Node is used as a transit server forwarding interface example sharing

This article mainly introduces the relevant information of Node as a transit server forwarding interface. Friends who need it can refer to it. I hope it can help everyone.

Since the project is separating the front-end and back-end, involving cross-domain and protocol issues, I was temporarily overwhelmed and chose to use nodejs for transit. I think many people should use it. But there is no problem in forwarding ordinary forms. When uploading and forwarding attachments, all kinds of pain have been solved!

1. The project is quite special. It has two platforms in the background, one is java and the other is donet, which is quite useless. I will not explain the specific reasons.

2. When doing node forwarding, there is no file forwarding operation at the beginning, so it is very simple. The user can intercept whatever is passed in and forward it, and everything is fine!

3. File forwarding is very troublesome. My idea is to save files uploaded by users to the node server. Use formidable .

Install via npm:

npm install formidable@latest

Use it to transfer files and save them to a temporary directory to get file information.

Reorganize through the file package. to upload. Note that the upload here must follow the w3c file upload form standard, please check the information yourself.

In fact, the idea is very simple, but the actual operation is still quite troublesome. I also encountered a lot of pitfalls in the process. It is also because my node is immature. After all, it is only used for transfer!

Let’s go straight to the code: it’s still clear when you look at the code:

server.js, used to start the service and forward it.

