AngularJS Rails Resource

A resource factory inspired by $resource from AngularJS and Misko's recommendation.

When starting out with AngularJS and Rails we initially were using $resource but there were three things we didn't like that this gem sets out to provide:

$resource didn't return promises
Rails prefers JSON be root wrapped
Our JSON contained snake case (underscored) keys coming from our database but we didn't want to mix snake case and camel case in our UI

In case you are unfamiliar, the intent of the resource is to behave a bit like a remote model object. One of the nice things about AngularJS is that it does not require you to create specific models for all of your data which gives you a lot of freedom for treating model data as basic javascript objects. However, on the Rails side when exposing models to a javascript application you are likely going to follow the same pattern for multiple models where you will have a controller that has your basic index (query), get, create, update, delete functionality.

The resource object created by this factory simplifies access to those models by exposing a mix of "class" methods (query, get) and "instance" methods (create, update, delete/remove).

This module is being used for applications we are writing and we expect that over time that we will be adding additional functionality but we welcome contributions and suggestions.

Changes

Make sure to check the CHANGELOG for any breaking changes between releases.

Installation

Add this line to your application's Gemfile:

gem 'angularjs-rails-resource', '~> 0.2.0'

Include the javascript somewhere in your asset pipeline:

//= require angularjs/rails/resource

Dependencies

Since this is an AngularJS module it of course depends on that but more specifically the it depends on the following AngularJS services:

Usage

There are a lot of different ways that you can use the resources and we try not to force you into any specific pattern

There are more examples available in EXAMPLES.md. We also published a complete working example (including the rails side) at Employee Training Tracker application.

Basic Example

In order to create a Book resource, we would first define the factory within a module.

angular.module('book.services', ['rails']);
angular.module('book.services').factory('Book', ['railsResourceFactory', function (railsResourceFactory) {
    return railsResourceFactory({url: '/books', name: 'book'});
}]);

We would then inject that service into a controller:

angular.module('book.controllers').controller('BookShelfCtrl', ['$scope', 'Book', function ($scope, Book) {
    $scope.searching = true;
    // Find all books matching the title
    $scope.books = Book.query({title: title});
    $scope.books.then(function(results) {
        $scope.searching = false;
    }, function (error) {
        $scope.searching = false;
    });

    // Find a single book and update it
    Book.get(1234).then(function (book) {
        book.lastViewed = new Date();
        book.update();
    });

    // Create a book and save it
    new Book({title: 'Gardens of the Moon', author: 'Steven Erikson', isbn: '0-553-81957-7'}).create();
}]);

Serializer

When defining a resource, you can pass a custom serializer using the serializer configuration option.

Author = railsResourceFactory({
    url: '/authors',
    name: 'author',
    serializer: railsSerializer(function () {
        this.exclude('birthDate', 'books');
        this.nestedAttribute('books');
        this.resource('books', 'Book');
    })
});

You can also specify a serializer as a factory and inject it as a dependency.

angular.module('rails').factory('BookSerializer', function(railsSerializer) {
    return railsSerializer(function () {
        this.exclude('publicationDate', 'relatedBooks');
        this.rename('ISBN', 'isbn');
        this.nestedAttribute('chapters', 'notes');
        this.serializeWith('chapters', 'ChapterSerializer');
        this.add('numChapters', function (book) {
            return book.chapters.length;
        });
    });
});

Book = railsResourceFactory({
    url: '/books',
    name: 'book',
    serializer: 'BookSerializer'
});

Resource Creation

Creating a resource using this factory is similar to using $resource, you just call railsResourceFactory with the config options and it returns a new resource function. The resource function serves two purposes. First is that you can use (or define new) "class" methods directly accessible such as query and get to retrieve instances from the backend rails service. The second is that it allows you to use it as a constructor to create new instances of that resource giving you access to create, update, and delete instance methods (or any others you add).

