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BREAKING CHANGES

This file lists breaking changes, ordered by revision number.

When you instantiate your adapter, include the API revision number, and ember-data will automatically warn you of any breaking changes.

The ember-data project follows semver versioning. Because we have not yet reached 1.0, breaking changes are allowed, but we want to make sure that you are alerted to intentional breaking changes.

Once we reach 1.0, we will remove this mechanism and use normal version numbers to indicate breaking changes.

Example:

App.Store = DS.Store.create({
  revision: 1
});

If a breaking change has been made to API revision 1, you will receive an exception pointing you to this document. Once you have reviewed the breaking changes and made any necessary changes to your application, you will want to update the revision:

App.Store = DS.Store.create({
  revision: 2
});

This will remove the exception about changes before revision 2. You will receive another warning if there is another change.

Revision 12

Several changes have been made to serialization conventions for the JSON and REST adapters.

Foreign Key IDs for Arrays

In order to be consistent with singular foreign keys, the REST serializer now serializes arrays of foreign keys with the singular form of the key name suffixed with _ids. Therefore, just as author_id represents a single author, author_ids (and not authors) now represents an array of authors associated with a parent record.

Custom key mappings can be configured to override these defaults as needed.

Sideload by Type

When loading data, the previous convention was to expect sideloaded data to be included alongside a parent record based on the name of its relationship.

For instance, given the following model:

App.Contact  = DS.Model.extend({
  name:         DS.attr('string'),
  phoneNumbers: DS.hasMany('App.PhoneNumber'),
  homeAddress:  DS.belongsTo('App.Address')
  workAddress:  DS.belongsTo('App.Address')
});

... the following payload would be deserialized properly:

{
  "contact": {
    "id": 1,
    "name": "Dan",
    "phone_numbers": [1, 2],
    "home_address_id": 3
    "work_address_id": 4
  },
  "phoneNumbers": [
    {
      "id": 1,
      "number": "555-1212"
    },
    {
      "id": 2,
      "number": "555-2222"
    }
  ],
  "homeAddress": [
    {
      "id": 3,
      "zip_code": "03086"
    }
  ],
  "workAddress": [
    {
      "id": 4,
      "zip_code": "94107"
    }
  ]
}

Now, homeAddress and workAddress will be expected to be sideloaded together as addresses because they are the same type. Furthermore, the default root naming conventions (underscore and lowercase) will now also be applied to sideloaded root names.

The new, more consistent and concise conventions for sideloading are:

{
  "contact": {
    "id": 1,
    "name": "Dan",
    "phone_number_ids": [1, 2],
    "home_address_id": 3
    "work_address_id": 4
  },
  "phone_numbers": [
    {
      "id": 1,
      "number": "555-1212"
    },
    {
      "id": 2,
      "number": "555-2222"
    }
  ],
  "addresses": [
    {
      "id": 3,
      "zip_code": "03086"
    },
    {
      "id": 4,
      "zip_code": "94107"
    }
  ]
}

Custom sideloadAs and key mappings can still be configured to override these defaults as required.

Revision 11

Payload Extraction

Previously, the serializer was responsible for materializing a single record. The adapter was responsible for decomposing multi-record payloads into digestible chunks that the serializer could handle.

For example, the REST adapter supports "sideloading", which allows you to include related records in a compact way. For example, the JSON payload for a blog post and its comments may look like this:

{
  "post": {
    "id": 1,
    "title": "Rails is omakase",
    "comments": [1, 2, 3]
  },

  "comments": [{
    "id": 1,
    "body": "But is it _lightweight_ omakase?"
  },
  {
    "id": 2,
    "body": "I for one welcome our new omakase overlords"
  },
  {
    "id": 3,
    "body": "Put me on the fast track to a delicious dinner"
  }]
}

Previously, the adapter would tease out each of the individual record representations here, then pass them, one at a time, to the serializer.

