content/browser/loader/prefetch_url_loader.cc

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/loader/prefetch_url_loader.h"

#include "base/feature_list.h"
#include "content/browser/web_package/signed_exchange_prefetch_handler.h"
#include "content/browser/web_package/signed_exchange_prefetch_metric_recorder.h"
#include "content/browser/web_package/signed_exchange_utils.h"
#include "content/public/common/content_features.h"
#include "net/url_request/url_request_context_getter.h"
#include "services/network/loader_util.h"
#include "services/network/public/cpp/features.h"
#include "services/network/public/cpp/shared_url_loader_factory.h"

namespace content {

namespace {

constexpr char kSignedExchangeEnabledAcceptHeaderForPrefetch[] =
    "application/signed-exchange;v=b2;q=0.9,*/*;q=0.8";

}  // namespace

PrefetchURLLoader::PrefetchURLLoader(
    int32_t routing_id,
    int32_t request_id,
    uint32_t options,
    base::RepeatingCallback<int(void)> frame_tree_node_id_getter,
    const network::ResourceRequest& resource_request,
    network::mojom::URLLoaderClientPtr client,
    const net::MutableNetworkTrafficAnnotationTag& traffic_annotation,
    scoped_refptr<network::SharedURLLoaderFactory> network_loader_factory,
    URLLoaderThrottlesGetter url_loader_throttles_getter,
    ResourceContext* resource_context,
    scoped_refptr<net::URLRequestContextGetter> request_context_getter,
    scoped_refptr<SignedExchangePrefetchMetricRecorder>
        signed_exchange_prefetch_metric_recorder)
    : frame_tree_node_id_getter_(frame_tree_node_id_getter),
      url_(resource_request.url),
      report_raw_headers_(resource_request.report_raw_headers),
      load_flags_(resource_request.load_flags),
      throttling_profile_id_(resource_request.throttling_profile_id),
      network_loader_factory_(std::move(network_loader_factory)),
      client_binding_(this),
      forwarding_client_(std::move(client)),
      url_loader_throttles_getter_(url_loader_throttles_getter),
      resource_context_(resource_context),
      request_context_getter_(std::move(request_context_getter)),
      signed_exchange_prefetch_metric_recorder_(
          std::move(signed_exchange_prefetch_metric_recorder)) {
  DCHECK(network_loader_factory_);

  if (resource_request.request_initiator)
    request_initiator_ = *resource_request.request_initiator;

  base::Optional<network::ResourceRequest> modified_resource_request;
  if (signed_exchange_utils::ShouldAdvertiseAcceptHeader(
          url::Origin::Create(resource_request.url))) {
    // Set the SignedExchange accept header only for the limited origins.
    // (https://wicg.github.io/webpackage/draft-yasskin-http-origin-signed-responses.html#internet-media-type-applicationsigned-exchange).
    modified_resource_request = resource_request;
    modified_resource_request->headers.SetHeader(
        network::kAcceptHeader, kSignedExchangeEnabledAcceptHeaderForPrefetch);
  }

  network::mojom::URLLoaderClientPtr network_client;
  client_binding_.Bind(mojo::MakeRequest(&network_client));
  client_binding_.set_connection_error_handler(base::BindOnce(
      &PrefetchURLLoader::OnNetworkConnectionError, base::Unretained(this)));
  network_loader_factory_->CreateLoaderAndStart(
      mojo::MakeRequest(&loader_), routing_id, request_id, options,
      modified_resource_request ? *modified_resource_request : resource_request,
      std::move(network_client), traffic_annotation);
}

PrefetchURLLoader::~PrefetchURLLoader() = default;

void PrefetchURLLoader::FollowRedirect(
    const std::vector<std::string>& removed_headers,
    const net::HttpRequestHeaders& modified_headers,
    const base::Optional<GURL>& new_url) {
  DCHECK(modified_headers.IsEmpty())
      << "Redirect with modified headers was not supported yet. "
         "crbug.com/845683";
  DCHECK(!new_url) << "Redirect with modified URL was not "
                      "supported yet. crbug.com/845683";
  DCHECK(new_url_for_redirect_.is_valid());
  if (signed_exchange_prefetch_handler_) {
    // Rebind |client_binding_| and |loader_|.
    client_binding_.Bind(signed_exchange_prefetch_handler_->FollowRedirect(
        mojo::MakeRequest(&loader_)));
    return;
  }

