624 lines
21 KiB
JavaScript
624 lines
21 KiB
JavaScript
/**
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* JsonRpcClient
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*
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* A JSON RPC Client that uses WebSockets if available otherwise fallbacks to ajax.
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* Depends on JSON, if browser lacks native support either use JSON3 or jquery.json.
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* Usage example:
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*
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* var foo = new $.JsonRpcClient({ ajaxUrl: '/backend/jsonrpc' });
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* foo.call(
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* 'bar', [ 'A parameter', 'B parameter' ],
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* function(result) { alert('Foo bar answered: ' + result.my_answer); },
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* function(error) { console.log('There was an error', error); }
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* );
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*
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* More examples are available in README.md
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*/
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(function($) {
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/**
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* @fn new
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* @memberof JsonRpcClient
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*
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* @param {object} options An object stating the backends:
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* ajaxUrl A url (relative or absolute) to a http(s) backend.
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* headers An object that will be passed along to $.ajax in options.headers
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* xhrFields An object that will be passed along to $.ajax in options.xhrFields
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* socketUrl A url (relative of absolute) to a ws(s) backend.
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* onmessage A socket message handler for other messages (non-responses).
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* onopen A socket onopen handler. (Not used for custom getSocket.)
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* onclose A socket onclose handler. (Not used for custom getSocket.)
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* onerror A socket onerror handler. (Not used for custom getSocket.)
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* getSocket A function returning a WebSocket or null.
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* It must take an onmessage_cb and bind it to the onmessage event
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* (or chain it before/after some other onmessage handler).
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* Or, it could return null if no socket is available.
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* The returned instance must have readyState <= 1, and if less than 1,
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* react to onopen binding.
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* timeout (optional) A number of ms to wait before timing out and failing a
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* call. If specified a setTimeout will be used to keep track of calls
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* made through a websocket.
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*/
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var JsonRpcClient = function(options) {
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var self = this;
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var noop = function() {};
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this.options = $.extend({
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ajaxUrl : null,
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headers : {}, ///< Optional additional headers to send in $.ajax request.
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socketUrl : null, ///< WebSocket URL. (Not used if a custom getSocket is supplied.)
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onmessage : noop, ///< Optional onmessage-handler for WebSocket.
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onopen : noop, ///< Optional onopen-handler for WebSocket.
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onclose : noop, ///< Optional onclose-handler for WebSocket.
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onerror : noop, ///< Optional onerror-handler for WebSocket.
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/// Custom socket supplier for using an already existing socket
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getSocket : function(onmessageCb) { return self._getSocket(onmessageCb); }
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}, options);
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// Declare an instance version of the onmessage callback to wrap 'this'.
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this.wsOnMessage = function(event) { self._wsOnMessage(event); };
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/// Holding the WebSocket on default getsocket.
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this._wsSocket = null;
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/// Object <id>: { success_cb: cb, error_cb: cb }
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this._wsCallbacks = {};
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/// The next JSON-RPC request id.
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this._currentId = 1;
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//queue for ws request sent *before* ws is open.
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this._wsRequestQueue = [];
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if (!window.JSON && $ && $.toJSON) {
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this.JSON = {
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stringify: $.toJSON,
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parse: $.parseJSON
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};
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} else {
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this.JSON = JSON;
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}
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};
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/**
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* @fn call
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* @memberof JsonRpcClient
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*
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* @param {string} method The method to run on JSON-RPC server.
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* @param {object|array} params The params; an array or object.
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* @param {function} successCb A callback for successful request.
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* @param {function} errorCb A callback for error.
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*
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* @return {object} Returns the deferred object that $.ajax returns or {null} for websockets
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*/
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JsonRpcClient.prototype.call = function(method, params, successCb, errorCb) {
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successCb = typeof successCb === 'function' ? successCb : function() {};
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errorCb = typeof errorCb === 'function' ? errorCb : function() {};
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// Construct the JSON-RPC 2.0 request.
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var request = {
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jsonrpc : '2.0',
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method : method,
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params : params,
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id : this._currentId++ // Increase the id counter to match request/response
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};
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// Try making a WebSocket call.
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var socket = this.options.getSocket(this.wsOnMessage);
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if (socket !== null) {
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this._wsCall(socket, request, successCb, errorCb);
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return null;
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}
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// No WebSocket, and no HTTP backend? This won't work.
