| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| // Author: slamm@google.com (Stephen Lamm) |
| |
| // The Google Analytics writer filter by scanning all the <script> elements. |
| // The rewriter follows these steps: |
| // 1. Match fixed strings that represent a synchronous load |
| // o Can be either document.write or <script src=...> |
| // 2. Match calls to _gat._getTracker |
| // o Only done if step #1 succeeds. |
| // 3. Match any methods that the rewriter cannot handle such as the |
| // Google Analytics methods that return values. |
| // o Only done if step #2 succeeds. |
| // o If any unhandled methods are found, the rewriter resets to the |
| // first step. |
| // 4. At the end of the document, perform the rewrite if steps #1 and #2 |
| // succeeded and the matched script elements are editable (i.e. in |
| // the current buffer). |
| // |
| |
| #include "net/instaweb/rewriter/public/google_analytics_filter.h" |
| |
| #include <memory> |
| #include <vector> |
| |
| #include "base/logging.h" |
| #include "net/instaweb/rewriter/google_analytics_snippet.h" |
| #include "pagespeed/kernel/base/scoped_ptr.h" |
| #include "pagespeed/kernel/base/statistics.h" |
| #include "pagespeed/kernel/base/stl_util.h" |
| #include "pagespeed/kernel/base/string.h" |
| #include "pagespeed/kernel/base/string_util.h" |
| #include "pagespeed/kernel/html/html_element.h" |
| #include "pagespeed/kernel/html/html_name.h" |
| #include "pagespeed/kernel/html/html_node.h" |
| #include "pagespeed/kernel/html/html_parse.h" |
| |
| namespace net_instaweb { |
| |
| const char kGaJsUrlSuffix[] = "google-analytics.com/ga.js"; |
| const char kGaJsDocumentWriteStart[] = "document.write("; |
| const char kGaJsDocumentWriteEnd[] = "%3C/script%3E\"));"; |
| const char kGaJsGetTracker[] = "_gat._getTracker("; |
| const char kGaJsCreateTracker[] = "_gat._createTracker("; |
| |
| |
| const char GoogleAnalyticsFilter::kPageLoadCount[] = |
| "google_analytics_page_load_count"; |
| const char GoogleAnalyticsFilter::kRewrittenCount[] = |
| "google_analytics_rewritten_count"; |
| |
| |
| ScriptEditor::ScriptEditor(HtmlElement* script_element, |
| HtmlCharactersNode *characters_node, |
| GoogleString::size_type pos, |
| GoogleString::size_type len, |
| Type editor_type) |
| : script_element_(script_element), |
| script_characters_node_(characters_node), |
| pos_(pos), |
| len_(len), |
| editor_type_(editor_type) {} |
| |
| void ScriptEditor::NewContents(const StringPiece& replacement, |
| GoogleString* contents) const { |
| if (pos_ == GoogleString::npos) { |
| replacement.CopyToString(contents); |
| } else { |
| StringPiece old_contents = script_characters_node_->contents(); |
| contents->clear(); |
| contents->append(old_contents.data(), pos_); |
| contents->append(replacement.data(), replacement.size()); |
| StringPiece suffix = old_contents.substr(pos_ + len_, |
| old_contents.size() - pos_ - len_); |
| contents->append(suffix.data(), suffix.size()); |
| } |
| } |
| |
| |
| GoogleAnalyticsFilter::GoogleAnalyticsFilter( |
| HtmlParse* html_parse, Statistics* stats) |
| : glue_methods_(new MethodVector), |
| unhandled_methods_(new MethodVector), |
| html_parse_(html_parse), |
| script_element_(NULL), |
| script_characters_node_(NULL), |
| page_load_count_(stats->GetVariable(kPageLoadCount)), |
