VERSION_VAL(3, 0, 0)
                     // Code for version 3.x
                    log_e("ERROR: Too many messages queued\n");
                   #else
                    // Code for version 2.x
                    ets_printf("ERROR: Too many messages queued\n");
                 #endif
                #endif  

fpermissive looping inside para,eters

I get this error:
error: invalid conversion from 'const AsyncWebParameter*' to 'AsyncWebParameter*' [-fpermissive]

In this line:
AsyncWebParameter* p = request->getParam(i);

What's the problem?? I never get it...just new pc installation...

Core Dump in StringArray.h

Since two years I use with my project (> 1k installations) the AsyncWebserver. In past I started with the original repository but came here in hope to have a maintained version of it.
In the mid of March I successfully switched to this fork and was very happy with it.

In version 3.1.0 I faced an issue which is not easy to reproduce.
From my sight it can happen if two clients are using the Webserver at the same time. My project provides an API which is often used by automated scripts. This API is provided by the Webserver as well as the Webinterface of the project itself.

https://github.com/lumapu/ahoy

Core Dump ESP32 (Wroom)

CORRUPT HEAP: Bad head at 0x3ffdfbb8. Expected 0xabba1234 got 0x00000000

assert failed: multi_heap_free multi_heap_poisoning.c:259 (head != NULL)


Backtrace: 0x40083cb1:0x3ffdeb90 0x4008c9b1:0x3ffdebb0 0x40092c69:0x3ffdebd0 0x40092861:0x3ffded00 0x40084245:0x3ffded20 0x40092c99:0x3ffded40 0x4017fc89:0x3ffded60 0x4017fc79:0x3ffded80 0x400f9681:0x3ffdeda0 0x400fb3d9:0x3ffdedc0 0x400f712b:0x3ffdede0 0x400f7137:0x3ffdee00 0x400f24a2:0x3ffdee20 0x400f25ea:0x3ffdee50 0x400f2600:0x3ffdee70 0x400f29b5:0x3ffdee90

  #0  0x40083cb1:0x3ffdeb90 in panic_abort at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/esp_system/panic.c:408
  #1  0x4008c9b1:0x3ffdebb0 in esp_system_abort at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/esp_system/esp_system.c:137
  #2  0x40092c69:0x3ffdebd0 in __assert_func at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/newlib/assert.c:85
  #3  0x40092861:0x3ffded00 in multi_heap_free at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/heap/multi_heap_poisoning.c:259 (discriminator 1)
  #4  0x40084245:0x3ffded20 in heap_caps_free at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/heap/heap_caps.c:382
  #5  0x40092c99:0x3ffded40 in free at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/newlib/heap.c:39
  #6  0x4017fc89:0x3ffded60 in operator delete(void*) at /builds/idf/crosstool-NG/.build/HOST-x86_64-w64-mingw32/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/del_op.cc:49
  #7  0x4017fc79:0x3ffded80 in operator delete(void*, unsigned int) at /builds/idf/crosstool-NG/.build/HOST-x86_64-w64-mingw32/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/del_ops.cc:33
  #8  0x400f9681:0x3ffdeda0 in LinkedList<AsyncWebHeader*, LinkedListNode>::free() at .pio/libdeps/esp32-wroom32-ethernet-de/ESPAsyncWebServer-esphome/src/StringArray.h:177
      (inlined by) AsyncWebServerRequest::~AsyncWebServerRequest() at .pio/libdeps/esp32-wroom32-ethernet-de/ESPAsyncWebServer-esphome/src/WebRequest.cpp:81
  #9  0x400fb3d9:0x3ffdedc0 in AsyncWebServer::_handleDisconnect(AsyncWebServerRequest*) at .pio/libdeps/esp32-wroom32-ethernet-de/ESPAsyncWebServer-esphome/src/WebServer.cpp:102 (discriminator 1)
  #10 0x400f712b:0x3ffdede0 in AsyncWebServerRequest::_onDisconnect() at .pio/libdeps/esp32-wroom32-ethernet-de/ESPAsyncWebServer-esphome/src/WebRequest.cpp:229
  #11 0x400f7137:0x3ffdee00 in std::_Function_handler<void (void*, AsyncClient*), AsyncWebServerRequest::AsyncWebServerRequest(AsyncWebServer*, AsyncClient*)::{lambda(void*, AsyncClient*)#6}>::_M_invoke(std::_Any_data const&, void*&&, AsyncClient*&&) at .pio/libdeps/esp32-wroom32-ethernet-de/ESPAsyncWebServer-esphome/src/WebRequest.cpp:74
      (inlined by) _M_invoke at c:\users\lukas\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\include\c++\8.4.0\bits/std_function.h:297
  #12 0x400f24a2:0x3ffdee20 in std::function<void (void*, AsyncClient*)>::operator()(void*, AsyncClient*) const at c:\users\lukas\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\include\c++\8.4.0\bits/std_function.h:687
  #13 0x400f25ea:0x3ffdee50 in AsyncClient::_fin(tcp_pcb*, signed char) at .pio/libdeps/esp32-wroom32-ethernet-de/AsyncTCP-esphome/src/AsyncTCP.cpp:945
      (inlined by) AsyncClient::_fin(tcp_pcb*, signed char) at .pio/libdeps/esp32-wroom32-ethernet-de/AsyncTCP-esphome/src/AsyncTCP.cpp:942
  #14 0x400f2600:0x3ffdee70 in AsyncClient::_s_fin(void*, tcp_pcb*, signed char) at .pio/libdeps/esp32-wroom32-ethernet-de/AsyncTCP-esphome/src/AsyncTCP.cpp:1296
  #15 0x400f29b5:0x3ffdee90 in _async_service_task(void*) at .pio/libdeps/esp32-wroom32-ethernet-de/AsyncTCP-esphome/src/AsyncTCP.cpp:167
      (inlined by) _async_service_task at .pio/libdeps/esp32-wroom32-ethernet-de/AsyncTCP-esphome/src/AsyncTCP.cpp:199

