Downloader.coffee

http        = require 'http'
https       = require 'https'
url         = require 'url'
querystring = require 'querystring'

class Downloader
  constructor: (@url, @method="GET", headers, @params) ->
    @headers = 
      'User-Agent': '*Coin-Monitor'
      'Content-Type': "application/x-www-form-urlencoded"

    @setHeader key, value for key, value of headers

  @setPersistentHeaders: (@persistentHeaders) ->
  @setSignGenerator = (@signGenerator) ->


  # instance methods
  setHeader: (key, value) -> @headers[key] = value

  setBodyParameter: (key, value) ->
    @params ?= {}
    @params[key] = value

  send: (includeAuthHeaders..., @callback) ->
    [@includeAuthHeaders, _...] = includeAuthHeaders
    @includeAuthHeaders ?= true

    return callback "invalid url" unless @url

    query = querystring.stringify @params
    @setHeader 'Content-Length', query.length if query.length

    u = url.parse @url

    protocol = if u.protocol is "http:" then http else https

    if @includeAuthHeaders
      if Downloader.persistentHeaders?
        @setHeader key, value for key, value of Downloader.persistentHeaders

      if Downloader.signGenerator?
        @setHeader 'Sign', Downloader.signGenerator @params

    options = 
      method: @method
      headers: @headers
      host: u.host
      path: u.path

    protocol.request options, (r) ->
      data = ""
      r.on 'data', (c) -> data += c
      r.on 'end', (err) ->
        return callback err if err

        try
          data = JSON.parse data

        catch e
          return callback e

        console.log ".coffee"
        callback null, data

    .on 'error', (e) -> callback e
    .end query


module.exports = Downloader;

Downloader.js

/**
 *
 * Object responsible for handling all REST requests
 *
 **/

var http        = require('http'),
    https       = require('https'),
    url         = require('url'),
    querystring = require('querystring'),
    _           = require('underscore');

var Downloader = function( url, method, headers, params ) {
    this.url = url;
    this.headers = {
        'User-Agent': "*Coin-Monitor",
        'Content-Type': "application/x-www-form-urlencoded"
    };

    var ctx = this;    
    if( !_.isUndefined(headers) ) _.each(headers, ctx._setHeader(ctx));
    if( !_.isUndefined(params) ) this.params = params;
    this.method = ( !_.isUndefined(method) ) ? method : "GET";
};

Downloader.persistentHeaders = null;
Downloader.setPersistentHeaders = function(headers) {
    this.persistentHeaders = headers;
};

Downloader.signGenerator = null;
Downloader.setSignGenerator = function( signGenerator ) {
    this.signGenerator = signGenerator;
};

Downloader.prototype.setHeader = function( key, value ) {
    this.headers[key] = value;
};

Downloader.prototype._setHeader = function( ctx ) { // the same as setHeader, but with reversed parameters
    return function(value, key) { ctx.setHeader(key, value) };
};

Downloader.prototype.setBodyParameter = function( key, value ) {
    if( !_.isObject(this.params) ) this.params = {};
    this.params[key] = value;
};

Downloader.prototype.send = function( arg1, arg2 ) {

    var includeAuthHeaders = true;
    if(typeof arg1==='boolean') {
        includeAuthHeaders = arg1;
        callback = arg2;

    } else callback = arg1;

    if( !this.url ) return callback("invalid url");

    var query = querystring.stringify(this.params);
    if( query.length ) this.setHeader('Content-Length', query.length);




    var u = url.parse( this.url );

    var protocol = u.protocol=="http:" ? http : https;

    if( includeAuthHeaders ) {
        var ctx = this;
        if( Downloader.persistentHeaders!=null ) 
            _.each(Downloader.persistentHeaders, ctx._setHeader(ctx));

        if( Downloader.signGenerator!=null ) 
            this.setHeader('Sign', Downloader.signGenerator(this.params));
    }

    var options = {
        method: this.method,
        headers: this.headers,
        host: u.host,
        path: u.path
    };

    protocol.request(options, function(r) {
        var data = "";
        r.on('data', function(c){ data+=c; });
        r.on('end', function(err) {
            if( err ) return callback(err);
            try {
                data = JSON.parse(data);

            } catch( e ) {
                return callback(e);

            }
            return callback(null, data);
        });

    }).on('error', function(e) {
        return callback(e);

    }).end(query);
};

module.exports = Downloader;