var http = require("http");
var url = require("url");
var fs = require('fs');
const querystring = require("querystring");
var path = require('path');
var formidable = require('formidable'),
  os = require('os'),
  util = require('util');
var config = require('./config').types; //
var netServerUrlFlag = require('./config').netServerUrlFlag;
var netServerhost = require('./config').netServerhost;
var netServerport = require('./config').netServerport;
var javaServerUrlFlag = require('./config').javaServerUrlFlag;
var javaServerhost = require('./config').javaServerhost;
var javaServerport = require('./config').javaServerport;
var fileServerUrlFlag = require('./config').fileServerUrlFlag;
var webapp = require('./config').webapp;
var PORT = require('./config').webport;
/**
 * 上传文件
 * @param files   经过formidable处理过的文件
 * @param req    httpRequest对象
 * @param postData  额外提交的数据
 */
function uploadFile(files, req, postData) {
  var boundaryKey = Math.random().toString(16);
  var endData = '\r\n----' + boundaryKey + '--';
  var filesLength = 0, content;
  // 初始数据，把post过来的数据都携带上去
  content = (function (obj) {
    var rslt = [];
    Object.keys(obj).forEach(function (key) {
      arr = ['\r\n----' + boundaryKey + '\r\n'];
      arr.push('Content-Disposition: form-data; name="' + obj[key][0] + '"\r\n\r\n');
      arr.push(obj[key][1]);
      rslt.push(arr.join(''));
    });
    return rslt.join('');
  })(postData); 
  // 组装数据
  Object.keys(files).forEach(function (key) {
    if (!files.hasOwnProperty(key)) {
      delete files.key;
      return;
    }
    content += '\r\n----' + boundaryKey + '\r\n' +
      'Content-Type: application/octet-stream\r\n' +
      'Content-Disposition: form-data; name="' + files[key][0] + '"; ' +
      'filename="' + files[key][1].name + '"; \r\n' +
      'Content-Transfer-Encoding: binary\r\n\r\n';
    files[key].contentBinary = new Buffer(content, 'utf-8');;
    filesLength += files[key].contentBinary.length + fs.statSync(files[key][1].path).size;
  });
  req.setHeader('Content-Type', 'multipart/form-data; boundary=--' + boundaryKey);
  req.setHeader('Content-Length', filesLength + Buffer.byteLength(endData));
  // 执行上传
  var allFiles = Object.keys(files);
  var fileNum = allFiles.length;
  var uploadedCount = 0;
  allFiles.forEach(function (key) {
    req.write(files[key].contentBinary);
    console.log("files[key].path:" + files[key][1].path);
    var fileStream = fs.createReadStream(files[key][1].path, { bufferSize: 4 * 1024 });
    fileStream.on('end', function () {
      // 上传成功一个文件之后，把临时文件删了
      fs.unlink(files[key][1].path);
      uploadedCount++;
      if (uploadedCount == fileNum) {
        // 如果已经是最后一个文件，那就正常结束
        req.end(endData);
      }
    });
    fileStream.pipe(req, { end: false });
  });
}
var server = http.createServer(function (request, response) {
  var clientUrl = request.url;
  var url_parts = url.parse(clientUrl); //解析路径
  var pathname = url_parts.pathname;
  var sreq = request;
  var sres = response;
  // .net 转发请求
  if (pathname.match(netServerUrlFlag) != null) {
    var clientUrl2 = clientUrl.replace("/" + netServerUrlFlag, '');
    console.log(".net转发请求......" + clientUrl2);
    var pramsJson = '';
    sreq.on("data", function (data) {
      pramsJson += data;
    }).on("end", function () {
      var contenttype = request.headers['content-type'];
      if (contenttype == undefined || contenttype == null || contenttype == '') {
        var opt = {
          host: netServerhost, //跨域访问的主机ip
          port: netServerport,
          path: clientUrl2,
          method: request.method,
          headers: {
            'Content-Length': Buffer.byteLength(pramsJson)
          }
        }
      } else {
        var opt = {
          host: netServerhost, //跨域访问的主机ip
          port: netServerport,
          path: clientUrl2,
          method: request.method,
          headers: {
            'Content-Type': request.headers['content-type'],
            'Content-Length': Buffer.byteLength(pramsJson)
          }
        }
      }
      console.log('method', opt.method);
      var body = '';
      var req = http.request(opt, function (res) {
        res.on('data', function (data) {
          body += data;
        }).on('end', function () {
          response.write(body);
          response.end();
        });
      }).on('error', function (e) {
        response.end('内部错误，请联系管理员！MSG:' + e);
        console.log("error: " + e.message);
      })
      req.write(pramsJson);
      req.end();
    })
  } else
    // java 转发请求
    if (pathname.match(javaServerUrlFlag) != null) {
      response.setHeader("Content-type", "text/plain;charset=UTF-8");
      var clientUrl2 = clientUrl.replace("/" + javaServerUrlFlag, '');
      console.log(".java转发请求......http://" + javaServerhost + ":" + javaServerport + "" + clientUrl2);
      var prams = '';
      sreq.on("data", function (data) {
        prams += data;
      }).on("end", function () {
        console.log("client pramsJson>>>>>" + prams);
        const postData = prams;
        console.log("client pramsJson>>>>>" + postData);
        var contenttype = request.headers['content-type'];
        if (contenttype == undefined || contenttype == null || contenttype == '') {
          var opt = {
            host: javaServerhost, //跨域访问的主机ip
            port: javaServerport,
            path: "/hrrp" + clientUrl2,
            method: request.method,
            headers: {
              'Content-Length': Buffer.byteLength(postData)
            }
          }
        } else {
          var opt = {
            host: javaServerhost, //跨域访问的主机ip
            port: javaServerport,
            path: "/hrrp" + clientUrl2,
            method: request.method,
            headers: {
              'Content-Type': request.headers['content-type'],
              'Content-Length': Buffer.byteLength(postData)
            }
          }
        }
        var body = '';
        console.log('method', opt.method);
        var req = http.request(opt, function (res) {
          //console.log("response: " + res.statusCode);
          res.on('data', function (data) {
            body += data;
          }).on('end', function () {
            response.write(body);
            response.end();
            //console.log("end:>>>>>>>" + body);
          });
        }).on('error', function (e) {
          response.end('内部错误，请联系管理员！MSG:' + e);
          console.log("error: " + e.message);
        })
        req.write(postData);
        req.end();
      })
    } else if (pathname.match(fileServerUrlFlag) != null) {
      //文件拦截保存到本地
      var form = new formidable.IncomingForm(),
        files = [],
        fields = [];
      form.uploadDir = os.tmpdir();
      form.on('field', function (field, value) {
        console.log(field, value);
        fields.push([field, value]);
      }).on('file', function (field, file) {
        console.log(field, file);
        files.push([field, file]);
      }).on('end', function () {
        //
        var clientUrl2 = clientUrl.replace("/" + fileServerUrlFlag, '');
        var opt = {
          host: netServerhost, //跨域访问的主机ip
          port: netServerport,
          path: clientUrl2,
          method: request.method
        }
        var body = '';
        var req = http.request(opt, function (res) {
          res.on('data', function (data) {
            body += data;
          }).on('end', function () {
            response.write(body);
            response.end();
          });
        }).on('error', function (e) {
          response.end('内部错误，请联系管理员！MSG:' + e);
          console.log("error: " + e.message);
        })
        //文件上传
        uploadFile(files, req, fields);
      });
      form.parse(sreq);
    }
    else {
      var realPath = path.join(webapp, pathname); //这里设置自己的文件名称;
      var ext = path.extname(realPath);
      ext = ext ? ext.slice(1) : 'unknown';
      fs.exists(realPath, function (exists) {
        //console.log("file is exists："+exists+" file path: " + realPath + "");
        if (!exists) {
          response.writeHead(404, {
            'Content-Type': 'text/plain'
          });
          response.write("This request URL " + pathname + " was not found on this server.");
          response.end();
        } else {
          fs.readFile(realPath, "binary", function (err, file) {
            if (err) {
              response.writeHead(500, {
                'Content-Type': 'text/plain'
              });
              //response.end(err);
              response.end("内部错误，请联系管理员");
            } else {
              var contentType = config[ext] || "text/plain";
              response.writeHead(200, {
                'Content-Type': contentType
              });
              response.write(file, "binary");
              response.end();
            }
          });
        }
      });
    }
});
server.listen(PORT);
console.log("Server runing at port: " + PORT + ".");

config.js, for configuration.

exports.types = {
 "css": "text/css",
 "gif": "image/gif",
 "html": "text/html",
 "htm": "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"
};
exports.netServerUrlFlag = "NETSERVER";
exports.netServerhost = "";
exports.netServerport = "";
exports.javaServerUrlFlag = "JAVASERVER";
exports.javaServerhost = ""; //转发的地址
exports.javaServerport = "";//转发的端口
exports.fileServerUrlFlag="FileUpload";
exports.webapp = "public";//项目目录
exports.webport = "82"; //项目启动端口

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