mopidy.models
— Data models¶
These immutable data models are used for all data transfer within the Mopidy backends and between the backends and the MPD frontend. All fields are optional and immutable. In other words, they can only be set through the class constructor during instance creation. Additionally fields are type checked.
If you want to modify a model, use the
replace()
method. It accepts keyword
arguments for the parts of the model you want to change, and copies the rest of
the data from the model you call it on. Example:
>>> from mopidy.models import Track
>>> track1 = Track(name='Christmas Carol', length=171)
>>> track1
Track(artists=[], length=171, name='Christmas Carol')
>>> track2 = track1.replace(length=37)
>>> track2
Track(artists=[], length=37, name='Christmas Carol')
>>> track1
Track(artists=[], length=171, name='Christmas Carol')
Data model relations¶
Data model API¶
-
class
mopidy.models.
Ref
(*args, **kwargs)[source]¶ Model to represent URI references with a human friendly name and type attached. This is intended for use a lightweight object “free” of metadata that can be passed around instead of using full blown models.
Parameters: - uri (string) – object URI
- name (string) – object name
- type (string) – object type
-
class
mopidy.models.
Track
(*args, **kwargs)[source]¶ Parameters: - uri (string) – track URI
- name (string) – track name
- artists (list of
Artist
) – track artists - album (
Album
) – track album - composers (string) – track composers
- performers (string) – track performers
- genre (string) – track genre
- track_no (integer or
None
if unknown) – track number in album - disc_no (integer or
None
if unknown) – disc number in album - date (string) – track release date (YYYY or YYYY-MM-DD)
- length (integer or
None
if there is no duration) – track length in milliseconds - bitrate (integer) – bitrate in kbit/s
- comment (string) – track comment
- musicbrainz_id (string) – MusicBrainz ID
- last_modified (integer or
None
if unknown) – Represents last modification time
-
class
mopidy.models.
Album
(*args, **kwargs)[source]¶ Parameters: - uri (string) – album URI
- name (string) – album name
- artists (list of
Artist
) – album artists - num_tracks (integer or
None
if unknown) – number of tracks in album - num_discs (integer or
None
if unknown) – number of discs in album - date (string) – album release date (YYYY or YYYY-MM-DD)
- musicbrainz_id (string) – MusicBrainz ID
- images (list of strings) – album image URIs
-
class
mopidy.models.
Artist
(*args, **kwargs)[source]¶ Parameters: - uri (string) – artist URI
- name (string) – artist name
- sortname (string) – artist name for sorting
- musicbrainz_id (string) – MusicBrainz ID
-
class
mopidy.models.
Playlist
(*args, **kwargs)[source]¶ Parameters: - uri (string) – playlist URI
- name (string) – playlist name
- tracks (list of
Track
elements) – playlist’s tracks - last_modified (int) – playlist’s modification time in milliseconds since Unix epoch
-
class
mopidy.models.
Image
(*args, **kwargs)[source]¶ Parameters: - uri (string) – URI of the image
- width (int) – Optional width of image or
None
- height (int) – Optional height of image or
None
-
class
mopidy.models.
TlTrack
(*args, **kwargs)[source]¶ A tracklist track. Wraps a regular track and it’s tracklist ID.
The use of
TlTrack
allows the same track to appear multiple times in the tracklist.This class also accepts it’s parameters as positional arguments. Both arguments must be provided, and they must appear in the order they are listed here.
This class also supports iteration, so your extract its values like this:
(tlid, track) = tl_track
Parameters: - tlid (int) – tracklist ID
- track (
Track
) – the track
Data model helpers¶
-
class
mopidy.models.
ImmutableObject
(*args, **kwargs)[source]¶ Superclass for immutable objects whose fields can only be modified via the constructor.
This version of this class has been retained to avoid breaking any clients relying on it’s behavior. Internally in Mopidy we now use
ValidatedImmutableObject
for type safety and it’s much smaller memory footprint.Parameters: kwargs (any) – kwargs to set as fields on the object -
replace
(**kwargs)[source]¶ Replace the fields in the model and return a new instance
Examples:
# Returns a track with a new name Track(name='foo').replace(name='bar') # Return an album with a new number of tracks Album(num_tracks=2).replace(num_tracks=5)
Parameters: kwargs (any) – kwargs to set as fields on the object Return type: instance of the model with replaced fields
-
-
class
mopidy.models.
ValidatedImmutableObject
(*args, **kwargs)[source]¶ Superclass for immutable objects whose fields can only be modified via the constructor. Fields should be
Field
instances to ensure type safety in our models.Note that since these models can not be changed, we heavily memoize them to save memory. So constructing a class with the same arguments twice will give you the same instance twice.
-
replace
(**kwargs)[source]¶ Replace the fields in the model and return a new instance
Examples:
# Returns a track with a new name Track(name='foo').replace(name='bar') # Return an album with a new number of tracks Album(num_tracks=2).replace(num_tracks=5)
Note that internally we memoize heavily to keep memory usage down given our overly repetitive data structures. So you might get an existing instance if it contains the same values.
Parameters: kwargs (any) – kwargs to set as fields on the object Return type: instance of the model with replaced fields
-
Data model (de)serialization¶
-
mopidy.models.
model_json_decoder
(dct)[source]¶ Automatically deserialize Mopidy models from JSON.
Usage:
>>> import json >>> json.loads( ... '{"a_track": {"__model__": "Track", "name": "name"}}', ... object_hook=model_json_decoder) {u'a_track': Track(artists=[], name=u'name')}
-
class
mopidy.models.
ModelJSONEncoder
(skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, sort_keys=False, indent=None, separators=None, encoding='utf-8', default=None)[source]¶ Automatically serialize Mopidy models to JSON.
Usage:
>>> import json >>> json.dumps({'a_track': Track(name='name')}, cls=ModelJSONEncoder) '{"a_track": {"__model__": "Track", "name": "name"}}'
Data model field types¶
-
class
mopidy.models.fields.
Field
(default=None, type=None, choices=None)[source]¶ Base field for use in
ValidatedImmutableObject
. These fields are responsible for type checking and other data sanitation in our models.For simplicity fields use the Python descriptor protocol to store the values in the instance dictionary. Also note that fields are mutable if the object they are attached to allow it.
Default values will be validated with the exception of
None
.Parameters: - default – default value for field
- type – if set the field value must be of this type
- choices – if set the field value must be one of these
-
class
mopidy.models.fields.
String
(default=None)[source]¶ Specialized
Field
which is wired up for bytes and unicode.Parameters: default – default value for field
-
class
mopidy.models.fields.
Identifier
(default=None)[source]¶ Field
for storing ASCII values such as GUIDs or other identifiers.Values will be interned.
Parameters: default – default value for field
-
class
mopidy.models.fields.
URI
(default=None)[source]¶ Field
for storing URIsValues will be interned, currently not validated.
Parameters: default – default value for field
-
class
mopidy.models.fields.
Date
(default=None)[source]¶ Field
for storing ISO 8601 dates as a string.Supported formats are
YYYY-MM-DD
,YYYY-MM
andYYYY
, currently not validated.Parameters: default – default value for field