如何在Express应用程序中使用JSON POST数据

Dear 丶 2022-11-26 15:56 262阅读 0赞

本文翻译自：[How do I consume the JSON POST data in an Express application][]

*I'm sending the following JSON string to my server.* **我正在将以下JSON字符串发送到我的服务器。**

(
            {
            id = 1;
            name = foo;
        },
            {
            id = 2;
            name = bar;
        }
    )

*On the server I have this.* **在服务器上，我有这个。**

app.post('/', function(request, response) {
    
        console.log("Got response: " + response.statusCode);
    
        response.on('data', function(chunk) {
            queryResponse+=chunk;
            console.log('data');
        });
    
        response.on('end', function(){
            console.log('end');
        });
    });

*When I send the string, it shows that I got a 200 response, but those other two methods never run.* **当我发送字符串时，它表明我得到了200的响应，但是其他两种方法却从未运行过。** *Why is that?* **这是为什么？**

--------------------

### \#1楼 ###

参考：[https://stackoom.com/question/FZ07/如何在Express应用程序中使用JSON-POST数据][https_stackoom.com_question_FZ07_Express_JSON-POST]

--------------------

### \#2楼 ###

*I think you're conflating the use of the `response` object with that of the `request` .* **我认为您正在将`response`对象的使用与`request`的使用混为一谈。**

*The `response` object is for sending the HTTP response back to the calling client, whereas you are wanting to access the body of the `request` .* **`response`对象用于将HTTP响应发送回调用方客户端，而您希望访问`request`的正文。** *See this [answer][] which provides some guidance.* **请参阅此[答案][answer] ，它提供了一些指导。**

*If you are using valid JSON and are POSTing it with `Content-Type: application/json` , then you can use the [`bodyParser`][bodyParser] middleware to parse the request body and place the result in `request.body` of your route.* **如果您使用有效的JSON并使用`Content-Type: application/json` ，则可以使用[`bodyParser`][bodyParser]中间件来解析请求正文并将结果放置在路由的`request.body`中。**

var express = require('express')
      , app = express.createServer();
    
    app.use(express.bodyParser());
    
    app.post('/', function(request, response){
      console.log(request.body);      // your JSON
      response.send(request.body);    // echo the result back
    });
    
    app.listen(3000);

*Test along the lines of:* **按照以下方式进行测试：**

$ curl -d '{"MyKey":"My Value"}' -H "Content-Type: application/json" http://127.0.0.1:3000/
    {"MyKey":"My Value"}

***Updated for Express 4+*** **已针对Express 4+更新**

*Body parser was split out into it's own npm package after v4, requires a separate install `npm install body-parser`* **v4之后，body解析器被拆分成自己的npm软件包，需要单独安装`npm install body-parser`**

var express = require('express')
      , bodyParser = require('body-parser');
    
    var app = express();
    
    app.use(bodyParser.json());
    
    app.post('/', function(request, response){
      console.log(request.body);      // your JSON
       response.send(request.body);    // echo the result back
    });
    
    app.listen(3000);

***Update for Express 4.16+*** **Express 4.16+的更新**

*Starting with release 4.16.0, a new [`express.json()`][express.json] middleware is available.* **从4.16.0版本开始，可以使用新的[`express.json()`][express.json]中间件。**

var express = require('express');
    
    var app = express();
    
    app.use(express.json());
    
    app.post('/', function(request, response){
      console.log(request.body);      // your JSON
       response.send(request.body);    // echo the result back
    });
    
    app.listen(3000);

--------------------

### \#3楼 ###

*For Express v4+* **对于Express v4 +**

*install body-parser from the npm.* **从npm安装body-parser。**

$ npm install body-parser

*[https://www.npmjs.org/package/body-parser\#installation][https_www.npmjs.org_package_body-parser_installation]* **[https://www.npmjs.org/package/body-parser\#installation][https_www.npmjs.org_package_body-parser_installation]**

var express    = require('express')
    var bodyParser = require('body-parser')
    
    var app = express()
    
    // parse application/json
    app.use(bodyParser.json())
    
    app.use(function (req, res, next) {
      console.log(req.body) // populated!
      next()
    })

--------------------

### \#4楼 ###

*Sometimes you don't need third party libraries to parse JSON from text.* **有时，您不需要第三方库来解析文本中的JSON。** *Sometimes all you need it the following JS command, try it first:* **有时，您需要使用以下JS命令，首先尝试它：**

const res_data = JSON.parse(body);

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### \#5楼 ###

*For those getting an empty object in `req.body`* **对于那些在`req.body`获得空对象的`req.body`**

*I had forgotten to set `headers: {"Content-Type": "application/json"}` in the request.* **我忘记了在请求中设置`headers: {"Content-Type": "application/json"}` 。** *Changing it solved the problem.* **更改它可以解决问题。**

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### \#6楼 ###

const express = require('express'); let app = express(); app.use(express.json());

*This app.use(express.json) will now let you read the incoming post JSON object* **这个app.use（express.json）现在可以让您读取传入的JSON对象**

[How do I consume the JSON POST data in an Express application]: https://oldbug.net/q/FZ07/How-do-I-consume-the-JSON-POST-data-in-an-Express-application
[https_stackoom.com_question_FZ07_Express_JSON-POST]: https://stackoom.com/question/FZ07/%E5%A6%82%E4%BD%95%E5%9C%A8Express%E5%BA%94%E7%94%A8%E7%A8%8B%E5%BA%8F%E4%B8%AD%E4%BD%BF%E7%94%A8JSON-POST%E6%95%B0%E6%8D%AE
[answer]: https://stackoverflow.com/a/4696338/112196
[bodyParser]: https://github.com/expressjs/body-parser
[express.json]: http://expressjs.com/en/4x/api.html#express.json
[https_www.npmjs.org_package_body-parser_installation]: https://www.npmjs.org/package/body-parser#installation