twister HTML + Javascript User Interface
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/**
* This plugin requires jquery.json.js to be available, or at least the methods $.toJSON and
* $.parseJSON.
*
* The plan is to make use of websockets if they are available, but work just as well with only
* http if not.
*
* Usage example:
*
* var foo = new $.JsonRpcClient({ ajaxUrl: '/backend/jsonrpc' });
* foo.call(
* 'bar', [ 'A parameter', 'B parameter' ],
* function(result) { alert('Foo bar answered: ' + result.my_answer); },
* function(error) { console.log('There was an error', error); }
* );
*
* More examples are available in README.md
*/
(function($) {
/**
* @fn new
* @memberof $.JsonRpcClient
*
* @param options An object stating the backends:
* ajaxUrl A url (relative or absolute) to a http(s) backend.
* socketUrl A url (relative of absolute) to a ws(s) backend.
* onmessage A socket message handler for other messages (non-responses).
* getSocket A function returning a WebSocket or null.
* It must take an onmessage_cb and bind it to the onmessage event
* (or chain it before/after some other onmessage handler).
* Or, it could return null if no socket is available.
* The returned instance must have readyState <= 1, and if less than 1,
* react to onopen binding.
*/
$.JsonRpcClient = function(options) {
var self = this;
this.options = $.extend({
ajaxUrl : null,
socketUrl : null, ///< The ws-url for default getSocket.
onmessage : null, ///< Other onmessage-handler.
getSocket : function(onmessage_cb) { return self._getSocket(onmessage_cb); }
}, options);
// Declare an instance version of the onmessage callback to wrap 'this'.
this.wsOnMessage = function(event) { self._wsOnMessage(event); };
};
/// Holding the WebSocket on default getsocket.
$.JsonRpcClient.prototype._ws_socket = null;
/// Object <id>: { success_cb: cb, error_cb: cb }
$.JsonRpcClient.prototype._ws_callbacks = {};
/// The next JSON-RPC request id.
$.JsonRpcClient.prototype._current_id = 1;
/**
* @fn call
* @memberof $.JsonRpcClient
*
* @param method The method to run on JSON-RPC server.
* @param params The params; an array or object.
* @param success_cb A callback for successful request.
* @param error_cb A callback for error.
*/
$.JsonRpcClient.prototype.call = function(method, params, success_cb, error_cb) {
// Construct the JSON-RPC 2.0 request.
var request = {
jsonrpc : '2.0',
method : method,
params : params,
id : this._current_id++ // Increase the id counter to match request/response
};
// Try making a WebSocket call.
var socket = this.options.getSocket(this.wsOnMessage);
if (socket !== null) {
this._wsCall(socket, request, success_cb, error_cb);
return;
}
// No WebSocket, and no HTTP backend? This won't work.
if (this.options.ajaxUrl === null) {
throw "$.JsonRpcClient.call used with no websocket and no http endpoint.";
}
var options = this.options;
$.ajax({
type : 'POST',
url : this.options.ajaxUrl,
data : $.toJSON(request),
dataType : 'json',
contentType: "application/json; charset=utf-8",
cache : false,
beforeSend: function (xhr) {
if( options.username != null && options.username != undefined ) {
xhr.setRequestHeader('Authorization', "Basic " + btoa(options.username + ":" + options.password));
}
},
success : function(data) {
if ('error' in data) error_cb(data.error);
success_cb(data.result);
},
// JSON-RPC Server could return non-200 on error
error : function(jqXHR, textStatus, errorThrown) {
try {
var response = $.parseJSON(jqXHR.responseText);
if ('console' in window) console.log(response);
error_cb(response.error);
}
catch (err) {
// Perhaps the responseText wasn't really a jsonrpc-error.
error_cb({ error: jqXHR.responseText });
}
}
});
};
/**
* Notify sends a command to the server that won't need a response. In http, there is probably
* an empty response - that will be dropped, but in ws there should be no response at all.
*
* This is very similar to call, but has no id and no handling of callbacks.
*
* @fn notify
* @memberof $.JsonRpcClient
*
* @param method The method to run on JSON-RPC server.
* @param params The params; an array or object.
