在转发到代理目标并将响应发送回客户端之前编辑 POST 参数

Question

我有一个 node/express 代理设置，使用 http-proxy-middleware 将请求路由到 java-tomcat Web 服务（代理目标）。

在将请求转发到代理目标之前，我需要将 POST 表单数据注入到上下文类型为“application/x-www-form-urlencoded”的请求原始正文中。在将响应发送到客户端之前，代理响应需要删除相同的 post 参数。

我使用了许多不同的代理，包括 http-proxy、http-proxy-middleware、node-proxy 和 express-proxy，但这些模块似乎都没有可用的解决方案来允许 POST 参数操作

这个问题最初发布于 https://github.com/chimurai/http-proxy-middleware/issues/61#issuecomment-205494577

'use strict';

var express = require('express');
var router = express.Router();
//var request = require("request");

var proxy_filter = function (path, req) {
    return path.match('^/report') && ( req.method === 'GET' ||    req.method === 'POST' );
};

var proxy_options = {
    target: 'http://localhost:8080',
    logLevel: 'debug',
    //logProvider:
    onError(err, req, res) {
        res.writeHead(500, {
            'Content-Type': 'text/plain'
        });
        res.end('Something went wrong. And we are reporting a custom error message.' + err);
    },
    onProxyRes(proxyRes, req, res) {
        //proxyRes.headers['x-added'] = 'foobar';     // add new header to response
        //delete proxyRes.headers['x-removed'];       // remove header from response
    },
    onProxyReq(proxyReq, req, res) {
        if ( req.method == "POST" && req.body ) {
            proxyReq.write( encodeURIComponent( JSON.stringify(   req.body ) ) );
            proxyReq.end();
        }
    }
};

// Proxy configuration
var proxy = require( 'http-proxy-middleware' )( proxy_filter, proxy_options );

/* GET home page. */
router.get('/', function(req, res, next) {
    res.render('index', { title: 'Node.js Express Proxy Test' });
});

router.all('/report/*', function( req, res, next ) {

    //req.body.jdbc_sas = 'jdbc:postgresql://pg_dev:5432/sasdb';
    //req.body.jdbc_agency = 'jdbc:postgresql://pg_dev:5432/agency0329';
    //console.log('proxy body:',req.body);

    proxy( req, res, next );
} );

module.exports = router;

非常感谢任何建议。

尊敬的，

沃伦。

Answer 1

好的，这是最终的解决方案。

以下示例允许您在转发到代理目标之前注入 POST 参数。据我所知，您没有从代理目标响应中清除任何参数，因为它保留了原始 POST 请求的副本。

另一方面，这也允许 http-proxy-middleware 与 body-parser 一起工作。

示例节点快速路由文件：

'use strict';

var express = require('express');
var router = express.Router();

var proxy_filter = function (path, req) {
    return path.match('^/docs') && ( req.method === 'GET' || req.method === 'POST' );
};

var proxy_options = {
    target: 'http://localhost:8080',
    pathRewrite: {
        '^/docs' : '/java/rep/server1' // Host path & target path conversion
    },
    onError(err, req, res) {
        res.writeHead(500, {
            'Content-Type': 'text/plain'
        });
        res.end('Something went wrong. And we are reporting a custom error message.' + err);
    },
    onProxyReq(proxyReq, req, res) {
        if ( req.method == "POST" && req.body ) {
            // Add req.body logic here if needed....

           // ....

            // Remove body-parser body object from the request
            if ( req.body ) delete req.body;

            // Make any needed POST parameter changes
            let body = new Object();

            body.filename = 'reports/statistics/summary_2016.pdf';
            body.routeid = 's003b012d002';
            body.authid = 'bac02c1d-258a-4177-9da6-862580154960';

            // URI encode JSON object
            body = Object.keys( body ).map(function( key ) {
                return encodeURIComponent( key ) + '=' + encodeURIComponent( body[ key ])
            }).join('&');

            // Update header
            proxyReq.setHeader( 'content-type', 'application/x-www-form-urlencoded' );
            proxyReq.setHeader( 'content-length', body.length );

            // Write out body changes to the proxyReq stream
            proxyReq.write( body );
            proxyReq.end();
        }
    }
};

// Proxy configuration
var proxy = require( 'http-proxy-middleware' )( proxy_filter, proxy_options );

/* GET home page. */
router.get('/', function(req, res, next) {
    res.render('index', { title: 'Node.js Express Proxy Test' });
});

router.all('/document', proxy );

module.exports = router;