Text Processing

New in version 27.1.0.

Nextcloud offers a Text Processing API. The overall idea is that there is a central OCP API that apps can use to prompt tasks to Large Language Models and similar text processing tools. To be technology agnostic any app can provide this functionality by registering Text Processing providers.

Consuming the Text Processing API

To consume the Language Model API, you will need to inject \OCP\TextProcessing\IManager. This manager offers the following methods:

hasProviders() This method returns a boolean which indicates if any providers have been registered. If this is false you cannot use the TextProcessing feature.

getAvailableTaskTypes() This method returns a list of class strings representing the tasks that are currently supported.

runTask(Task $task) This method provides the actual prompt functionality. The task is defined using Task class. This method runs the task synchronously, so depending on the implementation it is uncertain how long it will take (between 3s - 10min).

scheduleTask(Task $task) This method provides the actual prompt functionality. The task is defined using the Task class. This method runs the task asynchronously in a background job.

getTask(int $id) This method fetches a task specified by its id.

New in version 28.0.0:

runOrScheduleTask(Task $task) This method also runs a task, but fist checks the expected runtime of the provider to be used. If the runtime fits inside the available processing time for the current request the task is run synchronously, otherwise it is scheduled as a background job. The task is defined using the Task class.

If you would like to use the text processing functionality in a client, there are also OCS endpoints available for this: OCS Text Processing API

Tasks types

The following task types are available:

\OCP\TextProcessing\FreePromptTaskType: This task allows passing an arbitrary prompt to the language model.

\OCP\TextProcessing\HeadlineTaskType: This task will generate a headline for the passed input text.

\OCP\TextProcessing\TopicsTaskType: This task will generate a comma-separated list of topics for the passed input text.

\OCP\TextProcessing\SummaryTaskType: This task will summarize the passed input text.

Tasks

To create a task we use the \OCP\TextProcessing\Task class. Its constructor takes the following arguments: new \OCP\TextProcessing\Task(string $type, string $input, string $appId, ?string $userId, string $identifier = ''). For example:

if (in_array(SummaryTaskType::class, $textprocessingManager->getAvailableTaskTypes()) {
    $summaryTask = new Task(SummaryTaskType::class, $emailText, "my_app", $userId, (string) $emailId);
} else {
    // cannot use summarization
}

The task class objects have the following methods available:

getType() This returns the task type.

getStatus() This method returns one of the below statuses.

getId() This method will return null before the task has been passed to runTask or scheduleTask

getInput() This returns the input string.

getOutput() This method will return null unless the task is successful

getAppId() This returns the originating application ID of the task.

getIdentifier() This returns the original scheduler-defined identifier for the task

getUserId() This returns the originating user ID of the task.

You could now run the task directly as follows. However, this will block the current PHP process until the task is done, which can sometimes take dozens of minutes, depending on which provider is used.

try {
    $textprocessingManager->runTask($summaryTask);
} catch (\OCP\PreConditionNotMetException|\OCP\TextProcessing\Exception\TaskFailureException $e) {
    // task failed
    // return error
}
// task was successful

The wiser choice, when you are in the context of a HTTP controller, is to schedule the task for execution in a background job, as follows:

try {
    $textprocessingManager->scheduleTask($summaryTask);
} catch (\OCP\PreConditionNotMetException|\OCP\DB\Exception $e) {
    // scheduling task failed
}
// task was scheduled successfully

Conditional scheduling of tasks

New in version 28.0.0.

Of course, you might want to schedule the task in a background job only if it takes longer than the request timeout. This is what runOrScheduleTask does.

try {
    $textprocessingManager->runOrScheduleTask($summaryTask);
} catch (\OCP\PreConditionNotMetException|\OCP\DB\Exception $e) {
    // scheduling task failed
    // return error
} catch (\OCP\TextProcessing\Exception\TaskFailureException $e) {
    // task was run but failed
    // status will be STATUS_FAILED
    // return error
}

switch ($summaryTask->getStatus()) {
    case \OCP\TextProcessing\Task::STATUS_SUCCESSFUL:
        // task was run directly and was successful
    case \OCP\TextProcessing\Task::STATUS_RUNNING:
    case \OCP\TextProcessing\Task::STATUS_SCHEDULED:
        // task was deferred to background job
    default:
        // something went wrong
}

Task statuses

All tasks always have one of the below statuses:

Task::STATUS_FAILED = 4;
Task::STATUS_SUCCESSFUL = 3;
Task::STATUS_RUNNING = 2;
Task::STATUS_SCHEDULED = 1;
Task::STATUS_UNKNOWN = 0;

Listening to the text processing events

Since scheduleTask does not block, you will need to listen to the following events in your app to obtain the output or be notified of any failure.

OCP\TextProcessing\Events\TaskSuccessfulEvent This event class offers the getTask() method which returns the up-to-date task object, with the output from the model.

