amplify.js

/*!
 * Amplify 1.1.0
 *
 * Copyright 2011 appendTo LLC. (http://appendto.com/team)
 * Dual licensed under the MIT or GPL licenses.
 * http://appendto.com/open-source-licenses
 *
 * http://amplifyjs.com
 */
(function( global, undefined ) {

var slice = [].slice,
	subscriptions = {};

var amplify = global.amplify = {
	publish: function( topic ) {
		if ( typeof topic !== "string" ) {
			throw new Error( "You must provide a valid topic to publish." );
		}

		var args = slice.call( arguments, 1 ),
			topicSubscriptions,
			subscription,
			length,
			i = 0,
			ret;

		if ( !subscriptions[ topic ] ) {
			return true;
		}

		topicSubscriptions = subscriptions[ topic ].slice();
		for ( length = topicSubscriptions.length; i < length; i++ ) {
			subscription = topicSubscriptions[ i ];
			ret = subscription.callback.apply( subscription.context, args );
			if ( ret === false ) {
				break;
			}
		}
		return ret !== false;
	},

	subscribe: function( topic, context, callback, priority ) {
		if ( typeof topic !== "string" ) {
			throw new Error( "You must provide a valid topic to create a subscription." );
		}

		if ( arguments.length === 3 && typeof callback === "number" ) {
			priority = callback;
			callback = context;
			context = null;
		}
		if ( arguments.length === 2 ) {
			callback = context;
			context = null;
		}
		priority = priority || 10;

		var topicIndex = 0,
			topics = topic.split( /\s/ ),
			topicLength = topics.length,
			added;
		for ( ; topicIndex < topicLength; topicIndex++ ) {
			topic = topics[ topicIndex ];
			added = false;
			if ( !subscriptions[ topic ] ) {
				subscriptions[ topic ] = [];
			}

			var i = subscriptions[ topic ].length - 1,
				subscriptionInfo = {
					callback: callback,
					context: context,
					priority: priority
				};

			for ( ; i >= 0; i-- ) {
				if ( subscriptions[ topic ][ i ].priority <= priority ) {
					subscriptions[ topic ].splice( i + 1, 0, subscriptionInfo );
					added = true;
					break;
				}
			}

			if ( !added ) {
				subscriptions[ topic ].unshift( subscriptionInfo );
			}
		}

		return callback;
	},

	unsubscribe: function( topic, callback ) {
		if ( typeof topic !== "string" ) {
			throw new Error( "You must provide a valid topic to remove a subscription." );
		}

		if ( !subscriptions[ topic ] ) {
			return;
		}

		var length = subscriptions[ topic ].length,
			i = 0;

		for ( ; i < length; i++ ) {
			if ( subscriptions[ topic ][ i ].callback === callback ) {
				subscriptions[ topic ].splice( i, 1 );
				break;
			}
		}
	}
};

}( this ) );

(function( amplify, undefined ) {

var store = amplify.store = function( key, value, options ) {
	var type = store.type;
	if ( options && options.type && options.type in store.types ) {
		type = options.type;
	}
	return store.types[ type ]( key, value, options || {} );
};

store.types = {};
store.type = null;
store.addType = function( type, storage ) {
	if ( !store.type ) {
		store.type = type;
	}

	store.types[ type ] = storage;
	store[ type ] = function( key, value, options ) {
		options = options || {};
		options.type = type;
		return store( key, value, options );
	};
};
store.error = function() {
	return "amplify.store quota exceeded";
};

var rprefix = /^__amplify__/;
function createFromStorageInterface( storageType, storage ) {
	store.addType( storageType, function( key, value, options ) {
		var storedValue, parsed, i, remove,
			ret = value,
			now = (new Date()).getTime();

		if ( !key ) {
			ret = {};
			remove = [];
			i = 0;
			try {
				// accessing the length property works around a localStorage bug
				// in Firefox 4.0 where the keys don't update cross-page
				// we assign to key just to avoid Closure Compiler from removing
				// the access as "useless code"
				// https://bugzilla.mozilla.org/show_bug.cgi?id=662511
				key = storage.length;

				while ( key = storage.key( i++ ) ) {
					if ( rprefix.test( key ) ) {
						parsed = JSON.parse( storage.getItem( key ) );
						if ( parsed.expires && parsed.expires <= now ) {
							remove.push( key );
						} else {
							ret[ key.replace( rprefix, "" ) ] = parsed.data;
						}
					}
				}
				while ( key = remove.pop() ) {
					storage.removeItem( key );
				}
			} catch ( error ) {}
			return ret;
		}

