DS.ActiveModelSerializer Class

Extends: DS.RESTSerializer

Defined in:

Module: ember-data

The ActiveModelSerializer is a subclass of the RESTSerializer designed to integrate with a JSON API that uses an underscored naming convention instead of camelCasing. It has been designed to work out of the box with the activemodelserializers Ruby gem. This Serializer expects specific settings using ActiveModel::Serializers, embed :ids, include: true which sideloads the records.

This serializer extends the DS.RESTSerializer by making consistent use of the camelization, decamelization and pluralization methods to normalize the serialized JSON into a format that is compatible with a conventional Rails backend and Ember Data.

JSON Structure

The ActiveModelSerializer expects the JSON returned from your server to follow the REST adapter conventions substituting underscored keys for camelcased ones.

Conventional Names

Attribute names in your JSON payload should be the underscored versions of the attributes in your Ember.js models.

For example, if you have a Person model:

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App.FamousPerson = DS.Model.extend({
  firstName: DS.attr('string'),
  lastName: DS.attr('string'),
  occupation: DS.attr('string')
});

The JSON returned should look like this:

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{
  "famous_person": {
    "id": 1,
    "first_name": "Barack",
    "last_name": "Obama",
    "occupation": "President"
  }
}

Let's imagine that Occupation is just another model:

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App.Person = DS.Model.extend({
  firstName: DS.attr('string'),
  lastName: DS.attr('string'),
  occupation: DS.belongsTo('occupation')
});

App.Occupation = DS.Model.extend({
  name: DS.attr('string'),
  salary: DS.attr('number'),
  people: DS.hasMany('person')
});

The JSON needed to avoid extra server calls, should look like this:

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{
  "people": [{
    "id": 1,
    "first_name": "Barack",
    "last_name": "Obama",
    "occupation_id": 1
  }],

  "occupations": [{
    "id": 1,
    "name": "President",
    "salary": 100000,
    "person_ids": [1]
  }]
}
Show:

_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

applyTransforms

(type, 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:

type subclass of DS.Model
data Object
The data to transform

Returns:

Object
data The transformed data object

extract

(store, type, payload, id, requestType) Object

The extract method is used to deserialize payload data from the server. By default the JSONSerializer does not push the records into the store. However records that subclass JSONSerializer such as the RESTSerializer may push records into the store as part of the extract call.

This method delegates to a more specific extract method based on the requestType.

Example

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var get = Ember.get;
socket.on('message', function(message) {
  var modelName = message.model;
  var data = message.data;
  var type = store.modelFor(modelName);
  var serializer = store.serializerFor(type.typeKey);
  var record = serializer.extract(store, type, data, get(data, 'id'), 'single');
  store.push(modelName, record);
});

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractArray

(store, primaryType, payload) Array

Called when the server has returned a payload representing multiple records, such as in response to a findAll or findQuery.

It is your opportunity to clean up the server's response into the normalized form expected by Ember Data.

If you want, you can just restructure the top-level of your payload, and do more fine-grained normalization in the normalize method.

For example, if you have a payload like this in response to a request for all posts:

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{
  "_embedded": {
    "post": [{
      "id": 1,
      "title": "Rails is omakase"
    }, {
      "id": 2,
      "title": "The Parley Letter"
    }],
    "comment": [{
      "_id": 1,
      "comment_title": "Rails is unagi"
      "post_id": 1
    }, {
      "_id": 2,
      "comment_title": "Don't tread on me",
      "post_id": 2
    }]
  }
}

You could implement a serializer that looks like this to get your payload into shape:

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App.PostSerializer = DS.RESTSerializer.extend({
  // First, restructure the top-level so it's organized by type
  // and the comments are listed under a post's `comments` key.
  extractArray: function(store, type, payload) {
    var posts = payload._embedded.post;
    var comments = [];
    var postCache = {};

    posts.forEach(function(post) {
      post.comments = [];
      postCache[post.id] = post;
    });

    payload._embedded.comment.forEach(function(comment) {
      comments.push(comment);
      postCache[comment.post_id].comments.push(comment);
      delete comment.post_id;
    });

    payload = { comments: comments, posts: payload };

    return this._super(store, type, payload);
  },

  normalizeHash: {
    // Next, normalize individual comments, which (after `extract`)
    // are now located under `comments`
    comments: function(hash) {
      hash.id = hash._id;
      hash.title = hash.comment_title;
      delete hash._id;
      delete hash.comment_title;
      return hash;
    }
  }
})

When you call super from your own implementation of extractArray, the built-in implementation will find the primary array in your normalized payload and push the remaining records into the store.

