|
| 1 | +# Asynchronous Processing |
| 2 | + |
| 3 | +The JSON API specification |
| 4 | +[provides a recommendation](https://jsonapi.org/recommendations/#asynchronous-processing) |
| 5 | +for how APIs can implement long running processes. For example, if the operation to create a |
| 6 | +resource takes a long time, it is more appropriate to process the creation using |
| 7 | +[Laravel's queue system](https://laravel.com/docs/queues) |
| 8 | +and return a `202 Accepted` response to the client. |
| 9 | + |
| 10 | +This package provides an opt-in implementation of the JSON API's asynchronous processing recommendation |
| 11 | +that integrates with Laravel's queue. This works by storing information about the dispatched job |
| 12 | +in a database, and using Laravel's queue events to updating the stored information. |
| 13 | + |
| 14 | +## Installation |
| 15 | + |
| 16 | +### Migrations |
| 17 | + |
| 18 | +By default this package does not run migrations to create the database tables required to store |
| 19 | +information on the jobs that have been dispatched by the API. You must therefore opt-in to the |
| 20 | +migrations in the `register` method of your `AppServiceProvider`: |
| 21 | + |
| 22 | +```php |
| 23 | +<?php |
| 24 | + |
| 25 | +namespace App\Providers; |
| 26 | + |
| 27 | +use CloudCreativity\LaravelJsonApi\LaravelJsonApi; |
| 28 | +use Illuminate\Support\ServiceProvider; |
| 29 | + |
| 30 | +class AppServiceProvider extends ServiceProvider |
| 31 | +{ |
| 32 | + |
| 33 | + // ... |
| 34 | + |
| 35 | + public function register() |
| 36 | + { |
| 37 | + LaravelJsonApi::runMigrations(); |
| 38 | + } |
| 39 | + |
| 40 | +} |
| 41 | +``` |
| 42 | + |
| 43 | +### Migration Customisation |
| 44 | + |
| 45 | +If you want to customise the migrations, you can publish them as follows: |
| 46 | + |
| 47 | +```bash |
| 48 | +$ php artisan vendor:publish --tag="json-api-migrations" |
| 49 | +``` |
| 50 | + |
| 51 | +If you do this, you **must not** call `LaravelJsonApi::runMigrations()` in your service provider. |
| 52 | + |
| 53 | +### Generate Resource Classes |
| 54 | + |
| 55 | +You now need to generate JSON API classes for the resource type that will represent the asynchronous |
| 56 | +processes in your API. We do not provide these by default because the logic of how you want to page, |
| 57 | +filter, etc. your resources is specific to your own API. This also means you can serialize any |
| 58 | +attributes you want in the resource schema, and use your own API's convention for attribute names. |
| 59 | + |
| 60 | +To generate the classes, run the following command: |
| 61 | + |
| 62 | +```php |
| 63 | +$ php artisan make:json-api:resource -e queue-jobs |
| 64 | +``` |
| 65 | + |
| 66 | +> Replace `queue-jobs` in the above command if you want to call the resource something different. |
| 67 | +If you use a different name, you will need to change the `jobs.resource` config setting in your |
| 68 | +API's configuration file. |
| 69 | + |
| 70 | +In the generated schema, you will need to add the `AsyncSchema` trait, for example: |
| 71 | + |
| 72 | +```php |
| 73 | +use CloudCreativity\LaravelJsonApi\Queue\AsyncSchema; |
| 74 | +use Neomerx\JsonApi\Schema\SchemaProvider; |
| 75 | + |
| 76 | +class Schema extends SchemaProvider |
| 77 | +{ |
| 78 | + use AsyncSchema; |
| 79 | + |
| 80 | + // ... |
| 81 | +} |
| 82 | +``` |
| 83 | + |
| 84 | +### Model Customisation |
| 85 | + |
| 86 | +By default the implementation uses the `CloudCreativity\LaravelJsonApi\Queue\ClientJob` model. |
| 87 | +If you want to use a different model, then you can change this by editing the `jobs.model` config |