		// protect against name collisions with direct storage
		key = "__amplify__" + key;

		if ( value === undefined ) {
			storedValue = storage.getItem( key );
			parsed = storedValue ? JSON.parse( storedValue ) : { expires: -1 };
			if ( parsed.expires && parsed.expires <= now ) {
				storage.removeItem( key );
			} else {
				return parsed.data;
			}
		} else {
			if ( value === null ) {
				storage.removeItem( key );
			} else {
				parsed = JSON.stringify({
					data: value,
					expires: options.expires ? now + options.expires : null
				});
				try {
					storage.setItem( key, parsed );
				// quota exceeded
				} catch( error ) {
					// expire old data and try again
					store[ storageType ]();
					try {
						storage.setItem( key, parsed );
					} catch( error ) {
						throw store.error();
					}
				}
			}
		}

		return ret;
	});
}

// localStorage + sessionStorage
// IE 8+, Firefox 3.5+, Safari 4+, Chrome 4+, Opera 10.5+, iPhone 2+, Android 2+
for ( var webStorageType in { localStorage: 1, sessionStorage: 1 } ) {
	// try/catch for file protocol in Firefox and Private Browsing in Safari 5
	try {
		// Safari 5 in Private Browsing mode exposes localStorage
		// but doesn't allow storing data, so we attempt to store and remove an item.
		// This will unfortunately give us a false negative if we're at the limit.
		window[ webStorageType ].setItem( "__amplify__", "x" );
		window[ webStorageType ].removeItem( "__amplify__" );
		createFromStorageInterface( webStorageType, window[ webStorageType ] );
	} catch( e ) {}
}

// globalStorage
// non-standard: Firefox 2+
// https://developer.mozilla.org/en/dom/storage#globalStorage
if ( !store.types.localStorage && window.globalStorage ) {
	// try/catch for file protocol in Firefox
	try {
		createFromStorageInterface( "globalStorage",
			window.globalStorage[ window.location.hostname ] );
		// Firefox 2.0 and 3.0 have sessionStorage and globalStorage
		// make sure we default to globalStorage
		// but don't default to globalStorage in 3.5+ which also has localStorage
		if ( store.type === "sessionStorage" ) {
			store.type = "globalStorage";
		}
	} catch( e ) {}
}

// userData
// non-standard: IE 5+
// http://msdn.microsoft.com/en-us/library/ms531424(v=vs.85).aspx
(function() {
	// IE 9 has quirks in userData that are a huge pain
	// rather than finding a way to detect these quirks
	// we just don't register userData if we have localStorage
	if ( store.types.localStorage ) {
		return;
	}

	// append to html instead of body so we can do this from the head
	var div = document.createElement( "div" ),
		attrKey = "amplify";
	div.style.display = "none";
	document.getElementsByTagName( "head" )[ 0 ].appendChild( div );

	// we can't feature detect userData support
	// so just try and see if it fails
	// surprisingly, even just adding the behavior isn't enough for a failure
	// so we need to load the data as well
	try {
		div.addBehavior( "#default#userdata" );
		div.load( attrKey );
	} catch( e ) {
		div.parentNode.removeChild( div );
		return;
	}

	store.addType( "userData", function( key, value, options ) {
		div.load( attrKey );
		var attr, parsed, prevValue, i, remove,
			ret = value,
			now = (new Date()).getTime();

		if ( !key ) {
			ret = {};
			remove = [];
			i = 0;
			while ( attr = div.XMLDocument.documentElement.attributes[ i++ ] ) {
				parsed = JSON.parse( attr.value );
				if ( parsed.expires && parsed.expires <= now ) {
					remove.push( attr.name );
				} else {
					ret[ attr.name ] = parsed.data;
				}
			}
			while ( key = remove.pop() ) {
				div.removeAttribute( key );
			}
			div.save( attrKey );
			return ret;
		}

