translation-proxy

Translation-Proxy translates the contents from the origin by using Google Cloud Translation API when requested.

Requirements

redis
Node.js
Google Cloud SDK
Your Google Cloud Service Account and API Key
Your SSL Cert and Key

Installation

$ npm install translation-proxy
$ cd translation-proxy
$ npm install
$ npm run build

Google Service Account and API Key Setup

Log in to Google Cloud Platform Console.
Create a service account on your project on GCP.

GCP > IAM & admin > Service accounts

Create Service Account key for the account on GCP and download the key (json).

GCP > APIs & Services > Credentials

Move the API key on the machine where you intalled the proxy server.
Activate service account with SDK.

$ gcloud auth activate-service-account --key-file your-key.json

Set the API KEY path to Environmental Variable: GOOGLE_APPLICATION_CREDENTIALS

$ export GOOGLE_APPLICATION_CREDENTIALS="path/to/your-key.json"

Test your Service Account API Key

$ gcloud auth application-default print-access-token

Test

$ npm run test

Usage

$ sudo node dist/server.js

Configuration

copy config/sample.json and create config/config.json and modify it.

Sample Configuration JSON

{
  "cacheEnabled": true,
  "cacheSkipUrls": ["do-not-cache-if-requested-url-contains-keyword"],
  "cacheSkipCookies": ["do-not-cache-if-request-contains-cookie"],
  "cacheShortTTL": 60,
  "cacheTTL": [
      { "type": "text/html",       "ttl":  86400 },
      { "type": "text/css",        "ttl": 259200 },
      { "type": "text",            "ttl": 604800 },
      { "type": "application/pdf", "ttl": 604800 },
      { "type": "application",     "ttl": 259200 },
      { "type": "image",           "ttl": 604800 },
      { "type": "default",         "ttl": 604800 }
  ],
  "proxiedHosts": ["your.domain.com"],
  "purgeAllowedIps": ["127.0.0.1"],
  "translationSelectors": ["#header", "#main", "#footer"],
  "maxPageSize": 80000,
  "maxTextPerRequest": 12000,
  "domBreakdownThreshold": 250,
  "keyPath": "/path/to/key.json",
  "gcloudPath": "/path/to/google-cloud-sdk/bin/gcloud",
  "serverHttpPort": 80,
  "serverHttpsPort": 443,
  "targetHttpPort": 80,
  "targetHttpsPort": 443,
  "sslCert": "./certs/test.pem",
  "sslKey": "./certs/test.key",
  "redisHost": "127.0.0.1",
  "redisPort": 6379,
  "enableLog": true,
  "logLevel": "debug",
  "logDir": "./logs"
}

Sample For Wordpress Origin

{
  ...
  "cacheSkipUrls": ["wp-admin", "wp-login", "wp-cron.php"],
  "cacheSkipCookies": ["wordpress_logged_in", "resetpass"],
  ...
}

Configuration Options

Cache Related

Option	Description
cacheEnabled	Enable cache if true.
cacheSkipUrls	Bypass cach if the requested url containes one of the specified keywords.
cacheSkipCookies	Bypass cach if the request containes one of the specified cookies.
cacheShortTTL	Cache TTL (in seconds) for 302 (Moved Temporarily), 307 (Temporary Redirect), 500 (Internal Sever Error), 503 (Service Not Available) responses; default 60 secs.
cacheTTL	Cache TTL (in seconds) per matched Content Type; Array of { "type", "ttl" }
redisHost	Redis Host; default localhost
redisPort	Redis Port; default 6379
purgeAllowedIps	Allow specified IP addresses to send a cache purge request.

Translation Related

Option	Description
translationSelectors	DOM selectors which specify where to be translated; eg. 'body', 'div#main'
maxPageSize	Not allow the page to be translated if the total text size exceeds this limit (in character); default 50,000 characters.
maxTextPerRequest	Max text size (in character) per API request.
domBreakdownThreshold	If the size of a DOM component is larger than this threshold, the parser goes down into its children to break down the text when it creates API requests.
gcloudPath	The Google Cloud SDK installation path.
keyPath	The path to API Key.

Server Related

Option	Description
proxiedHosts	Allow the proxy to send a request only to hosts specified this. The proxy returns Bad Request when unspecified host is requested.
serverHttpPort	HTTP Port on which the proxy server listens.
serverHttpsPort	HTTPS Port on which the proxy server listens.
targetHttpPort	HTTP Port on which the origin web servers listen.
targetHttpsPort	HTTPS Port on which the origin web servers listen.
sslCert	The path to your SSL cert.
sslKey	The path to your SSL key.

Logging Related

Option	Description
enableLog	Enable Logging if true.
logLevel	Logging Level: (DEBUG\|INFO\|WARN\|ERROR\|FATAL)
logDir	Log file destination directory; default ./logs
logFile	Application log file name; default application.log
accessLogFile	Access log file name; default access.log

Translation

The requestd page will be translated if its URL has the lang parameter. The parameter value must conform to codes defined by the Google Cloud Translation API. Google Cloud Translation API Supported Langauges and Codes are here.

Example

http://example.com/path/to/page?lang=ja

Caching

The proxy caches every response from the origin server when caching is enabled and the following conditions are satisfied:

HTTP Request Method is:
- GET or HEAD
HTTP Response Code is:
- 200 (OK)
- 203 (Non Authoritative Information)
- 204 (No Content)
- 206 (Partial Content)
- 300 (Multiple Choices)
- 301 (Moved Permanently)
- 302 (Found (Moved Temporarily))
- 307 (Temporary Redirect)
- 308 (Permanent Redirect)
- 404 (Not Found)
- 405 (Method Not Allowed)
- 410 (Gone)
- 414 (URL Too Long)
- 500 (Internal Server Error)
- 501 (Not Implemented)
- 503 (Service Not Available)

NOTE:

You can bypass caching by configuring cachieSkipUrls or cacheSkipCookies options.
You can configure cache TTL per content type with cacheTTL option.
When the response code is 302, 307, 500, or 503, cache should expire in shorter period. You can specify it with cacheShortTTL option.

Purge Cache

There are two ways to purge cache:

purge a cached page
purge all the cache

For purging a cached resource, send a HTTP PURGE request to the URL which you want to purge. For purging all the cache, send a HTTP PURGE request to /purge-proxy-cache?page=all.