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- (disabled by VK) or retrieve wall messages.

Features

• Provides access to VK API. Interface options include: VK monad and vkq command line tool.
• Uses HTTPS protocol.
• Solves login form interaction, may be used to operate new/disposable VK accounts.
• VK monad is designed as an interruptable coroutine. The supervisor 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.
• No more dependencies on curlhs/taglib.

ToDo

• Decrypt 'RepeatedForm' errors
• Support storing access-tokens in a temp file
• Still no support for captchas, one probably should hack defaultSupervisor and add them.
• Re-implement VK monad as a Free monad special case
• Runhaskell: handle some standard command line arguments
• Minor issues here and there. Use git grep FIXME to find them
• File uploading still not functioning.
• Network connection timeout is not handled by the coroutine supervisor.
• Enhance the way vkq accepts arguments, support multy-line messages.
• Grammatical mistakes. Any corrections will be kindly accepted.

Installing

Installing from Hackage

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

$ cabal update
$ cabal install VKHS

Installing from source

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

Developing using Nix

The author of this project uses Nix as a main development platform. The default.nix file contain Nix expression describing the environment

Entering Nix shell environment

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

Usual development

$ ghci -isrc:app/vkq:app/common
$ cabal install
$ ^D

Returning to the system shell

$ ^D
$ nix-build
$ ls ./result

Building ctags file

./mktags.sh script may be used to build ctags tags file supported by many text editors. The script uses hasktags via haskdogs tools, available on 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 command --help to read online help.

Logging in to VK

In order to send API requests, the VK client typically needs an access token. vkq receives it as a result of signing in. Once received, the token may be saved to VKQ_ACCESS_TOKEN environment variable, into .vkhs-access-token file or passed to future instances directly using -a argument.

Saving access token in the environment variable

$ vkq login user@mail.org pass123
d8a41221616ef5ba19537125dc0349bad9d529fa15314ad765911726fe98b15185ac41a7ca2c62f3bf4b9
$ export VKQ_ACCESS_TOKEN=d785932b871f096bd73aac6a35d7a7c469dd788d796463a871e5beb5c61bc6c96788ec2

Alternatively, result may be achieved using --eval option

$ eval `vkq login user@mail.org pass123 --eval`

Saving access token to file

VKQ will cache the access token into a file. Newer versions of VKHS have --access-token-flag option enabled by default. Set it to empty value to disable the caching.

Performing API calls

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

$ vkq api --help
Usage: vkq api [--verbose] [--req-per-sec N] [--interactive] [--appid APPID]
               [--user USER] [--pass PASS] [-a ACCESS_TOKEN]
               [--access-token-file FILE] METHOD PARAMS [--pretty]
  Call VK API method

Available options:
  --verbose                Be verbose
  --req-per-sec N          Max number of requests per second
  --interactive            Allow interactive queries
  --appid APPID            Application ID, defaults to VKHS
  --user USER              User name or email
  --pass PASS              User password
  -a ACCESS_TOKEN          Access token. Honores VKQ_ACCESS_TOKEN environment
                           variable
  --access-token-file FILE Filename to store actual access token, should be used
                           to pass its value between sessions
  METHOD                   Method name
  PARAMS                   Method arguments, KEY=VALUE[,KEY2=VALUE2[,,,]]
  --pretty                 Pretty print resulting JSON
  -h,--help                Show this help text

The session may look like the following:

$ vkq api "messages.send" "user_id=111111,message=\"test\""  --pretty
bd7da7e9cfb4cc12c0a49093173ca8785c7d6c918f00edb7315bb8526f5f372f1174b643e50e1a47d35da

$ vkq api "users.get" ""
{"response":[{"first_name":"Сергей","uid":222222,"last_name":"Миронов"}]}

$ vkq api "messages.send" "user_id=333333,message=Hi theree!"
{"response":57505}

$ vkq api "groups.search" "q=Haskell"
{
    "response": [
        30,
        {
            "screen_name": "ml_mat_asm",
            "photo": "https://pp.userapi.com/c638217/v638217626/54113/v5Ib71-dDzo.jpg",
            "is_closed": 0,
            "photo_medium": "https://pp.userapi.com/c638217/v638217626/54112/Nu_si987vOc.jpg",
            "name": "Matlab | Assembler | MathCAD | Haskell | Prolog",
            "photo_big": "https://pp.userapi.com/c638217/v638217626/54111/HGnUbgUorVU.jpg",
            "gid": 78651325,
            "is_admin": 0,
            "is_member": 0,
            "type": "page"
        },
        ...
}

VKHS library/runhaskell mode

Starting from 1.7.2 the library supports runhaskell-mode.

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

import Web.VKHS
import Web.VKHS.Imports

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

The distribuption contains ./app/runhaskell folder with a couple of examples.

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 for details
• VK API documentation

License

BSD3 license

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