DS.JSONAPISerializer Class
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.
JSONAPISerializer
supports the http://jsonapi.org/ spec and is the
serializer recommended by Ember Data.
This serializer normalizes a JSON API payload that looks like:
import DS from 'ember-data';
export default DS.Model.extend({
name: DS.attr('string'),
skill: DS.attr('string'),
gamesPlayed: DS.attr('number'),
club: DS.belongsTo('club')
});
import DS from 'ember-data';
export default DS.Model.extend({
name: DS.attr('string'),
location: DS.attr('string'),
players: DS.hasMany('player')
});
{
"data": [
{
"attributes": {
"name": "Benfica",
"location": "Portugal"
},
"id": "1",
"relationships": {
"players": {
"data": [
{
"id": "3",
"type": "players"
}
]
}
},
"type": "clubs"
}
],
"included": [
{
"attributes": {
"name": "Eusebio Silva Ferreira",
"skill": "Rocket shot",
"games-played": 431
},
"id": "3",
"relationships": {
"club": {
"data": {
"id": "1",
"type": "clubs"
}
}
},
"type": "players"
}
]
}
to the format that the Ember Data store expects.
Customizing meta
Since a JSON API Document can have meta defined in multiple locations you can use the specific serializer hooks if you need to customize the meta.
One scenario would be to camelCase the meta keys of your payload. The example
below shows how this could be done using normalizeArrayResponse
and
extractRelationship
.
export default JSONAPISerializer.extend({
normalizeArrayResponse(store, primaryModelClass, payload, id, requestType) {
let normalizedDocument = this._super(...arguments);
// Customize document meta
normalizedDocument.meta = camelCaseKeys(normalizedDocument.meta);
return normalizedDocument;
},
extractRelationship(relationshipHash) {
let normalizedRelationship = this._super(...arguments);
// Customize relationship meta
normalizedRelationship.meta = camelCaseKeys(normalizedRelationship.meta);
return normalizedRelationship;
}
});
Item Index
Methods
- _canSerialize
- _extractType
- _getMappedKey
- _mustSerialize
- _normalizeDocumentHelper
- _normalizeRelationshipDataHelper
- _normalizeResourceHelper
- _normalizeResponse
- _shouldSerializeHasMany
- applyTransforms
- extractAttributes
- extractErrors
- extractId
- extractMeta
- extractPolymorphicRelationship
- extractRelationship
- extractRelationships
- keyForAttribute
- keyForLink
- keyForRelationship
- modelNameFromPayloadKey
- modelNameFromPayloadType
- normalize
- normalizeArrayResponse
- normalizeCreateRecordResponse
- normalizeDeleteRecordResponse
- normalizeFindAllResponse
- normalizeFindBelongsToResponse
- normalizeFindHasManyResponse
- normalizeFindManyResponse
- normalizeFindRecordResponse
- normalizeQueryRecordResponse
- normalizeQueryResponse
- normalizeRelationships
- normalizeResponse
- normalizeSaveResponse
- normalizeSingleResponse
- normalizeUpdateRecordResponse
- normalizeUsingDeclaredMapping
- payloadKeyFromModelName
- payloadTypeFromModelName
- pushPayload
- serialize
- serializeAttribute
- serializeBelongsTo
- serializeHasMany
- serializeId
- serializeIntoHash
- serializePolymorphicType
- shouldSerializeHasMany
- transformFor
Properties
Methods
_canSerialize
-
key
key
can be serialized
Parameters:
-
key
String
Returns:
_extractType
-
modelClass
-
resourceHash
Parameters:
-
modelClass
DS.Model -
resourceHash
Object
Returns:
_getMappedKey
-
key
attr
mapping
passed to the serializer.