  net::HttpRequestHeaders modified_request_headers_for_accept;
  if (signed_exchange_utils::NeedToCheckRedirectedURLForAcceptHeader()) {
    // Currently we send the SignedExchange accept header only for the limited
    // origins when SignedHTTPExchangeOriginTrial feature is enabled without
    // SignedHTTPExchange feature. So need to update the accept header by
    // checking the new URL when redirected.
    if (signed_exchange_utils::ShouldAdvertiseAcceptHeader(
            url::Origin::Create(new_url_for_redirect_))) {
      modified_request_headers_for_accept.SetHeader(
          network::kAcceptHeader,
          kSignedExchangeEnabledAcceptHeaderForPrefetch);
    } else {
      modified_request_headers_for_accept.SetHeader(
          network::kAcceptHeader, network::kDefaultAcceptHeader);
    }
  }

  loader_->FollowRedirect(removed_headers, modified_request_headers_for_accept,
                          base::nullopt);
}

void PrefetchURLLoader::ProceedWithResponse() {
  loader_->ProceedWithResponse();
}

void PrefetchURLLoader::SetPriority(net::RequestPriority priority,
                                    int intra_priority_value) {
  loader_->SetPriority(priority, intra_priority_value);
}

void PrefetchURLLoader::PauseReadingBodyFromNet() {
  loader_->PauseReadingBodyFromNet();
}

void PrefetchURLLoader::ResumeReadingBodyFromNet() {
  loader_->ResumeReadingBodyFromNet();
}

void PrefetchURLLoader::OnReceiveResponse(
    const network::ResourceResponseHead& response) {
  if (signed_exchange_utils::ShouldHandleAsSignedHTTPExchange(url_, response)) {
    DCHECK(!signed_exchange_prefetch_handler_);

    // Note that after this point this doesn't directly get upcalls from the
    // network. (Until |this| calls the handler's FollowRedirect.)
    signed_exchange_prefetch_handler_ =
        std::make_unique<SignedExchangePrefetchHandler>(
            frame_tree_node_id_getter_, report_raw_headers_, load_flags_,
            throttling_profile_id_, response, std::move(loader_),
            client_binding_.Unbind(), network_loader_factory_,
            request_initiator_, url_, url_loader_throttles_getter_,
            resource_context_, request_context_getter_, this,
            signed_exchange_prefetch_metric_recorder_);
    return;
  }
  forwarding_client_->OnReceiveResponse(response);
}

void PrefetchURLLoader::OnReceiveRedirect(
    const net::RedirectInfo& redirect_info,
    const network::ResourceResponseHead& head) {
  new_url_for_redirect_ = redirect_info.new_url;
  forwarding_client_->OnReceiveRedirect(redirect_info, head);
}

void PrefetchURLLoader::OnUploadProgress(int64_t current_position,
                                         int64_t total_size,
                                         base::OnceCallback<void()> callback) {
  forwarding_client_->OnUploadProgress(current_position, total_size,
                                       std::move(callback));
}

void PrefetchURLLoader::OnReceiveCachedMetadata(
    const std::vector<uint8_t>& data) {
  // Just drop this; we don't need to forward this to the renderer
  // for prefetch.
}

void PrefetchURLLoader::OnTransferSizeUpdated(int32_t transfer_size_diff) {
  forwarding_client_->OnTransferSizeUpdated(transfer_size_diff);
}

void PrefetchURLLoader::OnStartLoadingResponseBody(
    mojo::ScopedDataPipeConsumerHandle body) {
  // Just drain the original response's body here.
  DCHECK(!pipe_drainer_);
  pipe_drainer_ =
      std::make_unique<mojo::DataPipeDrainer>(this, std::move(body));

  // Send an empty response's body instead.
  mojo::ScopedDataPipeProducerHandle producer;
  mojo::ScopedDataPipeConsumerHandle consumer;
  if (CreateDataPipe(nullptr, &producer, &consumer) == MOJO_RESULT_OK) {
    forwarding_client_->OnStartLoadingResponseBody(std::move(consumer));
    return;
  }

  // No more resources available for creating a data pipe. Close the connection,
  // which will in turn make this loader destroyed.
  forwarding_client_->OnComplete(
      network::URLLoaderCompletionStatus(net::ERR_INSUFFICIENT_RESOURCES));
  forwarding_client_.reset();
  client_binding_.Close();
}

void PrefetchURLLoader::OnComplete(
    const network::URLLoaderCompletionStatus& status) {
  forwarding_client_->OnComplete(status);
}

void PrefetchURLLoader::OnNetworkConnectionError() {
  // The network loader has an error; we should let the client know it's closed
  // by dropping this, which will in turn make this loader destroyed.
  forwarding_client_.reset();
}

}  // namespace content