VKHS
====

VKHS provides access to [Vkontakte](http://vk.com) social network, popular
mainly in Russia.  Library can be used to login into the network as a standalone
application (OAuth implicit flow as they call it). Having the access token, it
is possible to call various API methods to query audio files or retrieve wall
messages. For now, vkhs offers limited error detection and no captcha support.

Features
========

* Provide access to VK API. Interface options include: VK monad and `vkq` command
  line tool.
* Use HTTPS protocol.
* Solve login form interaction, may be used to operate new/disposable VK accounts.
* VK monad is an interruptable coroutine. The superwiser supports ondemand
  re-login, and may be used for long-running tasks.
* Project includes a set of `Web.VKHS.API.Simple` wrappers designed to be
  copied into `runhaskell` scripts and tweaked according to ones need.

Issues
======

* Still no support for captchas, one probably should hack `defaultSuperwiser`
  and add them
* Network connection timeout is not handled by superwiser
* Minor issues here and there. Use `git grep FIXME` to find them
* File uploading still not functioning

Installing
==========

Installing from Hackage
-----------------------

In order to install VKHS, one typically should do the following

    $ cabal update
    $ cabal install VKHS

Note, that VKHS uses curlhs and should be linked with libcurl.so. Normally,
cabal handles it without problems.


Installing from source
----------------------

    $ git clone https://github.com/grwlf/vkhs
    $ cd vkhs
    $ cabal install

Developing using Nix
--------------------

The author of this project uses [Nix](http://nixos.org) as a main development
platform. Typical development procedure includes the following steps:

    $ git clone https://github.com/grwlf/vkhs
    $ cd vkhs
    $
    $ nix-shell

      .. Entering Nix shell environment

    $ ghci -isrc:app/vkq:app/common
    $ exit

      ..  Now exiting from the Nix shell

    $ nix-build

The `default.nix` file contain Nix expression describing the environment

Building ctags file
-------------------

`./mktags.sh` script may be used to build ctags file. It used `haskdogs` tool,
which should be installed from Hackage.

    $ haskdogs



VKQ command line application
============================

`vkq` is a command line tool which demonstrates API usage. It can be used for
logging in, downloading music and reading wall messages. Call `vkq --help` or
`vkq --help [command]` to read online help.


Log in to VK
------------

Here is an example session: Login first

    $ vkq login user@mail.org pass123
    d8a41221616ef5ba19537125dc0349bad9d529fa15314ad765911726fe98b15185ac41a7ca2c62f3bf4b9

VKQ returns three values. First one is an access token required to execute all
API requests. `vkq` tries to reads it from `VKQ_ACCESS_TOKEN` environment variable or
from `.vkhs-access-token` file (may be changed using options).

    $ export VKQ_ACCESS_TOKEN=d785932b871f096bd73aac6a35d7a7c469dd788d796463a871e5beb5c61bc6c96788ec2

VKQ may cache the access tokein into a state file:

    $ vkq login --access-token-file=.access-token

    .. VKQ will ask for email/password and cache the access token

    $ vkq call groups.search q=Beatles --pretty --access-token-file=.access-token

Latest versions of the library have `--access-token-flag` option enabled by
default. Set it to empty value to disable the caching feature.


Performing custom API calls
---------------------------

vkq allows user to call arbitrary API method. The format is as follows:

    Usage: vkq call [--verbose] [--req-per-sec N] [--interactive] [--appid APPID]
                    [--user USER] [--pass PASS] [-a ACCESS_TOKEN] METHOD PARAMS


For example, lets call ausio.search method to get some Beatles records:

    $ vkq call group.search q=Beatles --pretty

      { "response": [
        614751,
        {
            "lyrics_id": "6604412",
            "url": "http://cs1-36v4.vk-cdn.net/p16/59674dd8717db2.mp3?extra=k0s2ja3l6pq6aIDOEW5y5XUCs2--JLX9wZpzOT3iuSnZPR-DNhJSF075NUhICB_szMOKKlVJFFlqLlg691q6cKhwiGZgTRU1oAimXzXY396cfNAHnotc8--7w-0xnvoPK6qVoI8",
            "aid": 85031440,
            "title": "Twist and Shout  ",
            "genre": 1,
            "owner_id": 9559206,
            "duration": 156,
            "artist": "The Beatles"
        },
    ...


VKHS library/runhaskell mode
============================

Starting from 1.7.2 the library supports RunHaskell-mode. Consider the
following example:


    #!/usr/bin/env runhaskell
    {-# LANGUAGE RecordWildCards #-}

    import Prelude ()
    import Web.VKHS
    import Web.VKHS.Imports

    main :: IO ()
    main = runVK_ defaultOptions $ do
      Sized cnt cs <- getCountries
      forM_ cs $ \Country{..} -> do
        liftIO $ putStrLn co_title

When executed, the program asks for login/password and outputs list of countries
known to VK.  `getCountries` and several other methods are defined in
`Web.VKHS.API.Simple`. `vkq` application may be used as a more elaborated
example.

Debugging
=========

Verbosity may be increased using `--verbose` flag or `o_verbose` field of
`GenericOptions`. Login automata saves `latest.html` file during operation.

References
==========
* Implicit-flow authentication, see
  [documentation in Russian](http://vk.com/developers.php?oid=-1&p=Авторизация_клиентских_приложений)
  for details
* [VK API documentation](https://vk.com/dev/methods)

License
=======

BSD3 license

Copyright (c) 2014, Sergey Mironov <grrwlf@gmail.com>