Parameters:
-
key
String
Returns:
_mustSerialize
-
key
Parameters:
-
key
String
Returns:
_normalizeDocumentHelper
-
documentHash
Parameters:
-
documentHash
Object
Returns:
_normalizeRelationshipDataHelper
-
relationshipDataHash
Parameters:
-
relationshipDataHash
Object
Returns:
_normalizeResourceHelper
-
resourceHash
Parameters:
-
resourceHash
Object
Returns:
_normalizeResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
-
isSingle
Parameters:
Returns:
JSON-API Document
_shouldSerializeHasMany
-
snapshot
-
key
-
relationshipType
Parameters:
-
snapshot
DS.Snapshot -
key
String -
relationshipType
String
Returns:
applyTransforms
-
typeClass
-
data
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
ObjectThe data to transform
Returns:
extractAttributes
-
modelClass
-
resourceHash
Parameters:
-
modelClass
Object -
resourceHash
Object
Returns:
extractErrors
-
store
-
typeClass
-
payload
-
id
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:
`
js
{
"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:
`
javascript
{
"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
:
`
handlebars
{{#each model.errors.base as |error|}}
`
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:
extractId
-
modelClass
-
resourceHash
Parameters:
-
modelClass
Object -
resourceHash
Object
Returns:
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
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:
extractRelationship
-
relationshipModelName
-
relationshipHash
Parameters:
-
relationshipModelName
Object -
relationshipHash
Object
Returns:
extractRelationships
-
modelClass
-
resourceHash
Parameters:
-
modelClass
Object -
resourceHash
Object
Returns:
keyForAttribute
-
key
-
method
keyForAttribute
can be used to define rules for how to convert an
attribute name in your model to a key in your JSON.
By default JSONAPISerializer
follows the format used on the examples of
http://jsonapi.org/format and uses dashes as the word separator in the JSON
attribute keys.
This behaviour can be easily customized by extending this method.
Example
import DS from 'ember-data';
import { dasherize } from '@ember/string';
export default DS.JSONAPISerializer.extend({
keyForAttribute(attr, method) {
return dasherize(attr).toUpperCase();
}
});
Parameters:
-
key
String -
method
String
Returns:
normalized key
keyForLink
-
key
-
kind
keyForLink
can be used to define a custom key when deserializing link
properties.
Parameters:
-
key
String -
kind
StringbelongsTo
orhasMany
Returns:
keyForRelationship
-
key
-
typeClass
-
method
keyForRelationship
can be used to define a custom key when
serializing and deserializing relationship properties.
By default JSONAPISerializer
follows the format used on the examples of
http://jsonapi.org/format and uses dashes as word separators in
relationship properties.
This behaviour can be easily customized by extending this method.
Example
import DS from 'ember-data';
import { underscore } from '@ember/string';
export default DS.JSONAPISerializer.extend({
keyForRelationship(key, relationship, method) {
return underscore(key);
}
});
Parameters:
-
key
String -
typeClass
String -
method
String
Returns:
normalized key
modelNameFromPayloadKey
-
key
Dasherizes and singularizes the model name in the payload to match the format Ember Data uses internally for the model name.
For example the key posts
would be converted to post
and the
key studentAssesments
would be converted to student-assesment
.
Parameters:
-
key
String
Returns:
the model's modelName
modelNameFromPayloadType
-
payloadType
modelNameFromPayloadType
can be used to change the mapping for a DS model
name, taken from the value in the payload.
Say your API namespaces the type of a model and returns the following
payload for the post
model:
// GET /api/posts/1
{
"data": {
"id": 1,
"type: "api::v1::post"
}
}
By overwriting modelNameFromPayloadType
you can specify that the
post
model should be used:
import DS from 'ember-data';
export default DS.JSONAPISerializer.extend({
modelNameFromPayloadType(payloadType) {
return payloadType.replace('api::v1::', '');
}
});
By default the modelName for a model is its singularized name in dasherized
form. Usually, Ember Data can use the correct inflection to do this for
you. Most of the time, you won't need to override
modelNameFromPayloadType
for this purpose.
Also take a look at payloadTypeFromModelName to customize how the type of a record should be serialized.