Config Options

The following options are available for the config object passed to the factory function.

url - This is the url of the service. See Resource URLs below for more information.
enableRootWrapping - (Default: true) Turns on/off root wrapping on JSON (de)serialization.
name - This is the name used for root wrapping when dealing with singular instances.
pluralName (optional) - If specified this name will be used for unwrapping array results. If not specified then the serializer's pluralize method is used to calculate the plural name from the singular name.
httpConfig (optional) - By default we will add the following headers to ensure that the request is processed as JSON by Rails. You can specify additional http config options or override any of the defaults by setting this property. See the AngularJS $http API for more information.
- headers
  - Accept - application/json
  - Content-Type - application/json
defaultParams (optional) - If the resource expects a default set of query params on every call you can specify them here.
requestTransformers *(optional) - See Transformers / Interceptors
responseInterceptors (optional) - See Transformers / Interceptors
afterResponseInterceptors (optional) - See Transformers / Interceptors

NOTE: The names should be specified using camel case when using the key transformations because that happens before the root wrapping by default. For example, you should specify "publishingCompany" and "publishingCompanies" instead of "publishing_company" and "publishing_companies".

Resource URLs

The URL can be specified as one of three ways:

function (context) - You can pass your own custom function that converts a context variable into a url string
basic string - A string without any expression variables will be treated as a base URL and assumed that instance requests should append id to the end.

AngularJS expression - An expression url is evaluated at run time based on the given context for non-instance methods or the instance itself. For example, given the url expression: /stores/{storeId}/items/{id}

Item.query({category: 'Software'}, {storeId: 123}) would generate a GET to /stores/1234/items?category=Software
Item.get({storeId: 123, id: 1}) would generate a GET to /stores/123/items/1

new Item({store: 123}).create() would generate a POST to /stores/123/items
new Item({id: 1, storeId: 123}).update() would generate a PUT to /stores/123/items/1

Promises

$http documentation describes the promise data very well so I highly recommend reading that.

In addition to the fields listed in the $http documentation an additional field named originalData is added to the response object to keep track of what the field was originally pointing to. The originalData is not a deep copy, it just ensures that if response.data is reassigned that there's still a pointer to the original response.data object.

Resource Methods

Resources created using railsResourceFactory have the following class and instance methods available.

Class Methods

Constructor(data) - The Resource object can act as a constructor function for use with the JavaScript new keyword.
- data object (optional) - Optional data to set on the new instance
$url(context, path) - Returns the resource URL using the given context with the optional path appended if provided.
- context * - The context to use when building the url. See Resource URLs above for more information.
- path string (optional) - A path to append to the resource's URL.
- returns string - The resource URL
query(queryParams, context) - Executes a GET request against the resource's base url (e.g. /books).
- query params object (optional) - An map of strings or objects that are passed to $http to be turned into query parameters
- context * (optional) - A context object that is used during url evaluation to resolve expression variables
- returns promise - A promise that will be resolved with an array of new Resource instances
get(context) - Executs a GET request against the resource's url (e.g. /books/1234).
- context * - A context object that is used during url evaluation to resolve expression variables. If you are using a basic url this can be an id number to append to the url.
- returns promise A promise that will be resolved with a new instance of the Resource
$get(customUrl, queryParams) - Executes a GET request against the given URL.
- customUrl string - The url to GET
- queryParams object (optional) - The set of query parameters to include in the GET request
- returns promise A promise that will be resolved with a new Resource instance (or instances in the case of an array response).
$post(customUrl, data), $put(customUrl, data), $patch(customUrl, data) - Serializes the data parameter using the Resource's normal serialization process and submits the result as a POST / PUT / PATCH to the given URL.
- customUrl string - The url to POST / PUT / PATCH to
- data object - The data to serialize and POST / PUT / PATCH
- returns promise A promise that will be resolved with a new Resource instance (or instances in the case of an array response).
$delete(customUrl) - Executes a DELETE to a custom URL. The main difference between this and $http.delete is that a server response that contains a body will be deserialized using the normal Resource deserialization process.
- customUrl string - The url to DELETE to
- returns promise A promise that will be resolved with a new Resource instance (or instances in the case of an array response) if the server includes a response body.
beforeRequest(fn(data, resource)) - See Transformers for more information. The function is called prior to the serialization process so the data passed to the function is still a Resource instance as long as another transformation function has not returned a new object to serialize.
- fn(data, resource) function - The function to add as a transformer.
  - data object - The data being serialized
  - resource class - The Resource class that is calling the function
  - returns | undefined - If the function returns a new object that object will instead be used for serialization.
beforeResponse(fn(data, resource, context)) - See Interceptors for more information. The function is called after the response data has been deserialized.
- fn(data, resource, context) function - The function to add as an interceptor
  - data object - The data received from the server
  - resource function - The Resource constructor that is calling the function
  - context Resource|undefined - The Resource instance that is calling the function or undefined if called from a class level method (get, query).
afterResponse(fn(data, resource, context)) - See Interceptors for more information. This function is called after all internal processing and beforeResponse callbacks have been completed.
- fn(data, resource) function - The function to add as an interceptor
  - data object - The result, either an array of resource instances or a single resource instance.
  - resource function - The Resource constructor that is calling the function

Instance Methods

The instance methods can be used on any instance (created manually or returned in a promise response) of a resource. All of the instance methods will update the instance in-place on response and will resolve the promise with the current instance.

