locale-host

ExpressJS plugin to support setting the locale through the host

npm install locale-host
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Overview

locale-host is a simple plugin for ExpressJS (it could be made to work with raw NodeJS, I think it only uses res.redirect() from ExpressJS) that supports setting the locale through the host name, e.g.: http://en.example.org/, http://fr.example.org/, etc.

You provide it with a list of accepted locales, as well as a default one, and either it can find the locale for a given request and makes it available for other code to use, or it can't and will redirect to the default locale.

It is designed to integrate with node-jus-i18n if it's there (or any other module that adds a locale() method to HTTP requests).

Example

var lh = require("locale-host");

// ... as part of your ExpressJS setup ...
app.use(lh.middleware({
    baseHost:       "example.org"
,   locales:        ["en", "fr"]
,   https:          false
,   defaultLocale:  "en"
}));

// ... in any code that handles a request ...
var current_locale = req.locale();

Installation

$ npm install locale-host

Interface

This module exports a single method: middleware(). It is designed to generate an ExpressJS middleware based on a set of options. You should place it before any code that uses locale information.

The options that middleware() accepts are:

  • baseHost (required). This is the host without the locale subdomain. If you want en.example.org, then this is "example.org".
  • locales (required). This is an array of the locales that you accept in your application.
  • port. If specified, redirects to a host using a specific port. If unspecified you simply get port-less redirects.
  • https (defaults to false). Indicates whether you're using HTTPS (and therefore redirects should be to https:// URIs). This may be autodetected in the future (if possible).
  • defaultLocale. The default locale to redirect to for requests that don't have a locale. A simple string that if omitted, defaults to the first values in locales. It can also be a callback (which can prove useful if you want to default the locale depending for instance on the user's IP). The arguments that the callback takes are: req, res, locales, next; where req and res are the usual request and response, locales is the list of locales that the application has been configured to accept, and next is a callback to call when the default locale has been determined (this allows you to do so in an asynchronous fashion). The next callback expects to be called with an error and a locale. If it is called with an error it will just redirect to the first locale in locales as a fallback; otherwise it will use the provided locale.

In middleware that is placed after locale-host, two methods are available on req:

  • locale(). Returns the locale that was set through the host. Note that this is the same method that is used by node-jus.i18n (on purpose). If for whatever reason you wish to override the locale for this host, you can do so by passing this method a value (do this only if you know what you're doing though).
  • uriWithLocale(locale). Provided a locale, this returns a URI with the same features as the one of the current request but with the given locale in the host. Say you are visiting http://en.example.org/foo, calling req.uriWithLocale("fr") will return http://fr.example.org/foo. This is particularly useful for the generation of language switching menus.

Proxies

If you're using a proxy server in front of your Node instance, you will want to make sure that it is passing on at least the original Host: header as that is required for locale-host to do its work. You may want to be cautious about the way in which your proxy may rewrite redirects as those could get in the way. For nginx, you should probably use a configuration similar to:

upstream node_app {
        server 127.0.0.1:3000;
}

server {
    listen          80;
    server_name     example.org *.example.org;

    location / {
        # you can of course set other proxy headers as needed
        proxy_set_header Host $http_host;
        proxy_pass http://node_app/;
        proxy_redirect off;
    }
}

License

(The MIT License)

Copyright (c) 2011-2012 Robin Berjon <robin@berjon.com>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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