RPC（远程过程调用）

##参考链接：
thrift文档说明：http://thrift.apache.org/

ubuntu 安装thrift编译包

apt install thrift-compiler

下载demo模板文件

下载地址：http://mirrors.shu.edu.cn/apache/thrift/0.11.0/thrift-0.11.0.tar.gz

解压获取tutorial.thrift模板文件：

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

# Thrift Tutorial
# Mark Slee (mcslee@facebook.com)
#
# This file aims to teach you how to use Thrift, in a .thrift file. Neato. The
# first thing to notice is that .thrift files support standard shell comments.
# This lets you make your thrift file executable and include your Thrift build
# step on the top line. And you can place comments like this anywhere you like.
#
# Before running this file, you will need to have installed the thrift compiler
# into /usr/local/bin.

/**
 * The first thing to know about are types. The available types in Thrift are:
 *
 *  bool        Boolean, one byte
 *  i8 (byte)   Signed 8-bit integer
 *  i16         Signed 16-bit integer
 *  i32         Signed 32-bit integer
 *  i64         Signed 64-bit integer
 *  double      64-bit floating point value
 *  string      String
 *  binary      Blob (byte array)
 *  map<t1,t2>  Map from one type to another
 *  list<t1>    Ordered list of one type
 *  set<t1>     Set of unique elements of one type
 *
 * Did you also notice that Thrift supports C style comments?
 */

// Just in case you were wondering... yes. We support simple C comments too.

/**
 * Thrift files can reference other Thrift files to include common struct
 * and service definitions. These are found using the current path, or by
 * searching relative to any paths specified with the -I compiler flag.
 *
 * Included objects are accessed using the name of the .thrift file as a
 * prefix. i.e. shared.SharedObject
 */
include "shared.thrift"

/**
 * Thrift files can namespace, package, or prefix their output in various
 * target languages.
 */
namespace cpp tutorial
namespace d tutorial
namespace dart tutorial
namespace java tutorial
namespace php tutorial
namespace perl tutorial
namespace haxe tutorial
namespace netcore tutorial

/**
 * Thrift lets you do typedefs to get pretty names for your types. Standard
 * C style here.
 */
typedef i32 MyInteger

/**
 * Thrift also lets you define constants for use across languages. Complex
 * types and structs are specified using JSON notation.
 */
const i32 INT32CONSTANT = 9853
const map<string,string> MAPCONSTANT = {'hello':'world', 'goodnight':'moon'}

/**
 * You can define enums, which are just 32 bit integers. Values are optional
 * and start at 1 if not supplied, C style again.
 */
enum Operation {
  ADD = 1,
  SUBTRACT = 2,
  MULTIPLY = 3,
  DIVIDE = 4
}

/**
 * Structs are the basic complex data structures. They are comprised of fields
 * which each have an integer identifier, a type, a symbolic name, and an
 * optional default value.
 *
 * Fields can be declared "optional", which ensures they will not be included
 * in the serialized output if they aren't set.  Note that this requires some
 * manual management in some languages.
 */
struct Work {
  1: i32 num1 = 0,
  2: i32 num2,
  3: Operation op,
  4: optional string comment,
}

/**
 * Structs can also be exceptions, if they are nasty.
 */
exception InvalidOperation {
  1: i32 whatOp,
  2: string why
}

/**
 * Ahh, now onto the cool part, defining a service. Services just need a name
 * and can optionally inherit from another service using the extends keyword.
 */
service Calculator extends shared.SharedService {

  /**
   * A method definition looks like C code. It has a return type, arguments,
   * and optionally a list of exceptions that it may throw. Note that argument
   * lists and exception lists are specified using the exact same syntax as
   * field lists in struct or exception definitions.
   */

   void ping(),

   i32 add(1:i32 num1, 2:i32 num2),

   i32 calculate(1:i32 logid, 2:Work w) throws (1:InvalidOperation ouch),

   /**
    * This method has a oneway modifier. That means the client only makes
    * a request and does not listen for any response at all. Oneway methods
    * must be void.
    */
   oneway void zip()

}

/**
 * That just about covers the basics. Take a look in the test/ folder for more
 * detailed examples. After you run this file, your generated code shows up
 * in folders with names gen-<language>. The generated code isn't too scary
 * to look at. It even has pretty indentation.
 */

不同语言执行文件生成（php为例）

• 第一步：进入tutorial.thrift同文件夹目录
• 第二步：
  生成客户端文件：thrift -r --gen php tutorial.thrift
  生成gen-php文件
• 第三步：
  生成服务器端文件：thrift -r --gen php:server tutorial.thrift
  生成gen-php文件
• 第四步：
  启动服务器：php -S localhost:8080 ./php/PhpServer.php
• 第五步：
  开启客户端访问： php ./php/PhpClient.php --http

thrift的运行和调用完成。

模板文件生成的目录结构：

/path/to/tutrial:
.
├── gen-php
│   ├── shared
│   │   ├── SharedService.php
│   │   └── Types.php
│   └── tutorial
│   ├── Calculator.php
│   └── Types.php
├── php
│   ├── PhpClient.php
│   ├── PhpServer.php
│   └── runserver.py
├── shared.thrift
└── tutorial.thrift

开发理解：

• 客户端无需多余功能开发，只需要在模板中定义好需要调用的接口即可。
• Server端在PhpServer.php实现需要实现的方法implements 通过模板生成的gen下面的文件即可。

原理理解

客户端请求

• 1 创建socket链接（此处可以创建代理）

$socket = new TSocket('localhost', 9090);

• 2 限定socket传输时确定buffer的读写大小

$transport = new TBufferedTransport($socket, 1024, 1024);

• 3 创建传输协议（包头，包体，以及封包规则）

$protocol = new TBinaryProtocol($transport);

• 4 实例化client，并进行业务逻辑数据处理

  $transport->open(); //打开socket链接

 $client = new \tutorial\lculatorClient($protocol);

  $client->ping();

swoole 代理池