We realized that conceptually it made more sense for the serializer to be responsible for extracting records from the entire payload.

This became particularly important for us as we were working on the new embedded feature. Because records may now include other records embedded inside their JSON representation (arbitrarily deep), the lines between the entire payload and an individual record representation became blurred.

If you are sideloading data in your application and you are using JSONSerializer (like the DS.RESTAdapter does by default), you will need to utilize the DS.Adapter configure method for configuration:

DS.RESTAdapter.configure('App.Post', {
  sideloadAs: 'posts' 
});

New Adapter Acknowledgment API

Previously, if you were writing a custom adapter, you would acknowledge that you had saved outstanding changes to your persistence layer by invoking the related method on the store. For example, if the store asked your adapter to update a given record, you would call store.didSaveRecord(record); when you had completed the operation.

Because we noticed that there was significant boilerplate around this operation, especially given the changes described above, the acknowledgment hooks now live on the adapter and not the store. This allows us to implement default behavior that interacts with both the serializer and the store on your behalf, making authoring adapters easier.

For example, instead of this:

updateRecord: function(store, type, record) {
  this.ajax('/person/'+record.get('id'), {
    success: function(json) {
      store.didSaveRecord(record, json);
    }
  });
}

You would now call the adapter's own didSaveRecord:

updateRecord: function(store, type, record) {
  this.ajax('/person/'+record.get('id'), {
    success: function(json) {
      this.didSaveRecord(store, type, record, json);
    }
  });
}

Making this small change automatically gives you support for sideloaded and embedded records.

Previously, if the store asked your adapter to find a record by calling its find method, you could simply load the record with the given ID into the store by calling store.load():

find: function(store, type, id) {
  var url = type.url;
  url = url.fmt(id);

  jQuery.getJSON(url, function(data) {
    store.load(type, id, data);
  });
}

Now, you should instead call the adapter's own didFindRecord acknowledgment method:

find: function(store, type, id) {
  var url = type.url,
      self = this;

  url = url.fmt(id);

  jQuery.getJSON(url, function(data) {
    self.didFindRecord(store, type, data, id);
  });
}

Like with the above improvements, this small change automatically add support for sideloaded and embedded records when your JSON server responds to a request for a record.

Similarly, you should call the new adapter hooks didFindAll, didFindQuery, and didFindMany when acknowledging the associated operation.

Normalized Relationship Names

Throughout Ember Data, we were referring to relationships as either "relationships" or "associations." We have now tightened up our terminology (and the related APIs) to always refer to them as relationships.

For example, DS.Model's eachAssociation became eachRelationship.

Loading Data

Previously, some features of the store, such as load(), assumed a single adapter.

If you want to load data from your backend without the application asking for it (for example, through a WebSockets stream), use this API:

store.adapterForType(App.Person).load(store, App.Person, payload);

This API will also handle sideloaded and embedded data. We plan to add a more convenient version of this API in the future.

Changes to Dirtying Records

If you previously implemented the developer hooks in your adapter for dirtyRecordsForHasManyChange or any of the other dirtyRecords hooks, you will need to double check how you're utilizing the passed in arguments.

A description of the relationship is now passed in representing both sides of the relationship.

For example, if you had this previously:

dirtyRecordsForHasManyChange: function(dirtySet, parent, relationship){
  if (relationship.hasManyName === "people") {
    dirtySet.add(parent);
  }
}

You would now use this:

dirtyRecordsForHasManyChange: function(dirtySet, parent, relationship){
  if (relationship.secondRecordName === "people") {
    dirtySet.add(parent);
  }
}

TL;DR

If you are using the REST adapter, you can now include embedded records without making any changes. Additionally, if you are sideloading records, you will need to make the changes described in the Payload Extraction section.

If you were manually loading data into the store, use the new Adapter#load API instead of Store#load.

Revision 10

In Revision 8, we started the work of making serializers agnostic to the underlying serialization format.

