Class JSONSerializer
Ember Data 2.0 Serializer:
In Ember Data a Serializer is used to serialize and deserialize records when they are transferred in and out of an external source. This process involves normalizing property names, transforming attribute values and serializing relationships.
By default, Ember Data uses and recommends the JSONAPISerializer
.
JSONSerializer
is useful for simpler or legacy backends that may
not support the http://jsonapi.org/ spec.
For example, given the following User
model and JSON payload:
app/models/user.js | |
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import Model, { attr, belongsTo, hasMany } from '@ember-data/model'; export default Model.extend({ friends: hasMany('user'), house: belongsTo('location'), name: attr('string') }); |
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{ id: 1, name: 'Sebastian', friends: [3, 4], links: { house: '/houses/lefkada' } } |
JSONSerializer
will normalize the JSON payload to the JSON API format that the
Ember Data store expects.
You can customize how JSONSerializer processes its payload by passing options in
the attrs
hash or by subclassing the JSONSerializer
and overriding hooks:
- To customize how a single record is normalized, use the
normalize
hook. - To customize how
JSONSerializer
normalizes the whole server response, use thenormalizeResponse
hook. - To customize how
JSONSerializer
normalizes a specific response from the server, use one of the many specificnormalizeResponse
hooks. - To customize how
JSONSerializer
normalizes your id, attributes or relationships, use theextractId
,extractAttributes
andextractRelationships
hooks.
The JSONSerializer
normalization process follows these steps:
normalizeResponse
- entry method to the serializer.normalizeCreateRecordResponse
- anormalizeResponse
for a specific operation is called.normalizeSingleResponse
|normalizeArrayResponse
- for methods likecreateRecord
we expect a single record back, while for methods likefindAll
we expect multiple records back.normalize
-normalizeArray
iterates and callsnormalize
for each of its records whilenormalizeSingle
calls it once. This is the method you most likely want to subclass.extractId
|extractAttributes
|extractRelationships
-normalize
delegates to these methods to turn the record payload into the JSON API format.
extractAttributes (modelClass, resourceHash) Object
Defined in ../serializer/addon/json.js:572
- modelClass
- Object
- resourceHash
- Object
- returns
- Object
Returns the resource's attributes formatted as a JSON-API "attributes object".
http://jsonapi.org/format/#document-resource-object-attributes
extractErrors (store, typeClass, payload, id) Object
Defined in ../serializer/addon/json.js:1304
- store
- Store
- typeClass
- Model
- payload
- Object
- id
- (String|Number)
- returns
- Object
- json The deserialized errors
extractErrors
is used to extract model errors when a call
to Model#save
fails with an InvalidError
. By default
Ember Data expects error information to be located on the errors
property of the payload object.
This serializer expects this errors
object to be an Array similar
to the following, compliant with the https://jsonapi.org/format/#errors specification:
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{ "errors": [ { "detail": "This username is already taken!", "source": { "pointer": "data/attributes/username" } }, { "detail": "Doesn't look like a valid email.", "source": { "pointer": "data/attributes/email" } } ] } |
The key detail
provides a textual description of the problem.
Alternatively, the key title
can be used for the same purpose.
The nested keys source.pointer
detail which specific element
of the request data was invalid.
Note that JSON-API also allows for object-level errors to be placed
in an object with pointer data
, signifying that the problem
cannot be traced to a specific attribute:
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{ "errors": [ { "detail": "Some generic non property error message", "source": { "pointer": "data" } } ] } |
When turn into a Errors
object, you can read these errors
through the property base
:
Example of alternative implementation, overriding the default behavior to deal with a different format of errors:
app/serializers/post.js | |
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import DS from 'ember-data'; export default JSONSerializer.extend({ extractErrors(store, typeClass, payload, id) { if (payload && typeof payload === 'object' && payload._problems) { payload = payload._problems; this.normalizeErrors(typeClass, payload); } return payload; } }); |
extractId (modelClass, resourceHash) String
Defined in ../serializer/addon/json.js:558
- modelClass
- Object
- resourceHash
- Object
- returns
- String
Returns the resource's ID.
extractMeta (store, modelClass, payload)
Defined in ../serializer/addon/json.js:1270
- store
- Store
- modelClass
- Model
- payload
- Object
extractMeta
is used to deserialize any meta information in the
adapter payload. By default Ember Data expects meta information to
be located on the meta
property of the payload object.