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if (this.options.ajaxUrl === null) {
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throw 'JsonRpcClient.call used with no websocket and no http endpoint.';
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}
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var self = this;
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var deferred = $.ajax({
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type : 'POST',
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url : this.options.ajaxUrl,
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contentType: 'application/json',
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data : this.JSON.stringify(request),
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dataType : 'json',
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cache : false,
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headers : this.options.headers,
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xhrFields : this.options.xhrFields,
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timeout : this.options.timeout,
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success : function(data) {
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if ('error' in data) {
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errorCb(data.error);
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} else {
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successCb(data.result);
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}
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},
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// JSON-RPC Server could return non-200 on error
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error : function(jqXHR, textStatus, errorThrown) {
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try {
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var response = self.JSON.parse(jqXHR.responseText);
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if ('console' in window) { console.log(response); }
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errorCb(response.error);
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}
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catch (err) {
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// Perhaps the responseText wasn't really a jsonrpc-error.
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errorCb({error: jqXHR.responseText});
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}
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}
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});
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return deferred;
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};
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/**
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* Notify sends a command to the server that won't need a response. In http, there is probably
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* an empty response - that will be dropped, but in ws there should be no response at all.
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*
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* This is very similar to call, but has no id and no handling of callbacks.
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*
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* @fn notify
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* @memberof JsonRpcClient
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*
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* @param {string} method The method to run on JSON-RPC server.
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* @param {object|array} params The params; an array or object.
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*
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* @return {object} Returns the deferred object that $.ajax returns or {null} for websockets
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*/
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JsonRpcClient.prototype.notify = function(method, params) {
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// Construct the JSON-RPC 2.0 request.
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var request = {
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jsonrpc: '2.0',
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method: method,
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params: params
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};
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// Try making a WebSocket call.
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var socket = this.options.getSocket(this.wsOnMessage);
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if (socket !== null) {
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this._wsCall(socket, request);
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return null;
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}
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// No WebSocket, and no HTTP backend? This won't work.
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if (this.options.ajaxUrl === null) {
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throw 'JsonRpcClient.notify used with no websocket and no http endpoint.';
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}
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var deferred = $.ajax({
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type : 'POST',
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url : this.options.ajaxUrl,
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contentType: 'application/json',
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data : this.JSON.stringify(request),
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dataType : 'json',
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cache : false,
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headers : this.options.headers,
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xhrFields : this.options.xhrFields
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});
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return deferred;
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};
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/**
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* Make a batch-call by using a callback.
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*
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* The callback will get an object "batch" as only argument. On batch, you can call the methods
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* "call" and "notify" just as if it was a normal JsonRpcClient object, and all calls will be
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* sent as a batch call then the callback is done.
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*
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* @fn batch
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* @memberof JsonRpcClient
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*
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* @param {function} callback This function will get a batch handler to run call and notify on.
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* @param {function} allDoneCb A callback function to call after all results have been handled.
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* @param {function} errorCb A callback function to call if there is an error from the server.
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* Note, that batch calls should always get an overall success, and the
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* only error
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*/
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JsonRpcClient.prototype.batch = function(callback, allDoneCb, errorCb) {
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var batch = new JsonRpcClient._batchObject(this, allDoneCb, errorCb);
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callback(batch);
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batch._execute();
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};
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/**
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* The default getSocket handler.
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*
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* @param {function} onmessageCb The callback to be bound to onmessage events on the socket.
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*
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* @fn _getSocket
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* @memberof JsonRpcClient
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*/
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JsonRpcClient.prototype._getSocket = function(onmessageCb) {
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// If there is no ws url set, we don't have a socket.
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// Likewise, if there is no window.WebSocket.
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if (this.options.socketUrl === null || !('WebSocket' in window)) { return null; }
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if (this._wsSocket === null || this._wsSocket.readyState > 1) {
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try {
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// No socket, or dying socket, let's get a new one.
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this._wsSocket = new WebSocket(this.options.socketUrl);
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} catch (e) {
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// This can happen if the server is down, or malconfigured.
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return null;
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}
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// Set up onmessage handler.
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this._wsSocket.onmessage = onmessageCb;
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var that = this;
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// Set up onclose handler.
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this._wsSocket.onclose = function(ev) { that._wsOnClose(ev); };
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// Set up onerror handler.
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this._wsSocket.onerror = function(ev) { that._wsOnError(ev); };
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}
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return this._wsSocket;
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};
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/**
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* Internal handler to dispatch a JRON-RPC request through a websocket.
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*
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* @fn _wsCall
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* @memberof JsonRpcClient
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*/
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JsonRpcClient.prototype._wsCall = function(socket, request, successCb, errorCb) {
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var requestJson = this.JSON.stringify(request);
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// Setup callbacks. If there is an id, this is a call and not a notify.