This was a good start but did not go far enough. Additionally, many people hated our initial API naming decisions, so some of the changes in this revision are an attempt to evolve the naming in a more intuitive direction.

JSON Serializer

Despite our attempts in Revision 8, there were still some lingering JSON semantics in DS.Serializer. Now, we have extracted all of these into a new class called DS.JSONSerializer, which inherits from DS.Serializer.

DS.Serializer is an abstract base class that implements hooks for serializing records common to all serialization formats, whether they are JSON, typed arrays, binary representations, or whatever other format your server engineers dream up.

DS.JSONSerializer is a concrete implementation that encodes specific JSON semantics. If your adapter needs to "speak JSON" and you need to customize how that happens, you should now subclass DS.JSONSerializer instead of DS.Serializer.

Additionally, DS.RESTAdapter uses a subclass of DS.JSONSerializer called DS.RESTSerializer. The RESTSerializer adds relational semantics to the JSONSerializer, encoding one-to-many relationships as foreign keys on child records.

TL;DR

If you are using the REST adapter, no changes are necessary.

If your app was subclassing DS.Serializer, change it to subclass DS.JSONSerializer.

If you are serializing to binary representations, hooray! You can use DS.Serializer and you will not need to fight against assumptions about it being JSON. This is a very advanced use case that most users will not need to worry about.

fromData/toData Rename

Feedback about our rename of the toJSON method to toData and fromJSON to fromData was not positive. Instead, we are now changing these to serialize and deserialize, respectively. This change applies to DS.Model, DS.Serializer, and the serializer's transform API.

Revision 9

Adapter-Specified Record Dirtying

One of the goals of Ember Data is to separate application semantics from server semantics. For example, you should be able to handle changes to a back-end API formats with minimal changes to your application's code. You could even switch to using a browser-resident database like IndexedDB or WebSQL and have only a single file to change.

Ember Data accomplishes this by isolating server-specific code in the adapter. The adapter is responsible for translating application-specific semantics into the appropriate actions for the current backend.

To do this, the store must be able to provide as much information as possible to the adapter, so that developers can write adapters for key-value stores, like Riak and MongoDB; JSON APIs powered by relational databases, like Rails talking to PostgreSQL or MySQL; novel transport mechanisms, like WebSockets; local databases, like IndexedDB; and whatever other persistence schemes may be dreamed up in the future.

Previously, the store would gather up as much information as possible as changes happened in the application. Only when the current transaction was committed (via transaction.commit() or store.commit()) would all of the information about what changed be bundled up and sent to the adapter to be saved.

Remember that the store needs to keep track of the state of records so it knows what needs to be saved. In particular, a record loaded into the store starts off "clean"—this means that, as far as we know, the copy we have on the client is the same as the copy on the server.

A record becomes "dirty" when we change it in some way from the version we received from the server.

Obviously, a record becomes dirty if we change an attribute. For example, if we change a record's firstName attribute from "Peter" to "Louis", the record is dirty.

But what happens if the relationship between two records changes? Which records should be considered dirty?

Consider the case where we have two App.User records, user1 and user2, and an App.Post record, post, which represents a blog post. We want to change the author of the post from user1 to user2:

post.get('author');
//=> user1
post.set('author', user2);

Now, which of these records should we consider dirty? That is, which of these records needs to be sent to the adapter to be saved? Just the post? The old author, user1? The new author, user2? All three?

Your answer to this question depends heavily on how you are encoding your relationships, which itself depends heavily on the persistence strategy you're using.

