# Errors

# Introduction

The JSON:API specification defines error objects (opens new window) that are used to provide information to a client about problems encountered while performing an operation.

Errors are returned to the client in the top-level errors member of the JSON document.

Laravel JSON:API makes it easy to return errors to the client - either as responses, or by throwing exceptions. In addition, the exception renderer you added to your exception handler during installation takes care of converting standard Laravel exceptions to JSON:API error responses if the client has sent an Accept: application/vnd.api+json header.

# Error Objects

Use our LaravelJsonApi\Core\Document\Error object to create a JSON:API error object. The easiest way to construct an error object is using the static fromArray method. For example:

use LaravelJsonApi\Core\Document\Error;

$error = Error::fromArray([
  'status' => 400,
  'detail' => 'Something was wrong with your request.',
]);

The fromArray method accepts all the error object members defined in the specification. (opens new window)

Alternatively, if you want to use setters, use the static make method to fluently construct your error object:

$error = Error::make()
  ->setStatus(400)
  ->setDetail('Something was wrong with your request.');

The available setters are:

  • setAboutLink
  • setCode
  • setDetail
  • setId
  • setLinks
  • setMeta
  • setStatus
  • setSource
  • setSourceParameter
  • setSourcePointer
  • setTitle

# Error Lists

If you need to return multiple errors at once, use our LaravelJsonApi\Core\Document\ErrorList class. This accepts any number of error objects to its constructor. For example:

use LaravelJsonApi\Core\Document\ErrorList;

$errors = new ErrorList(
  Error::make()->setStatus(400)->setDetail('First error.'),
  Error::make()->setStatus(400)->setDetail('Second error.'),
);

Use the push method to add errors after constructing the error list:

$errors = new ErrorList();

foreach ($warnings as $message) {
  $errors->push(Error::fromArray([
    'status' => 400,
    'detail' => $message,
  ]));
}

# Responses

Both the Error and ErrorList classes implement Laravel's Responsable interface. This means you can return them directly from controller actions and they will be converted to a JSON:API error response.

If you need to customise the error response, then you need to use our LaravelJsonApi\Core\Responses\ErrorResponse class. Either create a new one, passing in the Error or ErrorList object:

use LaravelJsonApi\Core\Responses\ErrorResponse;

$response = ErrorResponse::make($errorOrErrors);

Or alternatively, use the prepareResponse method on either the Error or ErrorList object:

$response = $errorOrErrors->prepareResponse($request);

The ErrorResponse class has all the helper methods required to customise both the headers and the JSON:API document that is returned in the response.

For example, if we were adding a header and meta to our response:

return $error
    ->prepareResponse($request)
    ->withHeader('X-Foo', 'Bar')
    ->withMeta(['foo' => 'bar']);
// or
return ErrorResponse::make($error)
    ->withHeader('X-Foo', 'Bar')
    ->withMeta(['foo' => 'bar']);

# HTTP Status

The JSON:API specification says:

When a server encounters multiple problems for a single request, the most generally applicable HTTP error code SHOULD be used in the response. For instance, 400 Bad Request might be appropriate for multiple 4xx errors or 500 Internal Server Error might be appropriate for multiple 5xx errors.

Our ErrorResponse class takes care of calculating the HTTP status for you.

If there is only one error, or all the errors have the same status, then the response status will match this status.

If you have multiple errors with different statuses, the response status will be 400 Bad Request if the error objects only have 4xx status codes. If there are any 5xx status codes, the response status will be 500 Internal Server Error.

If the response has no error objects, or none of the error objects have a status, then the response will have a 500 Internal Server Error status.

If you want the response to have a specific HTTP status, use the withStatus method. For example:

return $error->prepareResponse($request)->withStatus(418);
// or
return ErrorResponse::make($error)->withStatus(418);

# JSON:API Exceptions

Our LaravelJsonApi\Core\Exceptions\JsonApiException allows you to terminate processing of a request by throwing an exception with JSON:API errors attached.

The exception expects its first argument to be either an Error or an ErrorList object. For example:

use LaravelJsonApi\Core\Exceptions\JsonApiException;

throw new JsonApiException($errorOrErrors, $previous);

The JsonApiException class has all the helper methods required to customise both the headers and the JSON:API document that is returned in the response. Use the static make method if you need to call any of these methods. For example:

throw JsonApiException::make($error)
    ->withHeader('X-Foo', 'Bar')
    ->withMeta(['foo' => 'bar']);

There is also a handy static error method. This allows you to fluently construct an exception for a single error, providing either an Error object or an array. For example:

throw JsonApiException::error([
  'status' => 400,
  'detail' => 'Your request is incorrect.',
]);

# Validation Errors

Our implementation of resource requests and query parameter requests already takes care of converting Laravel validation error messages to JSON:API errors.

If however you have a scenario where you want to convert a failed validator to JSON:API errors manually, we provide the ability to do this.

You will need to resolve an instance of LaravelJsonApi\Validation\Factory out of the service container. For example, you could use the app helper, or use dependency injection by type-hinting it in a constructor of a service.

