kodgemisi / servlet-url-mapper

A library helps to use multiple different URLs with one Servlet with ease.

Servlet Url Mapper

This small and non-invasive library is intended to be used in servlet-only environments where for some reasons developers are forced to use Servlet API directly (like in Atlassian plugin SDK).

In such servlet-only environments, this library helps to handle nested URL structures in one servlet.

Non-invasive: You don't need to use servlet url mapper in every servlet, you can use only in some of them.

Assume you have a ProductsServlet with /products, /products/* URL mapping. Then you would handle request like follows:

Traditional way

doGet method gets messy.

URL	Method	Handling Method
/products	GET	ProductsServlet#doGet
/products/13	GET	ProductsServlet#doGet
/products/13/campaigns	GET	ProductsServlet#doGet
/products	POST	ProductsServlet#doPost

Servlet URL Mapper way

You can use different methods for different URLs in the same servlet. You can even use another Class' method to handle requests.

URL	Method	Handling Method
/products	GET	ProductsServlet#list
/products/13	GET	ProductsServlet#show
/products/13/campaigns	GET	CampaignsHelper#show
/products	POST	ProductsServlet#create

Quick start

1. Add the dependency

You should use jitpack to add this library as a dependency for Maven or Gradle (or others).

<repositories>
  <repository>
      <id>jitpack.io</id>
      <url>https://jitpack.io</url>
  </repository>
</repositories>

<dependency>
    <groupId>com.github.kodgemisi</groupId>
    <artifactId>servlet-url-mapper</artifactId>
    <version>1.2.0</version>
</dependency>

See https://jitpack.io/#kodgemisi/servlet-url-mapper

2. Extend your servlet from MappingServlet

public class MyServlet extends MappingServlet {
	//...
}

3. Register your url mappings via protected urlMappingRegistrar field from MappingServlet. You can do this either in constructor or in init method.

@WebServlet(urlPatterns = {"/products", "/products/"})
public class MyServlet extends MappingServlet {
  public MyServlet() {
      this.urlMappingRegistrar
      
             // matches GET request to "host/context-root/products"
             .get("/", this::list)

             // matches GET request to "host/context-root/products/all"
             .get("/all", this::list) // note that the same method can be used for multiple url mappings

             // matches GET request to "host/context-root/products/{id}"
             .get("/{id}", this::show)

             // matches POST request to "host/context-root/products"
             .post("/", this::create)

             // matches POST request to "host/context-root/products/{id}/address"
             .post("/{id}/address", AddressHelper::addAddress);
      // and so on...
  }

  // any access modifier can be used
  private void list(HttpServletRequest request, HttpServletResponse response, ServletUrl servletUrl) throws ServletException, IOException {
      // your code...
  }

  private void show(HttpServletRequest request, HttpServletResponse response, ServletUrl servletUrl) throws ServletException, IOException {
      Integer id = servletUrl.variable("id"); // this is parsed from url: /{id}
      // your code...
  }

  // and rest of your methods...
}

Java 8 usage remainder: Note that (assuming you have an AddressHelper class in your project) AddressHelper::addAddress usage implies that addAddress is a static method. You can use non-static methods by providing an object instead of Class name like addressHelper::addAddress assuming addressHelper is an object of AddressHelper class.

License and Copyright

© 2017 - 2020 Kod Gemisi Ltd.

All material in this library's repository is copyrighted by Kod Gemisi Ltd unless stated otherwise.

This library is subject to the terms of the Mozilla Public License, v. 2.0. You can find full license in license.txt file or at http://mozilla.org/MPL/2.0/ adress.

There is also an easy to understand version of the license.

servlet-url-mapper's Issues

Path variable cannot be a number other than Integer

com.kodgemisi.servlet_url_mapping.ServletUrl#getObjectAs

docs improvement

add query parameter handling to the docs

this lib has nothing to do with query parameters. they're expected to be handled as usual. also state that there is no mapping according to query params.

add limitations

thread safety when dynamically adding new patterns.

removing patterns

Use Ant matcher

https://github.com/spring-projects/spring-framework/blob/master/spring-core/src/main/java/org/springframework/util/AntPathMatcher.java

name in ServletUrl should be optional

there should be this API as well: ServletUrl(String urlPattern, Class<?>[] types)

in that case name should be generated from urlPattern.

overload this method com.kodgemisi.servlet_url_mapping.ServletUrlPattern#register(java.lang.String, java.lang.String, com.kodgemisi.servlet_url_mapping.ServletRequestHandler, java.lang.Class<?>...)

path variable ignores '.'

instead of return "(\\w+)"; use return "([^/]+)";

	private String getRegexGroupByType(Class<?> clazz) {
		if (String.class.equals(clazz)) {
			return "(\\w+)";
		}
		if (Number.class.isAssignableFrom(clazz)) {
			return "(\\d+)";
		}
		if (Boolean.class.equals(clazz)) {
			return "(true|false|True|False|TRUE|FALSE)";
		}
		throw new IllegalArgumentException("Unsupported Type " + clazz.getName());
	}

Mapping documentation

URL //path didn't match any registered urls!
does it because of a missing mapping of /servlet-mapping/*

Default path variable type should be string

style improvements

• pathVariables (https://github.com/kodgemisi/servlet-url-mapper/blob/master/src/main/java/com/kodgemisi/servlet_url_mapping/ServletUrl.java#L50) may be final.
• ServletUrl.notFound should be all upper case
• com.kodgemisi.servlet_url_mapping.ServletUrlPattern#parse(java.lang.String) should throw illegalstateexception instead of runtimeexcpetion if it's never expected to throw.
• com.kodgemisi.servlet_url_mapping.ServletUrlPattern#handle should explicitly invoke the handler method (ServletRequestHandler#handleRequest).

if (invokeHandler && urlMappings.get(servletUrl) != null) {
    urlMappings.get(servletUrl).handleRequest(request, response, result);
}

above part doesn't belong to parseInternal. classical solid violation!