| rewritten_count_(stats->GetVariable(kRewrittenCount)) { |
| // The following are the methods that need to be forwarded to the asyn |
| // interface. This list was created by parsing ga.js and finding the method |
| // names in the documentation. Methods that return values were added to the |
| // list of unhandled methods. |
| glue_methods_->push_back("_trackPageview"); |
| glue_methods_->push_back("_trackEvent"); |
| glue_methods_->push_back("_trackTrans"); |
| glue_methods_->push_back("_addIgnoredOrganic"); |
| glue_methods_->push_back("_addIgnoredRef"); |
| glue_methods_->push_back("_addItem"); |
| glue_methods_->push_back("_addOrganic"); |
| glue_methods_->push_back("_addTrans"); |
| glue_methods_->push_back("_clearIgnoredOrganic"); |
| glue_methods_->push_back("_clearIgnoredRef"); |
| glue_methods_->push_back("_clearOrganic"); |
| glue_methods_->push_back("_clearXKey"); |
| glue_methods_->push_back("_clearXValue"); |
| glue_methods_->push_back("_cookiePathCopy"); |
| glue_methods_->push_back("_deleteCustomVar"); |
| glue_methods_->push_back("_link"); |
| glue_methods_->push_back("_linkByPost"); |
| glue_methods_->push_back("_sendXEvent"); |
| glue_methods_->push_back("_setAllowAnchor"); |
| glue_methods_->push_back("_setAllowHash"); |
| glue_methods_->push_back("_setAllowLinker"); |
| glue_methods_->push_back("_setAutoTrackOutbound"); |
| glue_methods_->push_back("_setCampCIdKey"); |
| glue_methods_->push_back("_setCampContentKey"); |
| glue_methods_->push_back("_setCampIdKey"); |
| glue_methods_->push_back("_setCampMediumKey"); |
| glue_methods_->push_back("_setCampNOKey"); |
| glue_methods_->push_back("_setCampNameKey"); |
| glue_methods_->push_back("_setCampSourceKey"); |
| glue_methods_->push_back("_setCampTermKey"); |
| glue_methods_->push_back("_setCampaignCookieTimeout"); |
| glue_methods_->push_back("_setCampaignTrack"); |
| glue_methods_->push_back("_setClientInfo"); |
| glue_methods_->push_back("_setCookiePath"); |
| glue_methods_->push_back("_setCookiePersistence"); |
| glue_methods_->push_back("_setCookieTimeout"); |
| glue_methods_->push_back("_setCustomVar"); |
| glue_methods_->push_back("_setDetectFlash"); |
| glue_methods_->push_back("_setDetectTitle"); |
| glue_methods_->push_back("_setDomainName"); |
| glue_methods_->push_back("_setHrefExamineLimit"); |
| glue_methods_->push_back("_setLocalGifPath"); |
| glue_methods_->push_back("_setLocalRemoteServerMode"); |
| glue_methods_->push_back("_setLocalServerMode"); |
| glue_methods_->push_back("_setMaxCustomVariables"); |
| glue_methods_->push_back("_setNamespace"); |
| glue_methods_->push_back("_setReferrerOverride"); |
| glue_methods_->push_back("_setRemoteServerMode"); |
| glue_methods_->push_back("_setSampleRate"); |
| glue_methods_->push_back("_setSessionCookieTimeout"); |
| glue_methods_->push_back("_setSessionTimeout"); |
| glue_methods_->push_back("_setTrackOutboundSubdomains"); |
| glue_methods_->push_back("_setTrans"); |
| glue_methods_->push_back("_setTransactionDelim"); |
| glue_methods_->push_back("_setVar"); |
| glue_methods_->push_back("_setVisitorCookieTimeout"); |
| glue_methods_->push_back("_setXKey"); |
| glue_methods_->push_back("_setXValue"); |
| |
| unhandled_methods_->push_back("_anonymizeIp"); |
| unhandled_methods_->push_back("_createEventTracker"); // getter method |
