How to rewrite location in nginx depending on the client-browser's language?

Question

How to rewrite location in nginx depending on the client-browser\'s language?

For example: My browser accept-language is \'uk,ru,en\'. When I request locati

Answer 1

In addition to @Marks answer above which does not honor language preferences. Here's a LUA chunk of code parsing Accept-Language Header value into language and preference value

-- need two LUA regex cause LUA's default regex is pretty broken
-- In my opinion a killer argument against using / supporting LUA

rx = "%s*([a-zA-Z-]+)%s*;%s*q%s*=%s*(%d*.?%d+)"
rx2 = "%s*([a-zA-Z-]+)%s*"

-- (arg .. ",") => concatenation operation
for chunk in (arg .. ","):gmatch("([^,]*),") do
    lang, q = string.match(chunk, rx)
    if (not lang) then
        lang = string.match(chunk, rx2)
        q = 1.0
    end
    print(string.format("lang=[%s] q=[%s]",lang, tonumber(q * 1.0)))
end

When applying, I'm getting:

$ lua demo.lua 'en-US , de , fr ; q = 0.1 , dk;q=1 '
lang=[en-US] q=[1.0]
lang=[de] q=[1.0]
lang=[fr] q=[0.1]
lang=[dk] q=[1.0]

$ lua demo.lua ' de'
lang=[de] q=[1.0]

$ lua demo.lua ' de;'
lang=[de] q=[1.0]

$ lua demo.lua ' de;q'
lang=[de] q=[1.0]

$ lua demo.lua ' de;q='
lang=[de] q=[1.0]

$ lua demo.lua ' de;q=0'
lang=[de] q=[0.0]

$ lua demo.lua ' de;q=0.1'
lang=[de] q=[0.1]

Eventually I'm using than a LUA script like below to redirect:

rx = "%s*([a-zA-Z-]+)%s*;%s*q%s*=%s*(%d*.?%d+)"
rx2 = "%s*([a-zA-Z-]+)%s*"


sup = {de = 0, en = 0, dk = 0}       -- supported languages
win = {lang = "en", q = 0}           -- default values / winner

for chunk in (arg[1] .. ","):gmatch("([^,]*),") do
    lang, q = string.match(chunk, rx)
    if (not lang) then
        lang = string.match(chunk, rx2)
        q = 1.0
    end
    lang = string.lower(lang)
    -- handle only supported languages
    if (sup[lang]) then
        q = tonumber(q)
        -- update winner table if a better match is found
        if (win.q < q) then
            win.q = q
            win.lang = lang
        end
    end
end

-- which language pref?
print(string.format("winner: %s",win.lang))

This gives:

$ lua test.lua 'en-US;q=.7 , de;q=0.9 , fr ; q = 0.1 , dk ; q  =  1 '
winner: dk