DS.JSONSerializer
DS.JSONSerializer Class
Extends: DS.Serializer
Defined in: addon/serializers/json.js:19
Module: ember-data
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
import DS from 'ember-data'; export default DS.Model.extend({ friends: DS.hasMany('user'), house: DS.belongsTo('location'), name: DS.attr('string') });
{ 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 methods 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.
_canSerialize (key) Boolean
private
Check attrs.key.serialize property to inform if the key
can be serialized
Parameters:
-
key
String
Returns:
-
Boolean
- true if the key can be serialized
_getMappedKey (key) String
private
Looks up the property key that was set by the custom attr
mapping passed to the serializer.
Parameters:
-
key
String
Returns:
-
String
- key
_mustSerialize (key) Boolean
private
When attrs.key.serialize is set to true then it takes priority over the other checks and the related attribute/relationship will be serialized
Parameters:
-
key
String
Returns:
-
Boolean
- true if the key must be serialized
_normalizeResponse (store, primaryModelClass, payload, id, requestType, isSingle) Object
private
Parameters:
Returns:
-
Object
- JSON-API Document
_shouldSerializeHasMany (snapshot, key, relationshipType) Boolean
private
Check if the given hasMany relationship should be serialized
Parameters:
-
snapshot
DS.Snapshot
-
key
String
-
relationshipType
String
Returns:
-
Boolean
- true if the hasMany relationship should be serialized
applyTransforms (typeClass, data) Object
private
Given a subclass of DS.Model
and a JSON object this method will iterate through each attribute of the DS.Model
and invoke the DS.Transform#deserialize
method on the matching property of the JSON object. This method is typically called after the serializer's normalize
method.
Parameters:
-
typeClass
DS.Model
-
data
Object
- The data to transform
Returns:
-
Object
- data The transformed data object
extractAttributes (modelClass, resourceHash) Object
Returns the resource's attributes formatted as a JSON-API "attributes object".
http://jsonapi.org/format/#document-resource-object-attributes
Parameters:
-
modelClass
Object
-
resourceHash
Object
Returns:
-
Object
extractErrors (store, typeClass, payload, id) Object
extractErrors
is used to extract model errors when a call to DS.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 JSON-API specification:
{ "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:
{ "errors": [ { "detail": "Some generic non property error message", "source": { "pointer": "data" } } ] }
When turn into a DS.Errors
object, you can read these errors through the property base
:
{{#each model.errors.base as |error|}} <div class="error"> {{error.message}} </div> {{/each}}
Example of alternative implementation, overriding the default behavior to deal with a different format of errors:
app/serializers/post.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ extractErrors(store, typeClass, payload, id) { if (payload && typeof payload === 'object' && payload._problems) { payload = payload._problems; this.normalizeErrors(typeClass, payload); } return payload; } });
Returns:
-
Object
- json The deserialized errors
extractId (modelClass, resourceHash) String
Returns the resource's ID.
Parameters:
-
modelClass
Object
-
resourceHash
Object
Returns:
-
String
extractMeta (store, modelClass, payload)
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
import DS from 'ember-data'; export default DS.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
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 from - relationshipKey
key under which the value for the relationship is extracted from the resourceHash - relationshipMeta
meta information about the relationship
Parameters:
-
relationshipModelName
Object
-
relationshipHash
Object
-
relationshipOptions
Object
Returns:
-
Object
extractRelationship (relationshipModelName, relationshipHash) Object
Returns a relationship formatted as a JSON-API "relationship object".
http://jsonapi.org/format/#document-resource-object-relationships
Parameters:
-
relationshipModelName
Object
-
relationshipHash
Object
Returns:
-
Object
extractRelationships (modelClass, resourceHash) Object
Returns the resource's relationships formatted as a JSON-API "relationships object".
http://jsonapi.org/format/#document-resource-object-relationships
Parameters:
-
modelClass
Object
-
resourceHash
Object
Returns:
-
Object
keyForAttribute (key, method) String
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
import DS from 'ember-data'; export default DS.RESTSerializer.extend({ keyForAttribute(attr, method) { return Ember.String.underscore(attr).toUpperCase(); } });
Parameters:
-
key
String
-
method
String
Returns:
-
String
- normalized key
keyForLink (key, kind) String
keyForLink
can be used to define a custom key when deserializing link properties.
