Class DS.ActiveModelSerializer

The extract method is used to deserialize the payload received from your data source into the form that Ember Data expects.

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:

{
  "_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:

import DS from 'ember-data';

export default 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: posts };

    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.

Returns the resource's attributes formatted as a JSON-API "attributes object".

http://jsonapi.org/format/#document-resource-object-attributes

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

extractDeleteRecord is a hook into the extract method used when a call is made to DS.Model#save and the record has been deleted. By default this method is alias for extractSave.

extractErrors is used to extract model errors when a call is made to DS.Model#save which fails with an InvalidError. By default Ember Data expects error information to be located on the errors property of the payload object.

Example

import DS from 'ember-data';

export default DS.JSONSerializer.extend({
  extractErrors: function(store, typeClass, payload, id) {
    if (payload && typeof payload === 'object' && payload._problems) {
      payload = payload._problems;
      this.normalizeErrors(typeClass, payload);
    }
    return payload;
  }
});

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.

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.

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.

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.

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.

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.

Returns the resource's ID.

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

import DS from 'ember-data';

export default DS.JSONSerializer.extend({
  extractMeta: function(store, typeClass, payload) {
    if (payload && payload._pagination) {
      store.setMetadataFor(typeClass, payload._pagination);
      delete payload._pagination;
    }
  }
});

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

Returns a relationship formatted as a JSON-API "relationship object".

http://jsonapi.org/format/#document-resource-object-relationships

Returns the resource's relationships formatted as a JSON-API "relationships object".

http://jsonapi.org/format/#document-resource-object-relationships

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.

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:

{
  "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:

import DS from 'ember-data';

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

    payload = { comments: comments, post: payload };
    return this._super(store, typeClass, 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.

extractUpdateRecord is a hook into the extract method used when a call is made to DS.Model#save and the record has been updated. By default this method is alias for extractSave.

Converts camelCased attributes to underscored when serializing.

keyForLink can be used to define a custom key when deserializing link properties. The ActiveModelSerializer camelizes link keys by default.

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

This method is used to convert each JSON root key in the payload into a modelName that it can use to look up the appropriate model for that part of the payload.

For example, your server may send a model name that does not correspond with the name of the model in your app. Let's take a look at an example model, and an example payload:

import DS from 'ember-data';

export default DS.Model.extend({
});

  {
    "blog/post": {
      "id": "1
    }
  }

Ember Data is going to normalize the payload's root key for the modelName. As a result, it will try to look up the "blog/post" model. Since we don't have a model called "blog/post" (or a file called app/models/blog/post.js in ember-cli), Ember Data will throw an error because it cannot find the "blog/post" model.

Since we want to remove this namespace, we can define a serializer for the application that will remove "blog/" from the payload key whenver it's encountered by Ember Data:

import DS from 'ember-data';

export default DS.RESTSerializer.extend({
  modelNameFromPayloadKey: function(payloadKey) {
    if (payloadKey === 'blog/post') {
      return this._super(payloadKey.replace('blog/', ''));
    } else {
     return this._super(payloadKey);
    }
  }
});

After refreshing, Ember Data will appropriately look up the "post" model.

By default the modelName for a model is its name in dasherized form. This means that a payload key like "blogPost" would be normalized to "blog-post" when Ember Data looks up the model. Usually, Ember Data can use the correct inflection to do this for you. Most of the time, you won't need to override modelNameFromPayloadKey for this purpose.

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

If your payload looks like:

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

The normalized version would look like this

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

The normalize method is used to convert a payload received from your external data source into the normalized form store.push() expects. You should override this method, munge the hash and return the normalized payload.

Normalizes an array of resource payloads and returns a JSON-API Document with primary data and, if any, included data as { data, included }.

Convert snake_cased links to camelCase

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 json = serializer.normalizeSingleResponse(store, modelClass, data, data.id);

  store.push(normalized);
});

Underscores the JSON root keys when serializing.

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

{
  "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.

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:

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.

import DS from 'ember-data';

export default DS.RESTSerializer.extend({
  serialize: function(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.

import DS from 'ember-data';

export default DS.RESTSerializer.extend({
  serialize: function(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.

import DS from 'ember-data';

export default DS.RESTSerializer.extend({
  serialize: function(snapshot, options) {
    var json = this._super(snapshot, options);

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

    return json;
  }
});

The serialize method is used when a record is saved in order to convert the record into the form that your external data source expects.

serialize takes an optional options hash with a single option:

• includeId: If this is true, serialize should include the ID in the serialized object it builds.

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:

import DS from 'ember-data';

export default DS.JSONSerializer.extend({
  serializeAttribute: function(snapshot, json, key, attributes) {
    json.attributes = json.attributes || {};
    this._super(snapshot, json.attributes, key, attributes);
  }
});

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

Example

import DS from 'ember-data';

export default DS.JSONSerializer.extend({
  serializeBelongsTo: function(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();
  }
});

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

Example

import DS from 'ember-data';

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

You can use this method to customize the root keys serialized into the JSON. By default the REST Serializer sends the modelName of a model, which is a camelized version of the name.

For example, your server may expect underscored root objects.

import DS from 'ember-data';

export default DS.RESTSerializer.extend({
  serializeIntoHash: function(data, type, record, options) {
    var root = Ember.String.decamelize(type.modelName);
    data[root] = this.serialize(record, options);
  }
});

Serializes a polymorphic type as a fully capitalized model name.

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

import DS from 'ember-data';

export default DS.JSONSerializer.extend({
  serializePolymorphicType: function(snapshot, json, relationship) {
    var key = relationship.key,
        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;
    }
  }
});