Extending functionality with plugins

You can use plugins to alter Scribe’s behaviour when extracting info about your endpoints. For instance, suppose all your listing endpoints support pagination query parameters pageSize and page, and you don’t want to annotate with @queryParam on each method. You can create a plugin that adds this to all your query parameters. Let’s see how to do this.

The stages of route processing

Route processing is performed in the following stages, in this order:

  • metadata (this includes title, description, groupName, groupDescription, and authentication status (authenticated))
  • urlParameters
  • queryParameters
  • headers (headers to be added to example request and response calls)
  • bodyParameters
  • responses
  • responseFields (descriptions of fields in the response)

For each stage, the Generator attempts to use various “strategies” to fetch data. The Generator will call all of the strategies configured in scribe.php, progressively combining their results together to produce the final output of that stage.

Note

Unlike other stages, the responses stage is additive. This means that all responses from all strategies in that stage will be saved. Responses cannot overwrite each other, even if they have the same status code. By contrast, if you return a value for a body parameter from one strategy, it will overwrite any other values for that parameter gotten from previous strategies.

There are a number of strategies included with the package, so you don’t have to set up anything to get it working. Here’s what’s included in scribe.php by default:

    'strategies' => [
        'metadata' => [
            \Knuckles\Scribe\Extracting\Strategies\Metadata\GetFromDocBlocks::class,
        ],
        'urlParameters' => [
            \Knuckles\Scribe\Extracting\Strategies\UrlParameters\GetFromLaravelAPI::class,
            \Knuckles\Scribe\Extracting\Strategies\UrlParameters\GetFromUrlParamTag::class,
        ],
        'queryParameters' => [
            \Knuckles\Scribe\Extracting\Strategies\QueryParameters\GetFromQueryParamTag::class,
        ],
        'headers' => [
            \Knuckles\Scribe\Extracting\Strategies\Headers\GetFromRouteRules::class,
            \Knuckles\Scribe\Extracting\Strategies\Headers\GetFromHeaderTag::class,
        ],
        'bodyParameters' => [
            \Knuckles\Scribe\Extracting\Strategies\BodyParameters\GetFromFormRequest::class,
            \Knuckles\Scribe\Extracting\Strategies\BodyParameters\GetFromBodyParamTag::class,
        ],
        'responses' => [
            \Knuckles\Scribe\Extracting\Strategies\Responses\UseTransformerTags::class,
            \Knuckles\Scribe\Extracting\Strategies\Responses\UseResponseTag::class,
            \Knuckles\Scribe\Extracting\Strategies\Responses\UseResponseFileTag::class,
            \Knuckles\Scribe\Extracting\Strategies\Responses\UseApiResourceTags::class,
            \Knuckles\Scribe\Extracting\Strategies\Responses\ResponseCalls::class,
        ],
        'responseFields' => [
            \Knuckles\Scribe\Extracting\Strategies\ResponseFields\GetFromResponseFieldTag::class,
        ],
    ],

Note

The included ResponseCalls strategy is designed to stop if a response with a 2xx status code has already been gotten via any other strategy.

Tip

Check out our community wiki for a list of strategies contributed by the community.

Creating a strategy

To create a strategy, create a class that extends \Knuckles\Scribe\Extracting\Strategies\Strategy. You can do this by running the scribe:strategy command. By default, this will place the strategy in your App\Docs\Strategies namespace. The first argument to scribe:strategy is the name of the strategy, the second is the stage it belongs to.

php artisan scribe:strategy AddPaginationParameters queryParameters

This creates a class like this:

<?php

namespace App\Docs\Strategies;

use Illuminate\Routing\Route;
use Knuckles\Scribe\Extracting\ParamHelpers;
use Knuckles\Scribe\Extracting\RouteDocBlocker;
use Knuckles\Scribe\Extracting\Strategies\Strategy;
use ReflectionClass;
use ReflectionFunctionAbstract;

class AddPaginationParameters extends Strategy
{
    public $stage = 'queryParameters';

    /**
     * Trait containing some helper methods for dealing with "parameters".
     * Useful if your strategy extracts information about parameters.
     */
    use ParamHelpers;

    /**
     * @link https://scribe.readthedocs.io/en/latest/plugins.html
     * @param Route $route The route which we are currently extracting queryParameters for.
     * @param ReflectionClass $controller The class handling the current route.
     * @param ReflectionFunctionAbstract $method The method/closure handling the current route.
     * @param array $routeRules Array of rules for the ruleset which this route belongs to.
     * @param array $alreadyExtractedData Data already extracted from previous stages and earlier strategies in this stage
     *
     * See the documentation linked above for more details about writing custom strategies.
     *
     * @return array|null
     */
    public function __invoke(
        Route $route,
        ReflectionClass $controller,
        ReflectionFunctionAbstract $method,
        array $routeRules,
        array $alreadyExtractedData = []
    )
    {
        return null;
    }

}

Alternatively, if you’re creating a strategy that you’d like people to download and install via Composer, you can generate one from this GitHub template.

