Class DS.EmbeddedRecordsMixin
Using Embedded Records
DS.EmbeddedRecordsMixin
supports serializing embedded records.
To set up embedded records, include the mixin when extending a serializer, then define and configure embedded (model) relationships.
Note that embedded records will serialize with the serializer for their model instead of the serializer in which they are defined.
Below is an example of a per-type serializer (post
type).
import DS from 'ember-data';
export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
attrs: {
author: { embedded: 'always' },
comments: { serialize: 'ids' }
}
});
Note that this use of { embedded: 'always' }
is unrelated to
the { embedded: 'always' }
that is defined as an option on DS.attr
as part of
defining a model while working with the ActiveModelSerializer
. Nevertheless,
using { embedded: 'always' }
as an option to DS.attr
is not a valid way to setup
embedded records.
The attrs
option for a resource { embedded: 'always' }
is shorthand for:
{
serialize: 'records',
deserialize: 'records'
}
Configuring Attrs
A resource's attrs
option may be set to use ids
, records
or false for the
serialize
and deserialize
settings.
The attrs
property can be set on the ApplicationSerializer
or a per-type
serializer.
In the case where embedded JSON is expected while extracting a payload (reading)
the setting is deserialize: 'records'
, there is no need to use ids
when
extracting as that is the default behavior without this mixin if you are using
the vanilla EmbeddedRecordsMixin
. Likewise, to embed JSON in the payload while
serializing serialize: 'records'
is the setting to use. There is an option of
not embedding JSON in the serialized payload by using serialize: 'ids'
. If you
do not want the relationship sent at all, you can use serialize: false
.
EmbeddedRecordsMixin defaults
If you do not overwrite attrs
for a specific relationship, the EmbeddedRecordsMixin
will behave in the following way:
BelongsTo: { serialize: 'id', deserialize: 'id' }
HasMany: { serialize: false, deserialize: 'ids' }
Model Relationships
Embedded records must have a model defined to be extracted and serialized. Note that
when defining any relationships on your model such as belongsTo
and hasMany
, you
should not both specify async: true
and also indicate through the serializer's
attrs
attribute that the related model should be embedded for deserialization.
If a model is declared embedded for deserialization (embedded: 'always'
or deserialize: 'records'
),
then do not use async: true
.
To successfully extract and serialize embedded records the model relationships must be setup correcty. See the defining relationships section of the Defining Models guide page.
Records without an id
property are not considered embedded records, model
instances must have an id
property to be used with Ember Data.
Example JSON payloads, Models and Serializers
When customizing a serializer it is important to grok what the customizations are. Please read the docs for the methods this mixin provides, in case you need to modify it to fit your specific needs.
For example review the docs for each method of this mixin:
normalize (typeClass, hash, prop) Object
Defined in addon/serializers/embedded-records-mixin.js:102
- typeClass
- DS.Model
- hash
- Object
to be normalized
- prop
- String
the hash has been referenced by
- returns
- Object
the normalized hash
Normalize the record and recursively normalize/extract all the embedded records while pushing them into the store as they are encountered
A payload with an attr configured for embedded records needs to be extracted:
{
"post": {
"id": "1"
"title": "Rails is omakase",
"comments": [{
"id": "1",
"body": "Rails is unagi"
}, {
"id": "2",
"body": "Omakase O_o"
}]
}
}
removeEmbeddedForeignKey (snapshot, embeddedSnapshot, relationship, json)
Defined in addon/serializers/embedded-records-mixin.js:455
- snapshot
- DS.Snapshot
- embeddedSnapshot
- DS.Snapshot
- relationship
- Object
- json
- Object
When serializing an embedded record, modify the property (in the json payload) that refers to the parent record (foreign key for relationship).
Serializing a belongsTo
relationship removes the property that refers to the
parent record
Serializing a hasMany
relationship does not remove the property that refers to
the parent record.
serializeBelongsTo (snapshot, json, relationship)
Defined in addon/serializers/embedded-records-mixin.js:143
- snapshot
- DS.Snapshot
- json
- Object
- relationship
- Object
Serialize belongsTo
relationship when it is configured as an embedded object.
This example of an author model belongs to a post model:
Post = DS.Model.extend({
title: DS.attr('string'),
body: DS.attr('string'),
author: DS.belongsTo('author')
});
Author = DS.Model.extend({
name: DS.attr('string'),
post: DS.belongsTo('post')
});
Use a custom (type) serializer for the post model to configure embedded author
import DS from 'ember-data';
export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
attrs: {
author: { embedded: 'always' }
}
})
A payload with an attribute configured for embedded records can serialize the records together under the root attribute's payload:
{
"post": {
"id": "1"
"title": "Rails is omakase",
"author": {
"id": "2"
"name": "dhh"
}
}
}
serializeHasMany (snapshot, json, relationship)
Defined in addon/serializers/embedded-records-mixin.js:242
- snapshot
- DS.Snapshot
- json
- Object
- relationship
- Object
Serializes hasMany
relationships when it is configured as embedded objects.
This example of a post model has many comments:
Post = DS.Model.extend({
title: DS.attr('string'),
body: DS.attr('string'),
comments: DS.hasMany('comment')
});
Comment = DS.Model.extend({
body: DS.attr('string'),
post: DS.belongsTo('post')
});
Use a custom (type) serializer for the post model to configure embedded comments
import DS from 'ember-data;
export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
attrs: {
comments: { embedded: 'always' }
}
})
A payload with an attribute configured for embedded records can serialize the records together under the root attribute's payload:
{
"post": {
"id": "1"
"title": "Rails is omakase",
"body": "I want this for my ORM, I want that for my template language..."
"comments": [{
"id": "1",
"body": "Rails is unagi"
}, {
"id": "2",
"body": "Omakase O_o"
}]
}
}
The attrs options object can use more specific instruction for extracting and
serializing. When serializing, an option to embed ids
, ids-and-types
or records
can be set.
When extracting the only option is records
.
So { embedded: 'always' }
is shorthand for:
{ serialize: 'records', deserialize: 'records' }
To embed the ids
for a related object (using a hasMany relationship):
import DS from 'ember-data;
export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
attrs: {
comments: { serialize: 'ids', deserialize: 'records' }
}
})
{
"post": {
"id": "1"
"title": "Rails is omakase",
"body": "I want this for my ORM, I want that for my template language..."
"comments": ["1", "2"]
}
}
To embed the relationship as a collection of objects with id
and type
keys, set
ids-and-types
for the related object.
This is particularly useful for polymorphic relationships where records don't share
the same table and the id
is not enough information.
By example having a user that has many pets:
User = DS.Model.extend({
name: DS.attr('string'),
pets: DS.hasMany('pet', { polymorphic: true })
});
Pet = DS.Model.extend({
name: DS.attr('string'),
});
Cat = Pet.extend({
// ...
});
Parrot = Pet.extend({
// ...
});
import DS from 'ember-data;
export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
attrs: {
pets: { serialize: 'ids-and-types', deserialize: 'records' }
}
});
{
"user": {
"id": "1"
"name": "Bertin Osborne",
"pets": [
{ "id": "1", "type": "Cat" },
{ "id": "1", "type": "Parrot"}
]
}
}