If you're using a key-value store, like IndexedDB or Riak, your instinct is probably to save one-to-many relationships on the parent. For example, if you were sending the JSON for user2 to your server via XHR, it would probably look something like this:

{
  "author": {
    "name": "Tony",
    "posts": [1, 2, 3]
  }
}

If, on the other hand, you were using a relational database with something like Ruby on Rails, your instinct would probably be to encode the relationship as a foreign key on the child. In other words, when this relationship changed, you would send post to the server via a JSON representation that looked like this:

{
  "post": {
    "title": "Allen Ginsberg on Node.js",
    "body": "I saw the best minds of my generation destroyed by madness, starving hysterical naked, dragging themselves through the negro streets at dawn looking for an angry fix,\
angelheaded hipsters burning for the ancient heavenly connection to the starry dynamo in the machinery of night,\
who poverty and tatters and hollow-eyed and high sat up smoking in the supernatural darkness of cold-water flats floating across the tops of cities contemplating jazz",

    "author_id": 1
  }
}

Previously, Ember Data implemented a strategy of picking the "lowest common denominator." In other words, because we did not know what information the adapter needed, or how it would encode relationships, we simply marked all records involved in a relationship change (old parent, new parent, and child) as dirty. If the adapter did not need to send changes to the server for a particular record, it was the responsibility of the adapter to immediately release those unneeded records.

This strategy served us well, until we came to the case of embedded records (which we are working on, but have not yet finished). In this case, choosing the "lowest common denominator" strategy and marking all records that could possibly be dirty quickly became pathological.

Imagine the case where you are writing a blog app. For legacy reasons, your JSON API embeds comments inside of posts, which are themselves embedded inside a root blog object. So, for example, when your app asks for a particular blog, it receives back a JSON payload that looks like this:

{
  "blog": {
    "title": "Shit HN Says",
    "posts": [{
      "title": "Achieving Roflscale",
      "comments": [{
        "body": "Why not choose a more lightweight solution?",
        "upvotes": 256
      }]
    }]
  }
}

Let's say we want to upvote the comment:

comment.incrementProperty('upvotes');

In this particular case, we actually need to mark the entire graph as dirty. And because the store had no visibility into whether or not the adapter treated records as embedded, the "lowest common denominator" rule that we had used before meant that we would have to mark entire graphs as dirty if a single attribute changed.

We knew we would be pilloried if we tried to suggest that as a serious solution to the problem.

So, after much discussion, we have introduced several new hooks into the adapter. These hooks allow the store to ask the adapter about dirtying semantics as soon as changes happen. This is a fundamental change from how the adapter/store relationship worked before.

Previously, the only time the store conferred with the adapter was when committing a transaction (with the exception of extractId, which is used to preprocess data payloads from the adapter).

Now, every time an attribute or relationship changes, it is the adapter's responsibility to populate the set of records which the store should consider dirty.

Here are the hooks available at present:

  • dirtyRecordsForAttributeChange
  • dirtyRecordsForBelongsToChange
  • dirtyRecordsForHasManyChange

Each hook gets passed a dirtySet that it should populate with records to consider dirty, via the add() method.

An implementation of the attribute change hook might look like this:

dirtyRecordsForAttributeChange: function(dirtySet, record, attributeName, newValue, oldValue) {
  // Only mark the record as dirty if the new value
  // is different from the old value
  if (newValue !== oldValue) {
    dirtySet.add(record);
  }
}

If you are implementing an adapter with relational semantics, you can tell the store to only dirty child records in response to relationship changes like this:

dirtyRecordsForBelongsToChange: function(dirtySet, child) {
  dirtySet.add(child);
}

Adapters with key-value semantics would simply implement the same hook for has-many changes:

dirtyRecordsForHasManyChange: function(dirtySet, parent) {
  dirtySet.add(parent);
}

As we explore this brave new world together, you can expect similar "runtime hooks" (as opposed to commit-time hooks) to appear in the adapter API.

TL;DR

Adapters can now tell the store which records become dirty in response to changes. If you are using the built-in DS.RESTAdapter, these changes do not affect you.

Removal of Dirty Factors

Previously, your adapter could query a record for the reasons it had been considered dirty. For example, record.isDirtyBecause('belongsTo') would return true if the adapter was dirty because one of its belongsTo relationships had changed.

