oatpp / oatpp-mongo

Oat++ native BSON + MongoDB driver implementation based on Oat++ object-mapping sub-framework.

oatpp-mongo

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NOTE:

• BSON ObjectMapper - ready-to-use.
• Database driver - in development. While you can do basic CRUD operations, it's still on POC stage. API is not ready and it's not recommended to use. To work with MongoDB - use BSON ObjectMapper + mongocxx driver.

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oatpp-mongo is the oatpp native client for MongoDB. It contains DTO to BSON mapper plus database driver.

Find the complete example project using oatpp-mongo here

More about Oat++:

• Oat++ Website
• Oat++ Github Repository

How To Build

oatpp-mongo has no extrernal dependencies (The main oatpp module is still required).
libmongoxcc is used (and linked) in module tests only. Use -DOATPP_BUILD_TESTS=OFF option to build without tests and without dependency on libmongoxcc.

Install oatpp-mongo

• Clone this repository.

• In the root of the repository run:

  mkdir build && cd build
  cmake -DOATPP_BUILD_TESTS=OFF ..
  make install

API

Temporary API (using libmongoxcc)

Since oatpp driver is not ready yet, you can use libmongoxcc together with oatpp BSON.

Why using oatpp BSON? - because it's based on oatpp object-mapping framework and it's extremely easy to use.

Create bsonxx::document From Any oatpp Object

/**
 * This is the utility function that you'll need while working libmongoxcc
 */
bsoncxx::document::value Database::createMongoDocument(const oatpp::Void &polymorph) {
  // if you have huge docs, you may want to increase starting BufferOutputStream size.
  // Or you may want to use oatpp::data::stream::ChunkedBuffer instead - for no-copy growth.
  oatpp::data::stream::BufferOutputStream stream;
  
  m_objectMapper.write(&stream, polymorph); //< Serialize oatpp object to BSON.
  
  bsoncxx::document::view view(stream.getData(), stream.getCurrentPosition());
  return bsoncxx::document::value(view);
}

Where m_objectMapper - is oatpp::mongo::bson::mapping::ObjectMapper.

Insert Document

Let's say you have such DTO defined:

class User : public oatpp::DTO {

  DTO_INIT(User, DTO)

  DTO_FIELD(String, _id);
  DTO_FIELD(String, username);
  DTO_FIELD(Boolean, active);
  DTO_FIELD(String, role);

};

Then you can insert your DTO in the database like this:

collection.insert_one(createMongoDocument(myDto));

You can also insert an arbitrary document using oatpp::Any

collection.insert_one(createMongoDocument(
  oatpp::Fields<oatpp::Any>({

    {"username", oatpp::String("Mr. Porridge")},
    {"role", oatpp::String("Admin")},
    {"jacket-color", oatpp::List<oatpp::String>({"red", "green", "blue"})}

  })
));

Read Document

Let's say we have the same DTO - User:

  auto result =
    collection.find_one(createMongoDocument( // <-- Filter
      oatpp::Fields<oatpp::String>({
        {"_id", oatpp::String("<id-to-find>")}
      })
    ));

  if(result) {
    auto view = result->view();
    auto bson = oatpp::String((const char*)view.data(), view.length(), false /* to not copy view data */);
    auto user = m_objectMapper.readFromString<oatpp::Object<User>>(bson);
    // TODO - do somthing with user:)
    // You can then serialize it to JSON using oatpp::parser::json::mapping::ObjectMapper
  }

Examples

• example-mongodb - CRUD with MongoDB and Swagger-UI.

oatpp-mongo's Issues

Is this still in development?

I was wondering if the package is stable now for production usage.

collection.find_one query by ObjectId

How can I query by "_id" : ObjectId?. For example:

auto result =
    collection.find_one(createMongoDocument( // <-- Filter
      oatpp::Fields<oatpp::String>({
        {"_id", "ObjectID(\"5f3258cfbaaccedaa5dd2d96\")"}
      })
    ));

How do I define a DTO field as int64 and mapped to MongoDB DateTime?

I'm having difficulty finding an example to define a DTO field and map it to MongoDB as DateTime. The example in this repo doesn't have such field.

