Method handle_response_keep_alive_headers

src/proxy/http/HttpTransact.cc:6894–7033

///////////////////////////////////////////////////////////////////////// void HttpTransact::handle_response_keep_alive_headers( State* s, bool ka_on, HTTPVersion ver, HTTPHdr *heads) Removes keep alive headers from origin server from Adds the appropriate Transfer-Encoding: chunked header. Adds the appropriate keep alive headers (if any) to for keep-alive state , and HTT

//
//////////////////////////////////////////////////////////////////////////////
void
HttpTransact::handle_response_keep_alive_headers(State *s, HTTPVersion ver, HTTPHdr *heads)
{
  enum KA_Action_t {
    KA_UNKNOWN,
    KA_DISABLED,
    KA_CLOSE,
    KA_CONNECTION,
  };
  KA_Action_t ka_action = KA_UNKNOWN;

  ink_assert(heads->type_get() == HTTP_TYPE_RESPONSE);

  // Since connection headers are hop-to-hop, strip the
  //  the ones we received from upstream
  heads->field_delete(MIME_FIELD_CONNECTION, MIME_LEN_CONNECTION);
  heads->field_delete(MIME_FIELD_PROXY_CONNECTION, MIME_LEN_PROXY_CONNECTION);

  // Handle the upgrade cases
  if (s->is_upgrade_request && heads->status_get() == HTTP_STATUS_SWITCHING_PROTOCOL && s->source == SOURCE_HTTP_ORIGIN_SERVER) {
    s->client_info.keep_alive = HTTP_NO_KEEPALIVE;
    if (s->is_websocket) {
      TxnDbg(dbg_ctl_http_trans, "transaction successfully upgraded to websockets.");
      // s->transparent_passthrough = true;
      heads->value_set(MIME_FIELD_CONNECTION, MIME_LEN_CONNECTION, MIME_FIELD_UPGRADE, MIME_LEN_UPGRADE);
      heads->value_set(MIME_FIELD_UPGRADE, MIME_LEN_UPGRADE, "websocket", 9);
    }

    // We set this state so that we can jump to our blind forwarding state once
    // the response is sent to the client.
    s->did_upgrade_succeed = true;
    return;
  }

  int         c_hdr_field_len;
  const char *c_hdr_field_str;
  if (s->client_info.proxy_connect_hdr) {
    c_hdr_field_str = MIME_FIELD_PROXY_CONNECTION;
    c_hdr_field_len = MIME_LEN_PROXY_CONNECTION;
  } else {
    c_hdr_field_str = MIME_FIELD_CONNECTION;
    c_hdr_field_len = MIME_LEN_CONNECTION;
  }

  // Check pre-conditions for keep-alive
  if (ver.get_major() == 0) { /* No K-A for 0.9 apps */
    ka_action = KA_DISABLED;
  } else if (heads->status_get() == HTTP_STATUS_NO_CONTENT &&
             ((s->source == SOURCE_HTTP_ORIGIN_SERVER && s->current.server->transfer_encoding != NO_TRANSFER_ENCODING) ||
              heads->get_content_length() != 0)) {
    // some systems hang until the connection closes when receiving a 204 regardless of the K-A headers
    // close if there is any body response from the origin
    ka_action = KA_CLOSE;
  } else {
    // Determine if we are going to send either a server-generated or
    // proxy-generated chunked response to the client. If we cannot
    // trust the content-length, we may be able to chunk the response
    // to the client to keep the connection alive.