DeepL Ruby Library
The DeepL API is a language translation API that allows other computer programs to send texts and documents to DeepL's servers and receive high-quality translations. This opens a whole universe of opportunities for developers: any translation product you can imagine can now be built on top of DeepL's best-in-class translation technology.
The DeepL Ruby library offers a convenient way for applications written in Ruby to interact with the DeepL API. We intend to support all API functions with the library, though support for new features may be added to the library after they’re added to the API.
Getting an authentication key
To use the DeepL Ruby Library, you'll need an API authentication key. To get a key, please create an account here. With a DeepL API Free account you can translate up to 500,000 characters/month for free.
Installation
Install this gem with
gem install deepl-rb
# Load it in your ruby file using `require 'deepl'`
Or add it to your Gemfile:
gem 'deepl-rb', require: 'deepl'
Usage
Setup an environment variable named DEEPL_AUTH_KEY
with your authentication key:
export DEEPL_AUTH_KEY="your-api-token"
Alternatively, you can configure the API client within a ruby block:
DeepL.configure do |config|
config.auth_key = 'your-api-token'
end
You can also configure the API host and the API version:
DeepL.configure do |config|
config.auth_key = 'your-api-token'
config.host = 'https://api-free.deepl.com' # Default value is 'https://api.deepl.com'
config.version = 'v1' # Default value is 'v2'
end
Available languages
Available languages can be retrieved via API:
languages = DeepL.languages
puts languages.class
# => Array
puts languages.first.class
# => DeepL::Resources::Language
puts "#{languages.first.code} -> #{languages.first.name}"
# => "ES -> Spanish"
Note that source and target languages may be different, which can be retrieved by using the type
option:
puts DeepL.languages(type: :source).count
# => 24
puts DeepL.languages(type: :target).count
# => 26
All languages are also defined on the official API documentation.
Note that target languages may include the supports_formality
flag, which may be checked
using the DeepL::Resources::Language#supports_formality?
.
Translate
To translate a simple text, use the translate
method:
translation = DeepL.translate 'This is my text', 'EN', 'ES'
puts translation.class
# => DeepL::Resources::Text
puts translation.text
# => 'Este es mi texto'
Enable auto-detect source language by skipping the source language with nil
:
translation = DeepL.translate 'This is my text', nil, 'ES'
puts translation.detected_source_language
# => 'EN'
Translate a list of texts by passing an array as an argument:
texts = ['Sample text', 'Another text']
translations = DeepL.translate texts, 'EN', 'ES'
puts translations.class
# => Array
puts translations.first.class
# => DeepL::Resources::Text
You can also use custom query parameters, like tag_handling
, split_sentences
, non_splitting_tags
or ignore_tags
:
translation = DeepL.translate '<p>A sample</p>', 'EN', 'ES',
tag_handling: 'xml', split_sentences: false,
non_splitting_tags: 'h1', ignore_tags: %w[code pre]
puts translation.text
# => "<p>Una muestra</p>"
To translate with context, simply supply the context
parameter:
translation = DeepL.translate 'That is hot!', 'EN', 'ES',
context: 'He did not like the jalapenos in his meal.'
puts translation.text
# => "¡Eso es picante!"
To specify a type of translation model to use, you can use the model_type
option:
translation = DeepL.translate 'That is hot!', 'EN', 'DE',
model_type: 'quality_optimized'
This would use next-gen translation models for the translation. The available values are
-
'quality_optimized'
: use a translation model that maximizes translation quality, at the cost of response time. This option may be unavailable for some language pairs. -
'prefer_quality_optimized'
: use the highest-quality translation model for the given language pair. -
'latency_optimized'
: use a translation model that minimizes response time, at the cost of translation quality.