$url(path) - Returns this Resource instance's URL with the optional path appended if provided.
- path string (optional) - A path to append to the resource's URL.
create() - Submits the resource instance to the resource's base URL (e.g. /books) using a POST
- returns promise - A promise that will be resolved with the instance itself
update() - Submits the resource instance to the resource's URL (e.g. /books/1234) using a PUT
- returns promise - A promise that will be resolved with the instance itself
save() - Calls create if isNew returns true, otherwise it calls update.
remove(), delete() - Executes an HTTP DELETE against the resource's URL (e.g. /books/1234)
- returns promise - A promise that will be resolved with the instance itself
$post(customUrl), $put(customUrl), $patch(customUrl) - Serializes and submits the instance using an HTTP POST/PUT/PATCH to the given URL.
- customUrl string - The url to POST / PUT / PATCH to
- returns promise - A promise that will be resolved with the instance itself
$delete(customUrl) - Executes a DELETE to a custom URL. The main difference between this and $http.delete is that a server response that contains a body will be deserialized using the normal Resource deserialization process.
- customUrl string - The url to DELETE to
- returns promise - A promise that will be resolved with the instance itself

Serializers

Out of the box, resources serialize all available keys and transform key names between camel case and underscores to match Ruby conventions. However, that basic serialization often isn't ideal in every situation. With the serializers users can define customizations that dictate how serialization and deserialization is performed. Users can: rename attributes, specify extra attributes, exclude attributes with the ability to exclude all attributes by default and only serialize ones explicitly allowed, specify other serializers to use for an attribute and even specify that an attribute is a nested resource.

AngularJS automatically excludes all attribute keys that begin with $ in their toJson code.

railsSerializer

railsSerializer(options, customizer) - Builds a Serializer constructor function using the configuration options specified.
- options object (optional) - Configuration options to alter the default operation of the serializers. This parameter can be excluded and the customizer function specified as the first argument instead.
- customizer function (optional) - A function that will be called to customize the serialization logic.
- returns Serializer - A Serializer constructor function

Configuration

The railsSerializer function takes a customizer function that is called on create within the context of the constructed Serializer. From within the customizer function you can call customization functions that affect what gets serialized and how or override the default options. In addition, railsSerializer exposes a field defaultOptions that allows you to globally override the defaults for the configuration options.

Configuration Options

Serializers have the following available configuration options:

underscore - (function) Allows users to supply their own custom underscore conversion logic.
- default: RailsInflector.underscore
- parameters
  - attribute string - The current name of the attribute
- returns string - The name as it should appear in the JSON
camelize - (function) Allows users to supply their own custom camelization logic.
- default: RailsInflector.camelize
- parameters
  - attribute string - The name as it appeared in the JSON
- returns string - The name as it should appear in the resource
pluralize - (function) Allows users to supply their own custom pluralization logic.
- default: RailsInflector.pluralize
- parameters
  - attribute string - The name as it appeared in the JSON
- returns string - The name as it should appear in the resource
excludeByDefault boolean - Specifies whether or not JSON serialization should exclude all attributes from serialization by default.
- default: false
exclusionMatchers array - An list of rules that should be applied to determine whether or not an attribute should be excluded. The values in the array can be one of the following types:
- string - Defines a prefix that is used to test for exclusion
- RegExp - A custom regular expression that is tested against the attribute name
- function - A custom function that accepts a string argument and returns a boolean with true indicating exclusion.

