The CakeDC API plugin was created with the goal to prepare abstract solutions that solve generic tasks -in case of creating a rest API. It provides such features like automatic rest API generation based on db schema, support nested routes. It also allows the use of different formats like json or xml, and easily adds their own custom format. It helps to solve generic tasks appearing in development of any API, like pagination, data validation, adding common data to response, or building metadata, about data objects.
Dependencies
The CakeDC API plugin hardly depends on the CakeDC Users Plugin. For authentication it is highly recommended to use CakePHP Authentication plugin configured as middleware.
Installation
You can install this plugin into your CakePHP application using composer.
The recommended way to install composer packages is:
composer require cakedc/cakephp-api
Load the Plugin
Ensure The CakeDC API Plugin is loaded in your src/Aplication.php in bootstrap method.
php
$this->addPlugin(\CakeDC\Users\Plugin::class);
$this->addPlugin(\CakeDC\Api\Plugin::class, ['bootstrap' => true, 'routes' => true]);
Configuration
Minimal configuration to allow non authorized requests require you to copy file: ./vendor/cakedc/cakephp-api/config/api_permissions.php.default to ./config/api_permissions.php
Examples
Lets bake table blogs with two fields id and name.
After that, the next requests would be possible to perform to api. Requests would be performed using curl.
Request:
curl http://localhost:8765/api/blogs
Response:
{
"status": "success",
"data": [
{
"id": 1,
"name": "blog001"
}
],
"pagination": {
"page": 1,
"limit": 20,
"pages": 1,
"count": 1
},
"links": [
{
"name": "self",
"href": "http:\/\/localhost:8765\/api\/blogs",
"rel": "\/api\/blogs",
"method": "GET"
},
{
"name": "blogs:add",
"href": "http:\/\/localhost:8765\/api\/blogs",
"rel": "\/api\/blogs",
"method": "POST"
}
]
}
Request:
curl -d "name=blog001" -H "Content-Type: application/x-www-form-urlencoded" -X POST http://localhost:8765/api/blogs
Response:
{
"status": "success",
"data": {
"name": "blog001",
"id": 1
},
"links": []
}
Request:
curl -d "name=blog002" -H "Content-Type: application/x-www-form-urlencoded" -X PUT http://localhost:8765/api/blogs/1
Response:
{
"status": "success",
"data": {
"id": 1,
"name": "blog002"
},
"links": []
}
Request:
curl -X DELETE http://localhost:8765/api/blogs/1
Response:
{
"status": "success",
"data": true,
"links": []
}
For more complex features about plugin initialization and configuration based on routes middlewares, we plan to create an additional article.
Services and Actions
In the REST recommendations documents names defined as a noun. Here, services come into play.
It describes business entities. From other side actions define the verbs that describe the operations that should be performed on the actions.
Common and difference between controller classes and services.
The common part is the service is the managing the choosing action to execute.
The primary difference is that service could be nested, if this is defined by request url.
Common and difference between controller actions and service actions.
The common part is the action defined logic of the request.
The primary is that each service’s action is defined as a separate class.
This means that generic actions could be defined as common class and reused in many services.
From the other side, an action class is able to extend if the system has slightly different actions.
This way it is possible to build actions hierarchy.
Both service and actions define an event during this execution flow.
Main service events:
* Service.beforeDispatch
* Service.beforeProcess
* Service.afterDispatch
Main action events:
* Action.beforeProcess
* Action.onAuth
* Action.beforeValidate
* Action.beforeValidateStopped
* Action.validationFailed
* Action.beforeExecute
* Action.beforeExecuteStopped
* Action.afterProcess
Crud actions define events that depend on the type of action, and more details could be checked in documentation.
* Action.Crud.onPatchEntity
* Action.Crud.onFindEntities
* Action.Crud.afterFindEntities
* Action.Crud.onFindEntity
Nested services
Consider we have request with method POST /blogs/1/posts with data like {"title": "...", "body": "..."}
As it is possible to see there is nothing in the given data about the blog_id to which the newly created post should belong to.
In the case of controllers we should define custom logic to parse a route, and to consume the blog_id from url.
For nested service all checks and records updates are automatically executed. This will happen for any crud operations, when detected by the route parent service. So for example: GET /blogs/1/posts, will return only posts for the blog with id 1.
Logical checks are also performed, so for request: DELETE /blogs/1/posts/2, a user gets an error if the post with id 2 belongs to the blog with id 2.
Action inheritance
As each action can be defined as a separate class, it is possible to use class inheritance to define common logic. For example: Add and Edit actions.
Extending services and actions with shared functionality
The alternative way for defining common logic actions is using action extensions. Action extension is a more powerful feature and could be used for global tasks like search or pagination.
