xhr.js

(function( jQuery ) {

var rquery_xhr = /\?/,
	rhash = /#.*$/,
	rheaders = /^(.*?):\s*(.*?)\r?$/mg, // IE leaves an \r character at EOL
	rnoContent = /^(?:GET|HEAD)$/,
	rts = /([?&])_=[^&]*/,
	rurl = /^(\w+:)?\/\/([^\/?#]+)/,
	
	sliceFunc = Array.prototype.slice;
	
// Creates a jQuery xhr object
jQuery.xhr = function( _native ) {

	if ( _native ) {
		return jQuery.ajaxSettings.xhr();
	}
	
	function reset( force ) {
		
		// We only need to reset if we went through the init phase
		// (with the exception of object creation)
		if ( force || internal ) {
			
			// Reset callbacks lists
			deferred = jQuery.Deferred();
			completeDeferred = jQuery._Deferred();
			
			xhr.success = xhr.then = deferred.then;
			xhr.error = xhr.fail = deferred.fail;
			xhr.complete = completeDeferred.then;
			
			// Reset private variables
			requestHeaders = {};
			responseHeadersString = responseHeaders = internal = done = timeoutTimer = s = undefined;

			// Reset state
			xhr.readyState = 0;
			sendFlag = 0;

			// Remove responseX fields
			for ( var name in xhr ) {
				if ( /^response/.test(name) ) {
					delete xhr[name];
				}
			}
		}
	}

	function init() {

		var // Options extraction

			// Remove hash character (#7531: first for string promotion)
			url = s.url = ( "" + s.url ).replace( rhash , "" ),

			// Uppercase the type
			type = s.type = s.type.toUpperCase(),

			// Determine if request has content
			hasContent = s.hasContent = ! rnoContent.test( type ),

			// Extract dataTypes list
			dataType = s.dataType,
			dataTypes = s.dataTypes = dataType ? jQuery.trim(dataType).toLowerCase().split(/\s+/) : ["*"],

			// Determine if a cross-domain request is in order
			parts = rurl.exec( url.toLowerCase() ),
			loc = location,
			crossDomain = s.crossDomain = !!( parts && ( parts[1] && parts[1] != loc.protocol || parts[2] != loc.host ) ),

			// Get other options locally
			data = s.data,
			originalContentType = s.contentType,
			prefilters = s.prefilters,
			accepts = s.accepts,
			headers = s.headers,

			// Other Variables
			transportDataType,
			i;

		// Convert data if not already a string
		if ( data && s.processData && typeof data != "string" ) {
			data = s.data = jQuery.param( data , s.traditional );
		}

		// Get internal
		internal = jQuery.xhr.prefilter( s ).transport( s );
		
		// Re-actualize url & data
		url = s.url;
		data = s.data;

		// If internal was found
		if ( internal ) {

			// Get transportDataType
			transportDataType = dataTypes[0];

			// More options handling for requests with no content
			if ( ! hasContent ) {

				// If data is available, append data to url
				if ( data ) {
					url += (rquery_xhr.test(url) ? "&" : "?") + data;
				}

				// Add anti-cache in url if needed
				if ( s.cache === false ) {

					var ts = jQuery.now(),
						// try replacing _= if it is there
						ret = url.replace(rts, "$1_=" + ts );

					// if nothing was replaced, add timestamp to the end
					url = ret + ((ret == url) ? (rquery_xhr.test(url) ? "&" : "?") + "_=" + ts : "");
				}

				s.url = url;
			}

			// Set the correct header, if data is being sent
			if ( ( data && hasContent ) || originalContentType ) {
				requestHeaders["content-type"] = s.contentType;
			}

			// Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
			if ( s.ifModified ) {
				if ( jQuery_lastModified[url] ) {
					requestHeaders["if-modified-since"] = jQuery_lastModified[url];
				}
				if ( jQuery_etag[url] ) {
					requestHeaders["if-none-match"] = jQuery_etag[url];
				}
			}

			// Set the Accepts header for the server, depending on the dataType
			requestHeaders.accept = transportDataType && accepts[ transportDataType ] ?
				accepts[ transportDataType ] + ( transportDataType !== "*" ? ", */*; q=0.01" : "" ) :
				accepts[ "*" ];