The primary array is the array found under posts.

The primary record has special meaning when responding to findQuery or findHasMany. In particular, the primary array will become the list of records in the record array that kicked off the request.

If your primary array contains secondary (embedded) records of the same type, you cannot place these into the primary array posts. Instead, place the secondary items into an underscore prefixed property _posts, which will push these items into the store and will not affect the resulting query.

Parameters:

store DS.Store
primaryType subclass of DS.Model
payload Object

Returns:

Array
The primary array that was returned in response to the original query.

extractCreateRecord

(store, type, payload, id, requestType) Object

extractCreateRecord is a hook into the extract method used when a call is made to DS.Store#createRecord. By default this method is alias for extractSave.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractDeleteRecord

(store, type, payload, id, requestType) Object

extractDeleteRecord is a hook into the extract method used when a call is made to DS.Store#deleteRecord. By default this method is alias for extractSave.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractFind

(store, type, payload, id, requestType) Object

extractFind is a hook into the extract method used when a call is made to DS.Store#find. By default this method is alias for extractSingle.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractFindAll

(store, type, payload, id, requestType) Array

extractFindAll is a hook into the extract method used when a call is made to DS.Store#findAll. By default this method is an alias for extractArray.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Array
array An array of deserialized objects

extractFindBelongsTo

(store, type, payload, id, requestType) Object

extractFindBelongsTo is a hook into the extract method used when a call is made to DS.Store#findBelongsTo. By default this method is alias for extractSingle.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractFindHasMany

(store, type, payload, id, requestType) Array

extractFindHasMany is a hook into the extract method used when a call is made to DS.Store#findHasMany. By default this method is alias for extractArray.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Array
array An array of deserialized objects

extractFindMany

(store, type, payload, id, requestType) Array

extractFindMany is a hook into the extract method used when a call is made to DS.Store#findMany. By default this method is alias for extractArray.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Array
array An array of deserialized objects

extractFindQuery

(store, type, payload, id, requestType) Array

extractFindQuery is a hook into the extract method used when a call is made to DS.Store#findQuery. By default this method is an alias for extractArray.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Array
array An array of deserialized objects

extractMeta

(store, type, 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

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App.PostSerializer = DS.JSONSerializer.extend({
  extractMeta: function(store, type, payload) {
    if (payload && payload._pagination) {
      store.metaForType(type, payload._pagination);
      delete payload._pagination;
    }
  }
});

Parameters:

store DS.Store
type subclass of DS.Model
payload Object

extractSave

(store, type, payload, id, requestType) Object

extractSave is a hook into the extract method used when a call is made to DS.Model#save. By default this method is alias for extractSingle.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

extractSingle

(store, primaryType, payload, recordId) Object

Called when the server has returned a payload representing a single record, such as in response to a find or save.

It is your opportunity to clean up the server's response into the normalized form expected by Ember Data.

If you want, you can just restructure the top-level of your payload, and do more fine-grained normalization in the normalize method.

For example, if you have a payload like this in response to a request for post 1:

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{
  "id": 1,
  "title": "Rails is omakase",

  "_embedded": {
    "comment": [{
      "_id": 1,
      "comment_title": "FIRST"
    }, {
      "_id": 2,
      "comment_title": "Rails is unagi"
    }]
  }
}

You could implement a serializer that looks like this to get your payload into shape:

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App.PostSerializer = DS.RESTSerializer.extend({
  // First, restructure the top-level so it's organized by type
  extractSingle: function(store, type, payload, id) {
    var comments = payload._embedded.comment;
    delete payload._embedded;

    payload = { comments: comments, post: payload };
    return this._super(store, type, payload, id);
  },

  normalizeHash: {
    // Next, normalize individual comments, which (after `extract`)
    // are now located under `comments`
    comments: function(hash) {
      hash.id = hash._id;
      hash.title = hash.comment_title;
      delete hash._id;
      delete hash.comment_title;
      return hash;
    }
  }
})

When you call super from your own implementation of extractSingle, the built-in implementation will find the primary record in your normalized payload and push the remaining records into the store.

The primary record is the single hash found under post or the first element of the posts array.

The primary record has special meaning when the record is being created for the first time or updated (createRecord or updateRecord). In particular, it will update the properties of the record that was saved.