Parameters:
-
key
String
-
kind
String
- `belongsTo` or `hasMany`
Returns:
-
String
- normalized key
keyForRelationship (key, typeClass, method) String
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
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ keyForRelationship(key, relationship, method) { return 'rel_' + Ember.String.underscore(key); } });
Parameters:
-
key
String
-
typeClass
String
-
method
String
Returns:
-
String
- normalized key
modelNameFromPayloadKey (key) String
Parameters:
-
key
String
Returns:
-
String
- the model's modelName
modelNameFromPayloadType (type) String
public
Parameters:
-
type
String
Returns:
-
String
- the model's modelName
normalize (typeClass, hash) 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 DS.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
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ normalize(typeClass, hash) { var fields = Ember.get(typeClass, 'fields'); fields.forEach(function(field) { var payloadField = Ember.String.underscore(field); if (field === payloadField) { return; } hash[field] = hash[payloadField]; delete hash[payloadField]; }); return this._super.apply(this, arguments); } });
Parameters:
-
typeClass
DS.Model
-
hash
Object
Returns:
-
Object
normalizeArrayResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeCreateRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeDeleteRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeFindAllResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeFindBelongsToResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeFindHasManyResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeFindManyResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeFindRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeQueryRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeQueryResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeRelationshipsprivate
normalizeResponse (store, primaryModelClass, payload, id, requestType) Object
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:
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); });
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeSaveResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeSingleResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeUpdateRecordResponse (store, primaryModelClass, payload, id, requestType) Object
Parameters:
Returns:
-
Object
- JSON-API Document
normalizeUsingDeclaredMappingprivate
serialize (snapshot, options) Object
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
import DS from 'ember-data'; export default DS.Model.extend({ title: DS.attr(), body: DS.attr(), author: DS.belongsTo('user') });
The default serialization would create a JSON object like:
{ "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 (DS.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
import DS from 'ember-data'; export default DS.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
import DS from 'ember-data'; export default DS.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(name.singularize()) + "_IDS"; }
This serializer will generate JSON that looks like this:
{ "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
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ serialize(snapshot, options) { var json = this._super(...arguments); json.subject = json.title; delete json.title; return json; } });
Parameters:
-
snapshot
DS.Snapshot
-
options
Object
Returns:
-
Object
- json
serializeAttribute (snapshot, json, key, attribute)
serializeAttribute
can be used to customize how DS.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
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ serializeAttribute(snapshot, json, key, attributes) { json.attributes = json.attributes || {}; this._super(snapshot, json.attributes, key, attributes); } });
Parameters:
-
snapshot
DS.Snapshot
-
json
Object
-
key
String
-
attribute
Object
serializeBelongsTo (snapshot, json, relationship)
serializeBelongsTo
can be used to customize how DS.belongsTo
properties are serialized.
Example
app/serializers/post.js
import DS from 'ember-data'; export default DS.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] = Ember.isNone(belongsTo) ? belongsTo : belongsTo.record.toJSON(); } });
Parameters:
-
snapshot
DS.Snapshot
-
json
Object
-
relationship
Object
serializeHasMany (snapshot, json, relationship)
serializeHasMany
can be used to customize how DS.hasMany
properties are serialized.
Example
app/serializers/post.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ serializeHasMany(snapshot, json, relationship) { var key = relationship.key; if (key === 'comments') { return; } else { this._super(...arguments); } } });
Parameters:
-
snapshot
DS.Snapshot
-
json
Object
-
relationship
Object
serializeId (snapshot, json, primaryKey) public
serializeId can be used to customize how id is serialized For example, your server may expect integer datatype of id
By default the snapshot's id (String) is set on the json hash via json[primaryKey] = snapshot.id.
app/serializers/application.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ serializeId(snapshot, json, primaryKey) { var id = snapshot.id; json[primaryKey] = parseInt(id, 10); } });
Parameters:
-
snapshot
DS.Snapshot
-
json
Object
-
primaryKey
String
serializeIntoHash (hash, typeClass, snapshot, options)
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
import DS from 'ember-data'; export default DS.RESTSerializer.extend({ serializeIntoHash(data, type, snapshot, options) { var root = Ember.String.decamelize(type.modelName); data[root] = this.serialize(snapshot, options); } });
Parameters:
-
hash
Object
-
typeClass
DS.Model
-
snapshot
DS.Snapshot
-
options
Object
serializePolymorphicType (snapshot, json, relationship)
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 DS.belongsTo
function.
Example
app/serializers/comment.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ serializePolymorphicType(snapshot, json, relationship) { var key = relationship.key; var belongsTo = snapshot.belongsTo(key); key = this.keyForAttribute ? this.keyForAttribute(key, 'serialize') : key; if (Ember.isNone(belongsTo)) { json[key + '_type'] = null; } else { json[key + '_type'] = belongsTo.modelName; } } });
Parameters:
-
snapshot
DS.Snapshot
-
json
Object
-
relationship
Object
shouldSerializeHasMany (snapshot, key, relationshipType) Boolean
Check if the given hasMany relationship should be serialized
Parameters:
-
snapshot
DS.Snapshot
-
key
String
-
relationshipType
String
Returns:
-
Boolean
- true if the hasMany relationship should be serialized
transformFor (attributeType, skipAssertion) DS.Transform
private
Parameters:
-
attributeType
String
-
skipAssertion
Boolean
Returns:
-
DS.Transform
- transform
attrs{Object}
The attrs
object can be used to declare a simple mapping between property names on DS.Model
records and payload keys in the serialized JSON object representing the record. An object with the property key
can also be used to designate the attribute's key on the response payload.
Example
app/models/person.js
import DS from 'ember-data'; export default DS.Model.extend({ firstName: DS.attr('string'), lastName: DS.attr('string'), occupation: DS.attr('string'), admin: DS.attr('boolean') });
app/serializers/person.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ attrs: { admin: 'is_admin', occupation: { key: 'career' } } });
You can also remove attributes by setting the serialize
key to false
in your mapping object.
Example
app/serializers/person.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ attrs: { admin: { serialize: false }, occupation: { key: 'career' } } });
When serialized:
{ "firstName": "Harry", "lastName": "Houdini", "career": "magician" }
Note that the admin
is now not included in the payload.
primaryKey{String}
The primaryKey
is used when serializing and deserializing data. Ember Data always uses the id
property to store the id of the record. The external source may not always follow this convention. In these cases it is useful to override the primaryKey
property to match the primaryKey
of your external store.
Example
app/serializers/application.js
import DS from 'ember-data'; export default DS.JSONSerializer.extend({ primaryKey: '_id' });
Default: 'id'
© 2017 Yehuda Katz, Tom Dale and Ember.js contributors
Licensed under the MIT License.
https://emberjs.com/api/data/classes/DS.JSONSerializer.html