Method fetch

src/uri/fetchers/curl.cpp:90–207

Future<Nothing> CurlFetcherPlugin::fetch(
    const URI& uri,
    const string& directory,
    const Option<string>& data,
    const Option<string>& outputFileName) const
{
  // TODO(jieyu): Validate the given URI.

  if (!uri.has_path()) {
    return Failure("URI path is not specified");
  }

  Try<Nothing> mkdir = os::mkdir(directory);
  if (mkdir.isError()) {
    return Failure(
        "Failed to create directory '" +
        directory + "': " + mkdir.error());
  }

  string output;
  if (outputFileName.isSome()) {
    output = path::join(directory, outputFileName.get());
  } else {
    output = path::join(directory, Path(path::from_uri(uri.path())).basename());
  }

#ifndef __WINDOWS__
  const string curl = "curl";
#else
  const string curl = "curl.exe";
#endif // __WINDOWS__

  vector<string> argv = {
    curl,
    "-s",                 // Don't show progress meter or error messages.
    "-S",                 // Makes curl show an error message if it fails.
    "-L",                 // Follow HTTP 3xx redirects.
    "-w", "%{http_code}", // Display HTTP response code on stdout.
    "-o", output,         // Write output to the file.
    strings::trim(stringify(uri))
  };

  // Add a timeout for curl to abort when the download speed keeps low
  // (1 byte per second by default) for the specified duration. See:
  // https://curl.haxx.se/docs/manpage.html#-y
  if (flags.curl_stall_timeout.isSome()) {
    argv.push_back("-y");
    argv.push_back(
        std::to_string(static_cast<long>(flags.curl_stall_timeout->secs())));
  }

  Try<Subprocess> s = subprocess(
      curl,
      argv,
      Subprocess::PATH(os::DEV_NULL),
      Subprocess::PIPE(),
      Subprocess::PIPE());