Parameters:

store DS.Store
primaryType subclass of DS.Model
payload Object
recordId String

Returns:

Object
the primary response to the original request

extractUpdateRecord

(store, type, payload, id, requestType) Object

extractUpdateRecord is a hook into the extract method used when a call is made to DS.Store#update. By default this method is alias for extractSave.

Parameters:

store DS.Store
type subclass of DS.Model
payload Object
id String or Number
requestType String

Returns:

Object
json The deserialized payload

keyForAttribute

(attribute)
Inherited from DS.JSONSerializer but overwritten in

Converts camelCased attributes to underscored when serializing.

Parameters:

attribute String

Returns:

String

keyForRelationship

(key, kind)
Inherited from DS.JSONSerializer but overwritten in

Underscores relationship names and appends "id" or "ids" when serializing relationship keys.

Parameters:

key String
kind String

Returns:

String

normalize

(type, hash, prop)
Inherited from DS.RESTSerializer but overwritten in

Add extra step to DS.RESTSerializer.normalize so links are normalized.

If your payload looks like:

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{
  "post": {
    "id": 1,
    "title": "Rails is omakase",
    "links": { "flagged_comments": "api/comments/flagged" }
  }
}

The normalized version would look like this

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{
  "post": {
    "id": 1,
    "title": "Rails is omakase",
    "links": { "flaggedComments": "api/comments/flagged" }
  }
}

Parameters:

type subclass of DS.Model
hash Object
prop String

Returns:

Object

normalizeAttributes

private

normalizeId

private

normalizeLinks

(data)
Defined in

Convert snake_cased links to camelCase

Parameters:

data Object

normalizePayload

(payload) Object

You can use this method to normalize all payloads, regardless of whether they represent single records or an array.

For example, you might want to remove some extraneous data from the payload:

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App.ApplicationSerializer = DS.JSONSerializer.extend({
  normalizePayload: function(payload) {
    delete payload.version;
    delete payload.status;
    return payload;
  }
});

Parameters:

payload Object

Returns:

Object
the normalized payload

normalizeRelationships

private
Inherited from DS.JSONSerializer but overwritten in

Normalize the polymorphic type from the JSON.

Normalize: js { id: "1" minion: { type: "evil_minion", id: "12"} }

To: js { id: "1" minion: { type: "evilMinion", id: "12"} }

normalizeUsingDeclaredMapping

private

pushPayload

(store, payload)

This method allows you to push a payload containing top-level collections of records organized per type.

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{
  "posts": [{
    "id": "1",
    "title": "Rails is omakase",
    "author", "1",
    "comments": [ "1" ]
  }],
  "comments": [{
    "id": "1",
    "body": "FIRST"
  }],
  "users": [{
    "id": "1",
    "name": "@d2h"
  }]
}

It will first normalize the payload, so you can use this to push in data streaming in from your server structured the same way that fetches and saves are structured.

Parameters:

store DS.Store
payload Object

serialize

(record, 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:

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App.Comment = DS.Model.extend({
  title: DS.attr(),
  body: DS.attr(),

  author: DS.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 (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.

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App.PostSerializer = DS.RESTSerializer.extend({
  serialize: function(post, options) {
    var json = {
      POST_TTL: post.get('title'),
      POST_BDY: post.get('body'),
      POST_CMS: post.get('comments').mapBy('id')
    }

    if (options.includeId) {
      json.POST_ID_ = post.get('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.

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App.ApplicationSerializer = DS.RESTSerializer.extend({
  serialize: function(record, options) {
    var json = {};

    record.eachAttribute(function(name) {
      json[serverAttributeName(name)] = record.get(name);
    })

    record.eachRelationship(function(name, relationship) {
      if (relationship.kind === 'hasMany') {
        json[serverHasManyName(name)] = record.get(name).mapBy('id');
      }
    });

    if (options.includeId) {
      json.ID_ = record.get('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:

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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.

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App.PostSerializer = DS.RESTSerializer.extend({
  serialize: function(record, options) {
    var json = this._super(record, options);

    json.subject = json.title;
    delete json.title;

    return json;
  }
});

Parameters:

record subclass of DS.Model
options Object

Returns:

Object
json

serializeAttribute

(record, 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:

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App.ApplicationSerializer = DS.JSONSerializer.extend({
  serializeAttribute: function(record, json, key, attributes) {
    json.attributes = json.attributes || {};
    this._super(record, json.attributes, key, attributes);
  }
});

Parameters:

record DS.Model
json Object
key String
attribute Object

serializeBelongsTo

(record, json, relationship)

serializeBelongsTo can be used to customize how DS.belongsTo properties are serialized.