The following parameters will be automatically converted:
Parameter | Conversion |
---|---|
preserve_formatting |
Converts false to '0' and true to '1'
|
split_sentences |
Converts false to '0' and true to '1'
|
outline_detection |
Converts false to '0' and true to '1'
|
splitting_tags |
Converts arrays to strings joining by commas |
non_splitting_tags |
Converts arrays to strings joining by commas |
ignore_tags |
Converts arrays to strings joining by commas |
formality |
No conversion applied |
glossary_id |
No conversion applied |
context |
No conversion applied |
Glossaries
To create a glossary, use the glossaries.create
method. The glossary entries
argument should be an array of text pairs. Each pair includes the source and the target translations.
entries = [
['Hello World', 'Hola Tierra'],
['car', 'auto']
]
glossary = DeepL.glossaries.create 'Mi Glosario', 'EN', 'ES', entries
puts glossary.class
# => DeepL::Resources::Glossary
puts glossary.id
# => 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts glossary.entry_count
# => 2
Created glossaries can be used in the translate
method by specifying the glossary_id
option:
translation = DeepL.translate 'Hello World', 'EN', 'ES', glossary_id: 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts translation.class
# => DeepL::Resources::Text
puts translation.text
# => 'Hola Tierra'
translation = DeepL.translate "I wish we had a car.", 'EN', 'ES', glossary_id: 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts translation.class
# => DeepL::Resources::Text
puts translation.text
# => Ojalá tuviéramos un auto.
To list all the glossaries available, use the glossaries.list
method:
glossaries = DeepL.glossaries.list
puts glossaries.class
# => Array
puts glossaries.first.class
# => DeepL::Resources::Glossary
To find an existing glossary, use the glossaries.find
method:
glossary = DeepL.glossaries.find 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts glossary.class
# => DeepL::Resources::Glossary
The glossary resource does not include the glossary entries. To list the glossary entries, use the glossaries.entries
method:
entries = DeepL.glossaries.entries 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts entries.class
# => Array
puts entries.size
# => 2
pp entries.first
# => ["Hello World", "Hola Tierra"]
To delete an existing glossary, use the glossaries.destroy
method:
glossary_id = DeepL.glossaries.destroy 'aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e'
puts glossary_id
# => aa48c7f0-0d02-413e-8a06-d5bbf0ca7a6e
You can list all the language pairs supported by glossaries using the glossaries.language_pairs
method:
language_pairs = DeepL.glossaries.language_pairs
puts language_pairs.class
# => Array
puts language_pairs.first.class
# => DeepL::Resources::LanguagePair
puts language_pairs.first.source_lang
# => en
puts language_pairs.first.target_lang
# => de
Monitor usage
To check current API usage, use:
usage = DeepL.usage
puts usage.character_count
# => 180118
puts usage.character_limit
# => 1250000
Translate documents
To translate a document, use the document.translate_document
method. Example:
DeepL.document.translate_document('/path/to/spanish_document.pdf', '/path/to/translated_document.pdf', 'ES', 'EN')
The lower level upload
, get_status
and download
methods are also exposed, as well as the convenience method wait_until_document_translation_finished
on the DocumentHandle
object, which would replace get_status
:
doc_handle = DeepL.document.upload('/path/to/spanish_document.pdf', 'ES', 'EN')
doc_status = doc_handle.wait_until_document_translation_finished # alternatively poll `DeepL.document.get_status`
# until the `doc_status.successful?`
DeepL.document.download(doc_handle, '/path/to/translated_document.pdf') unless doc_status.error?
Handle exceptions
You can capture and process exceptions that may be raised during API calls. These are all the possible exceptions:
Exception class | Description |
---|---|
DeepL::Exceptions::AuthorizationFailed |
The authorization process has failed. Check your auth_key value. |
DeepL::Exceptions::BadRequest |
Something is wrong in your request. Check exception.message for more information. |
DeepL::Exceptions::DocumentTranslationError |
An error occured during document translation. Check exception.message for more information. |
DeepL::Exceptions::LimitExceeded |
You've reached the API's call limit. |
DeepL::Exceptions::QuotaExceeded |
You've reached the API's character limit. |
DeepL::Exceptions::RequestError |
An unkown request error. Check exception.response and exception.request for more information. |
DeepL::Exceptions::NotSupported |
The requested method or API endpoint is not supported. |
DeepL::Exceptions::RequestEntityTooLarge |
Your request is too large, reduce the amount of data you are sending. The API has a request size limit of 128 KiB. |
DeepL::Exceptions::ServerError |
An error occured in the DeepL API, wait a short amount of time and retry. |
An exampling of handling a generic exception:
def my_method
item = DeepL.translate 'This is my text', nil, 'ES'
rescue DeepL::Exceptions::RequestError => e
puts 'Oops!'
