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| 1 // Copyright 2015 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 #ifndef CONTENT_PUBLIC_TEST_TEST_DOWNLOAD_REQUEST_HANDLER_H_ |
| 6 #define CONTENT_PUBLIC_TEST_TEST_DOWNLOAD_REQUEST_HANDLER_H_ |
| 7 |
| 8 #include <stdint.h> |
| 9 #include <queue> |
| 10 |
| 11 #include "base/callback_forward.h" |
| 12 #include "base/files/file.h" |
| 13 #include "base/macros.h" |
| 14 #include "base/memory/scoped_ptr.h" |
| 15 #include "base/memory/weak_ptr.h" |
| 16 #include "base/threading/non_thread_safe.h" |
| 17 #include "net/base/completion_callback.h" |
| 18 #include "net/base/net_errors.h" |
| 19 #include "net/http/http_byte_range.h" |
| 20 #include "net/http/http_response_headers.h" |
| 21 #include "net/http/http_util.h" |
| 22 #include "net/url_request/url_request_job.h" |
| 23 #include "url/gurl.h" |
| 24 |
| 25 namespace content { |
| 26 |
| 27 // A request handler that can be used to mock the behavior of a URLRequestJob |
| 28 // for a download. |
| 29 // |
| 30 // Testing of download interruption scenarios typically involve simulating |
| 31 // errors that occur: |
| 32 // 1. On the client, prior to the request being sent out, |
| 33 // 2. On the network, between the client and the server, |
| 34 // 3. On the server, |
| 35 // 4. Back on the client, while writing the response to disk, |
| 36 // 5. On the client, after the response has been written to disk. |
| 37 // |
| 38 // This test class is meant to help test failures in #2 and #3 above. The test |
| 39 // implementation depends on content::BrowserThread and assumes that the |
| 40 // thread identified by BrowserThread::IO is the network task runner thread. |
| 41 // |
| 42 // TestDownloadRequestHandler can be used on any thread as long as it is used |
| 43 // and destroyed on the same thread it was constructed on. |
| 44 // |
| 45 // To use the test request handler: |
| 46 // |
| 47 // // Define the request handler. Note that initialization of the |
| 48 // // TestDownloadRequestHandler object immediately registers it as well and is |
| 49 // // a blocking operation. |
| 50 // TestDownloadRequestHandler request_handler; |
| 51 // |
| 52 // // Set up parameters for the partial request handler. |
| 53 // TestDownloadRequestHandler::Parameters parameters; |
| 54 // |
| 55 // // Inject an error at offset 100. |
| 56 // parameters.injected_errors.push(TestDownloadRequestHandler::InjectedError( |
| 57 // 100, net::ERR_CONNECTION_RESET)); |
| 58 // |
| 59 // // Start serving. |
| 60 // request_handler.StartServing(parameters); |
| 61 // |
| 62 // At this point, you can initiate a URLRequest for request_handler.url(). The |
| 63 // request will fail when offset 100 is reached with the error specified above. |
| 64 class TestDownloadRequestHandler : public base::NonThreadSafe { |
| 65 public: |
| 66 // OnStartHandler can be used to intercept the Start() event of a new |
| 67 // URLRequest. Set it as the |on_start_handler| member of Parameters below. |
| 68 // |
| 69 // The callback is invoked on the thread on which TestDownloadRequestHandler |
| 70 // was created. Once the callback has a response ready, it can invoke the |
| 71 // OnStartResponseCallback object. The latter can be invoked on any thread and |
| 72 // will post back to the IO thread to continue with processing the Start() |
| 73 // event. |
| 74 // |
| 75 // The parameters to the OnStartResponseCallback are: |
| 76 // |
| 77 // * a |const std::string&| containing the headers to be sent in response to |
| 78 // the request. The headers should be formatted according to the |
| 79 // requirements of net::HttpUtil::AssembleRawHeaders(). The headers are only |
| 80 // used if the |net::Error| parameters is net::OK. |
| 81 // |
| 82 // * a |net::Error| indicating the result of the operation. If this parameters |
| 83 // is not net::OK, then that error value is set as the result of the Start() |
| 84 // operation. The headers are ignored in this case. |
| 85 // |
| 86 // If the error is net::OK, and the headers are empty, then the request is |
| 87 // handled based on the remaining parameters in |Parameters|. |
| 88 using OnStartResponseCallback = |
| 89 base::Callback<void(const std::string&, net::Error)>; |
| 90 |
| 91 using OnStartHandler = base::Callback<void(const net::HttpRequestHeaders&, |
| 92 const OnStartResponseCallback&)>; |
| 93 |
| 94 // An injected error. |
| 95 struct InjectedError { |
| 96 InjectedError(int64_t offset, net::Error error); |
| 97 |
| 98 int64_t offset; |
| 99 net::Error error; |
| 100 }; |
| 101 |
| 102 // Parameters used by StartServing(). |
| 103 struct Parameters { |
| 104 // Constructs a Parameters structure using the default constructor, but with |
| 105 // the addition of a net::ERR_CONNECTION_RESET which will be triggered at |
