liblastfm: Lastfm API interface

[ library, mit, network-apis ] [ Propose Tags ]

Provides interface to Lastfm REST API, supports XML and JSON formats.

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Versions [RSS],,,,,,,,,,,,,,,,,,,,, 0.5.0, 0.5.1, 0.6.0, 0.6.1, 0.7.0 (info)
Change log CHANGELOG.markdown
Dependencies aeson, base (>=4 && <5), bytestring, cereal, containers (>=0.5), cryptonite (>=0.7), http-client (>=0.5), http-client-tls (>=0.2), network-uri, profunctors, semigroups, text, transformers, xml-conduit (>=1.1) [details]
License MIT
Author Matvey Aksenov, Dmitry Malikov
Maintainer Matvey Aksenov <>
Category Network APIs
Source repo head: git clone
this: git clone 0.7.0)
Uploaded by DmitryMalikov at 2018-08-07T19:59:58Z
Reverse Dependencies 1 direct, 0 indirect [details]
Downloads 18902 total (71 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2018-08-07 [all 1 reports]

Readme for liblastfm-0.7.0

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Complete API interface to service. Documentation is available in two flavours:


liblastfm provides Applicative interface for constructing requests. Also, it handles all machinery needed to prepare request for sending:

  • signing

  • url-encoding

  • miscellaneous stuff like choosing correct HTTP method, etc

Once request is ready, liblastfm can send it and get you back a response. Response format might be:


To install either use hackage:

% cabal install liblastfm

Or git:

% git clone
% cd liblastfm
% cabal install


Suppose, you need to use API method. First find it in liblastfm: Tag would be the name of the module and search would be the name of function. Here it is. So import a couple of modules:

>>> import           Lastfm            -- a bunch of useful utilities
>>> import qualified Lastfm.Tag as Tag -- for

Now you may use applicative <*> for required and <* or *> for optional parameters to construct desired request: <*> tag "russian-folk" <* limit 3 <*> apiKey "29effec263316a1f8a97f753caaa83e0" <* json

To send constructed request use lastfm:

>>> con <- newConnection
>>> lastfm con $ <*> tag "russian-folk" <* limit 10 <*> apiKey "29effec263316a1f8a97f753caaa83e0" <* json
Right (Object (fromList [("results",Object (fromList [("tagmatches", ...

Wiki describes how to parse responses.


Q: I'm getting the following error. How do I fix it?

>>> Artist.getInfo <*> artist "Pink Floyd" <*> apiKey "29effec263316a1f8a97f753caaa83e0"

    Couldn't match expected type `Data.Text.Lazy.Internal.Text'
                with actual type `[Char]

A: This means you haven't OverloadedStrings extension enabled. To enable it (either one works):

  • type in :set -XOverloadedStrings while in ghci session.

  • add {-# LANGUAGE OverloadedStrings #-} to the top of the file

  • compile with -XOverloadedStrings switch

Q: I'm getting the following error. How do I fix it?

>>> lastfm (Artist.getInfo <*> artist "Pink Floyd" <*> apiKey "29effec263316a1f8a97f753caaa83e0")

    No instance for (Show (IO (Either LastfmError r0)))
      arising from a use of `print'
    Possible fix:
      add an instance declaration for (Show (IO (Either LastfmError r0)))
    In the first argument of `print', namely `it'
    In a stmt of an interactive GHCi command: print it

A: This error message indicates that GHC cannot infer response format for the Request. To fix it, add use json or xml helpers, depending on your needs

A note on testing

To test Lastfm API compatibility (api test suite)—specifically, authentication requiring examples—you will need to set HASKELL_LIBLASTFM_APIKEY, HASKELL_LIBLASTFM_SESSIONKEY, and HASKELL_LIBLASTFM_SECRET environment variables to your api key, session key, and secret respectively; for example (bash):


Please, consult Lastfm API documentation and example/*-authentication.hs examples if you don't know where to get your credentials.