webkit/appcache/appcache_request_handler.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "webkit/appcache/appcache_request_handler.h"
   6
   7 #include "net/url_request/url_request.h"
   8 #include "net/url_request/url_request_job.h"
   9 #include "webkit/appcache/appcache.h"
  10 #include "webkit/appcache/appcache_policy.h"
  11 #include "webkit/appcache/appcache_url_request_job.h"
  12
  13 namespace appcache {
  14
  15 AppCacheRequestHandler::AppCacheRequestHandler(
  16     AppCacheHost* host, ResourceType::Type resource_type)
  17     : host_(host), resource_type_(resource_type),
  18       is_waiting_for_cache_selection_(false), found_group_id_(0),
  19       found_cache_id_(0), found_network_namespace_(false),
  20       cache_entry_not_found_(false), maybe_load_resource_executed_(false) {
  21   DCHECK(host_);
  22   host_->AddObserver(this);
  23 }
  24
  25 AppCacheRequestHandler::~AppCacheRequestHandler() {
  26   if (host_) {
  27     storage()->CancelDelegateCallbacks(this);
  28     host_->RemoveObserver(this);
  29   }
  30 }
  31
  32 AppCacheStorage* AppCacheRequestHandler::storage() const {
  33   DCHECK(host_);
  34   return host_->service()->storage();
  35 }
  36
  37 void AppCacheRequestHandler::GetExtraResponseInfo(
  38     int64* cache_id, GURL* manifest_url) {
  39   if (job_ && job_->is_delivering_appcache_response()) {
  40     *cache_id = job_->cache_id();
  41     *manifest_url = job_->manifest_url();
  42   }
  43 }
  44
  45 AppCacheURLRequestJob* AppCacheRequestHandler::MaybeLoadResource(
  46     net::URLRequest* request, net::NetworkDelegate* network_delegate) {
  47   maybe_load_resource_executed_ = true;
  48   if (!host_ || !IsSchemeAndMethodSupported(request) || cache_entry_not_found_)
  49     return NULL;
  50
  51   // This method can get called multiple times over the life
  52   // of a request. The case we detect here is having scheduled
  53   // delivery of a "network response" using a job setup on an
  54   // earlier call thru this method. To send the request thru
  55   // to the network involves restarting the request altogether,
  56   // which will call thru to our interception layer again.
  57   // This time thru, we return NULL so the request hits the wire.
  58   if (job_) {
  59     DCHECK(job_->is_delivering_network_response() ||
  60            job_->cache_entry_not_found());
  61     if (job_->cache_entry_not_found())
  62       cache_entry_not_found_ = true;
  63     job_ = NULL;
  64     storage()->CancelDelegateCallbacks(this);
  65     return NULL;
  66   }
  67
  68   // Clear out our 'found' fields since we're starting a request for a
  69   // new resource, any values in those fields are no longer valid.
  70   found_entry_ = AppCacheEntry();
  71   found_fallback_entry_ = AppCacheEntry();
  72   found_cache_id_ = kNoCacheId;
  73   found_manifest_url_ = GURL();
  74   found_network_namespace_ = false;
  75
  76   if (is_main_resource())
  77     MaybeLoadMainResource(request, network_delegate);
  78   else
  79     MaybeLoadSubResource(request, network_delegate);
  80
  81   // If its been setup to deliver a network response, we can just delete
  82   // it now and return NULL instead to achieve that since it couldn't
  83   // have been started yet.
  84   if (job_ && job_->is_delivering_network_response()) {
  85     DCHECK(!job_->has_been_started());
  86     job_ = NULL;
  87   }
  88
  89   return job_;
  90 }
  91
  92 AppCacheURLRequestJob* AppCacheRequestHandler::MaybeLoadFallbackForRedirect(
  93     net::URLRequest* request,
  94     net::NetworkDelegate* network_delegate,
  95     const GURL& location) {
  96   if (!host_ || !IsSchemeAndMethodSupported(request) || cache_entry_not_found_)
  97     return NULL;
  98   if (is_main_resource())
  99     return NULL;
 100   // TODO(vabr) This is a temporary fix (see crbug/141114). We should get rid of
 101   // it once a more general solution to crbug/121325 is in place.