It is also possible to create service level extensions. Those extensions work on the top level of the execution process, and could be used for things like adding cors feature, or to append some counter into response.
Add service actions from service::initialize
This is a recommended way to register non crud actions. The mapAction uses the Router class syntax for parsing routes. So on any special use cases well described in cakephp core.
public function initialize()
{
parent::initialize();
$this->mapAction('view_edit', ViewEditAction::class, [
'method' => ['GET'],
'path' => 'view_edit/:id'
]);
}
Configure actions using action class map.
Each action class uses $_actionsClassMap for defining a map between crud (and non crud) actions on the name of the action class.
Non crud actions should be additionally mapped, which is described in the previous step.
use App\Service\Protocols\IndexAction;
class ProtocolsService extends AppFallbackService
{
/**
* Actions classes map.
*
* @var array
*/
protected $_actionsClassMap = [
'index' => IndexAction::class,
];
}
Configure service and action in config file
Service options are defined in the config/api.php in Api.Service section.
Let's consider configuration options for ArticlesService.
Configuration are hierarchical in the next sense:
- define default options for any service within the application in the
Api.Service.default.optionssection. - define options for any service within the application in
Api.Service.articles.optionssection.
All defined options are overridden from up to down in described order.
This allows common service settings, and the ability to overwrite them in bottom level.
- Api.Service.classMap - defines name map, that allows defining services action classes with custom location logic.
Any action, that could be loaded as default action defined in fallback class, or specific action class could be configured using configuration file.
Let's consider how one can configure options forIndexActionofArticlesService.
Configuration are hierarchical in the next sense: - one can define default options for any action for all services in the application in the
Api.Service.default.Action.defaultsection. - one can define default options for
indexaction for all services in the application in theApi.Service.default.Action.indexsection. - one can define options for any action in the specific (
articles) service in theApi.Service.articles.Action.defaultsection. - one can define options for
indexaction in the specific (articles) service in theApi.Service.articles.Action.indexsection.
Crud and non crud methods. Mapping non-crud actions.
Crud services mapped automatically in two levels routing by FallbackService.
Index and view. Formatting output
The CakeDC Api Plugin is flexible and provides multiple ways to prepare result data for the response objects.
There is a list of main options.
Use Entity serialization
The most trivial way to convert data is using entity serialization.
When converting an entity to a JSON, the virtual and hidden field lists are applied.
Entities are recursively converted to JSON as well.
This means that if you eager, and loading entities and their associations, CakePHP will correctly handle converting the associated data into the correct format.
Additional fields could be defined using Entity::$_virtual and hidden using Entity::$$_hidden.
Build object manually from Action::execute
In this case users manually perform mapping of requests received from model layer to output array.
public function process()
{
$entity = $this->getTable()->get($this->getId());
return [
'id' => $entity->id,
'name' => $entity->name,
];
}
Use Query::formatResults in model layer
The request could be formatted in model layer using: Query::formatResults.
So in this case, the process action just calls for a needed finder from the model layer and returns the result.
public function findApiFormat(Query $query, array $options)
{
return $query
->select(['id', 'body', 'created', 'modified', 'author_id'])
->formatResults(function ($results) use ($options) {
return $results->map(function ($row) use ($options) {
$row['author'] = $this->Authors->getFormatted($row['author_id']);
unset($row['author_id']);
return $row;
});
});
}
Use Action extensions to format output
In index action defined callback Action.Crud.afterFindEntities, which called after data fetched, could be used to extend or overload results coming from the database.
Callbacks are catch-in-action extensions and could be applied to multiple endpoints.
For view action defined Action.Crud.afterFindEntity, which called after single record fetched.
Use Action extensions to append additional data to output
Sometimes there is some additional information needed to be presented in some group of endpoints. In this case it is possible to implement an action extension to append additional data.
For example, pagination provides information about number of pages, records count, and current page number.
Another example for additional data is some execution statistics about the query.
Here you see main parts of appending such data from extension.
class PaginateExtension extends Extension implements EventListenerInterface
{
public function implementedEvents(): array
{
return [
'Action.Crud.afterFindEntities' => 'afterFind',
];
}
...
public function afterFind(EventInterface $event): void
{
...
$pagination = [
'page' => $this->_page($action),
'limit' => $limit,
'pages' => ceil($count / $limit),
'count' => $count,
];
$result->appendPayload('pagination', $pagination);
}
The renderer class describes how to handle payload data.
For example in JSend renderer, all payload records appended to the root of the resulting json object.
Rendering output. Renderers.
Renderers perform final mapping of response records to output format.
Such formats like xml, json, or file are provided by The CakeDC API plugin.
JSend is the json extension with some additional agreements about returning results.