With a uint64, it's mapped a timestamp which is not quite what I want. I'm getting compiler error if I do the following complaining "DateTime" is not a defined type.

class MyGroup : public oatpp::DTO {
    DTO_INIT(FingerprintGroup, DTO)

    DTO_FIELD(String, _id);

    DTO_FIELD(String, fpGroupName);
    DTO_FIELD(String, status);
    DTO_FIELD(String, type);
    DTO_FIELD(Int32, version) = 0;
    DTO_FIELD(DateTime, created) = 0L;
    DTO_FIELD(DateTime, updated) = 0L;
};

Is there any example with DTO object containing an array/vector field?

Looks like I may be able to do

DTO_FIELD(List, value);

then I have a std::vector vec;
but I when do value->push_back(vec[i]), I got some SEGV error.

wonder if there's any example of saving and retrieving an array/vector of objects to/from MongoDB using this framework.

Thanks.

API question

In file: oatpp-mongo/bson/Types.hpp

Question

Hi there, we are using BODY_DTO(oatpp::Any, value) to capture raw json into our endpoints but having issues with quotes around JSON. We would like to use our own json formats and objects (not DTOs). Therefor we need to be able to retrieve raw json without being encapsulated in quotes. Is there a way to receive JSON in the body and push it into a string or another object type without wrapping the whole JSON object is quotes. For example we want to send: {"user":"admin"} instead of "{"user":"admin"}".

[TODO] add ObjectId constructor from String

Until this implemented users can use the following method:

#include "oatpp-mongo/bson/Types.hpp"
#include "oatpp/encoding/Hex.hpp"
#include "oatpp/core/data/stream/BufferStream.hpp"

oatpp::mongo::bson::ObjectId objectIdFromString(const oatpp::String& hexText) {
  oatpp::data::stream::BufferOutputStream stream(12);
  oatpp::encoding::Hex::decode(&stream, hexText->getData(), hexText->getSize(), false);
  if(stream.getCurrentPosition() != 12) {
    throw std::runtime_error("Error. Invalid string.");
  }
  return oatpp::mongo::bson::ObjectId(stream.getData());
}

auto objId = objectIdFromString("5f9b6ecb21a7da049662e7d2");
OATPP_LOGD("AAA", "objId='%s'", objId->toString()->c_str());

Object mapper gives error when deserializing Int64

This problem is relatively easy to reproduce. When Object Mapper (default) is trying to decode a serialized string (JSON) of an object containing a field that is a list of Int64 and when one of the number's absolute value is small (-103 in this case). The object mapper would throw exception:

2023-07-08 00:06:29 ERROR localhost 494264 DLPFP 0: UploadController.cpp:00678 trid=342343234 rqid=0 tenantid=2400 user='' Decoding error for: { "simhash" : [ -1374461674807444439, -103, 1803150389721624332, -292347449805 ]}, err: [oatpp::mongo::bson::Utils::readPrimitive()]: Error. Can't deserialize Int64 value. BSON document value type is expected to be Int64.

Sample string:
{ "simhash" : [ -1374461674807444439, -103, 1803150389721624332, -292347449805 ]}"

The condition I found for this error is that the int64 absolute value is small. In the test code, it works for testString2 where I changed the small value to a big one. Looks like when the value is between [-2147483648, 2147483648) ie. 2^31, the deserializer will give this error.

Code snippets:

class TestDto : public oatpp::DTO {
    DTO_INIT(TestDto, DTO)

    DTO_FIELD(List<Int64>, simhash);
};

oatpp::Object<TestDto> decodeTestDto(const std::string &line)
{
    auto doc = bsoncxx::from_json(line);
    auto view = doc.view();
    auto bson = oatpp::String((const char *)view.data(), view.length());
    return m_objectMapper.readFromString<oatpp::Object<TestDto>>(bson);
}

Testing Code and sample string:

std::string testString = "{ \"simhash\" : [ -1374461674807444439, -103, 1803150389721624332, -292347449805 ]}";
// the following string works
// std::string testString2 = "{ \"simhash\" : [ -1374461674807444439, -103446167480744443, 1803150389721624332, -292347449805 ]}";
try {
    oatpp::Object<TestDto> testDto = m_allFpGenerator->decodeTestDto(testString);
    LOG(INFO) << "TestDto decode OK for " << testString;
} catch (const std::exception &exc) {
    LOG(ERROR) << "Decoding error for: " << testString << ", err: " << exc.what(); 
}