puts "Code: #{e.response.code}"
puts "Response body: #{e.response.body}"
puts "Request body: #{e.request.body}"
end
Logging
To enable logging, pass a suitable logging object (e.g. the default Logger
from the Ruby standard library) when configuring the library. The library logs HTTP requests to INFO
and debug information to DEBUG
. Example:
require 'logger'
logger = Logger.new(STDOUT)
logger.level = Logger::INFO
deepl.configure do |config|
config.auth_key = configuration.auth_key
config.logger = logger
end
Proxy configuration
To use HTTP proxies, a session needs to be used. The proxy can then be configured as part of the HTTP client options:
client_options = HTTPClientOptions.new({ 'proxy_addr' => 'http://localhost', 'proxy_port' => 80 })
deepl.with_session(client_options) do |session|
# ...
end
Anonymous platform information
By default, we send some basic information about the platform the client library is running on with each request, see here for an explanation. This data is completely anonymous and only used to improve our product, not track any individual users. If you do not wish to send this data, you can opt-out by setting the send_platform_info
flag in the configuration to false
like so:
deepl.configure({}, nil, nil, false) do |config|
# ...
end
You can also complete customize the User-Agent
header like so:
deepl.configure do |config|
config.user_agent = 'myCustomUserAgent'
end
Sending multiple requests
When writing an application that send multiple requests, using a HTTP session will give better performance through HTTP Keep-Alive. You can use it by simply wrapping your requests in a with_session
block:
deepl.with_session do |session|
deepl.translate(sentence1, 'DE', 'EN-GB')
deepl.translate(sentence2, 'DE', 'EN-GB')
deepl.translate(sentence3, 'DE', 'EN-GB')
end
Writing a plugin
If you use this library in an application, please identify the application by setting the name and version of the plugin:
deepl.configure({}, 'MyTranslationPlugin', '1.0.1') do |config|
# ...
end
This information is passed along when the library makes calls to the DeepL API. Both name and version are required. Please note that setting the User-Agent
header via deepl.configure
will override this setting, if you need to use this, please manually identify your Application in the User-Agent
header.
Integrations
Ruby on Rails
You may use this gem as a standalone service by creating an initializer on your
config/initializers
folder with your DeepL configuration. For example:
# config/initializers/deepl.rb
DeepL.configure do |config|
# Your configuration goes here
end
Since the DeepL service is defined globally, you can use service anywhere in your code (controllers, models, views, jobs, plain ruby objects… you name it).
i18n-tasks
You may also take a look at i18n-tasks
, which is a gem
that helps you find and manage missing and unused translations. deepl-rb
is used as one of the
backend services to translate content.
Development
Clone the repository, and install its dependencies:
git clone https://github.com/DeepLcom/deepl-rb
cd deepl-rb
bundle install
To run tests (rspec and rubocop), use
bundle exec rake test
Caution: Changing VCR Tests
If you need to rerecord some of the VCR tests, simply setting record: :new_episodes
and rerunning rspec
won't be enough in some cases, specifically around document translation (due to its statefulness) and glossaries (since a glossary ID is associated with a specific API account).
For example, there are document translations tests that split up the upload
, get_status
and download
calls into separate test cases. You need to first rerecord the upload
call, you can do execute a single test like this (the line should be where the it
block of the test starts):
rspec ./spec/api/deepl_spec.rb:152
This will return a document_id
and a document_key
, you will need to update the values in the get_status
and download
tests accordingly. You can find examples for this in the git history.
Similarly, for the glossary tests you will need to delete the recorded HTTP requests for certain glossary IDs so that rspec
will create the glossaries on your account instead. Feel free to reach out on our discord if you run into any trouble here.
Acknowledgements
This library was originally developed by Daniel Herzog, we are grateful for his contributions. Beginning with v3.0.0, DeepL took over development and officially supports and maintains the library together with Daniel.