Customization API

The customizer function passed to the railsSerializer has available to it the following methods for altering the serialization of an object. None of these methods support nested attribute names (e.g. 'books.publicationDate'), in order to customize the serialization of the books objects you would need to specify a custom serializer for the books attribute.

exclude (attributeName...) - Accepts a variable list of attribute names to exclude from JSON serialization. This has no impact on what is deserialized from the server.
only (attributeName...) - Accepts a variable list of attribute names that should be included in JSON serialization. This has no impact on what is deserialized from the server. Using this method will by default exclude all other attributes and only the ones explicitly included using only will be serialized.
rename (javascriptName, jsonName) - Specifies a custom name mapping for an attribute. On serializing to JSON the jsonName will be used. On deserialization, if jsonName is seen then it will be renamed as javascriptName in the resulting resource. Right now it is still passed to underscore so you could do 'publicationDate' -> 'releaseDate' and it will still underscore as release_date. However, that may be changed to prevent underscore from breaking some custom name that it doesn't handle properly.
nestedAttribute (attributeName...) - This is a shortcut for rename that allows you to specify a variable number of attributes that should all be renamed to _attributes to work with the Rails nested_attributes feature. This does not perform any additional logic to accomodate specifying the _destroy property.
resource (attributeName, resource, serializer) - Specifies an attribute that is a nested resource within the parent object. Nested resources do not imply nested attributes, if you want both you still have to specify call nestedAttribute as well. A nested resource serves two purposes. First, it defines the resource that should be used when constructing resources from the server. Second, it specifies how the nested object should be serialized. An optional third parameter serializer is available to override the serialization logic of the resource in case you need to serialize it differently in multiple contexts.
add (attributeName, value) - Allows custom attribute creation as part of the serialization to JSON. The parameter value can be defined as function that takes a parameter of the containing object and returns a value that should be included in the JSON.
serializeWith (attributeName, serializer) - Specifies a custom serializer that should be used for the attribute. The serializer can be specified either as a string reference to a registered service or as a Serializer constructor returned from railsSerializer

Serializer Methods

The serializers are defined using mostly instance prototype methods. For information on those methods please see the inline documentation. There are however a couple of class methods that are also defined to expose underscore, camelize, and pluralize. Those functions are set to the value specified by the configuration options sent to the serializer.

Transformers / Interceptors

The transformers and interceptors can be specified using an array containing transformer/interceptor functions or strings that can be resolved using Angular's DI. The transformers / interceptors concept was prior to the serializers but we kept the API available because there may be use cases that can be accomplished with these but not the serializers.

Request Transformers

Transformer functions are called to transform the data before we send it to $http for POST/PUT.

A transformer function is called with two parameters:

data - The data that is being sent to the server
resource - The resource class that is calling the transformer

A transformer function must return the data. This is to allow transformers to return entirely new objects in place of the current data (such as root wrapping).

The resource also exposes a class method beforeRequest(fn) that accepts a function to execute and automatically wraps it as a transformer and appends it to the list of transformers for the resource class. The function passed to beforeRequest is called with the same two parameters. One difference is that the functions are not required to return the data, though they still can if they need to return a new object. See example.

Response Interceptors

Interceptor functions utilize $q promises to process the data returned from the server.

The interceptor is called with the promise returned from $http and is expected to return a promise for chaining. The promise passed to each interceptor contains two additional properties:

resource - The Resource constructor function for the resource calling the interceptor
context - The Resource instance if applicable (create, update, delete) calling the interceptor

Each interceptor promise is expected to return the response or a $q.reject. See Promises for more information about the promise data.

The resource also exposes a class method beforeResponse(fn) that accepts a function to execute and automatically wraps it as an interceptor and appends it to the list of interceptors for the resource class. Functions added with beforeResponse don't need to know anything about promises since they are automatically wrapped as an interceptor.

After Response Interceptors

After response interceptors are called after all processing and response interceptors have completed. An after response interceptor is analogous to chaining a promise after the resource method call but is instead for all methods.

The after response interceptors are called with the final processing promise and is expected to return a promise for chaining. The promise is resolved with the result of the operation which will be either a resource instance or an array of resource instances. The promise passed to the interceptor has the following additional property:

resource - The Resource constructor function for the resource calling the interceptor

The resource also exposes a class method afterResponse(fn) that accepts a function to execute and automatically wraps it as an interceptor and appends it to the list of after response interceptors for the resource class. Functions added with afterResponse don't need to know anything about promises since they are automatically wrapped as an interceptor.

Tests

The tests are written using Jasmine and are run using Karma.

Running the tests should be as simple as following the instructions

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Added some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.