| 106 // byte offset (filesize / 2). |
| 107 static Parameters WithSingleInterruption(); |
| 108 |
| 109 // The default constructor initializes the parameters for serving a 100 KB |
| 110 // resource with no interruptions. The response contains an ETag and a |
| 111 // Last-Modified header and the server supports byte range requests. |
| 112 Parameters(); |
| 113 |
| 114 // Parameters is expected to be copyable and moveable. |
| 115 Parameters(Parameters&&); |
| 116 Parameters(const Parameters&); |
| 117 Parameters& operator=(Parameters&&); |
| 118 Parameters& operator=(const Parameters&); |
| 119 ~Parameters(); |
| 120 |
| 121 // Clears the errors in injected_errors. |
| 122 void ClearInjectedErrors(); |
| 123 |
| 124 // Contents of the ETag header field of the response. No Etag header is |
| 125 // sent if this field is empty. |
| 126 std::string etag; |
| 127 |
| 128 // Contents of the Last-Modified header field of the response. No |
| 129 // Last-Modified header is sent if this field is empty. |
| 130 std::string last_modified; |
| 131 |
| 132 // The Content-Type of the response. No Content-Type header is sent if this |
| 133 // field is empty. |
| 134 std::string content_type; |
| 135 |
| 136 // The total size of the entity. If the entire entity is requested, then |
| 137 // this would be the same as the value returned in the Content-Length |
| 138 // header. |
| 139 int64_t size; |
| 140 |
| 141 // Seed for the pseudo-random sequence that defines the response body |
| 142 // contents. The seed is with GetPatternBytes() to generate the body of the |
| 143 // response. |
| 144 int pattern_generator_seed; |
| 145 |
| 146 // If true, the response contains a 'Accept-Ranges: bytes' header. |
| 147 bool support_byte_ranges; |
| 148 |
| 149 // If on_start_handler is valid, it will be invoked when a new request is |
| 150 // received. See details about the OnStartHandler above. |
| 151 OnStartHandler on_start_handler; |
| 152 |
| 153 // Errors to be injected. Each injected error is defined by an offset and an |
| 154 // error. Request handler will successfully fulfil requests to read up to |
| 155 // |offset|. An attempt to read the byte at |offset| will result in the |
| 156 // error defined by the InjectErrors object. |
| 157 // |
| 158 // If a read spans the range containing |offset|, then the portion of the |
| 159 // request preceding |offset| will succeed. The next read would start at |
| 160 // |offset| and hence would result in an error. |
| 161 // |
| 162 // E.g.: injected_errors.push(InjectedError(100, ERR_CONNECTION_RESET)); |
| 163 // |
| 164 // A network read for 1024 bytes at offset 0 would result in successfully |
| 165 // reading 100 bytes (bytes with offset 0-99). The next read would, |
| 166 // therefore, start at offset 100 and would result in |
| 167 // ERR_CONNECTION_RESET. |
| 168 // |
| 169 // Injected errors are processed in the order in which they appear in |
| 170 // |injected_errors|. When handling a network request for the range [S,E] |
| 171 // (inclusive), all events in |injected_errors| where |offset| is less than |
| 172 // S will be ignored. The first event remaining will trigger an error once |
| 173 // the sequence of reads proceeds to a point where its |offset| is included |
| 174 // in [S,E]. |
| 175 // |
| 176 // This implies that |injected_errors| must be specified in increasing order |
| 177 // of |offset|. I.e. |injected_errors| must be sorted by |offset|. |
| 178 // |
| 179 // Errors at relative offset 0 are ignored for a partial request. I.e. If |
| 180 // the request is for the byte range 100-200, then an error at offset 100 |
| 181 // will not trigger. This is done so that non-overlapping continuation |
| 182 // attempts don't require resetting parameters to succeed. |
| 183 // |
| 184 // E.g.: If the caller injects an error at offset 100, then a request for |
| 185 // the entire entity will fail after reading 100 bytes (offsets 0 through |
| 186 // 99). A subsequent request for byte range "100-" (offsets 100 through EOF) |
| 187 // will succeed since the error at offset 100 is ignored. |
| 188 // |
| 189 // Notes: |
| 190 // |
| 191 // * Distinctions about which read requests signal the error is often only |
| 192 // important at the //net layer. From //content, it would appear that 100 |
| 193 // bytes were read and then request failed with ERR_CONNECTION_RESET. |
| 194 std::queue<InjectedError> injected_errors; |
| 195 }; |
| 196 |
| 197 // Details about completed requests returned by GetCompletedRequestInfo(). |
| 198 struct CompletedRequest { |
| 199 // Count of bytes read by the client of the URLRequestJob. This counts the |
| 200 // number of bytes of the entity that was transferred *after* content |
| 201 // decoding is complete. |
