微信小程序可用的Protobuf（含demo）

Protobuf： 一种轻便高效的结构化数据存储格式，平台无关、语言无关、可扩展，可用于通讯协议和数据存储等领域;

微信小程序： 基于微信平台的小程序

此库意义： 在微信小程序中Function 和 eval 相关的动态执行代码方式都给屏蔽了，以致google官方Protobuf不能正常使用；针对以上问题，修改了dcodeIO 的protobuf.js部分实现方式，以致微信小程序中运行protobuf.js。

安装以及使用

• 1、首先下载本代码，将其中weichatPb文件夹加入到你的小程序项目中

• 2、安装pbjs工具

  • 基于node.js，首先安装protobufjs

   $ npm install -g protobufjs
  

  会出现

   /usr/local/lib
   └─┬ [email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @protobufjs/[email protected] 
     ├── @types/[email protected] 
     ├── @types/[email protected] 
     └── [email protected] 
  
  

  证明安装成功

  • 接着安装 pbjs需要的库 命令行执行下“pbjs”就ok

   $ pbjs
  

  会出现

   -t, --target     Specifies the target format. Also accepts a path to require a custom target.
  
                  json          JSON representation
                  json-module   JSON representation as a module
                  proto2        Protocol Buffers, Version 2
                  proto3        Protocol Buffers, Version 3
                  static        Static code without reflection (non-functional on its own)
                  static-module Static code without reflection as a module
  
   -p, --path       Adds a directory to the include path.
  
   -o, --out        Saves to a file instead of writing to stdout.
  
   --sparse         Exports only those types referenced from a main file (experimental).
  
   Module targets only:
  
   -w, --wrap       Specifies the wrapper to use. Also accepts a path to require a custom wrapper.
  
                  	default   Default wrapper supporting both CommonJS and AMD
                  	commonjs  CommonJS wrapper
                  	amd       AMD wrapper
                  	es6       ES6 wrapper (implies --es6)
                  	closure   A closure adding to protobuf.roots where protobuf is a global
  
   --dependency     Specifies which version of protobuf to require. Accepts any valid module id
  
   -r, --root       Specifies an alternative protobuf.roots name.
  
   -l, --lint       Linter configuration. Defaults to protobuf.js-compatible rules:
  
                  	eslint-disable block-scoped-var, no-redeclare, no-control-regex, no-prototype-builtins
  
   --es6            	Enables ES6 syntax (const/let instead of var)
  
   Proto sources only:
  
   --keep-case      Keeps field casing instead of converting to camel case.
  
   Static targets only:
  
   --no-create      Does not generate create functions used for reflection compatibility.
   --no-encode      Does not generate encode functions.
   --no-decode      Does not generate decode functions.
   --no-verify      Does not generate verify functions.
   --no-convert     Does not generate convert functions like from/toObject
   --no-delimited   Does not generate delimited encode/decode functions.
   --no-beautify    Does not beautify generated code.
   --no-comments    Does not output any JSDoc comments.
  
   --force-long     Enfores the use of 'Long' for s-/u-/int64 and s-/fixed64 fields.
   --force-number   Enfores the use of 'number' for s-/u-/int64 and s-/fixed64 fields.
   --force-message  Enfores the use of message instances instead of plain objects.
   
  

  证明安装成功

• 3、接下来我们使用pbjs 转换一下.proto文件

  • 我们先准备一份awesome.proto文件，内容如下

   // awesome.proto
   syntax = "proto3";
  
   message AwesomeMessage {
   	string awesome_field = 1; // becomes awesomeField
   }
   
  

  • 接下来我们来转换awesome.proto文件

   $ pbjs -t json awesome.proto > awesome.json
  

  • 这时我们会得到一个awesome.json文件，内容如下

   {
    "nested": {
    	"AwesomeMessage": {
     		"fields": {
       	  "awesomeField": {
         	   "type": "string",
         	   "id": 1
       	  }
     	   }
       }
     }
   }

  • 但此时的json文件我们不能直接使用，不过我们可以将json对象取出放到小程序项目当中去，比如在小程序项目中新建一个awesome.js，内容为

   module.exports = {
   	"nested": {
       	"AwesomeMessage": {
           	"fields": {
               "awesomeField": {
                   "type": "string",
                   "id": 1
              }
           }
        }
      }
   };

• 4、此时总算到我们使用该文件的时候了，我们在项目中新建一个js文件（需要在项目中require该文件），其内容如下

var protobuf = require('../weichatPb/protobuf.js'); //引入protobuf模块
var  awesomeConfig = require('./awesome.js');//加载awesome.proto对应的json
var AwesomeMessage = AwesomeRoot.lookupType("AwesomeMessage");//这就是我们的Message类

var payload = {awesomeField: "我是test1"};
var message = AwesomeMessage.create(payload);
var buffer = AwesomeMessage.encode(message).finish();
console.log("buffer", buffer);
var deMessage = AwesomeMessage.decode(buffer);
console.log("deMessage", deMessage);

结语

附件中有我的测试demo小程序编辑器打开后，直接在控制台就可以看到我的测试过程，测试代码在testProtocoBuffer.js中。 如果您对于该工具库有更好的提升欢迎提出，如果您在使用中发现bug或者有疑惑也可以反馈，我都会解答的 (^__^) 嘻嘻……