用 express 替换 nginx 作为反向代理

Question

我想用 node js express 应用程序替换作为反向代理的 nginx 应用程序，这样我就可以设置动态规则并具有更好的日志记录和测试可能性。

我的 nginx 设置如下：

http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        off;
    keepalive_timeout  65;
    gzip  on;

    server {
        listen       8023;
        server_name  localhost;
        sendfile        off;

        location / {
            proxy_pass https://main.app.url.com/;
        }

        location /module1/v1/ {
            client_max_body_size 30000M;
            client_body_buffer_size 200000k;
            # local backend of module 1
            proxy_pass http://localhost:8080/module1/v1/;
        }

        location /module1/v1/web/ {
            # local front end files for module 1
            alias /some/local/path/build/dist;
        }

        location /module2/v1/web/ {
            # local front end files for module 1
            alias /some/other/local/path/build/dist;
        }
    }
}

我尝试使用 express-http-proxy 中间件，但我很难将上述规则应用于它。首先，我不完全理解 proxy_pass 和 alias 指令之间的区别。

第二次我尝试了以下操作：

const express   = require('express');
const app       = express();
const proxy     = require('express-http-proxy')

const path = '/some/local/path/build/dist';

app.all('/module1/v1/web/', proxy(path, {
            proxyReqPathResolver: (req) => {
                return '';
            }
        })
    );
};

我遇到了一个错误：

TypeError: Cannot read property 'request' of undefined
    at /Users/user1/Dev/local-dev-runner/node_modules/express-http-proxy/app/steps/sendProxyRequest.js:13:29
    at new Promise (<anonymous>)
    at sendProxyRequest (/Users/user1/Dev/local-dev-runner/node_modules/express-http-proxy/app/steps/sendProxyRequest.js:11:10)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)

虽然cont path = 'http://www.google.com'返回了一个有效的响应。

Answer 1

所以这就是我带来的：

诀窍是提供本地文件和代理网络请求。显然，nginx 可以自动识别请求的 URI 是本地路径还是远程路径。

我决定使用 nmp 包 is-url 和 express-http-proxy 所以，工作解决方案如下所示：

const express   = require('express');
const app       = express();
const isUrl     = require('is-url');
const proxy     = require('express-http-proxy');

...

/**
 * Function adding new redirects to the current server instance. If the target URL is an URL the request will be
 * handeled with the express-http-proxy middleware. If the target URL is some local directory the content will be serverd using the express-static middleware.
 * @param matchedPath The path (endpoint) for which the redireciton should be configured.
 * @param targetUrl The target URL or directory for the redirection.
 */
const setUpRedirect = (matchedPath, targetUrl, name) => {
    // Use proxy for Urls 
    if (isUrl(targetUrl)) {
        app.use(matchedPath,
            proxy(targetUrl,
                {
                    memoizeHost: false,
                    limit: '50mb',
                    proxyReqPathResolver: function(req) {
                        // I do not have (yet) any clue why I had to do this but it fixed the behavior
                        return req.originalUrl;
                    },
                }),
        )
    }
    else { // When targetUrl is directory serve static files from there
        app.use(matchedPath,
            express.static(targetUrl),
        );
    };  
};

...

setUpRedirect('/module1/v1/web/:major([0-9]+).:minor([0-9]+).:bugfix([0-9]+)', '/some/local/path/build/dist';)
setUpRedirect('/module2/v1/web/:major([0-9]+).:minor([0-9]+).:bugfix([0-9]+)', 'http://some/remote/url/';)
server = app.listen(8080);