 102   if (!maybe_load_resource_executed_)
 103     return NULL;
 104   if (request->url().GetOrigin() == location.GetOrigin())
 105     return NULL;
 106
 107   DCHECK(!job_);  // our jobs never generate redirects
 108
 109   if (found_fallback_entry_.has_response_id()) {
 110     // 6.9.6, step 4: If this results in a redirect to another origin,
 111     // get the resource of the fallback entry.
 112     job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 113     DeliverAppCachedResponse(
 114         found_fallback_entry_, found_cache_id_, found_group_id_,
 115         found_manifest_url_,  true, found_namespace_entry_url_);
 116   } else if (!found_network_namespace_) {
 117     // 6.9.6, step 6: Fail the resource load.
 118     job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 119     DeliverErrorResponse();
 120   } else {
 121     // 6.9.6 step 3 and 5: Fetch the resource normally.
 122   }
 123
 124   return job_;
 125 }
 126
 127 AppCacheURLRequestJob* AppCacheRequestHandler::MaybeLoadFallbackForResponse(
 128     net::URLRequest* request, net::NetworkDelegate* network_delegate) {
 129   if (!host_ || !IsSchemeAndMethodSupported(request) || cache_entry_not_found_)
 130     return NULL;
 131   if (!found_fallback_entry_.has_response_id())
 132     return NULL;
 133
 134   if (request->status().status() == net::URLRequestStatus::CANCELED) {
 135     // 6.9.6, step 4: But not if the user canceled the download.
 136     return NULL;
 137   }
 138
 139   // We don't fallback for responses that we delivered.
 140   if (job_) {
 141     DCHECK(!job_->is_delivering_network_response());
 142     return NULL;
 143   }
 144
 145   if (request->status().is_success()) {
 146     int code_major = request->GetResponseCode() / 100;
 147     if (code_major !=4 && code_major != 5)
 148       return NULL;
 149
 150     // Servers can override the fallback behavior with a response header.
 151     const std::string kFallbackOverrideHeader(
 152         "x-chromium-appcache-fallback-override");
 153     const std::string kFallbackOverrideValue(
 154         "disallow-fallback");
 155     std::string header_value;
 156     request->GetResponseHeaderByName(kFallbackOverrideHeader, &header_value);
 157     if (header_value == kFallbackOverrideValue)
 158       return NULL;
 159   }
 160
 161   // 6.9.6, step 4: If this results in a 4xx or 5xx status code
 162   // or there were network errors, get the resource of the fallback entry.
 163   job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 164   DeliverAppCachedResponse(
 165       found_fallback_entry_, found_cache_id_, found_group_id_,
 166       found_manifest_url_, true, found_namespace_entry_url_);
 167   return job_;
 168 }
 169
 170 void AppCacheRequestHandler::OnDestructionImminent(AppCacheHost* host) {
 171   storage()->CancelDelegateCallbacks(this);
 172   host_ = NULL;  // no need to RemoveObserver, the host is being deleted
 173
 174   // Since the host is being deleted, we don't have to complete any job
 175   // that is current running. It's destined for the bit bucket anyway.
