1 # Copyright 2014 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 import base64 6 import gzip 7 import hashlib 8 import io 9 import logging 10 import zlib 11 12 from metrics import Metric 13 from telemetry.page import page_test 14 # All network metrics are Chrome only for now. 15 from telemetry.core.backends.chrome import inspector_network 16 from telemetry.timeline import recording_options 17 from telemetry.value import scalar 18 19 20 class NetworkMetricException(page_test.MeasurementFailure): 21 pass 22 23 24 class HTTPResponse(object): 25 """ Represents an HTTP response from a timeline event.""" 26 def __init__(self, event): 27 self._response = ( 28 inspector_network.InspectorNetworkResponseData.FromTimelineEvent(event)) 29 self._content_length = None 30 31 @property 32 def response(self): 33 return self._response 34 35 @property 36 def url_signature(self): 37 return hashlib.md5(self.response.url).hexdigest() 38 39 @property 40 def content_length(self): 41 if self._content_length is None: 42 self._content_length = self.GetContentLength() 43 return self._content_length 44 45 @property 46 def has_original_content_length(self): 47 return 'X-Original-Content-Length' in self.response.headers 48 49 @property 50 def original_content_length(self): 51 if self.has_original_content_length: 52 return int(self.response.GetHeader('X-Original-Content-Length')) 53 return 0 54 55 @property 56 def data_saving_rate(self): 57 if (self.response.served_from_cache or 58 not self.has_original_content_length or 59 self.original_content_length <= 0): 60 return 0.0 61 return (float(self.original_content_length - self.content_length) / 62 self.original_content_length) 63 64 def GetContentLengthFromBody(self): 65 resp = self.response 66 body, base64_encoded = resp.GetBody() 67 if not body: 68 return 0 69 # The binary data like images, etc is base64_encoded. Decode it to get 70 # the actualy content length. 71 if base64_encoded: 72 decoded = base64.b64decode(body) 73 return len(decoded) 74 75 encoding = resp.GetHeader('Content-Encoding') 76 if not encoding: 77 return len(body) 78 # The response body returned from a timeline event is always decompressed. 79 # So, we need to compress it to get the actual content length if headers 80 # say so. 81 encoding = encoding.lower() 82 if encoding == 'gzip': 83 return self.GetGizppedBodyLength(body) 84 elif encoding == 'deflate': 85 return len(zlib.compress(body, 9)) 86 else: 87 raise NetworkMetricException, ( 88 'Unknown Content-Encoding %s for %s' % (encoding, resp.url)) 89 90 def GetContentLength(self): 91 cl = 0 92 try: 93 cl = self.GetContentLengthFromBody() 94 except Exception, e: 95 resp = self.response 96 logging.warning('Fail to get content length for %s from body: %s', 97 resp.url[:100], e) 98 cl_header = resp.GetHeader('Content-Length') 99 if cl_header: 100 cl = int(cl_header) 101 else: 102 body, _ = resp.GetBody() 103 if body: 104 cl = len(body) 105 return cl 106 107 @staticmethod 108 def GetGizppedBodyLength(body): 109 if not body: 110 return 0 111 bio = io.BytesIO() 112 try: 113 with gzip.GzipFile(fileobj=bio, mode="wb", compresslevel=9) as f: 114 f.write(body.encode('utf-8')) 115 except Exception, e: 116 logging.warning('Fail to gzip response body: %s', e) 117 raise e 118 return len(bio.getvalue()) 119 120 121 class NetworkMetric(Metric): 122 """A network metric based on timeline events.""" 123 124 def __init__(self): 125 super(NetworkMetric, self).__init__() 126 127 # Whether to add detailed result for each sub-resource in a page. 128 self.add_result_for_resource = False 129 self.compute_data_saving = False 130 self._events = None 131 132 def Start(self, page, tab): 133 self._events = None 134 opts = recording_options.TimelineRecordingOptions() 135 opts.record_network = True 136 tab.StartTimelineRecording(opts) 137 138 def Stop(self, page, tab): 139 assert self._events is None 140 tab.StopTimelineRecording() 141 142 def IterResponses(self, tab): 143 if self._events is None: 144 self._events = tab.timeline_model.GetAllEventsOfName('HTTPResponse') 145 if len(self._events) == 0: 146 return 147 for e in self._events: 148 yield self.ResponseFromEvent(e) 149 150 def ResponseFromEvent(self, event): 151 return HTTPResponse(event) 152 153 def AddResults(self, tab, results): 154 content_length = 0 155 original_content_length = 0 156 157 for resp in self.IterResponses(tab): 158 # Ignore content length calculation for cache hit. 159 if resp.response.served_from_cache: 160 continue 161 162 resource = resp.response.url 163 resource_signature = resp.url_signature 164 cl = resp.content_length 165 if resp.has_original_content_length: 166 ocl = resp.original_content_length 167 if ocl < cl: 168 logging.warning('original content length (%d) is less than content ' 169 'lenght(%d) for resource %s', ocl, cl, resource) 170 if self.add_result_for_resource: 171 results.AddValue(scalar.ScalarValue( 172 results.current_page, 173 'resource_data_saving_' + resource_signature, 'percent', 174 resp.data_saving_rate * 100)) 175 results.AddValue(scalar.ScalarValue( 176 results.current_page, 177 'resource_original_content_length_' + resource_signature, 'bytes', 178 ocl)) 179 original_content_length += ocl 180 else: 181 original_content_length += cl 182 if self.add_result_for_resource: 183 results.AddValue(scalar.ScalarValue( 184 results.current_page, 185 'resource_content_length_' + resource_signature, 'bytes', cl)) 186 content_length += cl 187 188 results.AddValue(scalar.ScalarValue( 189 results.current_page, 'content_length', 'bytes', content_length)) 190 results.AddValue(scalar.ScalarValue( 191 results.current_page, 'original_content_length', 'bytes', 192 original_content_length)) 193 if self.compute_data_saving: 194 if (original_content_length > 0 and 195 original_content_length >= content_length): 196 saving = (float(original_content_length-content_length) * 100 / 197 original_content_length) 198 results.AddValue(scalar.ScalarValue( 199 results.current_page, 'data_saving', 'percent', saving)) 200 else: 201 results.AddValue(scalar.ScalarValue( 202 results.current_page, 'data_saving', 'percent', 0.0)) 203