		// convert invalid characters to dashes
		// http://www.w3.org/TR/REC-xml/#NT-Name
		// simplified to assume the starting character is valid
		// also removed colon as it is invalid in HTML attribute names
		key = key.replace( /[^\-._0-9A-Za-z\xb7\xc0-\xd6\xd8-\xf6\xf8-\u037d\u037f-\u1fff\u200c-\u200d\u203f\u2040\u2070-\u218f]/g, "-" );
		// adjust invalid starting character to deal with our simplified sanitization
		key = key.replace( /^-/, "_-" );

		if ( value === undefined ) {
			attr = div.getAttribute( key );
			parsed = attr ? JSON.parse( attr ) : { expires: -1 };
			if ( parsed.expires && parsed.expires <= now ) {
				div.removeAttribute( key );
			} else {
				return parsed.data;
			}
		} else {
			if ( value === null ) {
				div.removeAttribute( key );
			} else {
				// we need to get the previous value in case we need to rollback
				prevValue = div.getAttribute( key );
				parsed = JSON.stringify({
					data: value,
					expires: (options.expires ? (now + options.expires) : null)
				});
				div.setAttribute( key, parsed );
			}
		}

		try {
			div.save( attrKey );
		// quota exceeded
		} catch ( error ) {
			// roll the value back to the previous value
			if ( prevValue === null ) {
				div.removeAttribute( key );
			} else {
				div.setAttribute( key, prevValue );
			}

			// expire old data and try again
			store.userData();
			try {
				div.setAttribute( key, parsed );
				div.save( attrKey );
			} catch ( error ) {
				// roll the value back to the previous value
				if ( prevValue === null ) {
					div.removeAttribute( key );
				} else {
					div.setAttribute( key, prevValue );
				}
				throw store.error();
			}
		}
		return ret;
	});
}() );

// in-memory storage
// fallback for all browsers to enable the API even if we can't persist data
(function() {
	var memory = {},
		timeout = {};

	function copy( obj ) {
		return obj === undefined ? undefined : JSON.parse( JSON.stringify( obj ) );
	}

	store.addType( "memory", function( key, value, options ) {
		if ( !key ) {
			return copy( memory );
		}

		if ( value === undefined ) {
			return copy( memory[ key ] );
		}

		if ( timeout[ key ] ) {
			clearTimeout( timeout[ key ] );
			delete timeout[ key ];
		}

		if ( value === null ) {
			delete memory[ key ];
			return null;
		}

		memory[ key ] = value;
		if ( options.expires ) {
			timeout[ key ] = setTimeout(function() {
				delete memory[ key ];
				delete timeout[ key ];
			}, options.expires );
		}

		return value;
	});
}() );

}( this.amplify = this.amplify || {} ) );

(function( amplify, undefined ) {

function noop() {}
function isFunction( obj ) {
	return ({}).toString.call( obj ) === "[object Function]";
}

function async( fn ) {
	var isAsync = false;
	setTimeout(function() {
		isAsync = true;
	}, 1 );
	return function() {
		var that = this,
			args = arguments;
		if ( isAsync ) {
			fn.apply( that, args );
		} else {
			setTimeout(function() {
				fn.apply( that, args );
			}, 1 );
		}
	};
}

amplify.request = function( resourceId, data, callback ) {
	// default to an empty hash just so we can handle a missing resourceId
	// in one place
	var settings = resourceId || {};

	if ( typeof settings === "string" ) {
		if ( isFunction( data ) ) {
			callback = data;
			data = {};
		}
		settings = {
			resourceId: resourceId,
			data: data || {},
			success: callback
		};
	}

	var request = { abort: noop },
		resource = amplify.request.resources[ settings.resourceId ],
		success = settings.success || noop,
		error = settings.error || noop;
	settings.success = async( function( data, status ) {
		status = status || "success";
		amplify.publish( "request.success", settings, data, status );
		amplify.publish( "request.complete", settings, data, status );
		success( data, status );
	});
	settings.error = async( function( data, status ) {
		status = status || "error";
		amplify.publish( "request.error", settings, data, status );
		amplify.publish( "request.complete", settings, data, status );
		error( data, status );
	});

	if ( !resource ) {
		if ( !settings.resourceId ) {
			throw "amplify.request: no resourceId provided";
		}
		throw "amplify.request: unknown resourceId: " + settings.resourceId;
	}

	if ( !amplify.publish( "request.before", settings ) ) {
		settings.error( null, "abort" );
		return;
	}