			// Check for headers option
			for ( i in headers ) {
				requestHeaders[ i.toLowerCase() ] = headers[ i ];
			}
		}
		
		callbackContext = s.context || s;
		globalEventContext = s.context ? jQuery(s.context) : jQuery.event;
		
		for ( i in { success:1, error:1, complete:1 } ) {
			xhr[ i ]( s[ i ] );
		}

		// Watch for a new set of requests
		if ( s.global && jQuery.active++ === 0 ) {
			jQuery.event.trigger( "ajaxStart" );
		}

		done = whenDone;
	}

	function whenDone(status, statusText, response, headers) {

		// Called once
		done = undefined;

		// Reset sendFlag
		sendFlag = 0;

		// Cache response headers
		responseHeadersString = headers || "";

		// Clear timeout if it exists
		if ( timeoutTimer ) {
			clearTimeout(timeoutTimer);
		}

		var // Reference url
			url = s.url,
			// and ifModified status
			ifModified = s.ifModified,

			// Is it a success?
			isSuccess = 0,
			// Stored success
			success,
			// Stored error
			error = statusText;

		// If not timeout, force a jQuery-compliant status text
		if ( statusText != "timeout" ) {
			statusText = ( status >= 200 && status < 300 ) ?
				"success" :
				( status === 304 ? "notmodified" : "error" );
		}

		// If successful, handle type chaining
		if ( statusText === "success" || statusText === "notmodified" ) {

			// Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
			if ( ifModified ) {
				var lastModified = xhr.getResponseHeader("Last-Modified"),
					etag = xhr.getResponseHeader("Etag");

				if (lastModified) {
					jQuery_lastModified[url] = lastModified;
				}
				if (etag) {
					jQuery_etag[url] = etag;
				}
			}

			if ( ifModified && statusText === "notmodified" ) {

				success = null;
				isSuccess = 1;

			} else {
				// Chain data conversions and determine the final value
				// (if an exception is thrown in the process, it'll be notified as an error)
				try {
					
					var i,
						current,
						prev,
						checker,
						conv1,
						conv2,
						oneConv,
						convertion,
						dataTypes = s.dataTypes,
						dataConverters = s.dataConverters,
						dataFilter = s.dataFilter,
						responses = {
							"xml": "XML",
							"text": "Text"
						};
					
					for( i = 0 ; i < dataTypes.length ; i++ ) {
						
						current = dataTypes[ i ];
						
						if ( responses[ current ] ) {
							xhr[ "response" + responses[ current ] ] = response;
							responses[ current ] = 0;
						}
						
						if ( i ) {
							
							if ( prev !== "*" && current !== "*" && prev !== current ) {
							
								oneConv = conv1 = 
									dataConverters[ ( conversion = prev + " " + current ) ] ||
									dataConverters[ "* " + current ];
								
								if ( oneConv !== true ) {
									
									if ( ! oneConv && prev !== "text" && current !== "text" ) {
										conv1 = dataConverters[ prev + " text" ] || dataConverters[ "* text" ];
										conv2 = dataConverters[ "text " + current ];
									}
									
									if ( oneConv || conv1 && conv2 ) {
										response = oneConv ? conv1( response ) : conv2( conv1( response ) );
									} else {
										throw "no " + conversion;
									}
								}
							}
						} else if ( dataFilter ) {
							
							response = s.dataFilter( response );
							dataTypes = s.dataTypes;
						}
						
						prev = current;
					}

					// We have a real success
					success = response;
					isSuccess = 1;

				} catch(e) {

					statusText = "parsererror";
					error = "" + e;

				}
			}

		} else { // if not success, mark it as an error

				error = error || statusText;

		}

		// Set data for the fake xhr object
		xhr.status = status;
		xhr.statusText = statusText;

		// Keep local copies of vars in case callbacks re-use the xhr
		var _s = s,
			_deferred = deferred,
			_completeDeferred = completeDeferred,
			_callbackContext = callbackContext,
			_globalEventContext = globalEventContext;
			
			
		// Set state if the xhr hasn't been re-used
		function _setState( value ) {
			if ( xhr.readyState && s === _s ) {
				setState( value );
			}
		}

		// Really completed?
		if ( status && s.async ) {
			setState( 2 );
			_setState( 3 );
		}

		// We're done
		_setState( 4 );
		
