I use puppeteer-sharp to dump data received and send by page via websockets. The code to dump data in C#:
async Task Dump()
{
var client = await _browser.Page.Target.CreateCDPSessionAsync();
await client.SendAsync("Network.enable");
client.MessageReceived += OnChromeDevProtocolMessage;
}
void OnChromeDevProtocolMessage(object sender, MessageEventArgs eventArgs)
{
if (eventArgs.MessageID == "Network.webSocketCreated")
{
Logger.Trace($"Network.webSocketCreated: {eventArgs.MessageData}");
}
else if (eventArgs.MessageID == "Network.webSocketFrameSent")
{
Logger.Trace($"Network.webSocketFrameSent: {eventArgs.MessageData}");
}
else if (eventArgs.MessageID == "Network.webSocketFrameReceived")
{
var cdpMessage = JsonConvert.DeserializeObject<CdpMessage>(eventArgs.MessageData.ToString());
ProcessMessage(cdpMessage);
}
}
Is there any way to send data to websockets using puppeteer or using directly Chrome Dev Protocol messages?
EDIT:
Or is it possible to get somehow WebSocket instanse (or handle) to use it in JavaScript code to send data using EvaluateFunctionAsync?
QueryObjects can be used in the command line API and also in Puppeteer in order to find the instance. After that you just use EvaluateFunction, to execute send method on object. In PuppeteerSharp it looks something like this:
//CODE SNIPPET
var prototype = await page.EvaluateExpressionHandleAsync("WebSocket.prototype");
var socketInstances = await page.QueryObjectsAsync(prototype);
await page.EvaluateFunctionAsync("(instances) => {let instance = instances[0]; instance.send('Hello')}, new[] {socketInstances}");
More information can be found in the documentation.
in case someone comes to this question looking for an answer in javascript:
const prototype = await page.evaluateHandle("WebSocket.prototype");
const socketInstances = await page.queryObjects(prototype);
await page.evaluate((instances) => {
let instance = instances[0];
instance.send('Hello');
}, socketInstances);
and for ViniCoder in the comments, pyppeteer in python:
prototype = await page.evaluateHandle("WebSocket.prototype")
socketInstances = await page.queryObjects(prototype)
await page.evaluate('''(instances) => {
let instance = instances[0];
instance.send('Hello');
}''', socketInstances)
I'm looking into implementing a "subscription" type using server-sent events as the backing api.
What I'm struggling with is the interface, to be more precise, the http layer of such operation.
The problem:
Using the native EventSource does not support:
Specifying an HTTP method, "GET" is used by default.
Including a payload (The GraphQL query)
While #1 is irrefutable, #2 can be circumvented using query parameters.
Query parameters have a limit of ~2000 chars (can be debated)
which makes relying solely on them feels too fragile.
The solution I'm thinking of is to create a dedicated end-point for each possible event.
For example: A URI for an event representing a completed transaction between parties:
/graphql/transaction-status/$ID
Will translate to this query in the server:
subscription TransactionStatusSubscription {
status(id: $ID) {
ready
}
}
The issues with this approach is:
Creating a handler for each URI-to-GraphQL translation is to be added.
Deploy a new version of the server
Loss of the flexibility offered by GraphQL -> The client should control the query
Keep track of all the end-points in the code base (back-end, front-end, mobile)
There are probably more issues I'm missing.
Is there perhaps a better approach that you can think of?
One the would allow a better approach at providing the request payload using EventSource?
Subscriptions in GraphQL are normally implemented using WebSockets, not SSE. Both Apollo and Relay support using subscriptions-transport-ws client-side to listen for events. Apollo Server includes built-in support for subscriptions using WebSockets. If you're just trying to implement subscriptions, it would be better to utilize one of these existing solutions.
That said, there's a library for utilizing SSE for subscriptions here. It doesn't look like it's maintained anymore, but you can poke around the source code to get some ideas if you're bent on trying to get SSE to work. Looking at the source, it looks like the author got around the limitations you mention above by initializing each subscription with a POST request that returns a subscription id.
As of now you have multiple Packages for GraphQL subscription over SSE.
graphql-sse
Provides both client and server for using GraphQL subscription over SSE. This package has a dedicated handler for subscription.
Here is an example usage with express.
import express from 'express'; // yarn add express
import { createHandler } from 'graphql-sse';
// Create the GraphQL over SSE handler
const handler = createHandler({ schema });
// Create an express app serving all methods on `/graphql/stream`
const app = express();
app.use('/graphql/stream', handler);
app.listen(4000);
console.log('Listening to port 4000');
#graphql-sse/server
Provides a server handler for GraphQL subscription. However, the HTTP handling is up to u depending of the framework you use.