	amplify.request.resources[ settings.resourceId ]( settings, request );
	return request;
};

amplify.request.types = {};
amplify.request.resources = {};
amplify.request.define = function( resourceId, type, settings ) {
	if ( typeof type === "string" ) {
		if ( !( type in amplify.request.types ) ) {
			throw "amplify.request.define: unknown type: " + type;
		}

		settings.resourceId = resourceId;
		amplify.request.resources[ resourceId ] =
			amplify.request.types[ type ]( settings );
	} else {
		// no pre-processor or settings for one-off types (don't invoke)
		amplify.request.resources[ resourceId ] = type;
	}
};

}( amplify ) );





(function( amplify, $, undefined ) {

var xhrProps = [ "status", "statusText", "responseText", "responseXML", "readyState" ],
    rurlData = /\{([^\}]+)\}/g;

amplify.request.types.ajax = function( defnSettings ) {
	defnSettings = $.extend({
		type: "GET"
	}, defnSettings );

	return function( settings, request ) {
		var xhr, handleResponse,
			url = defnSettings.url,
			abort = request.abort,
			ajaxSettings = $.extend( true, {}, defnSettings, { data: settings.data } ),
			aborted = false,
			ampXHR = {
				readyState: 0,
				setRequestHeader: function( name, value ) {
					return xhr.setRequestHeader( name, value );
				},
				getAllResponseHeaders: function() {
					return xhr.getAllResponseHeaders();
				},
				getResponseHeader: function( key ) {
					return xhr.getResponseHeader( key );
				},
				overrideMimeType: function( type ) {
					return xhr.overrideMimeType( type );
				},
				abort: function() {
					aborted = true;
					try {
						xhr.abort();
					// IE 7 throws an error when trying to abort
					} catch( e ) {}
					handleResponse( null, "abort" );
				},
				success: function( data, status ) {
					settings.success( data, status );
				},
				error: function( data, status ) {
					settings.error( data, status );
				}
			};

		handleResponse = function( data, status ) {
			$.each( xhrProps, function( i, key ) {
				try {
					ampXHR[ key ] = xhr[ key ];
				} catch( e ) {}
			});
			// Playbook returns "HTTP/1.1 200 OK"
			// TODO: something also returns "OK", what?
			if ( /OK$/.test( ampXHR.statusText ) ) {
				ampXHR.statusText = "success";
			}
			if ( data === undefined ) {
				// TODO: add support for ajax errors with data
				data = null;
			}
			if ( aborted ) {
				status = "abort";
			}
			if ( /timeout|error|abort/.test( status ) ) {
				ampXHR.error( data, status );
			} else {
				ampXHR.success( data, status );
			}
			// avoid handling a response multiple times
			// this can happen if a request is aborted
			// TODO: figure out if this breaks polling or multi-part responses
			handleResponse = $.noop;
		};

		amplify.publish( "request.ajax.preprocess",
			defnSettings, settings, ajaxSettings, ampXHR );

		$.extend( ajaxSettings, {
			success: function( data, status ) {
				handleResponse( data, status );
			},
			error: function( _xhr, status ) {
				handleResponse( null, status );
			},
			beforeSend: function( _xhr, _ajaxSettings ) {
				xhr = _xhr;
				ajaxSettings = _ajaxSettings;
				var ret = defnSettings.beforeSend ?
					defnSettings.beforeSend.call( this, ampXHR, ajaxSettings ) : true;
				return ret && amplify.publish( "request.before.ajax",
					defnSettings, settings, ajaxSettings, ampXHR );
			}
		});
		$.ajax( ajaxSettings );

		request.abort = function() {
			ampXHR.abort();
			abort.call( this );
		};
	};
};



amplify.subscribe( "request.ajax.preprocess", function( defnSettings, settings, ajaxSettings ) {
	var mappedKeys = [],
		data = ajaxSettings.data;

	if ( typeof data === "string" ) {
		return;
	}

	data = $.extend( true, {}, defnSettings.data, data );

	ajaxSettings.url = ajaxSettings.url.replace( rurlData, function ( m, key ) {
		if ( key in data ) {
			mappedKeys.push( key );
			return data[ key ];
		}
	});

