Method need_to_revalidate

src/proxy/http/HttpTransact.cc:2661–2721

////////////////////////////////////////////////////////////////////////// Name : need_to_revalidate Description: Checks if a document which is in the cache needs to be revalidates Details : Function calls AuthenticationNeeded and is_cache_response_returnable to determine if the cached document can be served ////////////////////////////////////////////////////////////////////////

//              if the cached document can be served
/////////////////////////////////////////////////////////////////////////////
bool
HttpTransact::need_to_revalidate(State *s)
{
  bool           needs_revalidate, needs_authenticate = false;
  bool           needs_cache_auth = false;
  CacheHTTPInfo *obj;

  if (s->api_update_cached_object == HttpTransact::UPDATE_CACHED_OBJECT_CONTINUE) {
    obj = &s->cache_info.object_store;
    ink_assert(obj->valid());
    if (!obj->valid()) {
      return true;
    }
  } else {
    obj = s->cache_info.object_read;
  }

  // do we have to authenticate with the server before
  // sending back the cached response to the client?
  Authentication_t authentication_needed = AuthenticationNeeded(s->txn_conf, &s->hdr_info.client_request, obj->response_get());

  switch (authentication_needed) {
  case AUTHENTICATION_SUCCESS:
    TxnDbg(dbg_ctl_http_seq, "Authentication not needed");
    needs_authenticate = false;
    break;
  case AUTHENTICATION_MUST_REVALIDATE:
    SET_VIA_STRING(VIA_DETAIL_CACHE_LOOKUP, VIA_DETAIL_MISS_METHOD);
    TxnDbg(dbg_ctl_http_seq, "Authentication needed");
    needs_authenticate = true;
    break;
  case AUTHENTICATION_MUST_PROXY:
    TxnDbg(dbg_ctl_http_seq, "Authentication needed");
    needs_authenticate = true;
    break;
  case AUTHENTICATION_CACHE_AUTH:
    TxnDbg(dbg_ctl_http_seq, "Authentication needed for cache_auth_content");
    needs_authenticate = false;
    needs_cache_auth   = true;
    break;
  default:
    ink_assert(!("AuthenticationNeeded has returned unsupported code."));
    return true;
    break;
  }

  ink_assert(is_cache_hit(s->cache_lookup_result));
  if (s->cache_lookup_result == CACHE_LOOKUP_HIT_STALE &&
      s->api_update_cached_object != HttpTransact::UPDATE_CACHED_OBJECT_CONTINUE) {
    needs_revalidate = true;
  } else {
    needs_revalidate = false;
  }

  bool send_revalidate = ((needs_authenticate == true) || (needs_revalidate == true) || (is_cache_response_returnable(s) == false));
  if (needs_cache_auth == true) {
    s->www_auth_content = send_revalidate ? CACHE_AUTH_STALE : CACHE_AUTH_FRESH;
    send_revalidate     = true;