x-accel-redirect - can I get list of headers from origin upstream response ( resp containing x-accel-redirect)

[Leszek Szarlej]

Hello

I am trying to make x-accel-redirect feature serve external url and pass response headers from origin response which contained X-Accel-Redirect header. Inside location after x-accel internal redirect I can access headers from origin response using $upstream_http_HEADER or ngx.var.upstream_http_HEADER in lua. Problem is that I don't know the names of headers that will be sent by origin upstream. I tried to get them by iterating through ngx.resp.get_headers() but it doesn't contain them.

origin upstream response:

foo:bar

X-Accel-Redirect:/x-accel-redirect/some_resource

Then location below will be used:

location /x-accel-redirect/ {

    internal;

    content_by_lua_block {

    ngx.header["foo"] = ngx.var.upstream_http_foo

    local h, err = ngx.resp.get_headers()

    for k, v in pairs(h) do

       ngx.say(k .. ":" .. v)

    end

    }

}

response is:

< HTTP/1.1 200 OK

< Content-Type: text/csv;charset=utf-8

< Date: Thu, 19 Sep 2019 16:13:33 GMT

< Server: openresty

< Vary: Accept-Encoding

< foo: bar

< Content-Length: 62

< Connection: keep-alive

<

connection:keep-alive

content-type:text/csv;charset=utf-8

I was able to read Foo header from origin response and pass it downstream but I can't list it using ngx.resp.get_headers().

Thanks for help

Leszek