Stability	alpha
Maintainer	Joachim Fasting <joachim.fasting@gmail.com>

Network.MPD

Contents

Basic data types
Connections
Command related data types
Query interface
Querying MPD's status
Playback options
Controlling playback
The current playlist
Stored playlist
The music database
Stickers
Connection
Audio output devices
Reflection

Description

An MPD client library. MPD is a daemon for playing music that is controlled over a network socket. Its site is at http://www.musicpd.org/.

To avoid name clashes with the standard Prelude functions, do:

 import qualified Network.MPD as MPD

Synopsis

Basic data types

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

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

Methods

close :: m ()

Close the connection.

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
TimedOut	The connection timed out
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
Error 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

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

The most configurable API for running an MPD action.

Command related data types

type Artist = String

type Album = String

type Title = String

type PlaylistName = String

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

type Path = String

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

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

Instances

Eq Metadata
Ord Metadata
Show Metadata
MPDArg Metadata

data ObjectType

Object types.

Constructors

SongObj

Instances

Eq ObjectType
Show ObjectType
MPDArg ObjectType

type Seconds = 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

Instances

Eq Subsystem
Show Subsystem
MPDArg Subsystem

data ReplayGainMode

Constructors

Off	Disable replay gain
TrackMode	Per track mode
AlbumMode	Per album mode

Instances

Eq ReplayGainMode
Show ReplayGainMode
MPDArg 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

data Output

Represents an output device.

Constructors

Output
Fields outID :: Int Output's ID number outName :: String Output's name as defined in the MPD configuration file outEnabled :: Bool

Instances

Eq Output
Show Output

data Song

Represents a single song item.

Constructors

Song
Fields sgFilePath :: String sgTags :: Map Metadata [String] Map of available tags (multiple occurences of one tag type allowed) sgLastModified :: Maybe UTCTime Last modification date sgLength :: Seconds Length of the song in seconds sgIndex :: Maybe (Int, Int) Position/ID in playlist

Instances

Eq Song
Show Song

sgGet :: Metadata -> Song -> Maybe [String]

Get list of specific tag type

data Playlist

Represents a single playlist item.

Constructors

Playlist
Fields plName :: String plLastModified :: Maybe UTCTime

Instances

Eq Playlist
Show Playlist

data Entry

Represents a single item in database.

Constructors

SongE Song
PlaylistE Playlist
DirectoryE String

Instances

Eq Entry
Show Entry

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

data Status

Container for MPD status.

Constructors

Status

Fields

stState :: State
stVolume :: Int: A percentage (0-100)
stRepeat :: Bool
stRandom :: Bool
stPlaylistID :: 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 Int: Current song's position in the playlist.
stSongID :: Maybe Int: Current song's playlist ID.
stNextSongPos :: Maybe Int: Next song's position in the playlist.
stNextSongID :: Maybe Int: Next song's playlist ID.
stTime :: (Double, Seconds): Time elapsed/total time.
stBitrate :: 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 :: 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

Query interface

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
MPDArg Query

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

Create a query.

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

Combine queries.

anything :: Query

An empty query. Matches anything.

Querying MPD's status

clearError :: MonadMPD m => m ()

Clear the current error message in status.

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

Get the current song.

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

Make MPD server notify the client if there is a noteworthy change in one or more of its subsystems. Note that after running this command you can either monitor handle for incoming notifications or cancel this by noidle. Any command other than noidle sent to MPD server while idle is active will be ignored.

getIdle :: MonadMPD m => m [Subsystem]

Get idle notifications. If there is no notifications ready at the moment, this function will block until they show up.

noidle :: MonadMPD m => m ()

Cancel idle.

status :: MonadMPD m => m Status

Get the server's status.

stats :: MonadMPD m => m Stats

Get server statistics.

Playback options

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]

Get the replay gain options.

Controlling playback

next :: MonadMPD m => m ()

Play the next song.

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

Pause playing.

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

Begin/continue playing.

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

Play a file with given id.

previous :: MonadMPD m => m ()

Play the previous song.

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

Seek to some point in a song.

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

Seek to some point in a song (id version)

stop :: MonadMPD m => m ()

Stop playing.

The current playlist

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

Like add_ but returns a list of the files added.

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

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

addId

Arguments

:: MonadMPD m
=> Path
-> Maybe Integer	Optional playlist position
-> m Int

Like add, but returns a playlist id.

clear :: MonadMPD m => m ()

Clear the current playlist.

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

Remove a song from the current playlist.

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

Remove a song from the current playlist.

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

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

moveId :: MonadMPD m => Int -> Int -> 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 [(Int, Path)]

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.

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

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

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

Search for songs in the current playlist with strict matching.

playlistInfo :: MonadMPD m => Maybe (Int, Int) -> m [Song]

Retrieve metadata for songs in the current playlist.

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 [(Int, Int)]

Like plChanges but only returns positions and ids.

shuffle

Arguments

:: MonadMPD m
=> Maybe (Int, Int)	Optional range (start, end)
-> m ()

Shuffle the playlist.

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

Swap the positions of two songs.

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

Swap the positions of two songs (Id version

Stored playlist

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 [Path]

Like playlistAdd but returns a list of the files added.

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

Arguments

:: MonadMPD m
=> PlaylistName
-> Integer	Playlist position
-> m ()

Remove a song from a playlist.

playlistMove :: MonadMPD m => PlaylistName -> Integer -> Integer -> 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.

The music database

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
-> Query
-> m [String]

List all metadata of metadata (sic).

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

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

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

Recursive lsInfo.

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

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 => [Path] -> m ()

Update the server's database. If no paths are given, all paths will be scanned. Unreadable or non-existent paths are silently ignored.

rescan :: MonadMPD m => [Path] -> m ()

Like update but also rescans unmodified files.

Stickers

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.

Connection

close :: MonadMPD m => m ()

Close the connection.

kill :: MonadMPD m => m ()

Kill the server. Obviously, the connection is then invalid.

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.

Audio output devices

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

Turn off an output device.

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

Turn on an output device.

outputs :: MonadMPD m => m [Output]

Retrieve information for all output devices.

Reflection

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.