Network.MPD

An MPD client library. MPD is a daemon for playing music that is controlled over a network socket.

To use the library, do:

import qualified Network.MPD as MPD

Basic data types

class (Monad m, MonadError MPDError m) => MonadMPD m

A typeclass to allow for multiple implementations of a connection to an MPD server.

Minimal complete definition

open, close, send, getPassword, setPassword, getVersion

Instances

MonadMPD MPD

data MPD a

The main implementation of an MPD client. It actually connects to a server and interacts with it.

To use the error throwing/catching capabilities:

import Control.Monad.Error (throwError, catchError)

To run IO actions within the MPD monad:

import Control.Monad.Trans (liftIO)

Instances

Monad MPD

Functor MPD

Applicative MPD

MonadIO MPD

MonadMPD MPD

MonadError MPDError MPD

data MPDError

The MPDError type is used to signal errors, both from the MPD and otherwise.

Constructors

NoMPD

MPD not responding

ConnectionError IOException

An error occurred while talking to MPD.

Unexpected String

MPD returned an unexpected response. This is a bug, either in the library or in MPD itself.

Custom String

Used for misc. errors

ACK ACKType String

ACK type and a message from the server

Instances

Eq MPDError

Show MPDError

Exception MPDError

Error MPDError

Typeable * MPDError

MonadError MPDError MPD

data ACKType

Represents various MPD errors (aka. ACKs).

Constructors

InvalidArgument

Invalid argument passed (ACK 2)

InvalidPassword

Invalid password supplied (ACK 3)

Auth

Authentication required (ACK 4)

UnknownCommand

Unknown command (ACK 5)

FileNotFound

File or directory not found ACK 50)

PlaylistMax

Playlist at maximum size (ACK 51)

System

A system error (ACK 52)

PlaylistLoad

Playlist loading failed (ACK 53)

Busy

Update already running (ACK 54)

NotPlaying

An operation requiring playback got interrupted (ACK 55)

FileExists

File already exists (ACK 56)

UnknownACK

An unknown ACK (aka. bug)

Instances

Eq ACKType

type Response = Either MPDError

A response is either an MPDError or some result.

type Host = String

type Port = Integer

type Password = String

Connections

withMPD :: MPD a -> IO (Response a)

A wrapper for withMPDEx that uses localhost:6600 as the default host:port, or whatever is found in the environment variables MPD_HOST and MPD_PORT. If MPD_HOST is of the form "password@host" the password will be supplied as well.

Examples:

withMPD $ play Nothing
withMPD $ add_ "tool" >> play Nothing >> currentSong

withMPD_

Arguments

:: Maybe String

optional override for MPD_HOST

-> Maybe String

optional override for MPD_PORT

-> MPD a

-> IO (Response a)

Same as withMPD, but takes optional arguments that override MPD_HOST and MPD_PORT.

This is e.g. useful for clients that optionally take --port and --host as command line arguments, and fall back to withMPD's defaults if those arguments are not given.

withMPDEx :: Host -> Port -> Password -> MPD a -> IO (Response a)

The most configurable API for running an MPD action.

data Query

An interface for creating MPD queries.

For example, to match any song where the value of artist is "Foo", we use:

Artist =? "Foo"

We can also compose queries, thus narrowing the search. For example, to match any song where the value of artist is "Foo" and the value of album is "Bar", we use:

Artist =? "Foo" <&> Album =? "Bar"

Instances

Show Query

Monoid Query

(=?) :: Metadata -> Value -> Query

Create a query.

(<&>) :: Query -> Query -> Query infixr 6

Combine queries.

anything :: Query

An empty query. Matches anything.

class ToString a where

A type class for values that can be converted to Strings.

Methods

toString :: a -> String

Convert given value to String.

toText :: a -> Text

Convert given value to Text.

toUtf8 :: a -> ByteString

Convert given value to a UTF-8 encoded ByteString.

Instances

ToString Value

ToString Path

ToString PlaylistName

type Artist = Value

type Album = Value

type Title = Value

newtype PlaylistName

Used for commands which require a playlist name. If empty, the current playlist is used.

Constructors

PlaylistName ByteString

Instances

Eq PlaylistName

Show PlaylistName

IsString PlaylistName

ToString PlaylistName

data Path

Used for commands which require a path within the database. If empty, the root path is used.

Instances

Eq Path

Show Path

IsString Path

ToString Path

data Metadata

Available metadata types/scope modifiers, used for searching the database for entries with certain metadata values.