| unhandled_methods_->push_back("_createXObj"); // getter method |
| unhandled_methods_->push_back("_require"); |
| unhandled_methods_->push_back("_visitCode"); // getter method |
| unhandled_methods_->push_back("_get"); |
| unhandled_methods_->push_back("_getAccount"); |
| unhandled_methods_->push_back("_getClientInfo"); |
| unhandled_methods_->push_back("_getDetectFlash"); |
| unhandled_methods_->push_back("_getDetectTitle"); |
| unhandled_methods_->push_back("_getLinkerUrl"); |
| unhandled_methods_->push_back("_getLocalGifPath"); |
| unhandled_methods_->push_back("_getName"); |
| unhandled_methods_->push_back("_getServiceMode"); |
| unhandled_methods_->push_back("_getTrackerByName"); |
| unhandled_methods_->push_back("_getVersion"); |
| unhandled_methods_->push_back("_getVisitorCustomVar"); |
| unhandled_methods_->push_back("_getXKey"); |
| unhandled_methods_->push_back("_getXValue"); |
| unhandled_methods_->push_back("_setAccount"); // async only |
| } |
| |
| |
| GoogleAnalyticsFilter::GoogleAnalyticsFilter( |
| HtmlParse* html_parse, Statistics* stats, |
| MethodVector* glue_methods, MethodVector* unhandled_methods) |
| : glue_methods_(glue_methods), |
| unhandled_methods_(unhandled_methods), |
| html_parse_(html_parse), |
| script_element_(NULL), |
| script_characters_node_(NULL), |
| page_load_count_((stats == NULL) ? NULL : |
| stats->GetVariable(kPageLoadCount)), |
| rewritten_count_((stats == NULL) ? NULL : |
| stats->GetVariable(kRewrittenCount)) |
| { } |
| |
| GoogleAnalyticsFilter::~GoogleAnalyticsFilter() {} |
| |
| void GoogleAnalyticsFilter::InitStats(Statistics* statistics) { |
| statistics->AddVariable(kPageLoadCount); |
| statistics->AddVariable(kRewrittenCount); |
| } |
| |
| void GoogleAnalyticsFilter::StartDocument() { |
| ResetFilter(); |
| page_load_count_->Add(1); |
| } |
| |
| void GoogleAnalyticsFilter::EndDocument() { |
| if (is_load_found_) { |
| if (is_init_found_) { |
| if (RewriteAsAsync()) { |
| rewritten_count_->Add(1); |
| html_parse_->InfoHere("Google Analytics rewritten: SUCCESS!"); |
| } else { |
| html_parse_->InfoHere("Google Analytics not rewritten: rewrite failed"); |
| } |
| } else { |
| html_parse_->InfoHere( |
| "Google Analytics not rewritten: only found ga.js load"); |
| } |
| } |
| ResetFilter(); |
| } |
| |
| void GoogleAnalyticsFilter::StartElement(HtmlElement* element) { |
| // No tags allowed inside script element. |
| if (script_element_ != NULL) { |
| html_parse_->ErrorHere("Google Analytics reset: Tag '%s' found inside " |
| "script.", CEscape(element->name_str()).c_str()); |
| ResetFilter(); |
| } |
| if (element->keyword() == HtmlName::kScript) { |
| script_element_ = element; |
| } |
| } |
| |
| void GoogleAnalyticsFilter::EndElement(HtmlElement* element) { |
| if (script_element_ != NULL) { |
| if (element != script_element_) { |
| html_parse_->ErrorHere("Google Analytics reset: Unexpected tag '%s' " |
| "inside a script.", |
| CEscape(element->name_str()).c_str()); |
| ResetFilter(); |
| } else { |
| FindRewritableScripts(); |
| script_element_ = NULL; |
| script_characters_node_ = NULL; |
| } |
| } |
| } |
| |
| void GoogleAnalyticsFilter::Flush() { |
| if (script_element_ != NULL) { |
| html_parse_->InfoHere("Google Analytics reset: flush in a script."); |
| ResetFilter(); |
| } |
| } |
| |