*/
$.JsonRpcClient.prototype.notify = function(method, params) {
// Construct the JSON-RPC 2.0 request.
var request = {
jsonrpc: '2.0',
method: method,
params: params
};
// Try making a WebSocket call.
var socket = this.options.getSocket(this.wsOnMessage);
if (socket !== null) {
this._wsCall(socket, request);
return;
}
// No WebSocket, and no HTTP backend? This won't work.
if (this.options.ajaxUrl === null) {
throw "$.JsonRpcClient.notify used with no websocket and no http endpoint.";
}
$.ajax({
type : 'POST',
url : this.options.ajaxUrl,
data : $.toJSON(request),
dataType : 'json',
contentType: "application/json; charset=utf-8",
cache : false,
beforeSend: function (xhr){
if( options.username != null && options.username != undefined ) {
xhr.setRequestHeader('Authorization', "Basic " + btoa(options.username + ":" + options.password));
}
},
});
};
/**
* Make a batch-call by using a callback.
*
* The callback will get an object "batch" as only argument. On batch, you can call the methods
* "call" and "notify" just as if it was a normal $.JsonRpcClient object, and all calls will be
* sent as a batch call then the callback is done.
*
* @fn batch
* @memberof $.JsonRpcClient
*
* @param callback The main function which will get a batch handler to run call and notify on.
* @param all_done_cb A callback function to call after all results have been handled.
* @param error_cb A callback function to call if there is an error from the server.
* Note, that batch calls should always get an overall success, and the
* only error
*/
$.JsonRpcClient.prototype.batch = function(callback, all_done_cb, error_cb) {
var batch = new $.JsonRpcClient._batchObject(this, all_done_cb, error_cb);
callback(batch);
batch._execute();
};
/**
* The default getSocket handler.
*
* @param onmessage_cb The callback to be bound to onmessage events on the socket.
*
* @fn _getSocket
* @memberof $.JsonRpcClient
*/
$.JsonRpcClient.prototype._getSocket = function(onmessage_cb) {
// If there is no ws url set, we don't have a socket.
// Likewise, if there is no window.WebSocket.
if (this.options.socketUrl === null || !("WebSocket" in window)) return null;
if (this._ws_socket === null || this._ws_socket.readyState > 1) {
// No socket, or dying socket, let's get a new one.
this._ws_socket = new WebSocket(this.options.socketUrl);
// Set up onmessage handler.
this._ws_socket.onmessage = onmessage_cb;
}
return this._ws_socket;
};
/**
* Internal handler to dispatch a JRON-RPC request through a websocket.
*
* @fn _wsCall
* @memberof $.JsonRpcClient
*/
$.JsonRpcClient.prototype._wsCall = function(socket, request, success_cb, error_cb) {
var request_json = $.toJSON(request);
if (socket.readyState < 1) {
// The websocket is not open yet; we have to set sending of the message in onopen.
self = this; // In closure below, this is set to the WebSocket. Use self instead.
// Set up sending of message for when the socket is open.
socket.onopen = function() {
// Send the request.
socket.send(request_json);
};
}
else {
// We have a socket and it should be ready to send on.
socket.send(request_json);
}
// Setup callbacks. If there is an id, this is a call and not a notify.
if ('id' in request && typeof success_cb !== 'undefined') {
this._ws_callbacks[request.id] = { success_cb: success_cb, error_cb: error_cb };
}
};
/**
* Internal handler for the websocket messages. It determines if the message is a JSON-RPC
* response, and if so, tries to couple it with a given callback. Otherwise, it falls back to
* given external onmessage-handler, if any.
*
* @param event The websocket onmessage-event.
*/
$.JsonRpcClient.prototype._wsOnMessage = function(event) {
// Check if this could be a JSON RPC message.
try {
var response = $.parseJSON(event.data);
/// @todo Make using the jsonrcp 2.0 check optional, to use this on JSON-RPC 1 backends.
if (typeof response === 'object'
&& 'jsonrpc' in response
&& response.jsonrpc === '2.0') {
/// @todo Handle bad response (without id).
// If this is an object with result, it is a response.
if ('result' in response && this._ws_callbacks[response.id]) {
// Get the success callback.
var success_cb = this._ws_callbacks[response.id].success_cb;
// Delete the callback from the storage.
delete this._ws_callbacks[response.id];
// Run callback with result as parameter.
success_cb(response.result);
return;
}
// If this is an object with error, it is an error response.
else if ('error' in response && this._ws_callbacks[response.id]) {
// Get the error callback.
var error_cb = this._ws_callbacks[response.id].error_cb;
// Delete the callback from the storage.
delete this._ws_callbacks[response.id];
// Run callback with the error object as parameter.
error_cb(response.error);
return;
}
}
}
catch (err) {
// Probably an error while parsing a non json-string as json. All real JSON-RPC cases are
// handled above, and the fallback method is called below.
