Function getCmcdNor

plugins/prefetch/plugin.cc:368–422

* @brief Look for and return the nor field of any Cmcd-Request header * * @param txnp HTTP transaction structure * @param buffer request TSMBuffer * @param hdrloc request TSMLoc * @return unquoted relative cmcd path from the nor field * * If the 'nrr' field is encountered the 'nor' field will be ignored. * * sample header: * Cmcd-Request: mtp=103600,bl=153500,nor="14_176.mp4a" */

 * Cmcd-Request: mtp=103600,bl=153500,nor="14_176.mp4a"
 */
static String
getCmcdNor(const TSMBuffer buffer, const TSMLoc hdrloc)
{
  String relpath;
  bool   hasnrr = false; // don't prefetch if range request

  const TSMLoc cmcdloc = TSMimeHdrFieldFind(buffer, hdrloc, CmcdHeader.data(), CmcdHeader.length());
  if (TS_NULL_MLOC != cmcdloc) {
    // iterate through the fields
    const int cnt = TSMimeHdrFieldValuesCount(buffer, hdrloc, cmcdloc);
    for (int ind = 0; ind < cnt; ++ind) {
      int               flen = 0;
      const char *const fval = TSMimeHdrFieldValueStringGet(buffer, hdrloc, cmcdloc, ind, &flen);

      StringView fv(fval, flen);
      PrefetchDebug("cmcd-request field: '%.*s'", (int)fv.length(), fv.data());
      if (0 == fv.compare(0, CmcdNrrFieldPrefix.length(), CmcdNrrFieldPrefix)) {
        PrefetchDebug("cmcd-request nrr field encountered, skipping prefetch!");
        hasnrr = true;
        break;
      }

      if (0 == fv.compare(0, CmcdNorFieldPrefix.length(), CmcdNorFieldPrefix)) {
        fv.remove_prefix(CmcdNorFieldPrefix.length());
        if (fv.front() == '"') {
          fv.remove_prefix(1);
        }
        if (fv.back() == '"') {
          fv.remove_suffix(1);
        }

        PrefetchDebug("Extracted nor field: '%.*s'", (int)fv.length(), fv.data());

        // Undo any percent encoding
        char   buf[8192];
        size_t blen = sizeof(buf);
        if (TS_SUCCESS == TSStringPercentDecode(fv.data(), fv.length(), buf, blen, &blen)) {
          relpath.assign(buf, blen);
        } else {
          PrefetchDebug("Error percent decoding nor field: '%.*s'", (int)fv.length(), fv.data());
        }
      }
    }
    TSHandleMLocRelease(buffer, hdrloc, cmcdloc);
  } else {
    PrefetchDebug("No Cmcd-Request header found");
  }

  // don't prefetch if range request
  if (hasnrr) {
    relpath.clear();
  }

  return relpath;
}

/**
 * @brief short-cut to set the response .