sftp node server

sftp-node-server.js

"use strict";
var fs = require('fs');
var SFTPServer = require("node-sftp-server");
var ReadableStreamClone = require("readable-stream-clone");

// create the server
var srv = new SFTPServer({
  privateKeyFile: "./id_rsa",
  temporaryFileDirectory: "./tmp"
});

srv.listen(8022);

srv.on("connect", function(auth, info) {
  console.warn("[::][SERVER] Client connected to the SFTP server");

  return auth.accept(function(session) {
    console.warn("[::][SESSION] Authenticated");

    // the client is attempting to read a file from the server
    // place or pipe the contents of the file into the writable_stream
    session.on("readfile", function(path, writestream) {
      console.log("[::][READ] Reading the server file " + path)
      console.log("[::][READ] Sending content to client through writestream");
      return fs.createReadStream("tmp" + path).pipe(writestream);
    });

    session.on("realpath",function (path,callback) {
      callback("/tmp/");
      console.log("REALPATH:::|:::REALPATH", path);
    });

    session.on("writefile", function(path, readstream, ex) {

      /*
       * SPOOL/IN
       */
      // clone read stream for spool in
      var readstreamIn = new ReadableStreamClone(readstream);
      readstreamIn.on("end", function() { console.warn("[::][WRITE SPOOL/OUT] File has been written") });
      // set spool in file path
      var inFile = path;
      // create empty file
      fs.closeSync(fs.openSync(inFile, "w"));
      // write stream content in inFile
      var writestreamIn = fs.createWriteStream(inFile);
      readstreamIn.pipe(writestreamIn);

      /*
       * SPOOL/OUT
       */

      // // clone read stream for spool out
      // var readstreamOut = new ReadableStreamClone(readstream);
      // readstreamOut.on("end", function() { console.warn("[::][WRITE SPOOL/OUT] File has been written") });
      // // set spool out file path
      // var merchant, method, timestamp;
      // [ merchant, method, timestamp ] = path.split('_');
      // var outFile = "./tmp/spool/out" + merchant.replace('.','') + '_RES_' + Date.now() + '.TXT';
      // // create empty file
      // fs.closeSync(fs.openSync(outFile, "w"));
      // // add csv information to write stram
      // readstreamOut.on("end", function() { writestreamOut.write('calm,honesty,truth,love\n') });
      // // write stream content in outFile
      // var writestreamOut = fs.createWriteStream(outFile, { flags:'a' });
      // return readstreamOut.pipe(writestreamOut);
    });

    // return session.on ...
    session.on("readdir",function (path, responder) {
       console.warn("[::][READ DIR] Request for path ./tmp/spool/out");
       var files, i, j, results;

       // collect the files placed in the out directory
       // it applies an async flow not clear to me
       files = (function() {
         results = [];
         fs.readdir('./tmp/spool/out', (err, files) => {
           files.forEach(file => {
             results.push(file);
           });
         })
         return results;
       }).apply(this);

       i = 0;
       responder.on("dir", function() {
         if (files[i]) {
           console.warn("Returning " + files[i]);
           responder.file(files[i]);
           return i++;
         } else {
           return responder.end();
         }
       });
       return responder.on("end", function() {
         return console.warn("[::][READ DIR] Directory has been read");
       });
    });

    session.on('stat', function(path, statkind, statresponder) {
      // avoid warning
    });
  });
});

srv.on("error", function() {
  return console.warn("[::][SERVER] Example server encountered an error");
});
srv.on("end", function() {
  return console.warn("[::][SERVER] Command completed");
});