Let me know if I can help something. My idea to solve it would be a mutex for the free() function or modifing the code to prevent double deletes:

void free(){
    while(_root != nullptr){
        auto it = _root;
        _root = _root->next;
        if (_onRemove) {
            _onRemove(it->value());
        }
        if(nullptr == it)
            continue;
        delete it;
        it = nullptr;
    }
    _root = nullptr;
}

In the meantime I try to get some reproduceable szenario. The core dump was captured by me arround 24th of April.

Crash once capture list is 'const' while responding by callback containing templates and extra headers

Strange thing - I try to get a function for the user to download the core dump from the coredump partition. During loading the data I faced an issue and get contiously core-dumps.

I'm developing on a standard ESP32-Wroom32.

The code is slightly changed for debugging purposes. The buffer is initialized by a for-loop to better check for valid data. First the capture list was only by reference [&] but then I saw that my buffer (data[]) was modified. Then I changed the capture-list to const reference. This leads to a reproduceable state where the ESP reboots.

Code snippet

void getCoreDump(AsyncWebServerRequest *request) {
    const esp_partition_t *partition = esp_partition_find_first(ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_COREDUMP, "coredump");
    if (partition != NULL) {
        size_t size = partition->size;
        uint8_t *data = new uint8_t[size];

        // must be separate from transfer - otherwise it failes during read
        //if (ESP_OK != esp_partition_read(partition, 0, data, size))
        //    DPRINTLN(DBG_ERROR, F("can't read partition"));

        for(int i = 0; i < size; i++) {
            data[i] = i % 256;
        }

        AsyncWebServerResponse *response = request->beginResponse("application/octet-stream", size, [&data, &size](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
            if((index + maxLen) > size)
                maxLen = size - index;
            DPRINTLN(DBG_INFO, "maxLen: " + String(maxLen)); // without this, the ESP crahses!?
            memcpy(buffer, &data[index], maxLen);

            if((index + maxLen) == size)
                delete[] data;

            return maxLen;
        });

        response->addHeader("Content-Description", "File Transfer");
        response->addHeader("Content-Disposition", "attachment; filename=coredump.bin");
        request->send(response);
    } else {
        AsyncWebServerResponse *response = request->beginResponse(200, F("application/json; charset=utf-8"), "{}");
        request->send(response);
    }
}

once I call my ESP with [IP]/coredump the following stacktrace will be printed

Core Dump

Guru Meditation Error: Core  0 panic'ed (LoadProhibited). Exception was unhandled.