Constructors

Artist

ArtistSort

Album

AlbumArtist

AlbumArtistSort

Title

Track

Name

Genre

Date

Composer

Performer

Comment

Disc

MUSICBRAINZ_ARTISTID

MUSICBRAINZ_ALBUMID

MUSICBRAINZ_ALBUMARTISTID

MUSICBRAINZ_TRACKID

MUSICBRAINZ_RELEASETRACKID

Instances

Bounded Metadata

Enum Metadata

Eq Metadata

Ord Metadata

Show Metadata

data Value

A metadata value.

Instances

Eq Value

Show Value

IsString Value

ToString Value

data ObjectType

Object types.

Constructors

SongObj

Instances

Eq ObjectType

Show ObjectType

type Seconds = Integer

type Decibels = Integer

data State

Represents the different playback states.

Constructors

Playing

Stopped

Paused

Instances

Eq State

Show State

data Subsystem

Represents the various MPD subsystems.

Constructors

DatabaseS

The song database

UpdateS

Database updates

StoredPlaylistS

Stored playlists

PlaylistS

The current playlist

PlayerS

The player

MixerS

The volume mixer

OutputS

Audio outputs

OptionsS

Playback options

StickerS

Sticker database

SubscriptionS

Subscription

MessageS

Message on subscribed channel

Instances

Eq Subsystem

Show Subsystem

data ReplayGainMode

Constructors

Off

Disable replay gain

TrackMode

Per track mode

AlbumMode

Per album mode

Instances

Eq ReplayGainMode

Show ReplayGainMode

data Count

Represents the result of running count.

Constructors

Count

Fields

cSongs :: Integer

Number of songs matching the query

cPlaytime :: Seconds

Total play time of matching songs

Instances

Eq Count

Show Count

Default Count

data LsResult

Result of the lsInfo operation

Constructors

LsDirectory Path

Directory

LsSong Song

Song

LsPlaylist PlaylistName

Playlist

Instances

Eq LsResult

Show LsResult

data Device

Represents an output device.

Constructors

Device

Fields

dOutputID :: Int

Output's ID number

dOutputName :: String

Output's name as defined in the MPD configuration file

dOutputEnabled :: Bool

Instances

Eq Device

Show Device

Default Device

data Song

Represents a single song item.

Constructors

Song

Fields

sgFilePath :: Path

sgTags :: Map Metadata [Value]

Map of available tags (multiple occurrences of one tag type allowed)

sgLastModified :: Maybe UTCTime

Last modification date

sgLength :: Seconds

Length of the song in seconds

sgId :: Maybe Id

Id in playlist

sgIndex :: Maybe Position

Position in playlist

Instances

Eq Song

Show Song

type Position = Int

The position of a song in a playlist.

newtype Id

Constructors

Id Int

Instances

Eq Id

Show Id

sgGetTag :: Metadata -> Song -> Maybe [Value]

Get list of specific tag type

sgAddTag :: Metadata -> Value -> Song -> Song

Add metadata tag value.

data Stats

Container for database statistics.

Constructors

Stats

Fields

stsArtists :: Integer

Number of artists.

stsAlbums :: Integer

Number of albums.

stsSongs :: Integer

Number of songs.

stsUptime :: Seconds

Daemon uptime in seconds.

stsPlaytime :: Seconds

Total playing time.

stsDbPlaytime :: Seconds

Total play time of all the songs in the database.

stsDbUpdate :: Integer

Last database update in UNIX time.

Instances

Eq Stats

Show Stats

Default Stats

data Status

Container for MPD status.

Constructors

Status

Fields

stState :: State

stVolume :: Maybe Int

A percentage (0-100).

Nothing indicates that the output lacks mixer support.

stRepeat :: Bool

stRandom :: Bool

stPlaylistVersion :: Integer

A value that is incremented by the server every time the playlist changes.

stPlaylistLength :: Integer

The number of items in the current playlist.

stSongPos :: Maybe Position

Current song's position in the playlist.

stSongID :: Maybe Id

Current song's playlist ID.

stNextSongPos :: Maybe Position

Next song's position in the playlist.

stNextSongID :: Maybe Id

Next song's playlist ID.

stTime :: Maybe (Double, Seconds)

Time elapsed/total time of playing song (if any).

stBitrate :: Maybe Int

Bitrate (in kilobytes per second) of playing song (if any).

stXFadeWidth :: Seconds

Crossfade time.

stMixRampdB :: Double

MixRamp threshold in dB

stMixRampDelay :: Double

MixRamp extra delay in seconds

stAudio :: (Int, Int, Int)

Samplerate/bits/channels for the chosen output device (see mpd.conf).

stUpdatingDb :: Maybe Integer

Job ID of currently running update (if any).

stSingle :: Bool

If True, MPD will play only one song and stop after finishing it.

stConsume :: Bool

If True, a song will be removed after it has been played.

stError :: Maybe String

Last error message (if any).