Parameters:
-
payloadType
Stringtype from payload
Returns:
modelName
normalize
-
typeClass
-
hash
`
app/serializers/application.js
import DS from 'ember-data';
import { underscore } from '@ember/string';
import { get } from '@ember/object';
export default DS.JSONSerializer.extend({
normalize(typeClass, hash) {
var fields = get(typeClass, 'fields');
fields.forEach(function(field) {
var payloadField = 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:
normalizeArrayResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeCreateRecordResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeDeleteRecordResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeFindAllResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeFindBelongsToResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeFindHasManyResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeFindManyResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeFindRecordResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeQueryRecordResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeQueryResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeRelationships
()
private
normalizeResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
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:
`
javascript
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:
normalizeSaveResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeSingleResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeUpdateRecordResponse
-
store
-
primaryModelClass
-
payload
-
id
-
requestType
Parameters:
Returns:
normalizeUsingDeclaredMapping
()
private
payloadKeyFromModelName
-
modelName
Converts the model name to a pluralized version of the model name.
For example post
would be converted to posts
and
student-assesment
would be converted to student-assesments
.
Parameters:
-
modelName
String
Returns:
payloadTypeFromModelName
-
modelname
payloadTypeFromModelName
can be used to change the mapping for the type in
the payload, taken from the model name.
Say your API namespaces the type of a model and expects the following
payload when you update the post
model:
// POST /api/posts/1
{
"data": {
"id": 1,
"type": "api::v1::post"
}
}
By overwriting payloadTypeFromModelName
you can specify that the
namespaces model name for the post
should be used:
import DS from 'ember-data';
export default JSONAPISerializer.extend({
payloadTypeFromModelName(modelName) {
return 'api::v1::' + modelName;
}
});
By default the payload type is the pluralized model name. Usually, Ember
Data can use the correct inflection to do this for you. Most of the time,
you won't need to override payloadTypeFromModelName
for this purpose.
Also take a look at modelNameFromPayloadType to customize how the model name from should be mapped from the payload.
Parameters:
-
modelname
StringmodelName from the record
Returns:
payloadType
serialize
-
snapshot
-
options
`
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:
`
javascript
{
"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';
import { singularize } from 'ember-inflector';
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(singularize(name)) + "_IDS";
}
`
This serializer will generate JSON that looks like this:
`
javascript
{
"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:
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';
import { isNone } from '@ember/utils';
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] = 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
`
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
`
app/serializers/application.js
import DS from 'ember-data';
import { decamelize } from '@ember/string';
export default DS.RESTSerializer.extend({
serializeIntoHash(data, type, snapshot, options) {
var root = decamelize(type.modelName);
data[root] = this.serialize(snapshot, options);
}
});
`
Parameters:
-
hash
Object -
typeClass
DS.Model -
snapshot
DS.Snapshot -
options
Object
serializePolymorphicType
-
snapshot
-
json
-
relationship
{ polymorphic: true }
is pass as the second argument to the
DS.belongsTo
function.
Example
`
app/serializers/comment.js
import DS from 'ember-data';
import { isNone } from '@ember/utils';
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 (isNone(belongsTo)) {
json[key + '_type'] = null;
} else {
json[key + '_type'] = belongsTo.modelName;
}
}
});
`
Parameters:
-
snapshot
DS.Snapshot -
json
Object -
relationship
Object
shouldSerializeHasMany
-
snapshot
-
key
-
relationshipType
Parameters:
-
snapshot
DS.Snapshot -
key
String -
relationshipType
String
Returns:
transformFor
-
attributeType
-
skipAssertion
Parameters:
-
attributeType
String -
skipAssertion
Boolean
Returns:
Properties
attrs
Object
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:
`
javascript
{
"firstName": "Harry",
"lastName": "Houdini",
"career": "magician"
}
`
Note that the admin
is now not included in the payload.
primaryKey
String
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'
store
DS.Store
public
store
property is the application's store
that contains
all records. It can be used to look up serializers for other model
types that may be nested inside the payload response.
Example:
`
js
Serializer.extend({
extractRelationship(relationshipModelName, relationshipHash) {
var modelClass = this.store.modelFor(relationshipModelName);
var relationshipSerializer = this.store.serializerFor(relationshipModelName);
return relationshipSerializer.normalize(modelClass, relationshipHash);
}
});
`