| void GoogleAnalyticsFilter::Characters(HtmlCharactersNode* characters_node) { |
| if (script_element_ != NULL) { |
| if (script_characters_node_ == NULL) { |
| script_characters_node_ = characters_node; |
| } else { |
| html_parse_->ErrorHere("Google Analytics reset: multiple character " |
| "nodes in script."); |
| ResetFilter(); |
| } |
| } |
| } |
| |
| void GoogleAnalyticsFilter::Comment(HtmlCommentNode* comment) { |
| if (script_element_ != NULL) { |
| html_parse_->InfoHere("Google Analytics reset: comment found inside " |
| "script."); |
| ResetFilter(); |
| } |
| } |
| |
| void GoogleAnalyticsFilter::Cdata(HtmlCdataNode* cdata) { |
| if (script_element_ != NULL) { |
| html_parse_->InfoHere("Google Analytics reset: CDATA found inside script."); |
| ResetFilter(); |
| } |
| } |
| |
| void GoogleAnalyticsFilter::IEDirective(HtmlIEDirectiveNode* directive) { |
| if (script_element_ != NULL) { |
| html_parse_->ErrorHere("Google Analytics reset: IE Directive found " |
| "inside script."); |
| ResetFilter(); |
| } |
| } |
| |
| void GoogleAnalyticsFilter::ResetFilter() { |
| script_element_ = NULL; |
| script_characters_node_ = NULL; |
| is_init_found_ = false; |
| is_load_found_ = false; |
| STLDeleteContainerPointers(script_editors_.begin(), |
| script_editors_.end()); |
| script_editors_.clear(); |
| } |
| |
| bool GoogleAnalyticsFilter::MatchSyncLoad(StringPiece contents, |
| GoogleString::size_type* pos, |
| GoogleString::size_type* len) const { |
| GoogleString::size_type url_pos = contents.find(kGaJsUrlSuffix); |
| if (url_pos != GoogleString::npos) { |
| // In the common case, document.write is 56 characters before the url. |
| // Allow a little extra wiggle room (e.g. for different formating), but |
| // not so much that an unrelated document.write is found. |
| const GoogleString::size_type max_distance = 80; |
| GoogleString::size_type write_start_pos = |
| url_pos < max_distance ? 0 : url_pos - max_distance; |
| StringPiece write_start(contents.data() + write_start_pos, |
| url_pos - write_start_pos); |
| GoogleString::size_type write_pos = write_start.find( |
| kGaJsDocumentWriteStart); |
| if (write_pos == GoogleString::npos) { |
| html_parse_->InfoHere("Found ga.js without a matching document.write"); |
| } else { |
| write_pos += write_start_pos; |
| GoogleString::size_type write_end_pos = contents.find( |
| kGaJsDocumentWriteEnd, |
| url_pos + StringPiece(kGaJsUrlSuffix).size()); |
| if (write_end_pos != GoogleString::npos) { |
| write_end_pos += StringPiece(kGaJsDocumentWriteEnd).size(); |
| *pos = write_pos; |
| *len = write_end_pos - write_pos; |
| html_parse_->InfoHere("Found ga.js load: document.write"); |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| bool GoogleAnalyticsFilter::MatchSyncInit(StringPiece contents, |
| GoogleString::size_type start_pos, |
| GoogleString::size_type* pos, |
| GoogleString::size_type* len) const { |
| StringPiece tracker_method(kGaJsGetTracker); |
| GoogleString::size_type tracker_method_pos = contents.find( |
| tracker_method, start_pos); |
| if (tracker_method_pos == GoogleString::npos) { |
| tracker_method = StringPiece(kGaJsCreateTracker); |
| tracker_method_pos = contents.find(tracker_method, start_pos); |
| } |
| if (tracker_method_pos != GoogleString::npos) { |
| html_parse_->InfoHere("Found ga.js init: %s", |
