Node JS Client Request and Server Response

Маленькая библиотека для получения данных сайта в стиле jQuery AJAX.

Файл init.js

var request = require('./request');
var cheerio = require('cheerio');

var data = JSON.stringify({
      'key1': 'value1'
    , 'key2': 'value2'
});

request.httpRequest({
      host: 'www.google.com'
    , port: 80
    , url: '/'
    , type: 'POST'
    , headers: {
                          'Content-Type': 'application/x-www-form-urlencoded'
                        , 'Content-Length': data.length
                    }
    , data: data
    , timeout: 120000
    , success: function (data) {
        var $ = cheerio.load(data);
        console.log('Request body text inside <p></p>: ' + $('p').first().text());
      }
    , error: function (error) {console.log('New request error');}
});

Файл request.js

var http = require('http');

function randomNumber (min, max) {
    min = parseInt(min, 10);
    max = parseInt(max, 10);
    return Math.floor(Math.random() * (max - min + 1)) + min;
}

var commonHeaders = {
      'Accept': 'text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.' + randomNumber(2, 5)
    , 'Accept-Language': 'en-us,en;q=0.' + randomNumber(5, 9)
    , 'Accept-Charset': 'utf-8,windows-1251;q=0.7,*;q=0.' + randomNumber(5, 7)
    , 'Keep-Alive': '300'
    , 'Expect': ''
};

function httpRequest (options) {
    if (!options.hasOwnProperty('host')) {options.host = 'localhost';}
    if (!options.hasOwnProperty('port')) {options.port = 80;}
    if (!options.hasOwnProperty('url')) {options.url = '/';}
    if (!options.hasOwnProperty('type')) {options.type = 'GET';}
    if (!options.hasOwnProperty('headers')) {options.headers = {};}
    if (!options.hasOwnProperty('data')) {options.data = {};}
    if (!options.hasOwnProperty('timeout')) {options.timeout = 120000;}
    if (!options.hasOwnProperty('success')) {options.success = function(){};}
    if (!options.hasOwnProperty('error')) {options.error = function(error){console.log('Request error: ' + error);};}

    for (var key in options.headers) {
        commonHeaders[key] = options.headers[key];
    }

    var requestOptions = {
          hostname: options.host
        , port: options.port
        , path: options.url
        , method: options.type
        , headers: options.headers
    };

    var request = http.request(requestOptions, function(response) {
        console.log('Response status code: ' + response.statusCode);
        console.log('Response header: ' + JSON.stringify(response.headers));
        response.setEncoding('utf8');
        var data = '';
        response.on('data', function(chunk){data += chunk;});
        response.on('end', function(){options.success(data);});
    });

    request.setTimeout(options.timeout, function(){console.log('Request timeout');});
 
    request.on('error', options.error);

    if (options.data.length > 0) {request.write(options.data);}
    request.end();
}

exports.httpRequest = httpRequest;

Пример запуска кода в консоли командной строки

node init.js

Пример полного взаимодействия клиента и сервера на Node JS.

Файл client.js

var http = require('http');

var postData = JSON.stringify({
  'msg' : 'Hello World!'
});

var options = {
  hostname: '127.0.0.1',
  port: 80,
  path: '/',
  method: 'POST',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded',
    'Content-Length': postData.length
  }
};

var request = http.request(options, function(response) {
  console.log('STATUS: ' + response.statusCode);
  console.log('HEADERS: ' + JSON.stringify(response.headers));
  response.setEncoding('utf8');
  response.on('data', function (chunk) {
    console.log('BODY: ' + chunk);
  });
});

request.on('error', function(error) {
  console.log('problem with request: ' + error.message);
});

// write data to request body
request.write(postData);
request.end(); // Always need to write request.end();

Файл server.js

var server = require("./export");
var router = require("./router");
var requestHandlers = require("./requestHandlers");

var handle = {}
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
handle["/show"] = requestHandlers.show;

server.start(router.route, handle);

Файл export.js

var http = require("http");
var url = require("url");

function start(route, handle) {
  function onRequest(request, response) {

    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");
/*
    var postData = "";

    request.setEncoding("utf8");

    request.addListener("data", function(postDataChunk) {
      postData += postDataChunk;
      console.log("Received POST data chunk '"+
      postDataChunk + "'.");
    });

    request.addListener("end", function() {
      route(handle, pathname, response, postData);
    });
*/
    route(handle, pathname, response, request);
  }

  http.createServer(onRequest).listen(80);
  console.log("Server has started.");
}

exports.start = start;

Файл router.js

function route(handle, pathname, response, request/*postData*/) {
  console.log("About to route a request for " + pathname);
  if (typeof handle[pathname] === 'function') {
    handle[pathname](response, request/*postData*/);
  } else {
    console.log("No request handler found for " + pathname);
    response.writeHead(404, {"Content-Type": "text/plain"});
    response.write("404 Not found");
    response.end();
  }
}

exports.route = route;

Файл requestHandler.js

var querystring = require("querystring"),
    fs = require("fs"),
    formidable = require("formidable");

function start(response) {
  console.log("Request handler 'start' was called.");

  var body = '<html>'+
    '<head>'+
    '<meta http-equiv="Content-Type" '+
    'content="text/html; charset=UTF-8" />'+
    '</head>'+
    '<body>'+
    '<form action="/upload" enctype="multipart/form-data" '+
    'method="post">'+
    '<input type="file" name="upload" multiple="multiple">'+
    '<input type="submit" value="Upload file" />'+
    '</form>'+
    '</body>'+
    '</html>';

    response.writeHead(200, {"Content-Type": "text/html"});
    response.write(body);
    response.end();
}

function upload(response, request) {
  console.log("Request handler 'upload' was called.");

  var form = new formidable.IncomingForm();
  console.log("about to parse");
  form.parse(request, function(error, fields, files) {
    console.log("parsing done");

/* Возможна ошибка в Windows: попытка переименования уже существующего файла */
    fs.rename(files.upload.path, "/tmp/test.png", function(err) {
      if (err) {
        fs.unlink("/tmp/test.png");
        fs.rename(files.upload.path, "/tmp/test.png");
      }
    });
    response.writeHead(200, {"Content-Type": "text/html"});
    response.write("received image:<br/>");
    response.write("<img src='/show' />");
    response.end();
  });
}

function show(response) {
  console.log("Request handler 'show' was called.");
  fs.readFile("/tmp/test.png", "binary", function(error, file) {
    if(error) {
      response.writeHead(500, {"Content-Type": "text/plain"});
      response.write(error + "\n");
      response.end();
    } else {
      response.writeHead(200, {"Content-Type": "image/png"});
      response.write(file, "binary");
      response.end();
    }
  });
}

exports.start = start;
exports.upload = upload;
exports.show = show;

Пример запуска кода сервера в консоли командной строки

node server.js

Пример запуска кода клиента в консоли командной строки

node client.js