I used CocoaPods for some of my projects. It's cool and easy to keep updated with my dependencies/open source frameworks.
But I have some doubts regarding the inner workings of CocoaPods.
In our Podfile we are giving only the the name of pods, sometimes the version also,like
pod "AFNetworking" , "1.3.2"
Then it correctly finds and clones the AFNetworking repo. How this is work? How the ruby gems know the actual repository is in Github. Are pods work with Github only? (Because I saw pods for only frameworks available on Github). If we can use pods for dependencies in other than Github (eg from Bitbuket), how can we add that pod to our Podfile?
CocoaPods does a whole lot behind the scenes to make everything you're talking about work. On a relatively high level the actual 'Pods' are managed in a repo that lives on Github here. This is where 3rd party library vendors submit their 'Pods' to work with CocoaPods. You'll notice that if you search for a Pod using the command line tool with pod search AFNetworking you will see all the available Pods matching your search term.
As far as Github vs other sites goes even though the repository full of CocoaPods specifications lives on Github, CocoaPods itself uses just plain old Git to pull down the source from the given repository. Because of this you could make specs from any git repo hosted on any site. We also support svn, mercurial and just plain old http(s). If you're interested in how the specs work overall you can look at some in the specs repo you can open them from ~/.cocoapods/repos/master on your local machine or edit one directly with pod spec edit AFNetworking from the command line.