Example
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; export default JSONSerializer.extend({ extractMeta(store, typeClass, payload) { if (payload && payload.hasOwnProperty('_pagination')) { let meta = payload._pagination; delete payload._pagination; return meta; } } }); |
extractPolymorphicRelationship (relationshipModelName, relationshipHash, relationshipOptions) Object
Defined in ../serializer/addon/json.js:630
- relationshipModelName
- Object
- relationshipHash
- Object
- relationshipOptions
- Object
- returns
- Object
Returns a polymorphic relationship formatted as a JSON-API "relationship object".
http://jsonapi.org/format/#document-resource-object-relationships
relationshipOptions
is a hash which contains more information about the
polymorphic relationship which should be extracted:
resourceHash
complete hash of the resource the relationship should be extracted fromrelationshipKey
key under which the value for the relationship is extracted from the resourceHashrelationshipMeta
meta information about the relationship
extractRelationship (relationshipModelName, relationshipHash) Object
Defined in ../serializer/addon/json.js:596
- relationshipModelName
- Object
- relationshipHash
- Object
- returns
- Object
Returns a relationship formatted as a JSON-API "relationship object".
http://jsonapi.org/format/#document-resource-object-relationships
extractRelationships (modelClass, resourceHash) Object
Defined in ../serializer/addon/json.js:653
- modelClass
- Object
- resourceHash
- Object
- returns
- Object
Returns the resource's relationships formatted as a JSON-API "relationships object".
http://jsonapi.org/format/#document-resource-object-relationships
keyForAttribute (key, method) String
Defined in ../serializer/addon/json.js:1415
- key
- String
- method
- String
- returns
- String
- normalized key
keyForAttribute
can be used to define rules for how to convert an
attribute name in your model to a key in your JSON.
Example
app/serializers/application.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { underscore } from '@ember/string'; export default JSONSerializer.extend({ keyForAttribute(attr, method) { return underscore(attr).toUpperCase(); } }); |
keyForLink (key, kind) String
Defined in ../serializer/addon/json.js:1469
- key
- String
- kind
- String
- `belongsTo` or `hasMany`
- returns
- String
- normalized key
keyForLink
can be used to define a custom key when deserializing link
properties.
keyForRelationship (key, typeClass, method) String
Defined in ../serializer/addon/json.js:1441
- key
- String
- typeClass
- String
- method
- String
- returns
- String
- normalized key
keyForRelationship
can be used to define a custom key when
serializing and deserializing relationship properties. By default
JSONSerializer
does not provide an implementation of this method.
Example
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { underscore } from '@ember/string'; export default JSONSerializer.extend({ keyForRelationship(key, relationship, method) { return `rel_${underscore(key)}`; } }); |
modelNameFromPayloadKey (key) String
Defined in ../serializer/addon/json.js:724
- key
- String
- returns
- String
- the model's modelName
normalize (typeClass, hash) Object
Defined in ../serializer/addon/json.js:495
- typeClass
- Model
- hash
- Object
- returns
- Object
Normalizes a part of the JSON payload returned by the server. You should override this method, munge the hash and call super if you have generic normalization to do.
It takes the type of the record that is being normalized (as a Model class), the property where the hash was originally found, and the hash to normalize.
You can use this method, for example, to normalize underscored keys to camelized or other general-purpose normalizations.