Disclaimer: I am the author of the #graphql-sse packages
Here is an example with express.
import express, { RequestHandler } from "express";
import {
getGraphQLParameters,
processSubscription,
} from "#graphql-sse/server";
import { schema } from "./schema";
const app = express();
app.use(express.json());
app.post(path, async (req, res, next) => {
const request = {
body: req.body,
headers: req.headers,
method: req.method,
query: req.query,
};
const { operationName, query, variables } = getGraphQLParameters(request);
if (!query) {
return next();
}
const result = await processSubscription({
operationName,
query,
variables,
request: req,
schema,
});
if (result.type === RESULT_TYPE.NOT_SUBSCRIPTION) {
return next();
} else if (result.type === RESULT_TYPE.ERROR) {
result.headers.forEach(({ name, value }) => res.setHeader(name, value));
res.status(result.status);
res.json(result.payload);
} else if (result.type === RESULT_TYPE.EVENT_STREAM) {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
Connection: 'keep-alive',
'Cache-Control': 'no-cache',
});
result.subscribe((data) => {
res.write(`data: ${JSON.stringify(data)}\n\n`);
});
req.on('close', () => {
result.unsubscribe();
});
}
});
Clients
The two packages mentioned above have companion clients. Because of the limitation of the EventSource API, both packages implement a custom client that provides options for sending HTTP Headers, payload with post, what the EvenSource API does not support. The graphql-sse comes together with it client while the #graphql-sse/server has companion clients in a separate packages.
graphql-sse client example
import { createClient } from 'graphql-sse';
const client = createClient({
// singleConnection: true, use "single connection mode" instead of the default "distinct connection mode"
url: 'http://localhost:4000/graphql/stream',
});
// query
const result = await new Promise((resolve, reject) => {
let result;
client.subscribe(
{
query: '{ hello }',
},
{
next: (data) => (result = data),
error: reject,
complete: () => resolve(result),
},
);
});
// subscription
const onNext = () => {
/* handle incoming values */
};
let unsubscribe = () => {
/* complete the subscription */
};
await new Promise((resolve, reject) => {
unsubscribe = client.subscribe(
{
query: 'subscription { greetings }',
},
{
next: onNext,
error: reject,
complete: resolve,
},
);
});
;
#graphql-sse/client
A companion of the #graphql-sse/server.
Example
import {
SubscriptionClient,
SubscriptionClientOptions,
} from '#graphql-sse/client';
const subscriptionClient = SubscriptionClient.create({
graphQlSubscriptionUrl: 'http://some.host/graphl/subscriptions'
});
const subscription = subscriptionClient.subscribe(
{
query: 'subscription { greetings }',
}
)
const onNext = () => {
/* handle incoming values */
};
const onError = () => {
/* handle incoming errors */
};
subscription.susbscribe(onNext, onError)
#gaphql-sse/apollo-client
A companion package of the #graph-sse/server package for Apollo Client.
import { split, HttpLink, ApolloClient, InMemoryCache } from '#apollo/client';
import { getMainDefinition } from '#apollo/client/utilities';
import { ServerSentEventsLink } from '#graphql-sse/apollo-client';
const httpLink = new HttpLink({
uri: 'http://localhost:4000/graphql',
});
const sseLink = new ServerSentEventsLink({
graphQlSubscriptionUrl: 'http://localhost:4000/graphql',
});
const splitLink = split(
({ query }) => {
const definition = getMainDefinition(query);
return (
definition.kind === 'OperationDefinition' &&
definition.operation === 'subscription'
);
},
sseLink,
httpLink
);
export const client = new ApolloClient({
link: splitLink,
cache: new InMemoryCache(),
});
If you're using Apollo, they support automatic persisted queries (abbreviated APQ in the docs). If you're not using Apollo, the implementation shouldn't be too bad in any language. I'd recommend following their conventions just so your clients can use Apollo if they want.
The first time any client makes an EventSource request with a hash of the query, it'll fail, then retry the request with the full payload to a regular GraphQL endpoint. If APQ is enabled on the server, subsequent GET requests from all clients with query parameters will execute as planned.
Once you've solved that problem, you just have to make a server-sent events transport for GraphQL (should be easy considering the subscribe function just returns an AsyncIterator)
I'm looking into doing this at my company because some frontend developers like how easy EventSource is to deal with.
There are two things at play here: the SSE connection and the GraphQL endpoint. The endpoint has a spec to follow, so just returning SSE from a subscription request is not done and needs a GET request anyway. So the two have to be separate.
How about letting the client open an SSE channel via /graphql-sse, which creates a channel token. Using this token the client can then request subscriptions and the events will arrive via the chosen channel.
The token could be sent as the first event on the SSE channel, and to pass the token to the query, it can be provided by the client in a cookie, a request header or even an unused query variable.
Alternatively, the server can store the last opened channel in session storage (limiting the client to a single channel).
If no channel is found, the query fails. If the channel closes, the client can open it again, and either pass the token in the query string/cookie/header or let the session storage handle it.