Writing strategies

Let’s take a look at the contents of our Strategy class.

First, there’s a $stage property that states the stage the strategy belongs too. Used internally by Scribe.

The __invoke method of the strategy is where you extract and return data. It receives the following arguments:

  • the route being processed (an instance of \Illuminate\Routing\Route)
  • the controller handling the route (\ReflectionClass)
  • the method handling the route (\ReflectionFunctionAbstract)
  • the rules specified in the scribe.php config file for the group this route belongs to, under the apply section (array)
  • alreadyExtractedData. This contains all data for the route that has been parsed thus far in the previous stages, as well as earlier strategies in this stage.

The strategy class also has access to the current Scribe configuration via its config property. For instance, you can retrieve the router in use with $this->config->get('router'). You can also specify a default value to be returned if the config key is not set:

$router = $this->config->get('router', 'laravel');

Let’s add some code to make our strategy work:

   public function __invoke(
       Route $route,
       ReflectionClass $controller,
       ReflectionFunctionAbstract $method,
       array $routeRules,
       array $alreadyExtractedData = []
   )
   {
       $isGetRoute = in_array('GET', $route->methods());
       $isIndexRoute = strpos($route->getName(), '.index') !== false;
       if ($isGetRoute && $isIndexRoute) {
           return [
               'page' => [
                   'description' => 'Page number to return.',
                   'required' => false,
                   'value' => 1,
               ],
               'pageSize' => [
                   'description' => 'Number of items to return in a page. Defaults to 10.',
                   'required' => false,
                   'value' => null, // So it doesn't get included in the examples
               ],
           ];
       }

       return null;
   }

Using your strategy

To use your strategy, you need to register it in the strategies key in the scribe.php file.

        'queryParameters' => [
            \Knuckles\Scribe\Extracting\Strategies\QueryParameters\GetFromQueryParamTag::class,
            \App\Docs\Strategies\AddPaginationParameters::class,
        ],

Tip

You can also publish your strategy to Packagist. Then others can install them via composer require and register them in their own configs.

And we’re done! Now, when we run php artisan scribe:generate, all our GET routes that end with .index will have the pagination parameters added.

_images/plugins.png

Utilities

You have access to a number of tools when developing strategies. They include:

  • The RouteDocBlocker class (in the \Knuckles\Scribe\Extracting namespace) has a single public static method, getDocBlocksFromRoute(Route $route). It allows you to retrieve the docblocks for a given route. It returns an array with two keys: method and class containing the docblocks for the method and controller handling the route respectively. Both are instances of \Mpociot\Reflection\DocBlock.
  • The ParamHelpers trait (in the \Knuckles\Scribe\Extracting namespace) can be included in your strategies. It contains a number of useful methods for working with parameters, including type casting and generating dummy values for different types.
  • The DatabaseTransactionHelpers trait (in the \Knuckles\Scribe\Extracting namespace), which is helpful to prevent data being persisted if your strategy needs to interact with the database. This trait contains methods to start and end database transactions.

API

Each strategy class must implement the __invoke method with the parameters as described above. This method must return the needed data for the intended stage, or null to indicate failure.

  • In the metadata stage, strategies should return an array with some or all of the following keys:
'groupName'
'groupDescription'
'title'
'description'
'authenticated' // boolean
  • In the urlParameters, queryParameters, and bodyParameters stages, you can return an array with arbitrary keys. These keys will be the names of your parameters. Array keys can be indicated with Laravel’s dot notation. The value of each key should be an array with the following structure:
[
  'name' => 'Parameter name',
  'type' => 'valid type',
  'description' => 'An optional description.', 
  'required => true, // or false
  'value' => "An example value for the parameter",
];

See the documentation on body parameters for a list of valid types.

Tip

If you would like a parameter (body or query) to be included in the documentation but excluded from examples, set required to false and value property to null, like we did in our example above.

  • In the headers stage, you can return a key-value array of headers. You may also get rid of already set headers by setting false as the header value.
  • In the responses stage, your strategy should return an array containing the responses it was able to extract. Each item in the array should be an array representing the response, with a status key containing the HTTP status code, and a content key, which is a string containing the response. For example:
    public function __invoke(Route $route, \ReflectionClass $controller, \ReflectionFunctionAbstract $method, array $routeRules, array $alreadyExtractedData = [])
    {
        return [
            [
                'content' => "Haha",
                'status' => 201
            ],
            [
                'content' => '{"error": "Nope"}',
                'status' => 404
            ],
        ]
    }
  • In the responseFields stage, you can return an array with arbitrary keys. These keys will be the names of fields in your response. The value of each key should be an array with the following structure:
[
  'name' => '',
  'type' => '',
  'description' => '',
]