Node.js 搭建本地HTTP服务器并应用node-http-proxy解决ajax跨域问题

摘要：搭建本地服务器参考了的搭建本地服务器做转发使用实现，官方文档配置服务器和转发接口地址判断如果是接口访问，则通过转发这里参考的源码，补充了几个字体文件的。

起因：公司的产品更换前端框架，接口的访问原本是通过nginx配置反向代理实现的，本地没有安装nginx，就用node.js做一个。

node.js搭建本地http服务器参考了shawn.xie的《nodejs搭建本地http服务器》

node.js做转发使用node-http-proxy实现，官方文档：https://github.com/nodejitsu/node-http-proxy#using-https

var http = require("http");
var httpProxy = require("http-proxy");
var fs = require("fs");
var mine = require("./mime").types;
var path = require("path");
var url = require("url");

var proxy = httpProxy.createProxyServer({
    target: "https://192.168.101.166:8088",//接口地址
    ssl: {
        key: fs.readFileSync("server_decrypt.key", "utf8"),
        cert: fs.readFileSync("server.crt", "utf8")
    },
    secure: false
});

proxy.on("error", function(err, req, res){
    res.writeHead(500, {
        "content-type": "text/plain"
    });
    console.log(err);
    res.end("Something went wrong. And we are reporting a custom error message.");
});

var server = http.createServer(function(req, res){
    var pathName = url.parse(req.url).pathname;
    var realPath = req.url.substring(1);

    var extName = realPath;
    var indexOfQuestionMark = extName.indexOf("?");
    if(indexOfQuestionMark >= 0){
        extName = extName.substring(0, indexOfQuestionMark);
        realPath = realPath.substring(0, indexOfQuestionMark);
    }
    extName = path.extname(extName);
    extName = extName ? extName.slice(1) : "unknown";


    //判断如果是接口访问，则通过proxy转发
    if(//svr/.*$/.test(pathName)){
        proxy.web(req, res);
        return;
    }

    fs.exists(realPath, function(exists){
        if(!exists){
            res.writeHead(404, {"content-type": "text/plain"});
            res.write("The request URL:" + realPath + " could not be found.");
            res.end();
            return;
        }

        fs.readFile(realPath, "binary", function(err, file){
            if(err){
                res.writeHead(500, {"content-type": "text/plain"});
                res.end(err);
                return;
            }

            var contentType = mine[extName] || "text/plain";
            res.writeHead(200, {"content-type": contentType});
            res.write(file, "binary");
            res.end();
        });
    });
});

server.listen(8088);

这里参考shawn.xie的源码，补充了几个字体文件的mime。

exports.types = {
  "css": "text/css",
  "gif": "image/gif",
  "html": "text/html",
  "ico": "image/x-icon",
  "jpeg": "image/jpeg",
  "jpg": "image/jpeg",
  "js": "text/javascript",
  "json": "application/json",
  "pdf": "application/pdf",
  "png": "image/png",
  "svg": "image/svg+xml",
  "swf": "application/x-shockwave-flash",
  "tiff": "image/tiff",
  "txt": "text/plain",
  "wav": "audio/x-wav",
  "wma": "audio/x-ms-wma",
  "wmv": "video/x-ms-wmv",
  "xml": "text/xml",
  "woff": "application/x-woff",
  "woff2": "application/x-woff2",
  "tff": "application/x-font-truetype",
  "otf": "application/x-font-opentype",
  "eot": "application/vnd.ms-fontobject"
};

以上是全部的源码，配置中遇到几个问题说明如下：

1、接口采用https，所以http-proxy需要配置证书，按照官方的配置如下：

var proxy = httpProxy.createProxyServer({
    target: "https://192.168.101.166:8088",
    ssl: {
        key: fs.readFileSync("server_decrypt.key", "utf8"),
        cert: fs.readFileSync("server.crt", "utf8")
    },
    secure: true
});

其中target是接口的IP地址，ssl配置key和证书，secure默认为true，运行访问接口后，node控制台提示：

{ [Error: unable to verify the first certificate] code: "UNABLE_TO_VERIFY_LEAF_SIGNATURE" }

google后，这段意思大致是说证书未通过验证，通常在node中配置不验证证书即可。

rejectUnauthorized: false

但是我用的是http-proxy，没有rejectUnauthorized这个参数，再次阅读文档：

//
// Create the proxy server listening on port 443
//
httpProxy.createServer({
  ssl: {
    key: fs.readFileSync("valid-ssl-key.pem", "utf8"),
    cert: fs.readFileSync("valid-ssl-cert.pem", "utf8")
  },
  target: "https://localhost:9010",
  secure: true // Depends on your needs, could be false.
}).listen(443);

其中secure这个参数的说明很模糊，尝试着将其设定为false，通过！

2、shawn.xie的源码中，对于url中扩展名的识别存在bug，比如这样的URL识别会取到最后一个点的位置，本来应该是woff2，结果却是0。
http://localhost:8000/ab/resources/fonts/font.woff2?v=4.5.0

本来尝试用正则处理，但是后向引用在js不支持，就老老实实的用indexOf解决：

var realPath = req.url.substring(1);
var extName = realPath;
var indexOfQuestionMark = extName.indexOf("?");
if(indexOfQuestionMark >= 0){
    extName = extName.substring(0, indexOfQuestionMark);
    realPath = realPath.substring(0, indexOfQuestionMark);
    //realPath是文件的真实路径，所以也要去掉扩展名后面?之后的部分
}
extName = path.extname(extName);
extName = extName ? extName.slice(1) : "unknown";