Instances

Eq Status

Show Status

Default Status

def :: Default a => a

The default value for this type.

clearError :: MonadMPD m => m ()

Clear the current error message in status.

currentSong :: MonadMPD m => m (Maybe Song)

Get the currently playing song.

idle :: MonadMPD m => [Subsystem] -> m [Subsystem]

Wait until there is a noteworthy change in one or more of MPD's susbystems.

The first argument is a list of subsystems that should be considered. An empty list specifies that all subsystems should be considered.

A list of subsystems that have noteworthy changes is returned.

Note that running this command will block until either idle returns or is cancelled by noidle.

noidle :: MonadMPD m => m ()

Cancel idle.

stats :: MonadMPD m => m Stats

Get server statistics.

status :: MonadMPD m => m Status

Get the server's status.

consume :: MonadMPD m => Bool -> m ()

Set consume mode

crossfade :: MonadMPD m => Seconds -> m ()

Set crossfading between songs.

random :: MonadMPD m => Bool -> m ()

Set random playing.

repeat :: MonadMPD m => Bool -> m ()

Set repeating.

setVolume :: MonadMPD m => Int -> m ()

Set the volume (0-100 percent).

single :: MonadMPD m => Bool -> m ()

Set single mode

replayGainMode :: MonadMPD m => ReplayGainMode -> m ()

Set the replay gain mode.

replayGainStatus :: MonadMPD m => m [(String, String)]

Get the replay gain options.

next :: MonadMPD m => m ()

Play the next song.

pause :: MonadMPD m => Bool -> m ()

Pause playing.

play :: MonadMPD m => Maybe Position -> m ()

Begin/continue playing.

playId :: MonadMPD m => Id -> m ()

Play a file with given id.

previous :: MonadMPD m => m ()

Play the previous song.

seek :: MonadMPD m => Position -> Seconds -> m ()

Seek to some point in a song.

seekId :: MonadMPD m => Id -> Seconds -> m ()

Seek to some point in a song (id version)

stop :: MonadMPD m => m ()

Stop playing.

addId :: MonadMPD m => Path -> Maybe Position -> m Id

Like add, but returns a playlist id.

add :: MonadMPD m => Path -> m ()

Add a song (or a whole directory) to the current playlist.

clear :: MonadMPD m => m ()

Clear the current playlist.

delete :: MonadMPD m => Position -> m ()

Remove a song from the current playlist.

deleteId :: MonadMPD m => Id -> m ()

Remove a song from the current playlist.

move :: MonadMPD m => Position -> Position -> m ()

Move a song to a given position in the current playlist.

moveId :: MonadMPD m => Id -> Position -> m ()

Move a song from (songid) to (playlist index) in the playlist. If to is negative, it is relative to the current song in the playlist (if there is one).

playlist :: MonadMPD m => m [(Position, Path)]

Warning: this is deprecated; please use playlistInfo instead.

Retrieve file paths and positions of songs in the current playlist. Note that this command is only included for completeness sake; it's deprecated and likely to disappear at any time, please use playlistInfo instead.

playlistFind :: MonadMPD m => Query -> m [Song]

Search for songs in the current playlist with strict matching.

playlistInfo :: MonadMPD m => Maybe Position -> m [Song]

Retrieve metadata for songs in the current playlist.

playlistInfoRange :: MonadMPD m => Maybe (Position, Position) -> m [Song]

Like playlistInfo but can restrict to a range of songs.

playlistId :: MonadMPD m => Maybe Id -> m [Song]

Displays a list of songs in the playlist. If id is specified, only its info is returned.

playlistSearch :: MonadMPD m => Query -> m [Song]

Search case-insensitively with partial matches for songs in the current playlist.

plChanges :: MonadMPD m => Integer -> m [Song]

Retrieve a list of changed songs currently in the playlist since a given playlist version.

plChangesPosId :: MonadMPD m => Integer -> m [(Position, Id)]

Like plChanges but only returns positions and ids.

shuffle

Arguments

:: MonadMPD m

=> Maybe (Position, Position)

Optional range (start, end)

-> m ()

Shuffle the playlist.

swap :: MonadMPD m => Position -> Position -> m ()

Swap the positions of two songs.

swapId :: MonadMPD m => Id -> Id -> m ()

Swap the positions of two songs (Id version)

listPlaylist :: MonadMPD m => PlaylistName -> m [Path]

Retrieve a list of files in a given playlist.

listPlaylistInfo :: MonadMPD m => PlaylistName -> m [Song]