Example
app/serializers/application.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { underscore } from '@ember/string'; import { get } from '@ember/object'; export default JSONSerializer.extend({ normalize(typeClass, hash) { var fields = get(typeClass, 'fields'); fields.forEach(function(type, field) { var payloadField = underscore(field); if (field === payloadField) { return; } hash[field] = hash[payloadField]; delete hash[payloadField]; }); return this._super.apply(this, arguments); } }); |
normalizeArrayResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:432
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeCreateRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:362
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeDeleteRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:376
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeFindAllResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:292
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeFindBelongsToResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:306
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeFindHasManyResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:320
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeFindManyResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:334
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeFindRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:264
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeQueryRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:278
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeQueryResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:348
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:204
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
The normalizeResponse
method is used to normalize a payload from the
server to a JSON-API Document.
http://jsonapi.org/format/#document-structure
This method delegates to a more specific normalize method based on
the requestType
.
To override this method with a custom one, make sure to call
return this._super(store, primaryModelClass, payload, id, requestType)
with your
pre-processed data.
Here's an example of using normalizeResponse
manually:
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socket.on('message', function(message) { var data = message.data; var modelClass = store.modelFor(data.modelName); var serializer = store.serializerFor(data.modelName); var normalized = serializer.normalizeSingleResponse(store, modelClass, data, data.id); store.push(normalized); }); |
normalizeSaveResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:404
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeSingleResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:418
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
normalizeUpdateRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Defined in ../serializer/addon/json.js:390
Available since v1.13.0
- store
- Store
- primaryModelClass
- Model
- payload
- Object
- id
- String|Number
- requestType
- String
- returns
- Object
- JSON-API Document
serialize (snapshot, options) Object
Defined in ../serializer/addon/json.js:881
- snapshot
- Snapshot
- options
- Object
- returns
- Object
- json
Called when a record is saved in order to convert the record into JSON.
By default, it creates a JSON object with a key for each attribute and belongsTo relationship.
For example, consider this model:
app/models/comment.js | |
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import Model, { attr, belongsTo } from '@ember-data/model'; export default Model.extend({ title: attr(), body: attr(), author: belongsTo('user') }); |
The default serialization would create a JSON object like:
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{ "title": "Rails is unagi", "body": "Rails? Omakase? O_O", "author": 12 } |
By default, attributes are passed through as-is, unless
you specified an attribute type (attr('date')
). If
you specify a transform, the JavaScript value will be
serialized when inserted into the JSON hash.
By default, belongs-to relationships are converted into IDs when inserted into the JSON hash.
IDs
serialize
takes an options hash with a single option:
includeId
. If this option is true
, serialize
will,
by default include the ID in the JSON object it builds.
The adapter passes in includeId: true
when serializing
a record for createRecord
, but not for updateRecord
.
Customization
Your server may expect a different JSON format than the built-in serialization format.
In that case, you can implement serialize
yourself and
return a JSON hash of your choosing.
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; export default JSONSerializer.extend({ serialize(snapshot, options) { var json = { POST_TTL: snapshot.attr('title'), POST_BDY: snapshot.attr('body'), POST_CMS: snapshot.hasMany('comments', { ids: true }) }; if (options.includeId) { json.POST_ID_ = snapshot.id; } return json; } }); |
Customizing an App-Wide Serializer
If you want to define a serializer for your entire
application, you'll probably want to use eachAttribute
and eachRelationship
on the record.
app/serializers/application.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { singularize } from 'ember-inflector'; export default JSONSerializer.extend({ serialize(snapshot, options) { var json = {}; snapshot.eachAttribute(function(name) { json[serverAttributeName(name)] = snapshot.attr(name); }); snapshot.eachRelationship(function(name, relationship) { if (relationship.kind === 'hasMany') { json[serverHasManyName(name)] = snapshot.hasMany(name, { ids: true }); } }); if (options.includeId) { json.ID_ = snapshot.id; } return json; } }); function serverAttributeName(attribute) { return attribute.underscore().toUpperCase(); } function serverHasManyName(name) { return serverAttributeName(singularize(name)) + "_IDS"; } |
This serializer will generate JSON that looks like this:
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{ "TITLE": "Rails is omakase", "BODY": "Yep. Omakase.", "COMMENT_IDS": [ 1, 2, 3 ] } |
Tweaking the Default JSON
If you just want to do some small tweaks on the default JSON, you can call super first and make the tweaks on the returned JSON.
