I've just started learning Mosquitto recently. I need to create a custom event handler (on client connect and on message received) that will be built in Mosquitto and run on server as a bundle. The idea is not in using separate program (client) subscribed to some topics (as it works in most use-cases) but make Mosquitto handle data.
My idea is:
Some imagine client do a pub to Mosquitto in some topic.
Mosquitto do its magic (default behavior) and also runs a callback (so the data handled the way I describe it in CB)
I've read Mosquitto API docs but can hardly understand how to use it.
Questions are:
Is that possible to create such plugin using Mosquitto/API?
Do you have a repository with an example of creating callbacks? Seen mysql example and auth-plug example but none worked for me - still no luck in building custom plugin.
Or maybe someone can describe the process of creating plugins / extending mosquitto?
Any instructions on building plugins and injecting them into Mosquitto?
If you know rust, this might be useful, I just wrote it. Just because I did not want to figure out how to do stuff in C.
https://crates.io/crates/mosquitto-plugin
There is an example showing how to use it.
Regarding your callback to do something with the data,I havent tried it, but I believe that you could use ACL rule check to do something with the data, even spawning a thread do do something asynchronous
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I would like to stop and start ALTactileGesture service through ServiceManager during my app. I'm using Choregraphe and python boxes. I have tried different options to initiate ServiceManager but none of them works. Is there any way of doing this?
Edit:
I have already tried self.sm = session.service('ServiceManager') but did not work.
The idea is to stop ALTactileGesture as soon as the app has started:
(1) ServiceManager.stopService('ALTactileGesture') (see this)
and start/restart ALTactileGesture before the application ends:
(2) ServiceManager.startService('ALTactileGesture')
My question is how to reach ServiceManager so I can then use (1) and (2)?
You have to understand that the word "service" actually means two different things in NAOqi. See an explanation here:
NAOqi services (also called "modules"), that expose an API and are
registered to the ServiceDirectory. You can call them with qicli,
subscribe to their signals, etc.
systemd services, that are standalone executables packaged in an
Application Package, declared in it's manifest with a tag.
These are managed by ALServiceManager, who can start and stop them
(they will have their own process). For clarity's sake, these are
called "Executables" in this doc.
The confusion between the two is increased by the fact that a common
pattern is to write an executable whose sole purpose is to run a NAOqi
service, and sometimes to identify both with the same name (e.g. both
are called “ALFuchsiaBallTracker”).
Your problem here is that the NAOqi service ALTactileGesture is run by the executable registered under the ID ALTactileGesture-serv. So you need to do
ALServiceManager.stop("ALTactileGesture-serv")
(I just tested it, it works fine)
(edit) by the way, I'm not sure that actually stopping and starting ALTactileGesture is the best way of doing what you're trying to do (it seems a bit hacky to me), but if you want to do it that way, this is how :)
Just try this in robot shell (old style proxy connection):
$ python
import naoqi
s = naoqi.ALProxy("ALServiceManager", "localhost", 9559 )
s.stopService('ALTactileGesture')
>>> False
s.startService('ALTactileGesture')
>>> False # (a bit weird, but ...)
So I think it's not completely working, but at least you can connect to the ServiceManager as requested...
I'm looking for the simplest possible (cross-platform, but not necessarily cross-browser) code to send data from a local web page to a C (not C++) application running locally. Basically, I have an HTML page with a form and I want to send the data from that form to another process in the simplest way possible. (I know that I can read local data from a webpage relatively easily, especially now with HTML5, but writing outside of the javascript sandbox is a mystery.)
I know that browsers make this very hard to do for security concerns, and I don't want to open up my machine to attacks, but maybe I can run a very simple server inside the C application to receive the submitted data... Either way, I cannot run any standard webserver, so I need to have a C library/app that does it for me.
I've looked into .hta files (seem to only work for Windows) and some C web servers (all I've found are *nix specific). A similar question is how to transfer of data from webpage to a server c program , except that user allows the use of Java and other webserver platforms (I must use C).
UPDATE: Promising libraries: https://stackoverflow.com/questions/175507/c-c-web-server-library
Have you considered FastCGI? I have a fast CGI library written in C that might be helpful. It still needs a lot of work and I'm not sure if I would want to use in a production environment.
If you find any bugs or make any enhancements, please share them so that it can help others.
https://github.com/manvscode/shrewd-cgi
You could write a very simple web server in C, serve the page from it (avoids security issues), and post the form to it.
If you're bound to c, you'll have to go low-level and deal with all the nifty details around the sockets library. (There's a reason why people abstract that in high-level languages). Check out some example code for RPC in C with server and client here. If you can afford to bind to C, e.g. using Tcl, i would implement the server in a tcl script and bind your C functions as a Tcl command. That way you pass the content directly to your c method while avoiding to write all the sockets code low-level.
Send the desired data from web to specific port of your system (for example port X). Then run your application (e.g. APP) in background using following command:
nc -l X | ./APP
And of course you need nc package.
We have an existing C library (DLL / .so) that processes some data. There's a call to initialise it, then a call to give it the parameters it needs to process, and then a few calls to retrieve the different output parameters you are interested in. The initialise is then called to reset the library for the next session. We have an app built around this to easily input the data and view the results.
Now we want to take this library and make it available as a web service. We are looking for the simplest (read quickest) way to do this. As I see it, we need:
A web services framework (Apache Axis2/C looks good for existing C code)
Some way to start a process for each incoming query (not sure if Axis2 can do something like this).
So my question is : Is Axis2/C the simplest way, or is there another simple solution?
If you have an external executable you can call, how about using something like Apache with FastCGI?
I want to create an application in C that allows two users to share a file. I'll call the person sending the file the server and the receiver the client. There are a few requirements:
The users need no identification, no "login". You could say they are unknown for my application.
The server selects a file for transfer and gets returned a simple ~10 character ID string/hash that the client can use to retrieve the file.
The same application is used for both serving and receiving.
My application must not need dedicated software running on a remote server, unless it's freely available (e.g. bittorrent trackers).
Now this sounds a lot like bittorrent and I am seriously thinking of doing this through bittorrent. I'm not sure how I would do this. Are there any good libraries for torrent creation / seeding / downloading?
Please answer this question by either:
Posing a viable alternative for bittorrent / other ideas.
Posting good libraries / snippets / implementations of the bittorrent protocol in C.
This does indeed sound like something best done with BitTorrent. Have you had a look at libbt? It's not very well documented but does include a sample client, which is btget.c in /src/.
I have now found this library: rasterbar libtorrent. It's in C++ but I don't mind (I don't know either that well anyway).
Sharing here for future reference if other people are looking for the same thing as me.
And an other solution, send the file through an IRC server (like Freenode). I came up with this solution after I had trouble with opening ports with bittorrent.
I am using the syndicated client experience (SCE) SDK. Has anyone had success with creating custom datafeeds for this? I want to be able to host the masterfeed and other feeds at a URL instead of compiling as embedded resources like the example. For instance, the client application would gather its feeds from http://somesite/masterfeed.xml.
I believe this can be done, but I keep getting an AccessViolation exception during the debugging of the SCE client.
The application just happened to be writing to a bad memory space.