Retrieve metadata for files in a given playlist.

listPlaylists :: MonadMPD m => m [PlaylistName]

Retreive a list of stored playlists.

load :: MonadMPD m => PlaylistName -> m ()

Load an existing playlist.

playlistAdd :: MonadMPD m => PlaylistName -> Path -> m ()

Add a song (or a whole directory) to a stored playlist. Will create a new playlist if the one specified does not already exist.

playlistClear :: MonadMPD m => PlaylistName -> m ()

Clear a playlist. If the specified playlist does not exist, it will be created.

playlistDelete :: MonadMPD m => PlaylistName -> Position -> m ()

Remove a song from a playlist.

playlistMove :: MonadMPD m => PlaylistName -> Id -> Position -> m ()

Move a song to a given position in the playlist specified.

rename

Arguments

:: MonadMPD m

=> PlaylistName

Original playlist

-> PlaylistName

New playlist name

-> m ()

Rename an existing playlist.

rm :: MonadMPD m => PlaylistName -> m ()

Delete existing playlist.

save :: MonadMPD m => PlaylistName -> m ()

Save the current playlist.

count :: MonadMPD m => Query -> m Count

Count the number of entries matching a query.

find :: MonadMPD m => Query -> m [Song]

Search the database for entries exactly matching a query.

findAdd :: MonadMPD m => Query -> m ()

Adds songs matching a query to the current playlist.

list

Arguments

:: MonadMPD m

=> Metadata

Metadata to list

-> Maybe Artist

-> m [Value]

List all tags of the specified type.

listAll :: MonadMPD m => Path -> m [Path]

List the songs (without metadata) in a database directory recursively.

listAllInfo :: MonadMPD m => Path -> m [LsResult]

Recursive lsInfo.

lsInfo :: MonadMPD m => Path -> m [LsResult]

Non-recursively list the contents of a database directory.

search :: MonadMPD m => Query -> m [Song]

Search the database using case insensitive matching.

update :: MonadMPD m => Maybe Path -> m Integer

Update the server's database.

If no path is given, the whole library will be scanned. Unreadable or non-existent paths are silently ignored.

The update job id is returned.

rescan :: MonadMPD m => Maybe Path -> m Integer

Like update but also rescans unmodified files.

stickerGet

Arguments

:: MonadMPD m

=> ObjectType

-> String

Object URI

-> String

Sticker name

-> m [String]

Reads a sticker value for the specified object.

stickerSet

Arguments

:: MonadMPD m

=> ObjectType

-> String

Object URI

-> String

Sticker name

-> String

Sticker value

-> m ()

Adds a sticker value to the specified object.

stickerDelete

Arguments

:: MonadMPD m

=> ObjectType

-> String

Object URI

-> String

Sticker name

-> m ()

Delete a sticker value from the specified object.

stickerList

Arguments

:: MonadMPD m

=> ObjectType

-> String

Object URI

-> m [(String, String)]

Sticker name/sticker value

Lists the stickers for the specified object.

stickerFind

Arguments

:: MonadMPD m

=> ObjectType

-> String

Path

-> String

Sticker name

-> m [(String, String)]

URI/sticker value

Searches the sticker database for stickers with the specified name, below the specified path.

password :: MonadMPD m => String -> m ()

Send password to server to authenticate session. Password is sent as plain text.

ping :: MonadMPD m => m ()

Check that the server is still responding.

disableOutput :: MonadMPD m => Int -> m ()

Turn off an output device.

enableOutput :: MonadMPD m => Int -> m ()

Turn on an output device.

outputs :: MonadMPD m => m [Device]

Retrieve information for all output devices.

commands :: MonadMPD m => m [String]

Retrieve a list of available commands.

notCommands :: MonadMPD m => m [String]

Retrieve a list of unavailable (due to access restrictions) commands.

tagTypes :: MonadMPD m => m [String]

Retrieve a list of available song metadata.

urlHandlers :: MonadMPD m => m [String]

Retrieve a list of supported urlhandlers.

decoders :: MonadMPD m => m [(String, [(String, String)])]

Retreive a list of decoder plugins with associated suffix and mime types.

config :: MonadMPD m => m [(String, String)]

Retrieve configuration keys and values.

Types

type ChannelName = String

type MessageText = String

Subscribing to channels

subscribe :: MonadMPD m => ChannelName -> m ()

unsubscribe :: MonadMPD m => ChannelName -> m ()

channels :: MonadMPD m => m [ChannelName]

Communicating with other clients

readMessages :: MonadMPD m => m [(ChannelName, MessageText)]

sendMessage :: MonadMPD m => ChannelName -> MessageText -> m ()