Core  0 register dump:
PC      : 0x4019bc71  PS      : 0x00060630  A0      : 0x8012908d  A1      : 0x3ffb30f0  
A2      : 0x8d11cd38  A3      : 0x00000006  A4      : 0x00000014  A5      : 0x0000ffff
A6      : 0x00000000  A7      : 0x00000001  A8      : 0x00000002  A9      : 0x0000ff00  
A10     : 0x00ff0000  A11     : 0x3ffdf898  A12     : 0x00000001  A13     : 0x00000002
A14     : 0x00000000  A15     : 0x00000001  SAR     : 0x00000019  EXCCAUSE: 0x0000001c  
EXCVADDR: 0x8d11cd38  LBEG    : 0x4008a234  LEND    : 0x4008a24a  LCOUNT  : 0xffffffff


Backtrace: 0x4019bc6e:0x3ffb30f0 0x4012908a:0x3ffb3110 0x4012936a:0x3ffb3130 0x4012a956:0x3ffb3160 0x4012f97a:0x3ffb31d0 0x401339c6:0x3ffb3200 0x401248c5:0x3ffb3220

  #0  0x4019bc6e:0x3ffb30f0 in pbuf_clen at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/pbuf.c:824
  #1  0x4012908a:0x3ffb3110 in tcp_free_acked_segments at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/tcp_in.c:1113
  #2  0x4012936a:0x3ffb3130 in tcp_receive at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/tcp_in.c:1289 (discriminator 4)
  #3  0x4012a956:0x3ffb3160 in tcp_process at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/tcp_in.c:987
      (inlined by) tcp_input at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/tcp_in.c:438
  #4  0x4012f97a:0x3ffb31d0 in ip4_input at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/core/ipv4/ip4.c:803
  #5  0x401339c6:0x3ffb3200 in ethernet_input at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/netif/ethernet.c:186
  #6  0x401248c5:0x3ffb3220 in tcpip_thread_handle_msg at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/api/tcpip.c:180
      (inlined by) tcpip_thread at /Users/ficeto/Desktop/ESP32/ESP32S2/esp-idf-public/components/lwip/lwip/src/api/tcpip.c:154




ELF file SHA256: e63468b51f8e834c

Rebooting...

Your documentation:
https://github.com/esphome/ESPAsyncWebServer/blob/main/README.md#respond-with-content-using-a-callback-containing-templates-and-extra-headers

Is there anything I'm missing? Don't know where the issue is related to.

release 3.2.0 breaks esphome web_server component

please see this issue esphome/issues#5793

Compile error

C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp: In function 'bool getMD5(uint8_t*, uint16_t, char*)':
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:74:3: error: 'mbedtls_md5_starts_ret' was not declared in this scope; did you mean 'mbedtls_md5_starts'?
74 | mbedtls_md5_starts_ret(&_ctx);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_starts
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:75:3: error: 'mbedtls_md5_update_ret' was not declared in this scope; did you mean 'mbedtls_md5_update'?
75 | mbedtls_md5_update_ret(&_ctx, data, len);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_update
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:76:3: error: 'mbedtls_md5_finish_ret' was not declared in this scope; did you mean 'mbedtls_md5_finish'?
76 | mbedtls_md5_finish_ret(&_ctx, _buf);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_finish
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\AsyncEventSource.cpp: In member function 'void AsyncEventSourceClient::_queueMessage(AsyncEventSourceMessage*)':
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\AsyncEventSource.cpp:189:7: error: 'ets_printf' was not declared in this scope; did you mean 'vswprintf'?
189 | ets_printf("ERROR: Too many messages queued\n");
| ^~~~~~~~~~
| vswprintf
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\AsyncWebSocket.cpp: In member function 'void AsyncWebSocketClient::_queueMessage(AsyncWebSocketMessage*)':
C:\Users\steph\OneDrive\Arduino\libraries\ESPAsyncWebServer\src\AsyncWebSocket.cpp:549:7: error: 'ets_printf' was not declared in this scope; did you mean 'vswprintf'?
549 | ets_printf("ERROR: Too many messages queued\n");
| ^~~~~~~~~~
| vswprintf

Decide which ESPAsyncWebServer fork should be canonical?

[edited based on discussions] The situation with ESPAsyncWebServer is a mess:

• the original repo appears to be unmaintained, and is extremely buggy
• this repo is quite popular and contains many fixes (but not all?) but is more oriented to esphome's needs?
• the Arduino registry's entry for ESPAsyncWebServer points to @lacamera's fork of this repository, which is just this repo plus library.properties
• the most visible platformio registry entry points to me-no-dev's original repo, and people are actively steered there
• other notable forks are @mathieucarbou's fork and the yubox-node-org fork

Ideally we'd designate one repo and merge the important fixes and improvements there, and any remaining forks would work off that if people need to add project-specific tweaks? And we could see about changing registry entries to point to that fork, or at least steer people there?

The most likely candidates seem like this one and @mathieucarbou's fork; Mathieu seems to be actively merging in fixes from elsewhere and seems to be willing to take up the mantle, so that's one promising option?

But, I'm sure people have Opinions...