Once you have the factory instance, use the createErrors method, providing it with the validator instance. For example, in a controller action:

return app(\LaravelJsonApi\Validation\Factory::class)
    ->createErrors($validator);

The object this returns is Responsable - so you can return it directly from a controller action. If you want to convert it to an error response, use our prepareResponse pattern as follows:

return app(\LaravelJsonApi\Validation\Factory::class)
    ->createErrors($validator)
    ->prepareResponse($request)
    ->withHeader('X-Foo', 'Bar')
    ->withMeta(['foo' => 'bar']);

# Source Pointers

By default this process will convert validation error keys to JSON source pointers. For example, if you have a failed message for the foo.bar value, the resulting error object will have a source pointer of /foo/bar.

If you need to prefix the pointer value, use the withSourcePrefix method. The following example would convert foo.bar to /data/attributes/foo/bar:

$errors = $factory
    ->createErrors($validator)
    ->withSourcePrefix('/data/attributes');

If you need to fully customise how the validation key should be converted, provide a Closure to the withPointers method:

$errors = $factory
    ->createErrors($validator)
    ->withPointers(fn($key) => "/foo/{$key}");

# Error Handling

As described in the installation instructions, the following should have been added to your application's exception handler:

class Handler extends ExceptionHandler
{
    // ...

    /**
     * Register the exception handling callbacks for the application.
     *
     * @return void
     */
    public function register()
    {
        $this->renderable(
            \LaravelJsonApi\Exceptions\ExceptionParser::make()->renderable()
        );
    }
}

The Laravel exception handler already takes care of converting exceptions to either application/json or text/html responses. Our exception handler effectively adds JSON:API error responses as a third media type. If the client has sent a request with an Accept header of application/vnd.api+json, then they will receive the exception response as a JSON:API error response - even if the endpoint they are hitting is not one of your JSON:API server endpoints.

WARNING

There are some scenarios where the Laravel exception handler does not call any registered renderables. For example, if an exception implements Laravel's Responsable interface, our exception parser will not be invoked as the handler uses the Responsable::toResponse() method on the exception to generate a response.

# JSON Responses

If a client encounters an exception when using an Accept header of application/json, they will still receive Laravel's default JSON exception response, rather than a JSON:API response.

If you want our exception parser to render JSON exception responses instead of the default Laravel response, use the acceptsJson() method when registering our exception parser:

$this->renderable(
    ExceptionParser::make()->acceptsJson()->renderable()
);

# Middleware Responses

Sometimes you may want exceptions to be converted to JSON:API errors if the current route has a particular middleware applied to it. The most common example of this would be if you want JSON:API errors to always be rendered if the current route has the api middleware.

In this scenario, use the acceptsMiddleware() method when registering our exception parser. For example:

$this->renderable(
    ExceptionParser::make()->acceptsMiddleware('api')->renderable()
);

TIP

You can provide multiple middleware names to the acceptsMiddleware() method. When you do this, it will match a route that contains any of the provided middleware.

# Always Rendering JSON:API Errors

If you want our exception parser to always convert exceptions to JSON:API errors, use the acceptsAll() helper method:

$this->renderable(
    ExceptionParser::make()->acceptsAll()->renderable()
);

# Custom Rendering Logic

If you want your own logic for when a JSON:API exception response should be rendered, pass a closure to the accept() method.

For example, let's say we wanted our API to always return JSON:API exception responses, regardless of what Accept header the client sent. We would use the request is() method to check if the path is our API:

$this->renderable(ExceptionParser::make()
    ->accept(fn(\Throwable $ex, $request) => $request->is('/api*'))
    ->renderable()
);

TIP

If you return false from the callback, the normal exception rendering logic will run - meaning a client that has sent an Accept header with the JSON:API media type will still receive a JSON:API response. This is semantically correct, as the Accept header value should be respected.

# Converting Exceptions

Our exception parser is built so that you can easily add support for custom exceptions to the JSON:API rendering process. The implementation works using a pipeline, meaning you can add your own handlers for converting exceptions to JSON:API errors.

For example, imagine our application had a PaymentFailed exception, that we wanted to convert to JSON:API errors if thrown to the exception handler. We would write the following class:

namespace App\JsonApi\Exceptions;

use App\Exceptions\PaymentFailedException;
use LaravelJsonApi\Core\Responses\ErrorResponse;

class PaymentFailedHandler
{

    /**
     * Handle the exception.
     *
     * @param \Throwable $ex
     * @param \Closure $next
     * @return ErrorResponse
     */
    public function handle(\Throwable $ex, \Closure $next): ErrorResponse
    {
        if ($ex instanceof PaymentFailedException) {
            return ErrorResponse::error([
                'code' => $ex->getCode(),
                'detail' => $ex->getMessage(),
                'status' => '400',
                'title' => 'Payment Failed'
            ]);
        }

        return $next($ex);
    }
}

We can then add it to the JSON:API exception parser using either the prepend or append method:

$this->renderable(ExceptionParser::make()
    ->append(\App\JsonApi\Exceptions\PaymentFailedHandler::class)
    ->renderable()
);
Last Updated: 4/15/2021, 3:34:29 PM