 176   if (job_) {
 177     job_->Kill();
 178     job_ = NULL;
 179   }
 180 }
 181
 182 void AppCacheRequestHandler::DeliverAppCachedResponse(
 183     const AppCacheEntry& entry, int64 cache_id, int64 group_id,
 184     const GURL& manifest_url,  bool is_fallback,
 185     const GURL& namespace_entry_url) {
 186   DCHECK(host_ && job_ && job_->is_waiting());
 187   DCHECK(entry.has_response_id());
 188
 189   if (ResourceType::IsFrame(resource_type_) && !namespace_entry_url.is_empty())
 190     host_->NotifyMainResourceIsNamespaceEntry(namespace_entry_url);
 191
 192   job_->DeliverAppCachedResponse(manifest_url, group_id, cache_id,
 193                                  entry, is_fallback);
 194 }
 195
 196 void AppCacheRequestHandler::DeliverErrorResponse() {
 197   DCHECK(job_ && job_->is_waiting());
 198   job_->DeliverErrorResponse();
 199 }
 200
 201 void AppCacheRequestHandler::DeliverNetworkResponse() {
 202   DCHECK(job_ && job_->is_waiting());
 203   job_->DeliverNetworkResponse();
 204 }
 205
 206 // Main-resource handling ----------------------------------------------
 207
 208 void AppCacheRequestHandler::MaybeLoadMainResource(
 209     net::URLRequest* request, net::NetworkDelegate* network_delegate) {
 210   DCHECK(!job_);
 211   DCHECK(host_);
 212
 213   const AppCacheHost* spawning_host =
 214       ResourceType::IsSharedWorker(resource_type_) ?
 215           host_ : host_->GetSpawningHost();
 216   GURL preferred_manifest_url = spawning_host ?
 217       spawning_host->preferred_manifest_url() : GURL();
 218
 219   // We may have to wait for our storage query to complete, but
 220   // this query can also complete syncrhonously.
 221   job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 222   storage()->FindResponseForMainRequest(
 223       request->url(), preferred_manifest_url, this);
 224 }
 225
 226 void AppCacheRequestHandler::OnMainResponseFound(
 227     const GURL& url, const AppCacheEntry& entry,
 228     const GURL& namespace_entry_url, const AppCacheEntry& fallback_entry,
 229     int64 cache_id, int64 group_id, const GURL& manifest_url) {
 230   DCHECK(job_);
 231   DCHECK(host_);
 232   DCHECK(is_main_resource());
 233   DCHECK(!entry.IsForeign());
 234   DCHECK(!fallback_entry.IsForeign());
 235   DCHECK(!(entry.has_response_id() && fallback_entry.has_response_id()));
 236
 237   if (!job_)
 238     return;
 239
 240   AppCachePolicy* policy = host_->service()->appcache_policy();
 241   bool was_blocked_by_policy = !manifest_url.is_empty() && policy &&
 242       !policy->CanLoadAppCache(manifest_url, host_->first_party_url());
 243
 244   if (was_blocked_by_policy) {
 245     if (ResourceType::IsFrame(resource_type_)) {
 246       host_->NotifyMainResourceBlocked(manifest_url);
 247     } else {
 248       DCHECK(ResourceType::IsSharedWorker(resource_type_));
 249       host_->frontend()->OnContentBlocked(host_->host_id(), manifest_url);
 250     }
 251     DeliverNetworkResponse();
 252     return;
 253   }
 254
 255   if (ResourceType::IsFrame(resource_type_) && cache_id != kNoCacheId) {
 256     // AppCacheHost loads and holds a reference to the main resource cache
 257     // for two reasons, firstly to preload the cache into the working set
 258     // in advance of subresource loads happening, secondly to prevent the
 259     // AppCache from falling out of the working set on frame navigations.
 260     host_->LoadMainResourceCache(cache_id);
 261     host_->set_preferred_manifest_url(manifest_url);
 262   }
 263
 264   // 6.11.1 Navigating across documents, steps 10 and 14.
