I try to make a nest.js server, that publishes events, and it doesn't know his subscribers. As far as I concerned, microservices in nest.js works in the same way as websockets. But I've met some problems. Looks like all microservices must know about each other. So I can't make a microservice-server (server_A), that emits events and microservices-clients, that subscribes events of server_A.
Using websockets, it is possible. Is it possible to do it, using microservices?
I tryied to create microservice (server_A) on localhost, then I created a subscriber on localhost also. I made them work on localhost as expected. But when I try to deploy server_A on remote server, I can't connect my microservice-subscriber from localhost, even if I fill correct host and ip.
There is the error: Error: listen EADDRNOTAVAIL: address not available x.x.x.x:port (real ip is masked)
But I think, if I make server_A a websocket server, and then subscribe by another nest.js application, it will work no matter wherefrom will I connect
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I'm a beginner to TCP client-server architecture. I am making a client-server application in C++ I need the server to be able to accept messages from multiple clients at once. I used this IBM example as my starter for the server
server.
The client side is irrelevant but this is my source client.
The problem is with the server side it allows multiple clients to connect but not asynchronously, so the server will connect with the second client after the first one finishes. I want the server to watch for messages from both clients.
I tried to read about select() on the Internet but I couldn't find anything to make the IBM code async. How can I edit the server code to allow the clients to connect and interact at the same time?
I have a process that runs in California that wants to talk to a process in New York, using Stomp over Websockets.
Also note that my process is not a web app, but I implemented a stomp over websocket client in C++, in order to connect things up to my backend. Maybe this was or wasn't a good idea. So, I want my client to talk to the server and subscribe, where their client pushed messages.
I was implementing my own server when I saw that ApacheMQ supported Stomp over Websockets. So, I started reading the docs.
It says with the last line under 'configuration' at
http://activemq.apache.org/websockets :
One thing worth noting is that web sockets (just as Ajax) implements ? > the same origin policy, so you can access only brokers running on the > same host as the web application running the client.
it says it again in several related searches such as http://sensatic.net/activemq/activemq-54-stomp-over-web-sockets.html
Is this a limitation of the server or the web client?
With that limitation, if I understand right, the server is not going to accept websocket connections from a client, of any kind, that is not on the same machine?
I am not sure I see the point of that...
If that is indeed its meaning, then how do I get around it in order to implement my scenario?
I've not found that bit of documentation you are referring to but from what I know of the STOMP implementation on the broker this seems incorrect. There shouldn't be any limit to the transport connector accepting connect requests from an outside host by default and I don't think the browser treats the websocket requests the same as it does other things like an Ajax case in terms of the same origin policy.
This probably a case that is best checked by actually trying it to see if it works, I've connected just fine from outside the same host using AMQP over websockets on ActiveMQ so I'd guess the STOMP stack should also work fine.
I was experimenting hashicorp/yamux over gorilla/websocket, and got stuck.
I started with vanilla WebSocket using the echo example from Gorilla WebSocket project. It was very a straight forward client-server setup. Then image that the server is now behind a firewall, thus the client cannot make a direct connection to it. So I introduced a hub and an agent. The hub is supposed to be publicly visible and connectable for the client. The agent would run alongside the server, who would first make a WebSocket connection to the hub and then multiplex the connection using Yamux so that the hub can then initiate requests to the server. In this way, I effectively "exposed" the server beyond the firewall.
For normal HTTP endpoints, things are good. The client can make requests to the hub, who would proxy these requests to the agent using the WebSocket connection initiated by the hub, and then the hub would further proxy these requests to the server.
However, this trick failed to work with WebSocket endpoints. For the echo example, the client can access the HTML on / through the hub-agent-server chain, but would fail on the /echo path, which is a WebSocket endpoint.
My question is, is this WebSocker over Yamux over WebSocket fundamentally impossible, or do I just need some extra lines to get things work? Here's the code I've been experimenting with. Really appreciate your helps!
[This post has been updated with a possible approach, which is added to the bottom]
I am trying to create a web socket connection between two devices((A). chrome in different computer and (B) a raspberry pi) in different networks. Thus, i can send video data over websockets. However, I cannot port forward the network of my router to expose my local IP to the network, thus, I can't send the data right away.
Figure below explains the architechture.
Thus ,I am trying to implement a logic so that Device A websockets the public ws of the cloud while, the cloud actually gets the data from Device B.So Device A websockets device B indirectly.
Device A<==>Cloud Server<==>Device B
The cloud could be something like a proxy or a relay websocket server.
The video feed needs to be sent in real time,
Please suggest how can i proceed with it.
Additional note, i have acquired an instance of digitalocean as VPS, following the blog Accessing home services from anywhere, without port forwarding! but not sure how to proceed.
Update(11th Nov,2019):
I am planning to use a websocket server on DigitalOcean instance(droplet),which would be listening to my local IP/port of my raspberry pi.And this VPS would act as a websocket server,which would redirect the traffic.
However, I am unsure how to use the same.And need your kind suggestions.
As illustrated above, I need to build a Vert.x Java app that will be an HTTP server/virtual host (TLS Http traffic, Web socket traffic) that will redirect/channel specific domain traffic to other Vert.x Java apps running on the same server, each in it's own JVM.
I have been reading for days but I remain uncertain as to how to approach all aspects of the task.
What I DO know or have experience with:
Creating an HTTP server, etc
Using a Vert.x VirtualHost handler to "handle" incoming traffic for a
specific domain
What I DO NOT know:
How do I "re-direct" a domain's traffic to another Vert.x app (this
other Vert.x app would also be running on the same server, in its own
JVM).
- Naturally this "other" Vert.x app would need to respond to HTTP
requests, etc. What Vert.x mechanisms do I employ to accomplish this
aspect of the task?
Are any of the following concepts part of the solution? I'm unfamiliar with these concepts and how they may or may not form part of the solution.:
Running each Vert.x app using -cluster option?
Vert.x Streams?
Vert.x Pumps?
There are multiple ways to let your microservices communicate with each other, the fact that all your apps are running on the same server doesn't change much, but it makes number 2.) easy to configure
1.) Rest based client - server communication
Both host and apps have a webserver
When you handle the incoming requests on the host, you simply call another app with a HttpClient
Typically all services find each others address via service discovery.
Eg: each service registers his address in a central registry then other services use this central registry to find the addresses.
Note: this maybe an overkill for you and you can just configure the addresses of the other services.
2.) You start the vertx microservices in clustered mode
the eventbus is then shared among the services
For all incoming requests you send a broadcast on the eventbus
the responsible app replies to the message
For further reading you can checkout https://vertx.io/docs/vertx-hazelcast/java/#configcluster. You start your projects with -cluster option and define the clustering in an xml configuration. I think by default it finds the services via local broadcast.
3.) You use a message broker like RabbitMq etc.
All your apps connect to a central message broker
When a new request comes in to the host, it sends a message to the message broker
The responible app then listens to the relevant messages and replies
The host receives the reply from the message broker
There are already many existing vertx clients for certain message brokers like kafka, camel, zeromq:
https://github.com/vert-x3/vertx-awesome#integration