VKHS

VKHS provides access to Vkontakte 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.
• Connection uses HTTPS protocol
• Automatic login form solving, may be used to operate on new/disposable accounts.
• The VK monad is designed as an interruptable coroutine. Default superwiser supports ondemand re-login and may be used for long-running tasks.
• Project includes a set of simplified API wrappers which are designed to be copied into runhaskell script and tweaked according to user needs.

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

We use Nix as a main development platform. In order to open development environment, do the following:

$ git clone https://github.com/grwlf/vkhs
$ cd vkhs
$ nix-shell
$ ...
$ ghci -isrc:app/vkq:app/common
$ cabal build

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.

Log in to VK

Here is an example session: Login first

$ vkq login user@mail.org pass123
d8a41221616ef5ba19537125dc0349bad9d529fa15314ad765911726fe98b15185ac41a7ca2c62f3bf4b9

VKQ returns three values. First is a access token which is required to execute future API requests. VKQ reads it from VKQ_ACCESS_TOKEN environment variable so we have to set it up

$ 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

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 there are initial support for 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 should ask for login and password and output list of countries known to VK. Consider reviewing Web.VKHS.API.Simple where getCountries and several other methods are defined. Also, check the source code of the vkq application for more elaborated usage example.

Debugging

RepatedForm message means that VKHS tries to fill the web form with available data, but the form appears again. Typically, that means that the password wa invalid or captcha is required.

References

• Implicit-flow authentication, see documentation in Russian for details
• VK API documentation

License

BSD3 license

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