Somebody tell me where is cowboy_http_handler in last version of Cowboy server?
You can get the information on github. here is a copy of the comment attached to cowboy_handler.erl:
Improve handler interface and documentation
This change simplifies a little more the sub protocols mechanism. Aliases have been removed. The renaming of loop handlers as long polling handlers has been reverted.
Plain HTTP handlers now simply do their work in the init/2 callback. There is no specific code for them.
Loop handlers now follow the same return value as Websocket, they use ok to continue and shutdown to stop.
Terminate reasons for all handler types have been documented. The terminate callback is now appropriately called in all cases (or should be).
Behaviors for all handler types have been moved in the module that implement them. This means that cowboy_handler replaces the cowboy_http_handler behavior, and similarly cowboy_loop replaces cowboy_loop_handler, cowboy_websocket replaces cowboy_websocket_handler. Finally cowboy_rest now has the start of a behavior in it and will have the full list of optional callbacks defined once Erlang 18.0 gets released.
The guide has been reorganized and should be easier to follow.