Enhanced HTTP Standard Capabilities of Triple Protocol

Enhanced HTTP Standard Capabilities of Triple Protocol - Support for Multiple Content-Type

Enhanced HTTP Standard Capabilities of Triple Protocol - Support for Multiple Content-Type

This article focuses on how Triple supports more of the HTTP standard Content-Type and how the service receives these requests.

Overview

Triple currently supports two serialization methods: Json and protobuf, corresponding to the ContentTypes:

  • application/json
  • application/grpc+proto

This poses no issue when both the consumer and provider are backend services. However, for browser clients, they may send a wider variety of ContentTypes, which requires server-side support for decoding, such as:

  • multipart/formdata
  • text/plain
  • application/x-www-form-urlencoded
  • application/xml

REST protocol has already largely implemented the above decoding capabilities. Enabling Triple to achieve these capabilities is an important step towards full interoperability between Triple server and browser clients.

Usage

multipart/formdata
POST /org.apache.dubbo.samples.tri.noidl.api.PojoGreeter/greetPojo HTTP/1.1
Host: 192.168.202.1:50052
Content-Type: multipart/form-data; boundary=example-part-boundary
Accept: application/json
--example-part-boundary
Content-Disposition: form-data; name="username"
Content-Type: text/plain
LuYue
--example-part-boundary
Content-Disposition: form-data; name="userdetail"
Content-Type: application/json
{
    "location":"beijing",
    "username":"LuYue"
}
--example-part-boundary
Content-Disposition: form-data; name="userimg";filename="user.jpeg"
Content-Type: image/jpeg
<binary image data>
--example-part-boundary--

Receiving:

    @Override
    public ServerResponse greetPojo(String username, User user, byte[] attachment) {
        //LuYue
        System.out.println(username); 
        //user.name=Luyue;user.location=beijing
        System.out.println(user); 
        //<binary image data>
        System.out.println(new String(attachment, StandardCharsets.UTF_8)); 
        return new ServerResponse("Server Received:" + username);
    }
  • Each part is decoded according to its Content-Type.
  • If the method parameter is byte[] or Byte[], the corresponding field will not be decoded.
  • The response is encoded using application/json.
application/x-www-form-urlencoded
POST /org.apache.dubbo.samples.tri.noidl.api.PojoGreeter/greetUrlForm HTTP/1.1
Host: 192.168.202.1:50052
Content-Type: application/x-www-form-urlencoded
Content-Length: 33
Accept: application/json
Hello=World&Apache=Dubbo&id=10086

Two ways of receiving:

    public ServerResponse greetUrlForm(String hello, String apache, long id){
        System.out.println("Hello:" + hello);
        System.out.println("Apache:" + apache);
        System.out.println("Id:" + id);
        return new ServerResponse("Server Received url form");
    }

    public ServerResponse greetUrlForm(Map<String, Object> params){
        System.out.println("Hello:" + params.get("Hello"));
        System.out.println("Apache:" + params.get("Apache"));
        System.out.println("Id:" + params.get("Id"));
        return new ServerResponse("Server Received url form");
    }
  • If the parameter is a Map, it is decoded into Map<String, String> for input.
  • If all parameters are Strings or numeric types, they are decoded and passed in according to the parameter list.
  • The response is encoded using application/json.
text/plain
POST /org.apache.dubbo.samples.tri.noidl.api.PojoGreeter/greetString HTTP/1.1
Host: 192.168.202.1:50052
Content-Type: text/plain; charset=UTF-8
Content-Length: 6
Accept: application/json
World!

Receiving:

    public ServerResponse greetString(String world){
        System.out.println("Hello:" + world);
        return new ServerResponse("Server Received url form.");
    }
  • Charset supports ASCII, UTF-8, UTF-16, etc., with UTF-8 as the default.
  • The response is encoded using application/json.
application/xml
POST /org.apache.dubbo.samples.tri.noidl.api.PojoGreeter/greetXml HTTP/1.1
Host: 192.168.202.1:50052
Content-Type: application/xml
Content-Length: 86
Accept: application/xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<User>
    <username>JohnDoe</username>
    <location>New York</location>
</User>

Receiving:

    @Override
public ServerResponse greetXml(User user) {
        System.out.println(user.getUsername());
        System.out.println(user.getLocation());
        return new ServerResponse("Server Received xml.");
        }
  • This implementation is the same as Rest’s XMLCodec.
  • The response is encoded using application/xml.