		// Success/Error
		if ( isSuccess ) {
			_deferred.fire( _callbackContext , [ success , statusText , xhr ] );
		} else {
			_deferred.fireReject( _callbackContext , [ xhr , statusText , error ] );
		}
		
		if ( _s.global ) {
			_globalEventContext.trigger( "ajax" + ( isSuccess ? "Success" : "Error" ) , [ xhr , _s , isSuccess ? success : error ] );
		}
		
		// Complete
		_completeDeferred.fire( _callbackContext, [ xhr , statusText ] );
		
		if ( _s.global ) {
			_globalEventContext.trigger( "ajaxComplete", [xhr, _s] );
			// Handle the global AJAX counter
			if ( ! --jQuery.active ) {
				jQuery.event.trigger( "ajaxStop" );
			}
		}
	}

	// Ready state control
	function checkState( expected , test ) {
		if ( expected !== true && ( expected === false || test === false || xhr.readyState !== expected ) ) {
			jQuery.error("INVALID_STATE_ERR");
		}
	}

	// Ready state change
	function setState( value ) {
		xhr.readyState = value;
		if ( jQuery.isFunction( xhr.onreadystatechange ) ) {
			xhr.onreadystatechange();
		}
	}

	var // jQuery lists
		jQuery_lastModified = jQuery.lastModified,
		jQuery_etag = jQuery.etag,
		// Options object
		s,
		// Callback stuff
		callbackContext,
		globalEventContext,
		deferred,
		completeDeferred,
		// Headers (they are sent all at once)
		requestHeaders,
		// Response headers
		responseHeadersString,
		responseHeaders,
		// Done callback
		done,
		// transport
		internal,
		// timeout handle
		timeoutTimer,
		// The send flag
		sendFlag,
		// Fake xhr
		xhr = {
			// state
			readyState: 0,

			// Callback
			onreadystatechange: null,

			// Open
			open: function(type, url, async, username, password) {

				xhr.abort();
				reset();

				s = {
					type: type,
					url: url,
					async: async,
					username: username,
					password: password
				};

				setState(1);

				return xhr;
			},

			// Send
			send: function(data, moreOptions) {

				checkState(1 , !sendFlag);

				s.data = data;

				s = jQuery.extend( true,
					{},
					jQuery.ajaxSettings,
					s,
					moreOptions || ( moreOptions === false ? { global: false } : {} ) );

				if ( moreOptions ) {
					// We force the original context
					// (plain objects used as context get extended)
					s.context = moreOptions.context;
				}

				init();

				// If not internal, abort
				if ( ! internal ) {
					done( 0 , "transport not found" );
					return false;
				}

				// Allow custom headers/mimetypes and early abort
				if ( s.beforeSend ) {

					var _s = s;

					if ( s.beforeSend.call(callbackContext, xhr, s) === false || ! xhr.readyState || _s !== s ) {

						// Abort if not done
						if ( xhr.readyState && _s === s ) {
							xhr.abort();
						}

						// Handle the global AJAX counter
						if ( _s.global && ! --jQuery.active ) {
							jQuery.event.trigger( "ajaxStop" );
						}

						return false;
					}
				}

				sendFlag = 1;

				// Send global event
				if ( s.global ) {
					globalEventContext.trigger("ajaxSend", [xhr, s]);
				}

				// Timeout
				if ( s.async && s.timeout > 0 ) {
					timeoutTimer = setTimeout(function(){
						xhr.abort("timeout");
					}, s.timeout);
				}

				if ( s.async ) {
					setState(1);
				}

				try {

					internal.send(requestHeaders, done);
					return xhr;

				} catch (e) {

					if ( done ) {

						done(0, "error", "" + e);

					} else {

						jQuery.error(e);

					}
				}

				return false;
			},

			// Caches the header
			setRequestHeader: function(name,value) {
				checkState(1, !sendFlag);
				requestHeaders[ name.toLowerCase() ] = value;
				return xhr;
			},

			// Raw string
			getAllResponseHeaders: function() {
				return xhr.readyState <= 1 ? "" : responseHeadersString;
			},

			// Builds headers hashtable if needed
			getResponseHeader: function( key ) {

				if ( xhr.readyState <= 1 ) {

					return null;

				}

				if ( responseHeaders === undefined ) {

					responseHeaders = {};

					if ( typeof responseHeadersString === "string" ) {

						var match;

						while( ( match = rheaders.exec( responseHeadersString ) ) ) {
							responseHeaders[ match[ 1 ].toLowerCase() ] = match[ 2 ];
						}
					}
				}
				return responseHeaders[ key.toLowerCase() ];
			},