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if ('id' in request && typeof successCb !== 'undefined') {
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this._wsCallbacks[request.id] = {successCb: successCb, errorCb: errorCb};
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}
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if (socket.readyState < 1) {
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// Queue request
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this._wsRequestQueue.push(requestJson);
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if (!socket.onopen) {
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// The websocket is not open yet; we have to set sending of the message in onopen.
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var self = this; // In closure below, this is set to the WebSocket. Use self instead.
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// Set up sending of message for when the socket is open.
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socket.onopen = function(event) {
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// Hook for extra onopen callback
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self.options.onopen(event);
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// Send queued requests.
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var timeout = self.options.timeout;
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var request;
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for (var i = 0; i < self._wsRequestQueue.length; i++) {
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request = self._wsRequestQueue[i];
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// Do we use timeouts, and if so, is it a call?
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if (timeout && self._wsCallbacks[request.id]) {
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self._wsCallbacks[request.id].timeout = self._createTimeout(request.id);
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}
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socket.send(request);
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}
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self._wsRequestQueue = [];
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};
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}
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} else {
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// Do we use timeouts, and if so, is it a call?
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if (this.options.timeout && this._wsCallbacks[request.id]) {
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this._wsCallbacks[request.id].timeout = this._createTimeout(request.id);
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}
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// We have a socket and it should be ready to send on.
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socket.send(requestJson);
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}
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};
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/**
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* Internal handler for the websocket messages. It determines if the message is a JSON-RPC
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* response, and if so, tries to couple it with a given callback. Otherwise, it falls back to
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* given external onmessage-handler, if any.
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*
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* @param {event} event The websocket onmessage-event.
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*/
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JsonRpcClient.prototype._wsOnMessage = function(event) {
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// Check if this could be a JSON RPC message.
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var response;
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try {
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response = this.JSON.parse(event.data);
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} catch (err) {
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this.options.onmessage(event);
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return;
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}
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/// @todo Make using the jsonrcp 2.0 check optional, to use this on JSON-RPC 1 backends.
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if (typeof response === 'object' && response.jsonrpc === '2.0') {
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/// @todo Handle bad response (without id).
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// If this is an object with result, it is a response.
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if ('result' in response && this._wsCallbacks[response.id]) {
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// Get the success callback.
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var successCb = this._wsCallbacks[response.id].successCb;
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// Clear any timeout
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if (this._wsCallbacks[response.id].timeout) {
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clearTimeout(this._wsCallbacks[response.id].timeout);
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}
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// Delete the callback from the storage.
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delete this._wsCallbacks[response.id];
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// Run callback with result as parameter.
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successCb(response.result);
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return;
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}
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// If this is an object with error, it is an error response.
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else if ('error' in response && this._wsCallbacks[response.id]) {
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// Get the error callback.
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var errorCb = this._wsCallbacks[response.id].errorCb;
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// Delete the callback from the storage.
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delete this._wsCallbacks[response.id];
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// Run callback with the error object as parameter.
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errorCb(response.error);
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return;
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}
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}
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// If we get here it's an invalid JSON-RPC response, pass to fallback message handler.
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this.options.onmessage(event);
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};
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/**
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* Internal WebSocket error handler.
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* Will execute all unresolved calls immideatly.
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**/
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JsonRpcClient.prototype._wsOnError = function(event) {
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this._failAllCalls('Socket errored.');
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this.options.onerror(event);
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};
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/**
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* Internal WebSocket close handler.
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* Will execute all unresolved calls immideatly.
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**/
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JsonRpcClient.prototype._wsOnClose = function(event) {
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this._failAllCalls('Socket closed.');
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this.options.onclose(event);
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};
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/**
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* Execute error handler on all pending calls.
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*/
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JsonRpcClient.prototype._failAllCalls = function(error) {
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for (var key in this._wsCallbacks) {
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if (this._wsCallbacks.hasOwnProperty(key)) {
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// Get the error callback.
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var errorCb = this._wsCallbacks[key].errorCb;
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// Run callback with the error object as parameter.
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errorCb(error);
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}
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}
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// Throw 'em away
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this._wsCallbacks = {};
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};
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/**
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* Create a timeout for this request
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*/
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JsonRpcClient.prototype._createTimeout = function(id) {
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if (this.options.timeout) {
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var that = this;
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return setTimeout(function() {
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if (that._wsCallbacks[id]) {
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var errorCb = that._wsCallbacks[id].errorCb;
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delete that._wsCallbacks[id];
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errorCb('Call timed out.');
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}
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}, this.options.timeout);
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}
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};
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/************************************************************************************************
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* Batch object with methods
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************************************************************************************************/
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/**
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* Handling object for batch calls.
