func fillErrorResponse(ev *event.HTTPResponseEvent, cause string) {
str := "You are not allowed to visit this site via proxy because %s."
content := fmt.Sprintf(str, cause)
ev.SetHeader("Content-Type", "text/plain")
ev.SetHeader("Content-Length", strconv.Itoa(len(content)))
ev.Content.WriteString(content)
}
func Fetch(context appengine.Context, ev *event.HTTPRequestEvent) event.Event {
errorResponse := new(event.HTTPResponseEvent)
if Cfg.IsMaster == 1 {
fillErrorResponse(errorResponse, "Proxy service is no enable in snova master node.")
return errorResponse
}
if isInBlacklist(ev.GetHeader("Host")) {
fillErrorResponse(errorResponse, "Current site is in blacklist.")
return errorResponse
}
req := buildHTTPRequest(ev)
if req == nil {
errorResponse.Status = 400
fillErrorResponse(errorResponse, "Invalid fetch url:"+ev.Url)
return errorResponse
}
var t urlfetch.Transport
t.Context = context
t.Deadline, _ = time.ParseDuration("10s")
t.AllowInvalidServerCertificate = true
//t := &transport
//t := &urlfetch.Transport{context, 0, true}
retryCount := Cfg.RetryFetchCount
for retryCount > 0 {
resp, err := t.RoundTrip(req)
if err == nil {
res := buildHTTPResponseEvent(resp)
if res.Status == 302 {
rangeHeader := req.Header.Get("Range")
if len(rangeHeader) > 0 {
res.AddHeader("X-Range", rangeHeader)
}
}
return res
}
context.Errorf("Failed to fetch URL[%s] for reason:%v", ev.Url, err)
retryCount--
if strings.EqualFold(req.Method, "GET") && strings.Contains(err.Error(), "RESPONSE_TOO_LARGE") {
rangeLimit := Cfg.RangeFetchLimit
rangestart := 0
rangeheader := req.Header.Get("Range")
if len(rangeheader) > 0 {
rangestart, _ = util.ParseRangeHeaderValue(rangeheader)
}
req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", rangestart, rangeLimit-1))
}
if strings.Contains(err.Error(), "RESPONSE_TOO_LARGE") {
time.Sleep(1 * time.Second)
return Fetch(context, ev)
}
}
errorResponse.Status = 408
fillErrorResponse(errorResponse, "Fetch timeout for url:"+ev.Url)
rangeHeader := req.Header.Get("Range")
if len(rangeHeader) > 0 {
errorResponse.SetHeader("X-Range", rangeHeader)
}
return errorResponse
}