	// We delete the keys later so duplicates are still replaced
	$.each( mappedKeys, function ( i, key ) {
		delete data[ key ];
	});

	ajaxSettings.data = data;
});



amplify.subscribe( "request.ajax.preprocess", function( defnSettings, settings, ajaxSettings ) {
	var data = ajaxSettings.data,
		dataMap = defnSettings.dataMap;

	if ( !dataMap || typeof data === "string" ) {
		return;
	}

	if ( $.isFunction( dataMap ) ) {
		ajaxSettings.data = dataMap( data );
	} else {
		$.each( defnSettings.dataMap, function( orig, replace ) {
			if ( orig in data ) {
				data[ replace ] = data[ orig ];
				delete data[ orig ];
			}
		});
		ajaxSettings.data = data;
	}
});



var cache = amplify.request.cache = {
	_key: function( resourceId, url, data ) {
		function chunk() {
			return data.charCodeAt( i++ ) << 24 |
				data.charCodeAt( i++ ) << 16 |
				data.charCodeAt( i++ ) << 8 |
				data.charCodeAt( i++ ) << 0;
		}

		data = url + data;
		var length = data.length,
			i = 0,
			checksum = chunk();

		while ( i < length ) {
			checksum ^= chunk();
		}

		return "request-" + resourceId + "-" + checksum;
	},

	_default: (function() {
		var memoryStore = {};
		return function( resource, settings, ajaxSettings, ampXHR ) {
			// data is already converted to a string by the time we get here
			var cacheKey = cache._key( settings.resourceId,
					ajaxSettings.url, ajaxSettings.data ),
				duration = resource.cache;

			if ( cacheKey in memoryStore ) {
				ampXHR.success( memoryStore[ cacheKey ] );
				return false;
			}
			var success = ampXHR.success;
			ampXHR.success = function( data ) {
				memoryStore[ cacheKey ] = data;
				if ( typeof duration === "number" ) {
					setTimeout(function() {
						delete memoryStore[ cacheKey ];
					}, duration );
				}
				success.apply( this, arguments );
			};
		};
	}())
};

if ( amplify.store ) {
	$.each( amplify.store.types, function( type ) {
		cache[ type ] = function( resource, settings, ajaxSettings, ampXHR ) {
			var cacheKey = cache._key( settings.resourceId,
					ajaxSettings.url, ajaxSettings.data ),
				cached = amplify.store[ type ]( cacheKey );

			if ( cached ) {
				ajaxSettings.success( cached );
				return false;
			}
			var success = ampXHR.success;
			ampXHR.success = function( data ) {
				amplify.store[ type ]( cacheKey, data, { expires: resource.cache.expires } );
				success.apply( this, arguments );
			};
		};
	});
	cache.persist = cache[ amplify.store.type ];
}

amplify.subscribe( "request.before.ajax", function( resource ) {
	var cacheType = resource.cache;
	if ( cacheType ) {
		// normalize between objects and strings/booleans/numbers
		cacheType = cacheType.type || cacheType;
		return cache[ cacheType in cache ? cacheType : "_default" ]
			.apply( this, arguments );
	}
});



amplify.request.decoders = {
	// http://labs.omniti.com/labs/jsend
	jsend: function( data, status, ampXHR, success, error ) {
		if ( data.status === "success" ) {
			success( data.data );
		} else if ( data.status === "fail" ) {
			error( data.data, "fail" );
		} else if ( data.status === "error" ) {
			delete data.status;
			error( data, "error" );
		} else {
			error( null, "error" );
		}
	}
};

amplify.subscribe( "request.before.ajax", function( resource, settings, ajaxSettings, ampXHR ) {
	var _success = ampXHR.success,
		_error = ampXHR.error,
		decoder = $.isFunction( resource.decoder ) ?
			resource.decoder :
			resource.decoder in amplify.request.decoders ?
				amplify.request.decoders[ resource.decoder ] :
				amplify.request.decoders._default;

	if ( !decoder ) {
		return;
	}

	function success( data, status ) {
		_success( data, status );
	}
	function error( data, status ) {
		_error( data, status );
	}
	ampXHR.success = function( data, status ) {
		decoder( data, status, ampXHR, success, error );
	};
	ampXHR.error = function( data, status ) {
		decoder( data, status, ampXHR, success, error );
	};
});

}( amplify, jQuery ) );