ocaml-twitterstream's Introduction

Twitter streaming for OCaml

An interface to the Twitter streaming API for OCaml. The main interface is through an LWT stream and can thus be used in conjuction with other LWT code.

(**
 Convert a channel of bytes (eg. raw stream output) to a
 {!Lwt_stream.t} of stautses
 *)
val stream_of_channel : 
  Lwt_io.input Lwt_io.channel -> 
  Twitterstream_message.t Lwt_stream.t
 
(**
 Open a new stream
 @param reconnect_policy the reconnection policy
 @param auth a tuple of
 @param stream the stream to connect to.
 @return producer thread and a {!Lwt_stream.t} of statuses
 *)
val open_stream :
  ?reconnect_policy:reconnect_policy ->
  string * string -> 
  [ `Custom of string | `Firehose | `Sample ] -> 
  unit Lwt.t * Twitterstream_message.t Lwt_stream.t

The first form - stream_of_channel - yields an LWT stream from an arbitrary LWT channel (eg. a streaming dump on disk). The second form establishes a new HTTP stream using Cohttp.

Example stream counter.

open Lwt

let setup_logging () =
  let open Lwt_log in
  default := channel
    ~close_mode:`Keep
    ~channel:Lwt_io.stderr
    ();
  Section.set_level Section.main Debug

let () =
  setup_logging ();
 
  let t, stream =
    Twitterstream_stream.open_stream
      ~max_tries:2 ("username", "password") `Firehose in
 
  let count = ref 0 in
 
  let tt = for_lwt status in stream do
    let open Twitterstream_message in
    let orig, message = status in 
    match message with
      | Status status ->
          let user = status#user in
          Lwt_log.info_f "%s(%d): %s"
            user#screen_name user#followers_count
            status#text
      | Delete _ -> return ()
      | Parsefail -> Lwt_log.info_f "failed to parse %s" orig 
  done in
   
  Lwt_main.run (Lwt.join [t; tt])

There is also an example included (fetch.ml).

ocaml-twitterstream's People