How do you extract POST data in Node.js?

2018-12-31 02:58发布

How do you extract form data (form[method="post"]) and file uploads sent from the HTTP POST method in Node.js?

I've read the documentation, googled and found nothing.

function (request, response) {
    //request.post????
}

Is there a library or a hack?

24条回答
弹指情弦暗扣
2楼-- · 2018-12-31 03:21

If it involves a file upload, the browser usually send it as a "multipart/form-data" content-type. You can use this in such cases

var multipart = require('multipart');
multipart.parse(req)

Reference 1

Reference 2

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姐姐魅力值爆表
3楼-- · 2018-12-31 03:23

If you don't want to chunk your data together with the data callback you can always use the readable callback like this:

// Read Body when Available
request.on("readable", function(){
  request.body = '';
  while (null !== (request.body += request.read())){}
});

// Do something with it
request.on("end", function(){
  request.body //-> POST Parameters as String
});

This approach modifies the incoming request, but as soon as you finish your response the request will be garbage collected, so that should not be a problem.

An advanced approach would be to check the body size first, if you're afraid of huge bodies.

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大哥的爱人
4楼-- · 2018-12-31 03:23

You can use the express middleware, which now has body-parser built into it. This means all you need to do is the following:

import express from 'express'

const app = express()

app.use(express.json())

app.post('/thing', (req, res) => {
  console.log(req.body) // <-- this will access the body of the post
  res.sendStatus(200)
})

That code example is ES6 with Express 4.16.x

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残风、尘缘若梦
5楼-- · 2018-12-31 03:25

I found a video which explains on how to achieve this: https://www.youtube.com/watch?v=nuw48-u3Yrg

It uses default "http" module together with "querystring" and "stringbuilder" modules. The application takes two numbers (using two textboxes) from a web page and upon submit, returns sum of those two (along with persisting the values in the textboxes). This is the best example I could find anywhere else.

Related source code:

var http = require("http");
var qs = require("querystring");
var StringBuilder = require("stringbuilder");

var port = 9000;

function getCalcHtml(req, resp, data) {
    var sb = new StringBuilder({ newline: "\r\n" });
    sb.appendLine("<html>");
    sb.appendLine(" <body>");
    sb.appendLine("     <form method='post'>");
    sb.appendLine("         <table>");
    sb.appendLine("             <tr>");
    sb.appendLine("                 <td>Enter First No: </td>");

    if (data && data.txtFirstNo) {
        sb.appendLine("                 <td><input type='text' id='txtFirstNo' name='txtFirstNo' value='{0}'/></td>", data.txtFirstNo);
    }
    else {
        sb.appendLine("                 <td><input type='text' id='txtFirstNo' name='txtFirstNo' /></td>");
    }

    sb.appendLine("             </tr>");
    sb.appendLine("             <tr>");
    sb.appendLine("                 <td>Enter Second No: </td>");

    if (data && data.txtSecondNo) {
        sb.appendLine("                 <td><input type='text' id='txtSecondNo' name='txtSecondNo' value='{0}'/></td>", data.txtSecondNo);
    }
    else {
        sb.appendLine("                 <td><input type='text' id='txtSecondNo' name='txtSecondNo' /></td>");
    }

    sb.appendLine("             </tr>");
    sb.appendLine("             <tr>");
    sb.appendLine("                 <td><input type='submit' value='Calculate' /></td>");
    sb.appendLine("             </tr>");

    if (data && data.txtFirstNo && data.txtSecondNo) {
        var sum = parseInt(data.txtFirstNo) + parseInt(data.txtSecondNo);
        sb.appendLine("             <tr>");
        sb.appendLine("                 <td>Sum: {0}</td>", sum);
        sb.appendLine("             </tr>");
    }

    sb.appendLine("         </table>");
    sb.appendLine("     </form>")
    sb.appendLine(" </body>");
    sb.appendLine("</html>");
    sb.build(function (err, result) {
        resp.write(result);
        resp.end();
    });
}

function getCalcForm(req, resp, data) {
    resp.writeHead(200, { "Content-Type": "text/html" });
    getCalcHtml(req, resp, data);
}

function getHome(req, resp) {
    resp.writeHead(200, { "Content-Type": "text/html" });
    resp.write("<html><html><head><title>Home</title></head><body>Want to some calculation? Click <a href='/calc'>here</a></body></html>");
    resp.end();
}

function get404(req, resp) {
    resp.writeHead(404, "Resource Not Found", { "Content-Type": "text/html" });
    resp.write("<html><html><head><title>404</title></head><body>404: Resource not found. Go to <a href='/'>Home</a></body></html>");
    resp.end();
}

function get405(req, resp) {
    resp.writeHead(405, "Method not supported", { "Content-Type": "text/html" });
    resp.write("<html><html><head><title>405</title></head><body>405: Method not supported</body></html>");
    resp.end();
}

http.createServer(function (req, resp) {
    switch (req.method) {
        case "GET":
            if (req.url === "/") {
                getHome(req, resp);
            }
            else if (req.url === "/calc") {
                getCalcForm(req, resp);
            }
            else {
                get404(req, resp);
            }
            break;
        case "POST":
            if (req.url === "/calc") {
                var reqBody = '';
                req.on('data', function (data) {
                    reqBody += data;
                    if (reqBody.length > 1e7) { //10MB
                        resp.writeHead(413, 'Request Entity Too Large', { 'Content-Type': 'text/html' });
                        resp.end('<!doctype html><html><head><title>413</title></head><body>413: Request Entity Too Large</body></html>');
                    }
                });
                req.on('end', function () {
                    var formData = qs.parse(reqBody);
                    getCalcForm(req, resp, formData);
                });
            }
            else {
                get404(req, resp);
            }
            break;
        default:
            get405(req, resp);
            break;
    }
}).listen(port);
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素衣白纱
6楼-- · 2018-12-31 03:26

You need to receive the POST data in chunks using request.on('data', function(chunk) {...})

const http = require('http');

http.createServer((req, res) => {
    if (req.method == 'POST') {
        whole = ''
        req.on('data', (chunk) => {
            # consider adding size limit here
            whole += chunk.toString()
        })

        req.on('end', () => {
            console.log(whole)
            res.writeHead(200, 'OK', {'Content-Type': 'text/html'})
            res.end('Data received.')
        })
    }
}).listen(8080)

You should consider adding a size limit at the indicated position as thejh suggested.

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看风景的人
7楼-- · 2018-12-31 03:26

you can extract post parameter without using express.

1: nmp install multiparty

2: import multiparty . as var multiparty = require('multiparty');

3: `

if(req.method ==='POST'){
   var form = new multiparty.Form();
   form.parse(req, function(err, fields, files) {
      console.log(fields['userfile1'][0]);
    });
    }

4: and HTML FORM IS .

<form method=POST enctype=multipart/form-data>
<input type=text name=userfile1><br>
<input type=submit>
</form>

I hope this will work for you. Thanks.

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