}
// This is not a JSON-RPC response. Call the fallback message handler, if given.
if (typeof this.options.onmessage === 'function') {
this.options.onmessage(event);
}
};
/************************************************************************************************
* Batch object with methods
************************************************************************************************/
/**
* Handling object for batch calls.
*/
$.JsonRpcClient._batchObject = function(jsonrpcclient, all_done_cb, error_cb) {
// Array of objects to hold the call and notify requests. Each objects will have the request
// object, and unless it is a notify, success_cb and error_cb.
this._requests = [];
this.jsonrpcclient = jsonrpcclient;
this.all_done_cb = all_done_cb;
this.error_cb = typeof error_cb === 'function' ? error_cb : function() {};
};
/**
* @sa $.JsonRpcClient.prototype.call
*/
$.JsonRpcClient._batchObject.prototype.call = function(method, params, success_cb, error_cb) {
this._requests.push({
request : {
jsonrpc : '2.0',
method : method,
params : params,
id : this.jsonrpcclient._current_id++ // Use the client's id series.
},
success_cb : success_cb,
error_cb : error_cb
});
};
/**
* @sa $.JsonRpcClient.prototype.notify
*/
$.JsonRpcClient._batchObject.prototype.notify = function(method, params) {
this._requests.push({
request : {
jsonrpc : '2.0',
method : method,
params : params
}
});
};
/**
* Executes the batched up calls.
*/
$.JsonRpcClient._batchObject.prototype._execute = function() {
var self = this;
if (this._requests.length === 0) return; // All done :P
// Collect all request data and sort handlers by request id.
var batch_request = [];
var handlers = {};
// If we have a WebSocket, just send the requests individually like normal calls.
var socket = self.jsonrpcclient.options.getSocket(self.jsonrpcclient.wsOnMessage);
if (socket !== null) {
for (var i = 0; i < this._requests.length; i++) {
var call = this._requests[i];
var success_cb = ('success_cb' in call) ? call.success_cb : undefined;
var error_cb = ('error_cb' in call) ? call.error_cb : undefined;
this._wsCall(socket, call.request, success_cb, error_cb);
}
if (typeof all_done_cb === 'function') all_done_cb(result);
return;
}
for (var i = 0; i < this._requests.length; i++) {
var call = this._requests[i];
batch_request.push(call.request);
// If the request has an id, it should handle returns (otherwise it's a notify).
if ('id' in call.request) {
handlers[call.request.id] = {
success_cb : call.success_cb,
error_cb : call.error_cb
};
}
}
var success_cb = function(data) { self._batchCb(data, handlers, self.all_done_cb); };
// No WebSocket, and no HTTP backend? This won't work.
if (self.jsonrpcclient.options.ajaxUrl === null) {
throw "$.JsonRpcClient.batch used with no websocket and no http endpoint.";
}
// Send request
$.ajax({
url : self.jsonrpcclient.options.ajaxUrl,
data : $.toJSON(batch_request),
dataType : 'json',
contentType: "application/json; charset=utf-8",
cache : false,
type : 'POST',
// Batch-requests should always return 200
error : function(jqXHR, textStatus, errorThrown) {
self.error_cb(jqXHR, textStatus, errorThrown);
},
success : success_cb
});
};
/**
* Internal helper to match the result array from a batch call to their respective callbacks.
*
* @fn _batchCb
* @memberof $.JsonRpcClient
*/
$.JsonRpcClient._batchObject.prototype._batchCb = function(result, handlers, all_done_cb) {
for (var i = 0; i < result.length; i++) {
var response = result[i];
// Handle error
if ('error' in response) {
if (response.id === null || !(response.id in handlers)) {
// An error on a notify? Just log it to the console.
if ('console' in window) console.log(response);
}
else handlers[response.id].error_cb(response.error);
}
else {
// Here we should always have a correct id and no error.
if (!(response.id in handlers) && 'console' in window) console.log(response);
else handlers[response.id].success_cb(response.result);
}
}
if (typeof all_done_cb === 'function') all_done_cb(result);
};
})(jQuery);