Method HandleCacheOpenReadMiss

src/proxy/http/HttpTransact.cc:3267–3351

////////////////////////////////////////////////////////////////////////// Name : HandleCacheOpenReadMiss Description: cache looked up, miss or hit, but needs authorization Details : Possible Next States From Here: - HttpTransact::SM_ACTION_DNS_LOOKUP; - HttpTransact::ORIGIN_SERVER_OPEN; - HttpTransact::PROXY_INTERNAL_CACHE_NOOP; - result of how_to_open_connection() /////////////////

//
///////////////////////////////////////////////////////////////////////////////
void
HttpTransact::HandleCacheOpenReadMiss(State *s)
{
  TxnDbg(dbg_ctl_http_trans, "--- MISS");
  TxnDbg(dbg_ctl_http_seq, "Miss in cache");

  if (delete_all_document_alternates_and_return(s, false)) {
    TxnDbg(dbg_ctl_http_trans, "Delete and return");
    s->cache_info.action = CACHE_DO_NO_ACTION;
    s->next_action       = SM_ACTION_INTERNAL_CACHE_NOOP;
    return;
  }
  // reinitialize some variables to reflect cache miss state.
  s->cache_info.object_read = nullptr;
  s->request_sent_time      = UNDEFINED_TIME;
  s->response_received_time = UNDEFINED_TIME;
  SET_VIA_STRING(VIA_CACHE_RESULT, VIA_CACHE_MISS);
  if (GET_VIA_STRING(VIA_DETAIL_CACHE_LOOKUP) == ' ') {
    SET_VIA_STRING(VIA_DETAIL_CACHE_LOOKUP, VIA_DETAIL_MISS_NOT_CACHED);
  }
  // We do a cache lookup for some non-GET requests as well.
  // We must, however, not cache the responses to these requests.
  if (does_method_require_cache_copy_deletion(s->txn_conf, s->method) && s->api_req_cacheable == false) {
    s->cache_info.action = CACHE_DO_NO_ACTION;
  } else if ((s->hdr_info.client_request.presence(MIME_PRESENCE_RANGE) && !s->txn_conf->cache_range_write) ||
             does_method_effect_cache(s->method) == false || s->range_setup == RANGE_NOT_SATISFIABLE ||
             s->range_setup == RANGE_NOT_HANDLED) {
    s->cache_info.action = CACHE_DO_NO_ACTION;
  } else if (s->api_server_response_no_store) { // plugin may have decided not to cache the response
    s->cache_info.action = CACHE_DO_NO_ACTION;
  } else {
    HttpTransact::set_cache_prepare_write_action_for_new_request(s);
  }

  ///////////////////////////////////////////////////////////////
  // a normal miss would try to fetch the document from the    //
  // origin server, unless the origin server isn't resolvable, //
  // but if "CacheControl: only-if-cached" is set, then we are //
  // supposed to send a 504 (GATEWAY TIMEOUT) response.        //
  ///////////////////////////////////////////////////////////////

  HTTPHdr *h = &s->hdr_info.client_request;

  if (!h->is_cache_control_set(HTTP_VALUE_ONLY_IF_CACHED)) {
    // Initialize the server_info structure if we haven't been through DNS
    // Otherwise, the http_version will not be initialized
    if (!s->current.server || !s->current.server->dst_addr.isValid()) {
      // Short term hack.  get_ka_info_from_config assumes if http_version is > 0,9 it has already been
      // set and skips the rest of the function.  The default functor sets it to 1,0
      s->server_info.http_version = HTTP_0_9;
      get_ka_info_from_config(s, &s->server_info);
    }
    find_server_and_update_current_info(s);
    // a parent lookup could come back as PARENT_FAIL if in parent.config go_direct == false and
    // there are no available parents (all down).
    if (s->parent_result.result == PARENT_FAIL) {
      handle_parent_down(s);
      return;