This was necessary because the adapter received all of the records associated with a relationship change at once, and had to "reverse engineer" what had happened and which records it cared about (see above section for more discussion.)

Now, because adapters are notified about changes as they happen, and can control which items are marked as dirty, it is no longer necessary for adapters to be able to introspect records for why they are dirty; de facto, if they are being given to the adapter, it is because the adapter told the store it wanted them to be dirty.

Therefore, DS.Model's isDirtyBecause() method has been removed. If you still need this information in your adapter, it will be your responsibility to do any bookkeeping in the dirtyRecordsForAttributeChange hook described above.

Single Commit Acknowledgment Hook

Previously, the store took responsibility for tracking which things were dirty about a record. Only after all "dirty factors" had been acknowledged by the adapter as saved would the store transition the record back into the "clean" state.

Now, responsibility for transitioning a record is solely the adapter's. This architecture lays the groundwork for the ability to have multiple adapters; for example, you can imagine having an IndexedDB-based write-through cache adapter for offline mode, and a WebSockets-based adapter for when your user has an internet connection.

Previous "acknowledgement" API methods on the store have been removed, such as didCreateRecord() and didDeleteRecord(). Now, the only acknowledgement an adapter can perform is didSaveRecord(), which tells the store that all changes to the record have been saved.

If saving changes to a record is not an atomic operation in your adapter, keeping track of which more granular operations have occurred is now the responsibility of the adapter.

Revision 8

Making Data Format-Agnostic

Previously, many areas of Ember Data assumed that data exchanged with the adapter was represented in JSON form. Many of the serializer APIs cemented this bias by including JSON in method names.

While we anticipate that most Ember.js applications will continue to use JSON as the primary mechanism for data interchange with a server, we also want to support innovation in how data is exchanged.

For example, MongoDB can exchange data as BSON--a binary encoded serialization of JSON. Or, if you are writing a data-heavy application, we want you to be free to transmit data to the client in whatever form is most efficient. Now that mainstream browsers support JavaScript Blob objects and TypedArrays, we anticipate this use case will become more and more common.

To that end, we have made two changes:

  1. Any information that the store needs from data provided by the adapter is interpreted via the serializer. For example, instead of asking for the ID of a data hash via data.id, the store will call the adapter's extractId method. This change should not affect applications.
  2. Any methods that contained the term JSON have been replaced with versions that use Data. For example, DS.Serializer's toJSON method has been renamed to toData. Similarly, the transformValueFromJSON method has been renamed to transformValueFromData. This change should only affect applications that use customized serializers, or were calling toJSON on records. Because only names and not semantics have changed, this should be a quick find and replace to bring your app up-to-date.

Revision 7

Acknowledging Relationships

Previously, we said that in order for your adapter to acknowledge a record as having been fully saved on the server, you would call store.didSaveRecord. In theory, this would mark all attributes and relationships as having been saved by the server.

However, this was too tightly coupled to adapters that change relationships by updating foreign keys. It was buggy in general, and didn't work at all for adapters using other strategies for persisting relationships.

Now, the adapter must treat relationships as separate entities which they acknowledge independently from records participating in them.

NOTE that if you are using the REST Adapter, we have updated it to reflect these new semantics and no changes in your app should be required.

There are three basic scenarios by which an adapter can save a relationship.

Foreign Key

An adapter can save all relationship changes by updating a foreign key on the child record. If it does this, it should acknowledge the changes when the child record is saved.

record.eachAssociation(function(name, meta) {
  if (meta.kind === 'belongsTo') {
    store.didUpdateRelationship(record, name);
  }
});

store.didSaveRecord(record, hash);

Embedded in Parent

An adapter can save one-to-many relationships by embedding IDs (or records) in the parent object. In this case, the relationship is not considered acknowledged until both the old parent and new parent have acknowledged the change.

In this case, the adapter should keep track of the old parent and new parent, and acknowledge the relationship change once both have acknowledged. If one of the two sides does not exist (e.g. the new parent does not exist because of nulling out the belongs-to relationship), the adapter should acknowledge the relationship once the other side has acknowledged.

