Basic and Simple to Use Request Class for CoffeeScript

request.coffee

# 
#  request.coffee
#  
#  Created by Wess Cope on 2012-01-30.
# 
# Just a start.  The basics in place and working
# to expand as elements are needed.
#

class Request

  xhrObjects : [
    -> new XMLHttpRequest()
    -> new ActiveXObject("Msxml2.XMLHTTP")
    -> new ActiveXObject("Microsoft.XMLHTTP")
  ]

  request : null

  constructor: ->
    throw new Error("XMLHttpRequest not supported") if @request?

    for request in @xhrObjects
      try
        requestObject = request()
        @request = requestObject
      catch err
                

  response: ->
    header  = @request.getResponseHeader("Content-Type")
    text    = @request.responseText

    if header.indexOf("javascript") >= 0
      return eval(text)
    else if header.indexOf("json") >= 0
      jsonResponse = null
      
      try
        jsonResponse = JSON.parse(text)
        return jsonResponse
      catch err
        console.log(err)
      
    return text
        
  parseHeaders: ->
    headerObject = {}
    headers      = @request.getAllResponseHeaders()
    leadSpace    = /^\s*/
    trailSpace   = /\s*$/
    lines        = headers.split("\n")

    for line in lines
      if line.length == 0
        continue

      pos     = line.indexOf(':')
      name    = line.substring(0, post).replace(leadSpace, "").replace(trailSpace, "")
      value   = line.substring((post + 1)).replace(leadSpace, "").replace(trailSpace, "")

      headerObject[name] = value

    return headerObject
        
  queryString: (params)->
    query = new Array

    for key, value of params
      query.push("%@=%@".$$(key, value))

    return query.join("&") 
        
  encodeData: (data)->
    params = []

    for key,value of data
      params.push(encodeURIComponent(key) + "=" + encodeURIComponent(value))

    return params.join('&')
        
  execute: (method, options)->
    throw new Error("No HTTP request method provided") unless method

    options ?= {}

    throw new Error("No URL was provided") unless options.url

    callback      = options.callback or (->)
    errorCallback = (status, reason, text)-> 
                          throw new Error("Status: %@ // Reason: %@ // Description: %@".$$(status, reason, text))
    url = options.url
    params  = options.params ? null
    async = options.async ? true

    @request.onreadystatechange = (=>
      if @request.readyState is 4
        if @request.status in [200..240]
          callback.apply(@, [@response()])
        else
          errorCallback.apply(@, [@request.status, @request.statusText, @request.responseText])
    )

    getParams   = "?" + @queryString(params) if params
    url         = (url + getParams) unless method isnt "GET"

    @request.open(method, url, async)
    
    if method is "POST"
      @request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded")
      @request.setRequestHeader("X-Request-With", "XMLHttpRequest")

      @request.send(@encodeData(params))
    else
      @request.send(null)

    return @response() unless async
        
  get: (options)->
    @execute("GET", options)

  post: (options)->
    @execute("POST", options)
        
module.exports = Request