Machine Translation

New in version 26.

Nextcloud offers a Translation API. The overall idea is that there is a central OCP API that apps can use to request machine translations of text. To be technology agnostic any app can provide this Translation functionality by registering a Translation provider.

Consuming the Translation API

To consume the Translation API, you will need to inject \OCP\Translation\ITranslationManager. 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 Translation feature.

• getLanguages() This method returns a list of OCP\Translation\LanguageTuple Objects which indicate which langauge pairs are currently supported for translation.

• translate(string $text, ?string $fromLanguage, string $toLanguage) This method provides the actual translation functionality. Note that, depending on the length of the text you want to translate, this may take longer than the HTTP request timeout or the PHP execution time limit.

• canDetectLanguage() This method returns a boolean indicating whether language auto-detection is possible. If this is true, you can pass null as a $fromLanguage parameter to translate and it will automatically figure out the source language.

If you would like to use the translation functionality in a client, there are also OCS endpoints available for this: OCS Translation API

Implementing a Translation provider

A Translation provider is a class that implements the interface OCP\Translation\ITranslationProvider.

<?php

declare(strict_types=1);

namespace OCA\MyApp\Translation;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\Translation\ITranslationProvider;
use OCP\IL10N;

class Provider implements ITranslationProvider {

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

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

    public function getAvailableLanguages(): array {
        // Return an array of OCP\Translation\LanguageTuple objects here
    }

    public function translate(?string $fromLanguage, string $toLanguage, string $text): string {
        // Do some fancy machine translation and return translated string
    }
}

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

The method translate translates the passed string and returns the translation. The two language parameters will be language codes that were returned by getAvailableLanguages of your provider. In case translation fails, you should throw a RuntimeException with an explanatory error message.

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

Provider with user context

New in version 29.0.0.

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

<?php

declare(strict_types=1);

namespace OCA\MyApp\Translation;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\Translation\ITranslationProviderWithUserId;
use OCP\IL10N;

class Provider implements ITranslationProviderWithUserId {

    private ?string $userId = null;

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

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

    public function getAvailableLanguages(): array {
        // Return an array of OCP\Translation\LanguageTuple objects here
    }

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

    public function translate(?string $fromLanguage, string $toLanguage, string $text): string {
        // Do some fancy machine translation and return translated string
    }
}

Providing language detection

There is also an IDetectLanguageProvider interface that allows specifying that your provider can auto-detect languages from text input. You can use this as follows:

<?php

declare(strict_types=1);

namespace OCA\MyApp\Translation;

use OCA\MyApp\AppInfo\Application;
use OCP\Files\File;
use OCP\Translation\ITranslationProvider;
use OCP\Translation\IDetectLanguageProvider;
use OCP\IL10N;

class Provider implements ITranslationProvider, IDetectLanguageProvider {

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

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

    public function getAvailableLanguages(): array {
        // Return an array of OCP\Translation\LanguageTuple objects here
    }

    public function translate(?string $fromLanguage, string $toLanguage, string $text): string {
        // Do some fancy machine translation and return translated string
    }

    public function detectLanguage(string $text): ?string {
        // Detect the language of $text
    }
}

The method detectLanguage takes a text in some language and outputs the code of that language, or null in case detection wasn’t successful. The language code that this method returns should be one of the languages returned in getAvailableLanguages.

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\Translation\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->registerTranslationProvider(Provider::class);
    }

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

}