Separate Entity

An adapter can save relationships as separate entities on the server. In this case, they should acknowledge the relationship as saved once the server has acknowledged the entity.

Revision 6

String-normalized IDs

Because a record's ID may be serialized and deserialized into the URL when using Ember.Router, it is common that the type of the ID is lost during this process. For example, if a Post has an ID of 42, serializing it to the URL /post/42 causes the ID to be coerced into a string. Once this happens, there is later ambiguity about whether the true ID is the number 42 or the string "42".

To resolve this ambiguity, the store now automatically coerces all IDs to strings. If your existing code uses numbers for IDs, they should continue to work with minimal change to your application.

Do note that if you ask a record for its id, it will always report the string representation:

var post = App.Post.find(1);
post.get('id'); // "1"

This may also have repercussions to your adapter. DS.Serializer now has a serializeId method that can be overridden to ensure that IDs are correctly formatted before being sent to the persistence layer. If you are using a custom adapter, make sure that methods like findMany are using the serializer's serializeId or serializeIds methods, if they include IDs in the data payload and your backend expects them to be in non-string format.

Revision 5

This is an extremely large refactor that changes many of the underlying semantics and object responsibilities. Primarily, we have moved many semantics that were hard-coded to relational databases to the REST adapter.

This means that Ember Data should work just as well with key-value stores as relational databases, or whatever persistence technology you choose. Additionally, changing between different types of back-end servers should have minimal impact on the Ember.js application itself.

This work also makes the FixtureAdapter less coupled to a particular backend, and sets the stage for local caching of Ember Data objects.

Mapping

Before, if you wanted to map key names from your server-provided data to your models, you would do this:

App.Post = DS.Model.extend({
  title: DS.attr('string', { key: 'TITLE' });
});

Now, all mapping is done via Adapter.map. You will now do this:

App.Adapter.map('App.Post', {
  title: { key: 'TITLE' }
});

This API works for attributes, belongs to associations and has many associations.

If you want to define a custom primary key, you will now do:

App.Adapter.map('App.Post', {
  primaryKey: '_id'
});

If you are using the RESTAdapter, you would do:

DS.RESTAdapter.map('App.Post', {
  primaryKey: '_id',
  title: { key: 'TITLE' }
});

ID as an Attribute

Some applications were erroneously declaring id as an attribute on their models. You do not need to do this. With this revision, you will start to see an error if you try.

For example, if you were doing this:

App.Person = DS.Model.extend({
  id: DS.attr('number'),
  name: DS.attr('string')
});

replace it with:

App.Person = DS.Model.extend({
  name: DS.attr('string')
});

Change in record.toJSON

In this revision, the record's toJSON method delegates directly to the adapter. This should not have any significant changes to the returned values (assuming you moved your mappings over to store.map as described above).

The one exception is that toJSON will no longer include the id by default. If you would like to include the id, call:

record.toJSON({ includeId: true });

If you were using record.toJSON in a custom adapter, make sure to include IDs where needed.

Fixtures

Because mappings and transforms are now defined on a per-adapter basis, you can use your app's attribute names in your fixtures, and not have to transform them based on your backend requirements.

Before:

App.Post = DS.Model.extend({
  primaryKey: '__id!__',
  name: DS.attr('string', { key: '!idbNAME!' }
});

App.Post.FIXTURES = [
  {
    '__id__!': 1,
    '!idbNAME!': "Tom Dale"
  },
  {
    '__id__!': 2,
    '!idbNAME!': "Yehuda Katz"
  }
]

After:

DS.RESTAdapter.map('App.Post', {
  primaryKey: '__id!__',
  name: { key: '!idbNAME!' }
});

App.Post.FIXTURES = [
  {
    id: 1,
    name: "Tom Dale"
  },
  {
    id: 2,
    name: "Yehuda Katz"
  }
]

This simplifies your fixtures, because:

  • It allows you to describe your fixtures in the language of your domain, rather than the language of your backend
  • It allows you to avoid modifying your fixtures if your backend API changes.

