onRequest method

@override void onRequest(RequestOptions options, RequestInterceptorHandler handler)

Called when the request is about to be sent.

Implementation

@override
void onRequest(
  RequestOptions options,
  RequestInterceptorHandler handler,
) async {
  // Add time when the request has been sent
  // for further expiry calculation.
  options.extra[CacheResponse.requestSentDate] = DateTime.now();

  final cacheOptions = _getCacheOptions(options);

  if (_shouldSkip(options, options: cacheOptions)) {
    handler.next(options);
    return;
  }

  // Early ends if policy does not require cache lookup.
  final policy = cacheOptions.policy;
  if (policy != CachePolicy.request && policy != CachePolicy.forceCache) {
    handler.next(options);
    return;
  }

  final strategy = await CacheStrategyFactory(
    request: options,
    cacheResponse: await _loadCacheResponse(options),
    cacheOptions: cacheOptions,
  ).compute();

  var cacheResponse = strategy.cacheResponse;
  if (cacheResponse != null) {
    // Cache hit

    // Update cached response if needed
    cacheResponse = await _updateCacheResponse(cacheResponse, cacheOptions);

    handler.resolve(
      cacheResponse.toResponse(options, fromNetwork: false),
      true,
    );
    return;
  }

  // Requests with conditional request if available
  // or requests with given options
  handler.next(strategy.request ?? options);
}