CONE: HTTP Content Negotiation

CONE provides HTTP content negotiation tools.

Usage

API

The main API function is cone.negotiate, which takes a content negotiation header (Accept, Accept-Charset, Accept-Encoding, or Accept-Language) value, and an array table of available values to negotiate between, with the first available value considered the default.

local cone = require('cone')
local http_accept_header = 'apples,oranges;q=0.7,bananas;q=0.5'
local available_values = {'bananas','oranges'}
local negotiated_value = cone.negotiate(http_accept_header, available_values)
print(negotiated_value)
-- Outputs "oranges".

nginx

Use CONE to add content negotiation to nginx. This is extremely powerful when serving static sites. Put cone.lua in nginx's Lua package path, or define your own package path with lua_package_path. Then negotiate Accept* header values with a Lua snippet. Example:

lua_package_path '/cone/?.lua;;';

server {
	listen 80;
    location / {
        set_by_lua_block $locale {
            return require('cone').negotiate(ngx.req.get_headers()['Accept-Language'], {'nl', 'de', 'en'})
        }
        add_header Content-Language $locale;
        return 200;
    }
}