Pending Records

Previously, transactions would automatically determine the dependencies between records when saving.

For example, if you had these models:

App.Deck = DS.Model.extend({
  name: DS.attr('string'),
  cards: DS.hasMany('App.Card')
});

App.Card = DS.Model.extend({
  front: DS.attr('string'),
  back: DS.attr('string'),
  deck: DS.belongsTo('App.Deck')
});

If you created a deck and a related card at the same time, the transaction would automatically put the Card into a pending state until the adapter assigned the Deck an id.

Unfortunately, this hardcoded relational semantics into the application, and also exposed adapter concerns into the application.

At present, you will need to handle these dependencies yourself, by observing the parent's id property. We plan to introduce a convenience in DS.Adapter to simplify this case.

If you are using the RESTAdapter, you may have temporary issues with records created using this pattern. In the interim, make sure not to create graphs of records in the same transaction with foreign key dependencies.

Transforms

Previously, custom transforms were hardcoded into Ember Data, and there was a temporary API for adding new transforms. Additionally, these transforms were defined per-application, making it impossible for fixtures to use different serialization than the server. Fixing this also paves the way for local caching.

There is now a supported API for adding new transforms to your application's adapter.

// your backend uses Cocoa-style YES/NO for booleans
App.CocoaAdapter.registerTransform('boolean', {
  fromJSON: function(value) {
    if (value === 'YES') {
      return true;
    } else if (value === 'NO') {
      return false;
    }
  },

  toJSON: function(value) {
    if (value === true) {
      return 'YES';
    } else if (value === false) {
      return 'NO';
    }
  }
});

Once you have done this, you can define attributes that use the transform like this:

App.Person = DS.Model.extend({
  name: DS.attr('string'),
  isDrugDealer: DS.attr('boolean')
});

In general, you want to keep these types generic, so they can be replaced with other serialization if the backend changes requirements, and to support simple fixtures. For example, in this case, you would not want to define cocoaBoolean as a type and use it throughout your application.

Naming Conventions

Previously, app-wide naming conventions were defined in a model superclass using a namingConvention object.

Now, you need to define a custom serializer for your adapter:

var store = DS.Store.create({
  adapter: DS.RESTAdapter.create({
    serializer: DS.Serializer.create({
      // `post` becomes `postId`. By default, the RESTAdapter's
      // serializer adds `_id` to the decamelized name.
      keyForBelongsTo: function(type, name) {
        return this.keyForAttributeName(type, name) + "Id";
      },

      // `firstName` stays as `firstName`. By default, the
      // RESTAdapter's serializer decamelizes name.
      keyForAttributeName: function(type, name) {
        return name;
      }
    })
  })
});

Adapter Semantics

If you were using the REST Adapter before, your app should continue to work. However, if you built a custom adapter, many of the APIs have changed.

Some examples:

  • An adapter is now responsible for saving relationship changes
  • If a record is involved in a relationship change, an adapter is now responsible for determining whether any server work needs to be done. For example, a relational adapter may not need to do anything to a Post when a Comment was moved into it. A key-value adapter may not want to do anything to the Comment in the same situation.
  • An adapter is now responsible for transforming data hashes it receives from the server into attributes and associations (via its serializer)
  • An adapter is now fully responsible for transforming records into JSON hashes to send to the server (via its serializer)
  • The commit adapter method has been renamed to save. You may still need to override commit in very custom scenarios. The default commit method now coalesces relationship changes (via the new shouldCommit adapter hook) and passes them to save. Most adapters will never need to override any of these methods.
  • Instead of receiving a set of commitDetails iterators, the save method receives a list of all changed records. A new groupByType convenience method allows you to group the changed records by type. The default save method does this automatically, which means that the existing createRecords, updateRecords, and deleteRecords APIs have not changed.

