I don’t feel comfortable using WebSocket with Codename One and Spring Boot. Maybe my “error” was the implementation of one my own communication protocol over websocket, featuring ack and other hard to implements things. My protocol have issues that I wasn’t able to fix... I spent a lot of time creating it, but there are too much complexities for me.
Today I discovered that I tried to reinvent the wheel... since there are protocols over websocket like STUMP:
https://www.toptal.com/java/stomp-spring-boot-websocket
STOMP is a simple text-based messaging protocol that was initially created for scripting languages such as Ruby, Python, and Perl to connect to enterprise message brokers. Thanks to STOMP, clients and brokers developed in different languages can send and receive messages to and from each other. The WebSocket protocol is sometimes called TCP for Web. Analogically, STOMP is called HTTP for Web. It defines a handful of frame types that are mapped onto WebSockets frames, e.g., CONNECT, SUBSCRIBE, UNSUBSCRIBE, ACK, or SEND. On one hand, these commands are very handy to manage communication while, on the other, they allow us to implement solutions with more sophisticated features like message acknowledgment.
Is there any Stomp implementation for Codename One? Or the implementation of any other protocol over websocket? Thank you
I'm afraid not at this time. I also tried looking for implementations in Java but couldn't find any. It would actually be really nice if we had something like that.
I found an implementation for Android but I didn't get the chance to look at the complexity of porting it to Codename One.
Related
So I've created a simple chatserver / chatclient in C. The chatclient reads from stdin and outputs to stdout. The goal is to adapt this to a frontend web UI. I was thinking of using React and it seems like the most commonly used socket libraries are socket.io or Websockets.
So my big question is: can I replace my chatclient I've built in C with a React chatclient that uses socket.io or Websockets to connect to my chatserver in C?
Are the two sockets compatible?
The answer is both "Yes" and "No", but the answer given by justcivah probably should have been "No", since it lacks vital information (edit: the referenced answer was deleted)...
The reason is that WebSockets is a protocol, so your server needs to understand that specific protocol.
The WebSockets protocol usually runs as an additional layer over TCP/IP sockets (which is the only layer you probably have on your C chatserver), and it includes additional ("header") data before the "message" (payload). WebSockets also require an HTTP based handshake (though other possible handshakes might be added in the future).
There are a number of different WebSocket libraries in C that could help you implement the WebSockets protocol in your C chatserver - just search for C WebSocket Framework or something like that.
I am finding some conflicting articles, some are old, about CN1 not having Sockets but I see the library com.codename1.io.Socket. I have seen some articles saying it works on Android as well but not iOS. I need the capability to listen on a socket on iOS and was hoping to use an internal library. The shannah/CN1Sockets project doesn't appear to support listening.
From 2014, https://www.codenameone.com/blog/sockets-multiline-trees.html , and lists non iOS support. Any update on this?
Codova/Phonegap does have a few libraries and someone implements Chrome's TCP/UDP API for it as well.
Server sockets are very problematic across platforms as the iOS implementation is radically different from the Android implementation and a bit challenging to implement using the listen paradigm.
It's probably possible to implement server sockets on iOS but because there wasn't much demand and this required some work we chose not to do it. It's also not very useful ans phones move around/change networks. You won't get a stable IP to work against anyway. A better way would be to initiate communication from the client and then communicate back. Notice you won't be able to use a server socket in a background process in iOS anyway as the process will be killed when sent to background!
The only Cordova implementation I found is this: https://github.com/MobileChromeApps/cordova-plugin-chrome-apps-sockets-tcpServer
You can probably use that with native interfaces or just use it as a baseline for a pull request to implement server sockets on iOS but again it's very unlikely that what you are trying to do with server sockets won't work due to iOS limitations.
But I can't seem to find much about how the NX protocol actually works. I have heard it does something with sending X11 commands. But does this mean that the listening clients need to have an x server to run the actual commands and display them?
Basically, I am trying to figure out if it is possible to write an NX client for a web browser, because it sounds interesting to me. Thoughts?
Yes. NX is essentially compressed X-Window protocol.
It's not a spec, but here is a general introduction to how it works: http://www.nomachine.com/documents/NX-XProtocolCompression.php
The client doesn't need to be an X-server, but it will probably need to be able to handle at least some subset of the X protocol.
If you are going to create an web based NX client, make sure you look at noVNC which is a web based VNC/RFB client. Better yet, fork noVNC and add NX support. That way you don't have to waste time on input, events positioning, networking, etc.
Disclaimer: I am the creator of noVNC. Implementing other remote desktop protocols (NX, RDP, Spice) is on my long term todo list (part of the reason for the name). If you're serious, contact me via github and I can give you some direction/thoughts and put you in touch with somebody else who has also expressed interest.
I need to decode a packet sent using TIBCO-RV and pull fields out of the header and skip over the message body. I have not been able to any examples or documentation. Does anybody know of any open source applications that might do this or if there is a Wireshark dissector out there somewhere?
Maybe you should try applying for a license and getting the official documentation. According to Wikipedia:
TIBCO provides messaging APIs in C,
C++, Java, Visual BASIC , Perl and
.NET to receive data feeds on MS Excel
spreadsheets and other applications of
choice.
Failing that, you could perhaps dive into the TIBCO:RV Perl module.
The methods which TibcoRV implements reliable mutli-cast are propriety, but one would assume easy to reverse engineer. I don't believe any of the official documentation goes into detail on the packet level detail. It's quite easy to get the data out if you have the API.
Several things come to mind:
Is the client on your machine running? This is required in order to create the multicast subscription (unless you are using broadcast mode). Otherwise, you need to have some client subscribe to the multicast channel, or your switch shouldn't forward the traffic.
Generally, you will have a single rrd running locally. You have TCP traffic between the RRD and your app. You can use an app like socketsniff to view the traffic between the two.
I want to get some ideas on how I might control a video camera through an IP address. I have an API to control pan and tilt from a local machine. The code is going to be in C/C++ on Windows. I am still designing if I want multiple cameras controlled from one application or have a one camera to one application. Would SOA be a useful architecture to structure my messaging?
I think you could be well served by something like REST for a task like this. Executing a command towards a REST server is really intuitive and simple, which sounds just like what you need. I'd probably make some kind of application that would be running inside a web-server, since this would handle most of the infrastructure, including authentication if needed. I'm sure both apache and IIS could do this for you quite easily. Even though your API is coded in C you could also consider using some higher-level scripting language as a client to the API (inside the web server).
SOA sounds a little overkill for a task like this.
I did something similar for aproject in my university. What we had was the cameras connected to a LAN and with message passing was very easy to communicate with them, is the same that communicate with any PC. We had the same application to communicate them. You can use SOA or any architecture you consider convinient, that depens on your application.
For our case was just an ad hoc architecture, it was not a complex thing.
Hessian is nice. It is basically REST, but has a binary protocol which is more efficient than XML and it also lets you make calls from other languages quite easily. So, you could develop the client GUI applciation in C# and the server in C. There are free libraries for a few different languages available.
http://hessian.caucho.com/