Example

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App.PostSerializer = DS.JSONSerializer.extend({
  serializeBelongsTo: function(record, json, relationship) {
    var key = relationship.key;

    var belongsTo = get(record, key);

    key = this.keyForRelationship ? this.keyForRelationship(key, "belongsTo") : key;

    json[key] = Ember.isNone(belongsTo) ? belongsTo : belongsTo.toJSON();
  }
});

Parameters:

record DS.Model
json Object
relationship Object

serializeHasMany

(record, json, relationship)

serializeHasMany can be used to customize how DS.hasMany properties are serialized.

Example

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App.PostSerializer = DS.JSONSerializer.extend({
  serializeHasMany: function(record, json, relationship) {
    var key = relationship.key;
    if (key === 'comments') {
      return;
    } else {
      this._super.apply(this, arguments);
    }
  }
});

Parameters:

record DS.Model
json Object
relationship Object

serializeIntoHash

(hash, type, record, options)
Inherited from DS.RESTSerializer but overwritten in

Underscores the JSON root keys when serializing.

Parameters:

hash Object
type subclass of DS.Model
record DS.Model
options Object

serializePolymorphicType

(record, json, relationship)
Inherited from DS.RESTSerializer but overwritten in

Serializes a polymorphic type as a fully capitalized model name.

Parameters:

record DS.Model
json Object
relationship Object

transformFor

(attributeType, skipAssertion) DS.Transform private

Parameters:

attributeType String
skipAssertion Boolean

Returns:

DS.Transform
transform

typeForRoot

(key) String

This method is used to convert each JSON root key in the payload into a typeKey that it can use to look up the appropriate model for that part of the payload. By default the typeKey for a model is its name in camelCase, so if your JSON root key is 'fast-car' you would use typeForRoot to convert it to 'fastCar' so that Ember Data finds the FastCar model.

If you diverge from this norm you should also consider changes to store._normalizeTypeKey as well.

For example, your server may return prefixed root keys like so:

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{
  "response-fast-car": {
    "id": "1",
    "name": "corvette"
  }
}

In order for Ember Data to know that the model corresponding to the 'response-fast-car' hash is FastCar (typeKey: 'fastCar'), you can override typeForRoot to convert 'response-fast-car' to 'fastCar' like so:

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App.ApplicationSerializer = DS.RESTSerializer.extend({
  typeForRoot: function(root) {
    // 'response-fast-car' should become 'fast-car'
    var subRoot = root.substring(9);

    // _super normalizes 'fast-car' to 'fastCar'
    return this._super(subRoot);
  }
});

Parameters:

key String

Returns:

String
the model's typeKey
Show:

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

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App.Person = DS.Model.extend({
  firstName: DS.attr('string'),
  lastName: DS.attr('string'),
  occupation: DS.attr('string'),
  admin: DS.attr('boolean')
});

App.PersonSerializer = 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

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App.PersonSerializer = DS.JSONSerializer.extend({
  attrs: {
    admin: {serialize: false},
    occupation: {key: 'career'}
  }
});

When serialized:

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{
  "career": "magician"
}

Note that the admin is now not included in the payload.

normalizeHash

{Object}

If you want to do normalizations specific to some part of the payload, you can specify those under normalizeHash.

For example, given the following json where the the IDs under "comments" are provided as _id instead of id.

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{
  "post": {
    "id": 1,
    "title": "Rails is omakase",
    "comments": [ 1, 2 ]
  },
  "comments": [{
    "_id": 1,
    "body": "FIRST"
  }, {
    "_id": 2,
    "body": "Rails is unagi"
  }]
}

You use normalizeHash to normalize just the comments:

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App.PostSerializer = DS.RESTSerializer.extend({
  normalizeHash: {
    comments: function(hash) {
      hash.id = hash._id;
      delete hash._id;
      return hash;
    }
  }
});

The key under normalizeHash is usually just the original key that was in the original payload. However, key names will be impacted by any modifications done in the normalizePayload method. The DS.RESTSerializer's default implementation makes no changes to the payload keys.

Default: undefined

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

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App.ApplicationSerializer = DS.JSONSerializer.extend({
  primaryKey: '_id'
});

Default: 'id'