Revision 4

Removal of hasOne

Previously, the DS.hasOne and DS.belongsTo associations were aliased to one another. Now, DS.belongsTo remains but DS.hasOne has been removed. We are planning on having different semantics for DS.hasOne at a later date.

Primarily, the semantic difference between the two are related to which record should be marked as dirty when the relationship changes. To ensure that the semantics of your application match the framework, please ensure that you are using DS.belongsTo at this time.

Revision 3

JSON Keys Automatically De-camelize

Previously, the key used to lookup an attribute from the JSON hash loaded into the store was the same as the attribute defined in your DS.Model. For example, if the model had a firstName attribute, we would look for the firstName property in the hash provided by the server..

If you wanted to use a different key, you would need to provide an options hash with the key property set:

App.Person = DS.Model.extend({
  firstName: DS.attr('string', { key: 'first_name' }),
  lastName: DS.attr('string', { key: 'last_name' }),
  middleName: DS.attr('string', { key: 'middle_name' })
});

This obviously got very annoying very fast.

Now, models can have a namingConvention object that is responsible for determining how record keys and hash keys are mapped. The namingConvention object should implement two functions, keyToJSONKey and foreignKey. You can create a subclass of DS.Model that you use in your application if you want to share a naming convention between all of your models:

App.Model = DS.Model.extend({
  namingConvention: {
    // LOUD NAMING CONVENTION
    // Changes fooKey to FOOKEY
    keyToJSONKey: function(key) {
      return key.toUpperCase();
    },

    // Determines the name of foreign keys in
    // belongsTo relationships
    foreignKey: function(key) {
      return key.toUpperCase()+"_ID";
    }
  }
});

By default, attributes are now de-camelized to determine hash keys, and _id is added to the association name to determine foreign keys.

For example, here is a model and what JSON hash it would expect:

App.Profile = DS.Model.extend({
  person: DS.belongsTo('App.Person'),

  firstName: DS.attr('string')
});

{
  id: 1,
  person_id: 3,
  first_name: "Steve"
}

If you want to revert to previous behavior, you can implement a simple naming convention object that returns the key passed to it:

DS.Model.reopen({
  namingConvention: {
    keyToJSONKey: function(key) {
      return key;
    },

    foreignKey: function(key) {
      return key;
    }
  }
});

Revision 2

Number Attributes

Previously, the attribute type used for number was integer. However, since it also is the correct attribute type for floats, you should now use number.

// instead of
App.Person = DS.Model.extend({
  age: DS.attr('integer')
});

// do
App.Person = DS.Model.extend({
  age: DS.attr('number')
});

Revision 1

Filter Functions

Previously, the store's filter() method took a filtering function that passed the hash in directly. It now passes a proxy object that implements a get() method.

Instead of accessing properties of the hash directly, please use get() inside your filter functions:

// instead of
var coolPeople = Person.filter(function(person) {
  return person.name.test(/Tom/);
});

// do
var coolPeople = Person.filter(function(person) {
  return person.get('name').test(/Tom/);
});

Retrieving JSON Representation in Adapters

Previously, a record's data property was a hash that contained the JSON representation of the record that should be sent to your persistence layer. Now that records store uncommitted changes in a separate hash, you should use the new toJSON() method to retrieve the data hash to be sent to the server.

We could have fixed up the data property to return the JSON representation, and used a different property internally, but didn't because:

  • Compatibility with ES5's JSON serialization protocol required the implementation of a toJSON method.
  • Before 1.0, we want to remove unnecessary cruft from the library. Since we need toJSON anyway for ES5 compatibility, we didn't want to keep around a legacy mechanism for doing the same thing.

(post 1.0, we absolutely would have left around the data hash)

// instead of
$.ajax({
  data: record.get('data')
});

// do
$.ajax({
  data: record.toJSON()
});
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