OCP\TextProcessing\Events\TaskFailedEvent In addition to the getTask() method, this event class provides the getErrorMessage() method which returns the error message as a string (only in English and for debugging purposes, so don’t show this to the user)

For example, in your lib/AppInfo/Application.php file:

$context->registerEventListener(OCP\TextProcessing\Events\TaskSuccessfulEvent::class, MyPromptResultListener::class);
$context->registerEventListener(OCP\TextProcessing\Events\TaskFailedEvent::class, MyPromptResultListener::class);

The corresponding MyPromptResultListener class can look like:

<?php
namespace OCA\MyApp\Listener;

use OCA\MyApp\AppInfo\Application;
use OCP\TextProcessing\Events\AbstractTextProcessingEvent;
use OCP\TextProcessing\Events\TaskSuccessfulEvent;
use OCP\TextProcessing\Events\TaskFailedEvent;
use OCP\EventDispatcher\Event;
use OCP\EventDispatcher\IEventListener;

class MyPromptResultListener implements IEventListener {
    public function handle(Event $event): void {
        if (!$event instanceof AbstractTextProcessingEvent || $event->getTask()->getAppId() !== Application::APP_ID) {
            return;
        }

        if ($event instanceof TaskSuccessfulEvent) {
            $output = $event->getTask()->getOutput()
            // store $output somewhere
        }

        if ($event instanceof TaskFailedEvent) {
            $error = $event->getErrorMessage()
            $userId = $event->getTask()->getUserId()
            // Notify relevant user about failure
        }
    }
}

Implementing a TextProcessing provider

A Text processing provider is a class that implements the interface OCP\TextProcessing\IProvider.

<?php

declare(strict_types=1);

namespace OCA\MyApp\TextProcessing;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\TextProcessing\IProvider;
use OCP\TextProcessing\SummaryTaskType;
use OCP\IL10N;

class Provider implements IProvider {

    public function __construct(
        private IL10N $l,
    ) {
    }

    public function getName(): string {
        return $this->l->t('My awesome text processing provider');
    }

    public function getTaskType(): string {
        return SummaryTaskType::class;
    }

    public function process(string $input): string {
        // Return the output here
    }
}

The method getName returns a string to identify the registered provider in the user interface.

The method process implements the text processing step, e.g. it passes the prompt to a language model. In case execution fails for some reason, you should throw a RuntimeException with an explanatory error message.

The class would typically be saved into a file in lib/TextProcessing of your app but you are free to put it elsewhere as long as it’s loadable by Nextcloud’s dependency injection container.

Processing tasks in the context of a user

New in version 28.0.0.

Sometimes the processing of a text processing task may depend upon which user requested the task. You can now obtain this information in your provider by additionally implementing the OCP\TextProcessing\IProviderWithUserId interface:

<?php

declare(strict_types=1);

namespace OCA\MyApp\TextProcessing;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\TextProcessing\IProvider;
use OCP\TextProcessing\IProviderWithUserId;
use OCP\TextProcessing\SummaryTaskType;
use OCP\IL10N;

class Provider implements IProvider, IProviderWithUserId {

    private ?string $userId = null;

    public function __construct(
        private IL10N $l,
    ) {
    }

    public function getName(): string {
        return $this->l->t('My awesome text processing provider');
    }

    public function getTaskType(): string {
        return SummaryTaskType::class;
    }

    public function setUserId(?string $userId): void {
        $this->userId = $userId;
    }

    public function process(string $input): string {
        // Return the output here, making use of $this->userId
    }
}

Streamlining processing for fast providers

New in version 28.0.0.

Downstream consumers of the TextProcessing API can optimize execution of tasks if they know how long a task will run with your provider. To allow this kind of optimization you can provide an estimate of how much time your provider typically takes. To do this you simply implement the additional OCP\TextProcessing\IProviderWithExpectedRuntime interface

<?php

declare(strict_types=1);

namespace OCA\MyApp\TextProcessing;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\TextProcessing\IProvider;
use OCP\TextProcessing\IProviderWithExpectedRuntime;
use OCP\TextProcessing\SummaryTaskType;
use OCP\IL10N;

class Provider implements IProvider, IProviderWithExpectedRuntime {

    public function __construct(
        private IL10N $l,
    ) {
    }

    public function getName(): string {
        return $this->l->t('My awesome text processing provider');
    }

    public function getTaskType(): string {
        return SummaryTaskType::class;
    }

    public function getExpectedRuntime(): int {
        return 10; // expected runtime of a task is 10s
    }

    public function process(string $input): string {
        // Return the output here
    }
}

Providing more task types

If you would like to implement providers that handle additional task types, you can create your own TaskType classes implementing the OCP\TextProcessing\ITaskType interface:

<?php

declare(strict_types=1);

namespace OCA\MyApp\TextProcessing;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\TextProcessing\ITaskType;
use OCP\IL10N;

class OscarWildeTaskType implements ITaskType {

     public function __construct(
        private IL10N $l,
    ) {
    }

    public function getName(): string {
        return $this->l->t('Oscar Wilde Generator');
    }

    public function getDescription(): string {
      return $this->l->t('Turn text into Oscar Wilde prose');
    }
}

Provider registration

The provider class is registered via the bootstrap mechanism of the Application class.

<?php

declare(strict_types=1);

namespace OCA\MyApp\AppInfo;

use OCA\MyApp\TextProcessing\Provider;
use OCP\AppFramework\App;
use OCP\AppFramework\Bootstrap\IBootContext;
use OCP\AppFramework\Bootstrap\IBootstrap;
use OCP\AppFramework\Bootstrap\IRegistrationContext;

class Application extends App implements IBootstrap {

    public function register(IRegistrationContext $context): void {
        $context->registerTextProcessingProvider(Provider::class);
    }

    public function boot(IBootContext $context): void {}

}