I tried to use the cometd streaming api with the push topic /systemTopic/Logging to get in lwc all notification when a log is created. I saw that only the api v36 can be used for that so I use the cometd library(upload with a static ressource ) and this code that I found and change fron internet :
sessionId = '';
url = '';
@api channel = 'systemTopic/Logging';
//Override the version of api to use cometd. By default it will use 45.
@api apiVersion = '36.0';
//If true then user can see console logs with data.
@api debug = false;
cometd;
subscription;
@track logsArray = [];
async connectedCallback()
{
let mapping = await initialization();
mapping = JSON.parse(mapping);
this.sessionId = mapping.userSessionId;
this.url = mapping.url;
console.log(this.sessionId)
this.loadCometdScript();
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Loads the cometd static resource.
*/
loadCometdScript(){
if( !this.subscription ){
Promise.all([
loadScript(this, cometdStaticResource + '/cometd.js')
])
.then(() => {
this.loadSessionId();
})
.catch(error => {
let message = error.message || error.body.message;
this.fireErrorEvent(message);
});
}
else{
this.fireErrorEvent('Subscription already exists.');
this.consoleLog('(LWC Streaming API) Error: Subscription already exists.');
}
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Loads the session id and create a connection with cometd.
*/
loadSessionId(){
//Initiating Cometd
this.cometd = new window.org.cometd.CometD();
//Configuring Cometd
this.cometd.configure({
url: this.url + '/cometd/'+this.apiVersion,
requestHeaders: { Authorization: 'Bearer ' + this.sessionId,'Content-Type': 'application/json'},
appendMessageTypeToURL : false
});
this.cometd.websocketEnabled = false;
//Initiating Cometd Handshake
this.cometd.handshake( (status) => {
if (status.successful) {
this.consoleLog('(LWC Streaming API) Handshake Successful on : '+ this.channel );
this.consoleLog('(LWC Streaming API) Handshake Status: '+ JSON.stringify(status) );
//Subscribe to channel
this.subscription = this.cometd.subscribe( this.channel , (message) => {
this.consoleLog('(LWC Streaming API) Message: '+ JSON.stringify(message) );
this.fireMessageEvent(message);
});
}
else{
this.consoleLog('(LWC Streaming API) Error in Handshake: '+ JSON.stringify(status) );
this.fireErrorEvent(status);
}
});
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Fire the error event.
*/
fireErrorEvent(logMsg){
this.dispatchEvent(
new CustomEvent('error', {
detail: {error: logMsg}
})
);
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Fire the Payload/Message event.
*/
fireMessageEvent(payload){
this.dispatchEvent(
new CustomEvent('message', {
detail: {payload: payload}
})
);
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Destroy the connection with channel.
*/
@api
unsubscribe(){
//Unsubscribing Cometd
this.cometd.unsubscribe( this.subscription, {}, (unsubResult) => {
if( unsubResult.successful ) {
this.consoleLog('(LWC Streaming API) unsubscribed successfully.');
//Disconnecting Cometd
this.cometd.disconnect((disResult) => {
if(disResult.successful) {
this.consoleLog('(LWC Streaming API) disconnected.');
}
else{
this.consoleLog('(LWC Streaming API) disconnection unsuccessful.');
}
});
}
else{
this.consoleLog('(LWC Streaming API) unsubscription failed.');
}
});
this.subscription = undefined;
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Reinitialize the connection with channel.
*/
@api
subscribe(){
this.loadCometdScript();
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Return true is connection is not destroyed.
*/
@api
checkConnection(){
if( this.subscription ){
return true;
}
return false;
}
/**
* @author Vishnu Kumar
* @email [email protected]
* @desc Print console logs if debug is turned on.
*/
consoleLog(msg){
if( this.debug ){
console.log(msg);
}
}
but when I launch it I receive : Access to XMLHttpRequest at 'https://customer-energy-6372-dev-ed.scratch.my.salesforce.com/cometd/36.0?jsonp=_cometd_jsonp_0&message=[{%22id%22:%222%22,%22version%22:%221.0%22,%22minimumVersion%22:%221.0%22,%22channel%22:%22/meta/handshake%22,%22supportedConnectionTypes%22:[%22callback-polling%22],%22advice%22:{%22timeout%22:60000,%22interval%22:0}}]' from origin 'https://customer-energy-6372-dev-ed.scratch.lightning.force.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Someone can help me ?
