title Preflight requests

Client->Reverse Proxy: Master request

note over Client, Reverse Proxy
    Accept: text/html
    Cookie: PHPSESSID=foobar 
end note

Reverse Proxy->Application: Preflight request

note over Reverse Proxy, Application
    Accept: application/vnd.t42.header-replay
end note

Application->Reverse Proxy: Replay headers

note over Application, Reverse Proxy
    Content-Type: application/vnd.t42.header-replay
    T42-Replay-Headers: Page-Layout, Foobar
    Page-Layout: mobile
    Foobar: whatever
end note

Reverse Proxy->Application: Master request with replay headers

note over Reverse Proxy, Application
    Accept: text/html
    Cookie: PHPSESSID=foobar
    Page-Layout: mobile
    Foobar: whatever
end note

Application->Reverse Proxy: Response

note over Application, Reverse Proxy
    Content-Type: text/html
    Vary: Page-Layout, Foobar
end note

Reverse Proxy->Client: Response