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; export default JSONSerializer.extend({ serialize(snapshot, options) { var json = this._super(...arguments); json.subject = json.title; delete json.title; return json; } }); |
serializeAttribute (snapshot, json, key, attribute)
Defined in ../serializer/addon/json.js:1090
- snapshot
- Snapshot
- json
- Object
- key
- String
- attribute
- Object
serializeAttribute
can be used to customize how attr
properties are serialized
For example if you wanted to ensure all your attributes were always
serialized as properties on an attributes
object you could
write:
app/serializers/application.js | |
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import JSONSerializer from '@ember-data/serializer/json'; export default JSONSerializer.extend({ serializeAttribute(snapshot, json, key, attributes) { json.attributes = json.attributes || {}; this._super(snapshot, json.attributes, key, attributes); } }); |
serializeBelongsTo (snapshot, json, relationship)
Defined in ../serializer/addon/json.js:1136
- snapshot
- Snapshot
- json
- Object
- relationship
- Object
serializeBelongsTo
can be used to customize how belongsTo
properties are serialized.
Example
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { isNone } from '@ember/utils'; export default JSONSerializer.extend({ serializeBelongsTo(snapshot, json, relationship) { var key = relationship.key; var belongsTo = snapshot.belongsTo(key); key = this.keyForRelationship ? this.keyForRelationship(key, "belongsTo", "serialize") : key; json[key] = isNone(belongsTo) ? belongsTo : belongsTo.record.toJSON(); } }); |
serializeHasMany (snapshot, json, relationship)
Defined in ../serializer/addon/json.js:1189
- snapshot
- Snapshot
- json
- Object
- relationship
- Object
serializeHasMany
can be used to customize how hasMany
properties are serialized.
Example
app/serializers/post.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import DS from 'ember-data'; export default JSONSerializer.extend({ serializeHasMany(snapshot, json, relationship) { var key = relationship.key; if (key === 'comments') { return; } else { this._super(...arguments); } } }); |
serializeIntoHash (hash, typeClass, snapshot, options)
Defined in ../serializer/addon/json.js:1058
- hash
- Object
- typeClass
- Model
- snapshot
- Snapshot
- options
- Object
You can use this method to customize how a serialized record is added to the complete JSON hash to be sent to the server. By default the JSON Serializer does not namespace the payload and just sends the raw serialized JSON object. If your server expects namespaced keys, you should consider using the RESTSerializer. Otherwise you can override this method to customize how the record is added to the hash. The hash property should be modified by reference.
For example, your server may expect underscored root objects.
app/serializers/application.js | |
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import RESTSerializer from '@ember-data/serializer/rest'; import { decamelize } from '@ember/string'; export default RESTSerializer.extend({ serializeIntoHash(data, type, snapshot, options) { var root = decamelize(type.modelName); data[root] = this.serialize(snapshot, options); } }); |
serializePolymorphicType (snapshot, json, relationship)
Defined in ../serializer/addon/json.js:1235
- snapshot
- Snapshot
- json
- Object
- relationship
- Object
You can use this method to customize how polymorphic objects are
serialized. Objects are considered to be polymorphic if
{ polymorphic: true }
is pass as the second argument to the
belongsTo
function.
Example
app/serializers/comment.js | |
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import JSONSerializer from '@ember-data/serializer/json'; import { isNone } from '@ember/utils'; export default JSONSerializer.extend({ serializePolymorphicType(snapshot, json, relationship) { var key = relationship.key; var belongsTo = snapshot.belongsTo(key); key = this.keyForAttribute ? this.keyForAttribute(key, 'serialize') : key; if (isNone(belongsTo)) { json[key + '_type'] = null; } else { json[key + '_type'] = belongsTo.modelName; } } }); |
shouldSerializeHasMany (snapshot, key, relationshipType) Boolean
Defined in ../serializer/addon/json.js:860
- snapshot
- Snapshot
- key
- String
- relationshipType
- String
- returns
- Boolean
- true if the hasMany relationship should be serialized
Check if the given hasMany relationship should be serialized
By default only many-to-many and many-to-none relationships are serialized.
This could be configured per relationship by Serializer's attrs
object.