func canHash(req *http.Request) (headResp *http.Response, etag string, hashingOk bool) {
if req.Method != "GET" {
return
}
if vias, ok := req.Header["Via"]; ok {
for _, v := range vias {
if v == proxy.MyVia {
// TODO: We should error out here probably
return
}
}
}
headReq := proxy.SanitizeRequest(req)
headReq.Method = "HEAD"
headReq.Body = nil
headReq.ContentLength = 0
headResp, err := http.DefaultTransport.RoundTrip(headReq)
if err != nil {
log.Printf("Head request to %s failed: %v", req.URL, err)
return
}
headResp.Body.Close()
etag = headResp.Header.Get("ETag")
// TODO: Maybe check that it is well-formed?
if etag == "" || etag[0] == 'W' {
// We require strong ETags to be sure that the hasher received the same entity.
return
}
// FIXME: Cache-Control
return headResp, etag, true
}
func directProxy(rw http.ResponseWriter, req *http.Request) {
r := proxy.SanitizeRequest(req)
resp, err := http.DefaultTransport.RoundTrip(r)
if err != nil {
http.Error(rw, fmt.Sprintf("Proxy error: %v", err), http.StatusInternalServerError)
return
}
defer resp.Body.Close()
proxy.SanitizeResponseHeaders(rw, resp)
io.Copy(rw, resp.Body)
}