| 88 | +setting in your API's configuration file. |
| 89 | + |
| 90 | +Note that if you use a different model, you may also want to customise the migration as described |
| 91 | +above. |
| 92 | + |
| 93 | +If you are not extending the `ClientJob` model provided by this package, note that your custom |
| 94 | +model must implement the `CloudCreativity\LaravelJsonApi\Contracts\Queue\AsynchronousProcess` |
| 95 | +interface. |
| 96 | + |
| 97 | +## Dispatching Jobs |
| 98 | + |
| 99 | +For a Laravel queue job to appear as an asynchronous process in your API, you must add the |
| 100 | +`CloudCreativity\LaravelJsonApi\Queue\ClientDispatchable` trait to it and use this to dispatch |
| 101 | +the job. |
| 102 | + |
| 103 | +For example: |
| 104 | + |
| 105 | +```php |
| 106 | +namespace App\Jobs; |
| 107 | + |
| 108 | +use CloudCreativity\LaravelJsonApi\Queue\ClientDispatchable; |
| 109 | +use Illuminate\Contracts\Queue\ShouldQueue; |
| 110 | + |
| 111 | +class ProcessPodcast implements ShouldQueue |
| 112 | +{ |
| 113 | + |
| 114 | + use ClientDispatchable; |
| 115 | + |
| 116 | + // ... |
| 117 | +} |
| 118 | + |
| 119 | +``` |
| 120 | + |
| 121 | +The job can then be dispatched as follows: |
| 122 | + |
| 123 | +```php |
| 124 | +/** @var \CloudCreativity\LaravelJsonApi\Queue\ClientJob $process */ |
| 125 | +$process = ProcessPodcast::client($podcast)->dispatch(); |
| 126 | +``` |
| 127 | + |
| 128 | +The object returned by the static `client` method extends Laravel's `PendingDispatch` class. This |
| 129 | +means you can use any of the normal Laravel methods. The only difference is you **must** call the |
| 130 | +`dispatch` method at the end of the chain so that you have access to the process that was stored |
| 131 | +and can be serialized into JSON by your API. |
| 132 | + |
| 133 | +You can use this method of dispatching jobs in either |
| 134 | +[Controller Hooks](../basics/controllers.md) or within |
| 135 | +[Resource Adapters](../basics/adapters.md), depending on your preference. |
| 136 | + |
| 137 | +### Dispatching in Controllers |
| 138 | + |
| 139 | +You can use controller hooks to return asynchronous processes. For example, if you needed |
| 140 | +to process a podcast after creating a podcast model you could use the `created` hook: |
| 141 | + |
| 142 | +```php |
| 143 | +use App\Podcast; |
| 144 | +use App\Jobs\ProcessPodcast; |
| 145 | +use CloudCreativity\LaravelJsonApi\Http\Controllers\JsonApiController; |
| 146 | + |
| 147 | +class PodcastsController extends JsonApiController |
| 148 | +{ |
| 149 | + |
| 150 | + // ... |
| 151 | + |
| 152 | + protected function created(Podcast $podcast) |
| 153 | + { |
| 154 |
F438
+ return ProcessPodcast::client($podcast)->dispatch(); |
| 155 | + } |
| 156 | +} |
| 157 | +``` |
| 158 | + |
| 159 | +> The `creating`, `created`, `updating`, `updated`, `saving`, `saved`, `deleting` and `deleted` |
| 160 | +hooks will be the most common ones to use for asynchronous processes. |
| 161 | + |
| 162 | +### Dispatching in Adapters |
| 163 | + |
| 164 | +If you prefer to dispatch your jobs in a resource adapters, then the adapters support returning |
| 165 | +asynchronous processes. |
| 166 | + |
| 167 | +For example, to process a podcast after creating it: |
| 168 | + |
| 169 | +```php |
| 170 | +namespace App\JsonApi\Podcasts; |
| 171 | + |
| 172 | +use App\Jobs\ProcessPodcast; |
| 173 | +use CloudCreativity\LaravelJsonApi\Eloquent\AbstractAdapter; |
| 174 | +use Neomerx\JsonApi\Contracts\Encoder\Parameters\EncodingParametersInterface; |
| 175 | + |
| 176 | +class Adapter extends AbstractAdapter |
| 177 | +{ |
| 178 | + |
| 179 | + // ... |
| 180 | + |
