Thrift笔记(四)--Thrift client源码分析

thrift文件

namespace java com.gxf.demo
namespace py tutorial

typedef i32 int // We can use typedef to get pretty names for the types we are using
service MultiplicationService
{
        int multiply(1:int n1, 2:int n2),
        int add(1:int n1, 2:int n2),
}

service SubService{
        int sub(1:int n1, 2:int n2),
}

struct User{
    1: i32 id = 0,
    2: required string name,
}

MultiplicationHandler.java

import org.apache.thrift.TException;

public class MultiplicationHandler implements MultiplicationService.Iface, SubService.Iface {

    @Override
    public int multiply(int n1, int n2) throws TException {
        System.out.println("Multiply(" + n1 + "," + n2 + ")");
        return n1 * n2;
    }

    @Override
    public int add(int n1, int n2) throws TException {
        System.out.println("add(" + n1 + "," + n2 + ")");
        return n1 + n2;
    }


    @Override
    public int sub(int n1, int n2) throws TException {
        System.out.println("sub(" + n1 + "," + n2 + ")");
        return n1 - n2;
    }
}

MultiplicationServer.java

import org.apache.thrift.server.TServer;
import org.apache.thrift.server.TServer.Args;
import org.apache.thrift.server.TSimpleServer;
import org.apache.thrift.transport.TServerSocket;
import org.apache.thrift.transport.TServerTransport;

public class MultiplicationServer {

    public static MultiplicationHandler handler;

    public static MultiplicationService.Processor processor;

    public static void main(String [] args) {
        try {
            handler = new MultiplicationHandler();
            processor = new MultiplicationService.Processor(handler);
            Runnable simple = () -> simple(processor);

            new Thread(simple).start();
        } catch (Exception x) {
            x.printStackTrace();
        }
    }

    public static void simple(MultiplicationService.Processor processor) {
        try {
            TServerTransport serverTransport = new TServerSocket(9090);
            TServer server = new TSimpleServer(new Args(serverTransport).processor(processor));

            System.out.println("Starting the simple server...");
            server.serve();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

MultiplicationClient.java

import org.apache.thrift.TException;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.transport.TSocket;
import org.apache.thrift.transport.TTransport;

public class MultiplicationClient {

    public static void main(String [] args) {
        try {
            TTransport transport;
            transport = new TSocket("localhost", 9090);
            transport.open();
            TProtocol protocol = new TBinaryProtocol(transport);
            MultiplicationService.Client client = new MultiplicationService.Client(protocol);
            SubService.Client subClient = new SubService.Client(protocol);
            perform(client, subClient);
            transport.close();
        } catch (TException x) {
            x.printStackTrace();
        }
    }

    private static void perform(MultiplicationService.Client client, SubService.Client subClient) throws TException
    {
        int product = client.multiply(3,5);
        System.out.println("3 * 5 = " + product);
        int sum = client.add(4, 6);
        System.out.println("4 + 6 = " + sum);
    }
}

跟进client代码

thrift主要把方法名，参数发送给服务方

跟进multiply(int n1, int n2)方法

public int multiply(int n1, int n2) throws org.apache.thrift.TException
    {
      send_multiply(n1, n2);
      return recv_multiply();
    }

send_multiply(n1, n2);跟进

public void send_multiply(int n1, int n2) throws org.apache.thrift.TException
    {
      multiply_args args = new multiply_args();
      args.setN1(n1);
      args.setN2(n2);
      sendBase("multiply", args);
    }

