Hi,

I'm currently using OpenResty, and one of the things I am trying to do is have the backend send a specific header, and if that header is present, run a body_filter_by_lua call on the output. However, while I can use the $upstream_http_* vars for populating (i.e. I can go add_header SomeHeader $upstream_http_foo, and if Foo has been sent see SomeHeader: FooVar in the output. However, all tests for them seem to break.

Example:

location @backend {
expires off;
proxy_pass http://_varnish;
set $test $upstream_http_csrf; # definitely exists, I can see it in the response headers
add_header SomeHeader $upstream_http_csrf; # And I can read it, but....
if ($upstream_http_csrf = 1) { # doesn't matter if it's 1, "one" ~* "one", anything....
# this block never gets called
}
add_header someOtherHeader $test; # Not present in output as empty
set_by_lua $use_token
'
if not ngx.var.sent_http_csrf == "" then
return ngx.var.upstream_http_csrf
end
return "baz"
'; # Always return 'baz'
add_header WIllThisWork $use_token; # Again, empty
}