etranslation-proxy

EU eTranslation Proxy

This application serves as a simple caching proxy / gateway between the EU eTranslation Service and other applications requiring translation of text snippets into one of the official EU languages.

How it works

The EU eTranslation service is an ansynchronous service requiring an HTTP-callback or ftp / mail service to send the translated snippets to.

• A third-party application sends a translation request via HTTP(S) to this translation proxy
• If the translation is already in the cache/database, the proxy does not contact the eTranslation service
• If the translation is not readily available, the proxy stores the snippet and sends a translation request to the EU eTranslation service
• The EU eTranslation service sends the translation back to the proxy via the HTTP(S)-callback (or an error response)
• Meanwhile the third-party application can send HTTP requests to the proxy on a regular basis ("is it available yet"), until the translation becomes available (or the client gives up)
• The proxy will try again if the EU eTranslation service is not available or the maximum amount of requests is reached

Limitations

The snippet must be a plain-text snippet, with a maximum of 5000 characters.

Example requests

Translation request parameters

Property	Description
sourceLang	Language code of the source text
targetLang	Language code of the target translation
text	Text to be translated (max 5000 characters)

Requests are posted as form encoded data, user name and password for the proxy can be inserted in the URL

curl -X POST http://rquser:rqpass@localhost:8080/request/submit \
    -H "Content-Type: application/x-www-form-urlencoded" 
    -d "sourceLang=en&targetLang=nl&text=Hallo"

This should return HTTP 202 - Accepted

Translation retrieval parameters

Property	Description
hash	SHA1 hash of the source text
targetLang	Language code of the target translation

curl -X GET "http://rquser:rqpass@localhost:8080/request/retrieve?hash=59d9a6df06b9f610f7db8e036896ed03662d168f&targetLang=en"

This should either return an

• HTTP 200 - OK, in which case the translated text is in the body
• or an HTTP 404 - Not Found, in which case the translation is not ready (yet), and the client should try again later

Application properties

Local translation cache database

Property	Description
spring.datasource.url	JDBC connection string of the local database
spring.datasource.username	User name of local database
spring.datasource.password	Password of local database

Request from local client to proxy

Property	Description
request.auth.user	User name to be used by local client
request.auth.pass	Password to be used by local client

EU eTranslation service

Property	Description
etranslate.url	URL of the EU eTranslation service
etranslate.auth.scope	Domain/scope of EU eTranslation authentication
etranslate.auth.user	User name for the EU eTranslation service
etranslate.auth.pass	Password for the EU eTranslation service
etranslate.auth.application	Application for the EU eTranslation service
etranslate.url	URL of the EU eTranslation service
etranslate.auth.user	User name for the EU eTranslation service
etranslate.auth.pass	Password for the EU eTranslation service
etranslate.auth.application	Application for the EU eTranslation service
etranslate.requests.delay	Delay in seconds between separate HTTP requests to the eTranslation service
etranslate.requests.queue.delay	Delay in seconds before the queue is sent as separate requests
etranslate.requests.quota.delay	Delay in seconds when eTranslation service has received too many requests
etranslate.requests.expire	Time in seconds after which untranslated strings are removed from local queue

Callback from EU eTranslation service to proxy

Property	Description
callback.auth.user	User name to be used by eTranslation service
callback.auth.pass	Password to be used by eTranslation service
callback.error	URL to call in case of error
callback.ok	URL to call in case of success