			// Cancel the request
			abort: function(statusText) {
				if (internal) {
					internal.abort( statusText || "abort" );
				}
				xhr.readyState = 0;
			}
		};

	// Init data (so that we can bind callbacks early
	reset(1);

	// Return the xhr emulation
	return xhr;
};

// Execute or select from functions in a given structure of options
function xhr_selectOrExecute( structure , s ) {

	var dataTypes = s.dataTypes,
		transportDataType,
		list,
		selected,
		i,
		length,
		checked = {},
		flag,
		noSelect = structure !== "transports";
		
	function initSearch( dataType ) {

		flag = transportDataType !== dataType && ! checked[ dataType ];

		if ( flag ) {

			checked[ dataType ] = 1;
			transportDataType = dataType;
			list = s[ structure ][ dataType ];
			i = -1;
			length = list ? list.length : 0 ;
		}

		return flag;
	}

	initSearch( dataTypes[ 0 ] );

	for ( i = 0 ; ( noSelect || ! selected ) && i <= length ; i++ ) {
		
		if ( i === length ) {

			initSearch( "*" );

		} else {

			selected = list[ i ]( s , determineDataType );

			// If we got redirected to another dataType
			// Search there (if not in progress or already tried)
			if ( typeof( selected ) === "string" &&
				initSearch( selected ) ) {

				dataTypes.unshift( selected );
				selected = 0;
			}
		}
	}

	return noSelect ? jQuery.xhr : selected;
}

// Add an element to one of the xhr structures in ajaxSettings
function xhr_addElement( structure , args ) {
		
	var i,
		j,
		start = 0,
		length = args.length,
		dataTypes = [ "*" ],
		dLength = 1,
		dataType,
		functors = [],
		first,
		append,
		list;
		
	if ( length ) {
		
		first = jQuery.type( args[ 0 ] );
		
		if ( first === "object" ) {
			return xhr_selectOrExecute( structure , args[ 0 ] );
		}
		
		structure = jQuery.ajaxSettings[ structure ];
		
		if ( first !== "function" ) {
			
			dataTypes = args[ 0 ].toLowerCase().split(/\s+/);
			dLength = dataTypes.length;
			start = 1;
			
		}
		
		if ( dLength && start < length ) {
			
			functors = sliceFunc.call( args , start );
			
			length -= start;
					
			for( i = 0 ; i < dLength ; i++ ) {
				
				dataType = dataTypes[ i ];
				
				first = /^\+/.test( dataType );
				
				if (first) {
					dataType = dataType.substr(1);
				}
				
				if ( dataType !== "" ) {
				
					append = Array.prototype[ first ? "unshift" : "push" ];
					
					list = structure[ dataType ] = structure[ dataType ] || [];
			
					for ( j = 0; j < length; j++ ) {
						append.call( list , functors[ j ] );
					}
				}
			}
		}
	}
	
	return jQuery.xhr;
}

// Install prefilter & transport methods
jQuery.each( [ "prefilter" , "transport" ] , function( _ , name ) {
	_ = name + "s";
	jQuery.xhr[ name ] = function() {
		return xhr_addElement( _ , arguments );
	};
} );
	
// Utility function that handles dataType when response is received
// (for those transports that can give text or xml responses)
function determineDataType( s , ct , text , xml ) {

	var autoDataType = s.autoDataType,
		type,
		regexp,
		dataTypes = s.dataTypes,
		transportDataType = dataTypes[0],
		response;

	// Auto (xml, json, script or text determined given headers)
	if ( transportDataType === "*" ) {

		for ( type in autoDataType ) {
			if ( ( regexp = autoDataType[ type ] ) && regexp.test( ct ) ) {
				transportDataType = dataTypes[0] = type;
				break;
			}
		}
	}

	// xml and parsed as such
	if ( transportDataType === "xml" &&
		xml &&
		xml.documentElement /* #4958 */ ) {

		response = xml;

	// Text response was provided
	} else {

		response = text;

		// If it's not really text, defer to dataConverters
		if ( transportDataType !== "text" ) {
			dataTypes.unshift( "text" );
		}

	}

	return response;
}

})( jQuery );