| 202 int64_t transferred_byte_count = -1; |
| 203 |
| 204 net::HttpRequestHeaders request_headers; |
| 205 }; |
| 206 |
| 207 using CompletedRequests = std::vector<CompletedRequest>; |
| 208 |
| 209 // Registers a request handler at the default URL. Call url() to determine the |
| 210 // URL. |
| 211 // |
| 212 // Notes: |
| 213 // * This constructor is only meant to be used for convenience when the caller |
| 214 // is not interested in the URL used for interception. The URL used is |
| 215 // generated at run time and should not be assumed to be the same across |
| 216 // different runs of the same test. |
| 217 // |
| 218 // * Initialization of the handler synchronously runs a task on the |
| 219 // BrowserThread::IO thread using a nested message loop. Only construct an |
| 220 // instance of this object after browser threads have been initialized. |
| 221 TestDownloadRequestHandler(); |
| 222 |
| 223 // Similar to the default constructor, but registers the handler at |url|. |
| 224 // |
| 225 // Notes: |
| 226 // * The behavior is undefined if more than one TestDownloadRequestHandler is |
| 227 // registered for the same URL. |
| 228 TestDownloadRequestHandler(const GURL& url); |
| 229 |
| 230 // Destroys and posts a task to the IO thread to dismantle the registered URL |
| 231 // request interceptor. Does not wait for the task to return. |
| 232 ~TestDownloadRequestHandler(); |
| 233 |
| 234 // Returns the URL that this instance is intercepting URLRequests for. |
| 235 const GURL& url() const { return url_; } |
| 236 |
| 237 // Start responding to URLRequests for url() with responses based on |
| 238 // |parameters|. |
| 239 // |
| 240 // This method invocation posts a task to the IO thread to update the |
| 241 // URLRequestInterceptor with the new parameters and returns immediately. URL |
| 242 // interception won't be updated until the posted task executes. The method |
| 243 // returns without waiting for the posted task to complete. |
| 244 // |
| 245 // Calling this method does not affect URLRequests that have already started. |
| 246 // The new parameters will only be used to respond to new URLRequests that are |
| 247 // starting. |
| 248 // |
| 249 // StartServing() can be called multiple times to change the operating |
| 250 // parameters of the current URL interceptor. |
| 251 void StartServing(const Parameters& parameters); |
| 252 |
| 253 // Start responding to URLRequests for url() with a static response |
| 254 // containing the headers in |headers|. |
| 255 // |
| 256 // The format of |headers| should comply with the requirements for |
| 257 // net::HttpUtil::AssembleRawHeaders(). |
| 258 void StartServingStaticResponse(const base::StringPiece& headers); |
| 259 |
| 260 // Get the list of requests that have already completed. |
| 261 // |
| 262 // This method posts a task to the IO thread to collect the list of completed |
| 263 // requests and waits for the task to complete. |
| 264 // |
| 265 // Requests that are currently in progress will not be reflected in |
| 266 // |requests|. |
| 267 void GetCompletedRequestInfo(CompletedRequests* requests); |
| 268 |
| 269 // Generate a pseudo random pattern. |
| 270 // |
| 271 // |seed| is the seed for the pseudo random sequence. |offset| is the byte |
| 272 // offset into the sequence. |length| is a count of bytes to generate. |
| 273 // |data| receives the generated bytes and should be able to store |length| |
| 274 // bytes. |
| 275 // |
| 276 // The pattern has the following properties: |
| 277 // |
| 278 // * For a given |seed|, the entire sequence of bytes is fixed. Any |
| 279 // subsequence can be generated by specifying the |offset| and |length|. |
| 280 // |
| 281 // * The sequence is aperiodic (at least for the first 1M bytes). |
| 282 // |
| 283 // * |seed| is chaotic. Different seeds produce "very different" data. This |
| 284 // means that there's no trivial mapping between sequences generated using |
| 285 // two distinct seeds. |
| 286 // |
| 287 // These properties make the generated bytes useful for testing partial |
| 288 // requests where the response may need to be built using a sequence of |
| 289 // partial requests. |
| 290 // |
| 291 // Note: Don't use this function to generate a cryptographically secure |
| 292 // pseudo-random sequence. |
| 293 static void GetPatternBytes(int seed, int64 offset, int length, char* data); |
| 294 |
| 295 private: |
| 296 class Interceptor; |
| 297 class PartialResponseJob; |
| 298 |
| 299 GURL url_; |
| 300 base::WeakPtr<Interceptor> interceptor_; |
| 301 DISALLOW_COPY_AND_ASSIGN(TestDownloadRequestHandler); |
| 302 }; |
| 303 |
| 304 } // namespace content |
| 305 |
| 306 #endif // CONTENT_PUBLIC_TEST_TEST_DOWNLOAD_REQUEST_HANDLER_H_ |
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