Actually I'm using node.js and socket.io to establish a socket connection. For some reasons I need to replace the server part with an ASP.NET application. Therefore I have to replace the existing socket.IO-server with a suitable .NET pendant.
From my understanding socket.IO as well as SignalR use websockets. So can I replace the socket.io-server with a signalR-server without or with even minimal changes in the clients?
Actually I tried to setup a SignalR-Server using the following example http://www.asp.net/signalr/overview/guide-to-the-api/hubs-api-guide-server
I'm able to connect to the hub when I use the sample code mentioned there.
But I'm not able to connect to this server using socket.IO or websockets in nodeJS. Maybe because of the magic with the hubs.
So is there any solution for an easy to use .NET package, hosted in IIS, that allows secured websocket-connections or secure tcp-socket connections between clients and my server. This solution should be quite standard so I can use Java or Node or anything else on client side?
Related
So I'm starting with the simple Greeter service from the VS2022 sample project template "ASP.NET Core gRPC Service", targeting .NET7, running on Windows. Name this side "A".
I was able to write a second console app (also .NET7) that connects as a gRPC client to that service, invoke the SayHello() rpc successfully and retrieve the expected response message. Name this side "B". So far, so good.
My scenario, however, is a bit different: I want the client B to connect to the server A and authenticate with the server (which is not part of the sample so far but I assume this will work fine as well). Then, the server A shall start acting as a gRPC client and the console-app-client B shall act as a gRPC server, i.e. I want them to switch roles (or establish another role if you like). The challenge is that I want the two parties to re-use the same TCP HTTP/2 connection that has already been established. So I'm looking for a way to create new instances of gRPC client/servers at runtime and provide them with the existing TCP connection. The reason why I need to do it this way are limitations coming from network security (the initial connection can only come B to A). I'm aware that by using streams I can make my server A send messages to B, but I'd prefer to have the full client/server support.
I saw a few discussions around the same question but the presented approaches are using GO as a language and it's hard for me to understand whether and how I can do the same in .NET7.
Possible? Thanks!
Recently I talked with some developers, and they said that they call one endpoint from their front-end (web app) and that endpoint is a web socket. All their REST calls go through this connection. This solution was in Java. So I started wondering how they do that. How they dispatch the endpoint, what is the payload, etc. but in Asp.NET Core.
I am wondering is it possible and how.
I see this is very interesting topic. I found this useful- https://developer.okta.com/blog/2019/11/21/csharp-websockets-tutorial
You can do this in dotnet core using SignalR: https://learn.microsoft.com/en-us/aspnet/core/signalr/introduction?view=aspnetcore-5.0
I think you're mixing two different technologies.
A REST endpoint belongs to WebServices and is an url, pointing to one or more methods in your code that can accept parameters and return results in XML/JSON format.
You can then fetch this url from your front-end and read the response.
An example of REST webservice is Google Maps API.
A Websocket, instead, is a continuous connection and works as a plain socket but between a webpage running on a client and another server application on another machine (i.e. the server).
It's used when you need an open tunnel with continuous exchange of data: chats, video and audio streaming, multiplayer games and more.
You cannot make a REST call to a websocket endpoint and if you want to use websockets you must write a server in C# (i use .net core). A console application.
I'm unsure what you are looking for exactly. If you want to start with websockets, this is where i started from:
Writing websocket server
Writing a websocket server in C#
For webservices:
Writing a web service in ASP.NET
So there are some libraries on github that try to implement the web-socket protocol using C#.
But then we have the mature signalr built by Microsoft and support Web socket protocol.
Is there a way to configure signalr as a pure web-socket server, so that a client can directly connect using ws://localhost/chat for example.
thank you.
No, you can't use websockets directly with SignalR at the moment. SignalR uses a protocol that needs to be followed or you won't be able to connect to the server at all.
EDIT
SignalR for Asp.NET Core allows connecting to the server using bare websockets. This post shows how to do this.
I'm looking for an open source, cross-platform, actively maintained .NET library which provides websocket functionality for both clients and servers, in such a way that most of the code (after connection is established) can use the same abstraction regardless of which side of the connection it is on. Ideally, it would be a platform-independent implementation of System.Net.WebSockets, but I don't really care if it defines its own types, so long as there's some single abstract WebSocket class that can be shared by client and server code.
Things that I've looked at and that did not qualify (but correct me if I'm wrong):
System.Net.WebSockets (client only, Win8+ only)
WebSocket4Net (client only)
WebSocket Portable (client only)
Fleck (server only)
WebSocketListener (server only)
SuperWebSocket (server only)
Owin.WebSocket (server only)
PowerWebSockets (proprietary)
XSockets (proprietary)
Alchemy Websockets (last release in 2012, many active bugs in the tracker with no answers)
The only one that I could find that seems to be matching the requirements is websocket-sharp. However, what worries me there is the sheer number of opened issues in the tracker along the lines of clients unable to connect, invalid data frames etc - it sounds like it's not very mature yet.
Are there any other candidates that match my requirements that I have missed? Or am I wrong about any of the libraries listed above being client/server only?
Look at Microsoft's SignalR. SignalR is a higher level abstraction around websockets. SignalR also allows the client to be written in .NET (C#). From the SignalR documentation:
The SignalR Hubs API enables you to make remote procedure calls (RPCs) from a server to connected clients and from clients to the server. In server code, you define methods that can be called by clients, and you call methods that run on the client. In client code, you define methods that can be called from the server, and you call methods that run on the server. SignalR takes care of all of the client-to-server plumbing for you.
SignalR also offers a lower-level API called Persistent Connections. For an introduction to SignalR, Hubs, and Persistent Connections, or for a tutorial that shows how to build a complete SignalR application, see SignalR - Getting Started.
One another solution is to make use of Edge.js. This is a .NET library that utilizes Node.js. You could let Node.js to act as both the server and client of the WebSocket channel. And then utilize Edge.js to act as the bridge between the worlds, Nodejs and the .Net. Have a look at the following, there are plenty of samples as well. github.com/tjanczuk/edge/tree/master#scripting-clr-from-nodejs. Both are excellent frameworks that are actively maintained.
However the use of Edge.js does introduce an additional dependency, node.js
You can take a look at the WebSocketRPC. The library is based on the System.Net.WebSockets and it is portable. Moreover, it auto-generates JavaScript client code and has support for ASP.NET Core.
I suggest you try-out samples first located inside the GitHub repository.
Disclaimer: I am the author of the library.
Here's the question, I need to connect to a remote MySQL database from my C# Application, problem is the MySQL instance will block all access to all IP's apart from localhost, this can not be changed as its too much of a security issue.
The question is, is it possible to connect via a tunnel instead to a php script hosted on the server, this would then act as the mysql connection.
Any ideas and suggestions?
SQLYog (a mysql management GUI utility) already has this php tunnel script with its own custom API, so if you consider writing it yourself, would be nice to have cross-support. See Is there any good universal PHP MySQL HTTP tunnel?
yes, just create a simple PHP script that will give you the desired output and use http request from the c# application to that php script to get the data - basically, you'll be building a very simple REST API (with authentication)
p.s. I don't see how that would be more secure than SSH tunnelling
I ended up with going for an SSH port tunnel and achieving what I needed to do that way.