 265
 266   found_entry_ = entry;
 267   found_namespace_entry_url_ = namespace_entry_url;
 268   found_fallback_entry_ = fallback_entry;
 269   found_cache_id_ = cache_id;
 270   found_group_id_ = group_id;
 271   found_manifest_url_ = manifest_url;
 272   found_network_namespace_ = false;  // not applicable to main requests
 273
 274   if (found_entry_.has_response_id()) {
 275     DCHECK(!found_fallback_entry_.has_response_id());
 276     DeliverAppCachedResponse(
 277         found_entry_, found_cache_id_, found_group_id_, found_manifest_url_,
 278         false, found_namespace_entry_url_);
 279   } else {
 280     DeliverNetworkResponse();
 281   }
 282 }
 283
 284 // Sub-resource handling ----------------------------------------------
 285
 286 void AppCacheRequestHandler::MaybeLoadSubResource(
 287     net::URLRequest* request, net::NetworkDelegate* network_delegate) {
 288   DCHECK(!job_);
 289
 290   if (host_->is_selection_pending()) {
 291     // We have to wait until cache selection is complete and the
 292     // selected cache is loaded.
 293     is_waiting_for_cache_selection_ = true;
 294     job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 295     return;
 296   }
 297
 298   if (!host_->associated_cache() ||
 299       !host_->associated_cache()->is_complete()) {
 300     return;
 301   }
 302
 303   job_ = new AppCacheURLRequestJob(request, network_delegate, storage());
 304   ContinueMaybeLoadSubResource();
 305 }
 306
 307 void AppCacheRequestHandler::ContinueMaybeLoadSubResource() {
 308   // 6.9.6 Changes to the networking model
 309   // If the resource is not to be fetched using the HTTP GET mechanism or
 310   // equivalent ... then fetch the resource normally.
 311   DCHECK(job_);
 312   DCHECK(host_->associated_cache() &&
 313          host_->associated_cache()->is_complete());
 314
 315   const GURL& url = job_->request()->url();
 316   AppCache* cache = host_->associated_cache();
 317   storage()->FindResponseForSubRequest(
 318       host_->associated_cache(), url,
 319       &found_entry_, &found_fallback_entry_, &found_network_namespace_);
 320
 321   if (found_entry_.has_response_id()) {
 322     // Step 2: If there's an entry, get it instead.
 323     DCHECK(!found_network_namespace_ &&
 324            !found_fallback_entry_.has_response_id());
 325     found_cache_id_ = cache->cache_id();
 326     found_group_id_ = cache->owning_group()->group_id();
 327     found_manifest_url_ = cache->owning_group()->manifest_url();
 328     DeliverAppCachedResponse(
 329         found_entry_, found_cache_id_, found_group_id_, found_manifest_url_,
 330         false, GURL());
 331     return;
 332   }
 333
 334   if (found_fallback_entry_.has_response_id()) {
 335     // Step 4: Fetch the resource normally, if this results
 336     // in certain conditions, then use the fallback.
 337     DCHECK(!found_network_namespace_ &&
 338            !found_entry_.has_response_id());
 339     found_cache_id_ = cache->cache_id();
 340     found_manifest_url_ = cache->owning_group()->manifest_url();
 341     DeliverNetworkResponse();
 342     return;
 343   }
 344
 345   if (found_network_namespace_) {
 346     // Step 3 and 5: Fetch the resource normally.
 347     DCHECK(!found_entry_.has_response_id() &&
 348            !found_fallback_entry_.has_response_id());
 349     DeliverNetworkResponse();
 350     return;
 351   }
 352
 353   // Step 6: Fail the resource load.
 354   DeliverErrorResponse();
 355 }
 356
 357 void AppCacheRequestHandler::OnCacheSelectionComplete(AppCacheHost* host) {
 358   DCHECK(host == host_);
 359   if (is_main_resource())
 360     return;
 361   if (!is_waiting_for_cache_selection_)
 362     return;
 363
 364   is_waiting_for_cache_selection_ = false;
 365
 366   if (!host_->associated_cache() ||
 367       !host_->associated_cache()->is_complete()) {
 368     DeliverNetworkResponse();
 369     return;
 370   }
 371
 372   ContinueMaybeLoadSubResource();
 373 }
 374
 375 }  // namespace appcache