| 181 | + public function create(array $document, EncodingParametersInterface $parameters) |
| 182 | + { |
| 183 | + $podcast = parent::create($document, $parameters); |
| 184 | + |
| 185 | + return ProcessPodcast::client($podcast)->dispatch(); |
| 186 | + } |
| 187 | +} |
| 188 | +``` |
| 189 | + |
| 190 | +## Linking Processes to Created Resources |
| 191 | + |
| 192 | +If a dispatched job creates a new resource (e.g. a new model), there is one additional step you will |
| 193 | +need to follow in the job's `handle` method. This is to link the stored process to the resource that was |
| 194 | +created as a result of the job completing successfully. The link must exist otherwise your API |
| 195 | +will not be able to inform a client of the location of the created resource once the job is complete. |
| 196 | + |
| 197 | +You can easily create this link by calling the `didCreate` method that the `ClientDispatchable` |
| 198 | +trait adds to your job. For example: |
| 199 | + |
| 200 | +```php |
| 201 | +namespace App\Jobs; |
| 202 | + |
| 203 | +use CloudCreativity\LaravelJsonApi\Queue\ClientDispatchable; |
| 204 | +use Illuminate\Contracts\Queue\ShouldQueue; |
| 205 | + |
| 206 | +class ProcessPodcast implements ShouldQueue |
| 207 | +{ |
| 208 | + |
| 209 | + use ClientDispatchable; |
| 210 | + |
| 211 | + // ... |
| 212 | + |
| 213 | + public function handle() |
| 214 | + { |
| 215 | + // ...logic to process a podcast |
| 216 | + |
| 217 | + $this->didCreate($podcast); |
| 218 | + } |
| 219 | +} |
| 220 | +``` |
| 221 | + |
| 222 | +## HTTP Requests and Responses |
| 223 | + |
| 224 | +Once you have followed the above instructions, you can now make HTTP requests and receive |
| 225 | +asynchronous process responses that following the |
| 226 | +[JSON API recommendation.](https://jsonapi.org/recommendations/#asynchronous-processing) |
| 227 | + |
| 228 | +For example, a request to create a podcast would receive the following response: |
| 229 | + |
| 230 | +```http |
| 231 | +HTTP/1.1 202 Accepted |
| 232 | +Content-Type: application/vnd.api+json |
| 233 | +Content-Location: http://homestead.local/podcasts/queue-jobs/1680e9a0-6643-42ab-8314-1f60f0b6a6b2 |
| 234 | +
|
| 235 | +{ |
| 236 | + "data": { |
| 237 | + "type": "queue-jobs", |
| 238 | + "id": "1680e9a0-6643-42ab-8314-1f60f0b6a6b2", |
| 239 | + "attributes": { |
| 240 | + "created-at": "2018-12-25T12:00:00", |
| 241 | + "updated-at": "2018-12-25T12:00:00" |
| 242 | + }, |
| 243 | + "links": { |
| 244 | + "self": "/podcasts/queue-jobs/1680e9a0-6643-42ab-8314-1f60f0b6a6b2" |
| 245 | + } |
| 246 | + } |
| 247 | +} |
| 248 | +``` |
| 249 | + |
| 250 | +> You are able to include a lot more attributes by adding them to your queue-jobs resource schema. |
| 251 | +
|
| 252 | +To check the status of the job process, a client can send a request to the `Content-Location` given |
| 253 | +in the previous response: |
| 254 | + |
| 255 | +```http |
| 256 | +GET /podcasts/queue-jobs/1680e9a0-6643-42ab-8314-1f60f0b6a6b2 HTTP/1.1 |
| 257 | +Accept: application/vnd.api+json |
| 258 | +``` |
| 259 | + |
| 260 | +If the job is still pending, a `200 OK` response will be returned and the content will contain the |
| 261 | +`queue-jobs` resource. |
| 262 | + |
| 263 | +When the job process is done, the response will return a `303 See Other` status. This will contain |
| 264 | +a `Location` header giving the URL of the created podcast resource: |
| 265 | + |
| 266 | +```http |
| 267 | +HTTP/1.1 303 See other |
| 268 | +Content-Type: application/vnd.api+json |
| 269 | +Location: http://homestead.local/podcasts/4577 |
| 270 | +``` |
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