Attaching the code snippet below. UniversalBot and ChatConnector has been deprecated in botbuilder 4.1.5.
var bot;
try {
bot = new BasicBot(conversationState, userState, botConfig);
} catch (err) {
console.error(`[botInitializationError]: ${ err }`);
process.exit();
}
// Create HTTP server
// let server = restify.createServer();
let server = express();
server.listen(process.env.port || process.env.PORT || 3978, function() {
console.log(`\n${ server.name } listening to ${ server.url }`);
console.log(`\nGet Bot Framework Emulator: https://aka.ms/botframework-emulator`);
console.log(`\nTo talk to your bot, open basic-bot.bot file in the Emulator`);
});
// Listen for incoming activities and route them to your bot main dialog.
server.post('/api/messages', (req, res) => {
// Route received a request to adapter for processing
adapter.processActivity(req, res, async (turnContext) => {
// route to bot activity handler.
await bot.onTurn(turnContext);
});
});
Your question is fairly general.
The session object from 3.x has been removed. Instead acccessors are used. You will want to do following in the bot class:
public onTurn = async (turnContext: TurnContext) => {
const userProfile = await this.userProfile.get(turnContext, new UserProfile());
const conversationData = await this.dialogStateAccessor.get(turnContext, { dialogStack: undefined });
// set vars in cache
userProfile.yourUserVarProp = "userValue";
conversationData.yourConversationVarProp = "conversationValue";
// persist userVars through dialog turn
await this.userProfile.set(turnContext, userProfile);
// persist conversationVars through dialog turn
await this.dialogStateAccessor.set(turnContext, conversationData);
//
// -> your dialogs here (await dc.beginDialog("dialogname");)
//
// save uservars to db at end of a turn
await this.userState.saveChanges(turnContext);
// save conversationVars to db at end of a turn
await this.conversationState.saveChanges(turnContext);
}
But there is some additional constructor stuff
#param {ConversationState} conversationState A ConversationState object used to store the dialog state.
#param {UserState} userState A UserState object used to store values specific to the user.
... and creating the userProfile and dialogStateAccessor itself.
For the whole picture have better a look at https://github.com/Microsoft/BotBuilder-Samples/tree/master/samples/javascript_nodejs .
Or try the generator: https://learn.microsoft.com/en-us/azure/bot-service/javascript/bot-builder-javascript-quickstart?view=azure-bot-service-4.0.
I'm trying to set up a server that can dynamically create many rooms for many namespaces. I'm currently just trying to broadcast to sockets of a room, when a new socket has joined that room.
So far I have been able to broadcast to a specific namespace and my event listeners on the client receives the message. However when I try to broadcast to a room, of a specific namespace, my event listener doesn't receive that message.
I've turned on the Debugger mode and see the socket.io-client:socket emitting the event with the right payload and event type. So I am not sure what I am missing since the documentation also seems fairly straightforward. Any help would be much appreciated. Below is my code.
Server
const colorNs = io.of('/color');
colorNs.on('connection', (socket) => {
const { id } = socket.handshake.query;
const { id:connId } = socket.conn;
if(id) {
socket.join(id);
socket.broadcast.to(id).emit('user:connect', { id: connId });
}
socket.on('disconnect', () => {
const { id } = socket.handshake.query;
const { id:connId } = socket.conn;
socket.broadcast.to(id).emit('user:disconnect', { id: connId });
});
});
Client
const socket = io('/color?id="123"');
socket.on('user:connect', () => console.log('data', data));
Client - Debug Trace
socket.io-parser decoded 2/color,["user:connect",{"id":"IZTTPidF121JCzf9AAAO"}] as {"type":2,"nsp":"/color","data":["user:connect",{"id":"IZTTPidF121JCzf9AAAO"}]} +1ms
browser.js:133
socket.io-client:socket emitting event ["user:connect",{"id":"IZTTPidF121JCzf9AAAO"}] +3ms
This is meant to be executed as a script for AJAX request:
app.use(route.post('/ajax_request', function(ctx) {
var p = new Promise(function(res){
res('Some result to be received as AJAX resp');
});
p.then(function (val){
ctx.body = val; //resolved after response is sent
});
}))
So how to send some asynchronously received (in this case wrapped in Promise) data back to client (as an AJAX response in this case)?
If you're using Koa 2, you should be using async functions for your middleware. If you're not familiar with using async/await or any other ES6+ features with Koa 2, I would recommend learning how to use Babel to transpile your code in order to allow the usage of them. If you don't want to have a transpilation step, you should currently just use Koa 1.X.
In Koa 2, the code would look like this:
app.use(route.post('/ajax_request', async (ctx) => {
let p = new Promise(function(res){
res('Some result to be received as AJAX resp');
});
let val = await p;
ctx.body = val;
}));