event-magic
Brief
What is it?
- library for linux. Probably not hard to port to other POSIX-like platforms.
- links againt libevent and SSL
- tab indented
- event-oriented
What's in it?
- SSL-connection-stuff you might not be using
- a MQTT-client-implementation you might not like
- a websocket-client-implementation you might not need
- base64
If you think that's great.. Great! If you think there's something wrong with it - tell me! Any questions? Just ask! -----> Feel free to steal my code <----- You can then still add my name in the source if you're nice - or not (go figure out which part of the previous sentence that refers to).
Dependencies
This will not work without an SSL-library or libevent. Not tested with the latest release of libevent. It should work with 2.1.5beta, though. I test with the latest git. Because i like being reckless.
Why bother?
Have you ever had a look at the HTTPS-client sample from libevent? I had - and i thought 'Isn't the example supposed to convince me it's going to be easy? There must a way to build a framework that allows to write this in just a few lines!'.
Turns out i haven't found a way to do just that. And my client doesn't seem to work in the same cases as the libevent-example. But at least it's a lot shorter and most of the code is about parsing user-input and less about actual logic for dealing with HTTP over SSL.
Have you tried using MQTT through libevent? Or websockets? Chances are that: No, you haven't and your fine. The blocking way of life is valid too. Just ignore this then.
The usual stuff
Hi, i like food. And women. And men too - generally speaking. I like them all. Only in different ways.
This is a personal project. If you want to add something or recommend a change drop a message or open a pull request.
Ohh.. And: The lists of downsides here might not be complete. Please tell me if you think they are.
SSL
Sadly, SSL isn't that well integrated into bufferevents. For instance, reconnecting the same bufferevent after disconnect probably wont work (at least they didn't the last time i checked). Maybe that will change but right now it's hard to use. I've seen me and my colleagues writing the same code over and over.
If you feel a similar way and really hope to see all your problems solved - make sure i don't get your hopes up and then disappoint you:
Downsides
- has global state (meaning you'll have to call
lew_ssl_lib_initandlew_ssl_lib_cleanup) - only wraps SSL and libevent calls; meaning that much of the ugliness will only be hidden
Essence
So what does it give you? The design is based around the idea to have a SSL-factory:
Initialise the factory with hostname and port.
You can give it a callback in which you can give the SSL_ctx special treatments.
After you have configured the factory you can call lew_ssl_connect(factory) and get a bufferevent.
Take it - it's yours. Call it again to have another. You are responsible for cleaning them up and they no longer need the factory.
Also, you can choose NOT to use SSL - that way you can use the same interface for having both.
MQTT
Looking for a MQTT-client-implementation running on libevent?
Try this - if you dare:
LD_LIBRARY_PATH=libout/ examplesout/mqtt_sub -t '/#' -t '+' -s test.mosquitto.org -p 1883 -a mosquitto.org.crt -r -v -l
Why this?
The most advanced MQTT-library i know is libmosquitto and it's fine for the most part. I haven't really looked for many others. But i've really had trouble making mosquitto work with libevent :-( It works - don't get me wrong - and i haven't really tried using it without libevent, so i won't claim it's bad. My experience with it just wasn't that magical :-( Ohh, it's so sad :*
Downsides
- Its author can't really think of any downsides. That's probably a bad thing.
- Or it means, he is tired.
Websockets
You know? It's getting late and i still want to write some code.