跟进sendBase

protected void sendBase(String methodName, TBase<?,?> args) throws TException {
    sendBase(methodName, args, TMessageType.CALL);
  }

protected void sendBaseOneway(String methodName, TBase<?,?> args) throws TException {
    sendBase(methodName, args, TMessageType.ONEWAY);
  }

private void sendBase(String methodName, TBase<?,?> args, byte type) throws TException {
    oprot_.writeMessageBegin(new TMessage(methodName, type, ++seqid_));
    args.write(oprot_);
    oprot_.writeMessageEnd();
    oprot_.getTransport().flush();
  }

methodName被封装到Tmessage中，跟进 writeMessageBegin

public void writeMessageBegin(TMessage message) throws TException {
    if (strictWrite_) {
      int version = VERSION_1 | message.type;
      writeI32(version);
      writeString(message.name);
      writeI32(message.seqid);
    } else {
      writeString(message.name);
      writeByte(message.type);
      writeI32(message.seqid);
    }
  }

public void writeI32(int i32) throws TException {
    inoutTemp[0] = (byte)(0xff & (i32 >> 24));
    inoutTemp[1] = (byte)(0xff & (i32 >> 16));
    inoutTemp[2] = (byte)(0xff & (i32 >> 8));
    inoutTemp[3] = (byte)(0xff & (i32));
    trans_.write(inoutTemp, 0, 4);
  }

public void write(byte[] buf, int off, int len) throws TTransportException {
    if (outputStream_ == null) {
      throw new TTransportException(TTransportException.NOT_OPEN, "Cannot write to null outputStream");
    }
    try {
      outputStream_.write(buf, off, len);
    } catch (IOException iox) {
      throw new TTransportException(TTransportException.UNKNOWN, iox);
    }
  }

这里通过socket outputstream发送

private void sendBase(String methodName, TBase<?,?> args, byte type) throws TException {
    oprot_.writeMessageBegin(new TMessage(methodName, type, ++seqid_));
    args.write(oprot_);
    oprot_.writeMessageEnd();
    oprot_.getTransport().flush();
  }

下面参数也是通过类似方法发送给服务端。发送完接收服务端发送的结果

public int recv_multiply() throws org.apache.thrift.TException
    {
      multiply_result result = new multiply_result();
      receiveBase(result, "multiply");
      if (result.isSetSuccess()) {
        return result.success;
      }
      throw new org.apache.thrift.TApplicationException(org.apache.thrift.TApplicationException.MISSING_RESULT, "multiply failed: unknown result");
    }

protected void receiveBase(TBase<?,?> result, String methodName) throws TException {
    TMessage msg = iprot_.readMessageBegin();
    if (msg.type == TMessageType.EXCEPTION) {
      TApplicationException x = new TApplicationException();
      x.read(iprot_);
      iprot_.readMessageEnd();
      throw x;
    }
    if (msg.seqid != seqid_) {
      throw new TApplicationException(TApplicationException.BAD_SEQUENCE_ID,
          String.format("%s failed: out of sequence response: expected %d but got %d", methodName, seqid_, msg.seqid));
    }
    result.read(iprot_);
    iprot_.readMessageEnd();
  }

private static class multiply_resultStandardScheme extends org.apache.thrift.scheme.StandardScheme<multiply_result> {

      public void read(org.apache.thrift.protocol.TProtocol iprot, multiply_result struct) throws org.apache.thrift.TException {
        org.apache.thrift.protocol.TField schemeField;
        iprot.readStructBegin();
        while (true)
        {
          schemeField = iprot.readFieldBegin();
          if (schemeField.type == org.apache.thrift.protocol.TType.STOP) { 
            break;
          }
          switch (schemeField.id) {
            case 0: // SUCCESS
              if (schemeField.type == org.apache.thrift.protocol.TType.I32) {
                struct.success = iprot.readI32();
                struct.setSuccessIsSet(true);
              } else { 
                org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
              }
              break;
            default:
              org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
          }
          iprot.readFieldEnd();
        }
        iprot.readStructEnd();

        // check for required fields of primitive type, which can't be checked in the validate method
        struct.validate();
      }

由于方法返回类型是int，这里读取结果主要判断是否成功，result值，以及解析结束。

后面在看下thrift服务端解析客户端请求代码