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*/
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JsonRpcClient._batchObject = function(jsonrpcclient, allDoneCb, errorCb) {
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// Array of objects to hold the call and notify requests. Each objects will have the request
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// object, and unless it is a notify, successCb and errorCb.
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this._requests = [];
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this.jsonrpcclient = jsonrpcclient;
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this.allDoneCb = allDoneCb;
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this.errorCb = typeof errorCb === 'function' ? errorCb : function() {};
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};
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/**
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* @sa JsonRpcClient.prototype.call
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*/
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JsonRpcClient._batchObject.prototype.call = function(method, params, successCb, errorCb) {
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this._requests.push({
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request : {
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jsonrpc : '2.0',
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method : method,
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params : params,
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id : this.jsonrpcclient._currentId++ // Use the client's id series.
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},
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successCb : successCb,
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errorCb : errorCb
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});
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};
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/**
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* @sa JsonRpcClient.prototype.notify
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*/
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JsonRpcClient._batchObject.prototype.notify = function(method, params) {
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this._requests.push({
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request : {
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jsonrpc : '2.0',
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method : method,
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params : params
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}
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});
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};
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/**
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* Executes the batched up calls.
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*
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* @return {object} Returns the deferred object that $.ajax returns or {null} for websockets
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*/
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JsonRpcClient._batchObject.prototype._execute = function() {
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var self = this;
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var deferred = null; // Used to store and return the deffered that $.ajax returns
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if (this._requests.length === 0) { return; } // All done :P
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// Collect all request data and sort handlers by request id.
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var batchRequest = [];
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// If we have a WebSocket, just send the requests individually like normal calls.
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var socket = self.jsonrpcclient.options.getSocket(self.jsonrpcclient.wsOnMessage);
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if (socket !== null) {
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// We need to keep track of results for the all done callback
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var expectedNrOfCb = 0;
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var cbResults = [];
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var wrapCb = function(cb) {
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if (!self.allDoneCb) { // No all done callback? no need to keep track
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return cb;
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}
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return function(data) {
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cb(data);
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cbResults.push(data);
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expectedNrOfCb--;
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if (expectedNrOfCb <= 0) {
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// Change order so that it maps to request order
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var i;
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var resultMap = {};
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for (i = 0; i < cbResults.length; i++) {
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resultMap[cbResults[i].id] = cbResults[i];
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}
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var results = [];
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for (i = 0; i < self._requests.length; i++) {
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if (resultMap[self._requests[i].id]) {
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results.push(resultMap[self._requests[i].id]);
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}
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}
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// Call all done!
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self.allDoneCb(results);
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}
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};
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};
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for (var i = 0; i < this._requests.length; i++) {
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var call = this._requests[i];
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|
|
|
if ('id' in call.request) {
|
|
// We expect an answer
|
|
expectedNrOfCb++;
|
|
}
|
|
|
|
self.jsonrpcclient._wsCall(
|
|
socket, call.request, wrapCb(call.successCb), wrapCb(call.errorCb)
|
|
);
|
|
}
|
|
|
|
return null;
|
|
} else {
|
|
// No websocket, let's use ajax
|
|
var handlers = {};
|
|
|
|
for (var i = 0; i < this._requests.length; i++) {
|
|
var call = this._requests[i];
|
|
batchRequest.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] = {
|
|
successCb : call.successCb,
|
|
errorCb : call.errorCb
|
|
};
|
|
}
|
|
}
|
|
|
|
var successCb = function(data) { self._batchCb(data, handlers, self.allDoneCb); };
|
|
|
|
// 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
|
|
deferred = $.ajax({
|
|
url : self.jsonrpcclient.options.ajaxUrl,
|
|
contentType: 'application/json',
|
|
data : this.jsonrpcclient.JSON.stringify(batchRequest),
|
|
dataType : 'json',
|
|
cache : false,
|
|
type : 'POST',
|
|
headers : self.jsonrpcclient.options.headers,
|
|
xhrFields : self.jsonrpcclient.options.xhrFields,
|
|
|
|
// Batch-requests should always return 200
|
|
error : function(jqXHR, textStatus, errorThrown) {
|
|
self.errorCb(jqXHR, textStatus, errorThrown);
|
|
},
|
|
success : successCb
|
|
});
|
|
|
|
return deferred;
|
|
|
|
}
|
|
|
|
};
|
|
|
|
/**
|
|
* 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, allDoneCb) {
|
|
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].errorCb(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].successCb(response.result);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (typeof allDoneCb === 'function') { allDoneCb(result); }
|
|
};
|
|
|
|
$.JsonRpcClient = JsonRpcClient;
|
|
|
|
})(this.jQuery);
|