| tracker_method.as_string().c_str()); |
| *pos = tracker_method_pos; |
| *len = tracker_method.size(); |
| return true; |
| } |
| return false; |
| } |
| |
| bool GoogleAnalyticsFilter::MatchUnhandledCalls( |
| StringPiece contents, GoogleString::size_type start_pos) const { |
| // TODO(slamm): Use a more efficient multiple pattern algorithm |
| while (1) { |
| GoogleString::size_type candidate_pos = contents.find("._"); |
| if (candidate_pos == GoogleString::npos) { |
| break; |
| } |
| contents = contents.substr(candidate_pos + 1); |
| for (int i = 0, ni = unhandled_methods_->size(); i < ni; ++i) { |
| const StringPiece& method = unhandled_methods_->at(i); |
| if (contents.starts_with(method)) { |
| for (int j = method.size(), nj = contents.size(); j < nj; ++j) { |
| char c = contents[j]; |
| if (c == '(') { |
| html_parse_->InfoHere("Matched unhandled call: %s", |
| method.as_string().c_str()); |
| return true; |
| } else if (!IsHtmlSpace(c)) { |
| break; |
| } |
| } |
| } |
| } |
| } |
| return false; |
| } |
| |
| void GoogleAnalyticsFilter::FindRewritableScripts() { |
| if (html_parse_->IsRewritable(script_element_)) { |
| StringPiece src = script_element_->AttributeValue(HtmlName::kSrc); |
| if (src != NULL && !src.empty()) { |
| if (src.ends_with(kGaJsUrlSuffix)) { |
| html_parse_->InfoHere("Found ga.js load: script src"); |
| is_load_found_ = true; |
| script_editors_.push_back(new ScriptEditor( |
| script_element_, script_characters_node_, |
| GoogleString::npos, GoogleString::npos, |
| ScriptEditor::kGaJsScriptSrcLoad)); |
| } |
| } else if (script_characters_node_ != NULL) { |
| StringPiece contents = script_characters_node_->contents(); |
| if (!contents.empty()) { |
| GoogleString::size_type start_pos = 0; |
| GoogleString::size_type pos, len; |
| if (MatchSyncLoad(contents, &pos, &len)) { |
| is_load_found_ = true; |
| script_editors_.push_back(new ScriptEditor( |
| script_element_, script_characters_node_, pos, len, |
| ScriptEditor::kGaJsDocWriteLoad)); |
| start_pos = pos + len; |
| } |
| if (is_load_found_ && MatchSyncInit(contents, start_pos, &pos, &len)) { |
| is_init_found_ = true; |
| script_editors_.push_back(new ScriptEditor( |
| script_element_, script_characters_node_, pos, len, |
| ScriptEditor::kGaJsInit)); |
| start_pos = pos + len; |
| } |
| if (is_init_found_ && MatchUnhandledCalls(contents, start_pos)) { |
| html_parse_->InfoHere("Google Analytics reset: unhandled call."); |
| ResetFilter(); |
| return; |
| } |
| } |
| } |
| } |
| } |
| |
| void GoogleAnalyticsFilter::GetSyncToAsyncScript(GoogleString *buffer) const { |
| buffer->clear(); |
| buffer->append(kGaSnippetPrefix); |
| int last_index = glue_methods_->size() - 1; |
| for (int i = 0; i <= last_index; i++) { |
| buffer->append(" '"); |
| buffer->append(glue_methods_->at(i).as_string()); |
| if (i == last_index) { |
| buffer->append("'\n"); |
| } else { |
| buffer->append("',\n"); |
| } |
| } |
| buffer->append(kGaSnippetSuffix); |
| } |
| |
| bool GoogleAnalyticsFilter::RewriteAsAsync() { |
| if (!is_init_found_ || !is_load_found_) { |
| return false; |
| } |
| ScriptEditor* first_editor = script_editors_[0]; |
| HtmlElement* first_script = first_editor->GetScriptElement(); |
| if (!html_parse_->IsRewritable(first_script)) { |
| html_parse_->InfoHere("First script is not rewritable."); |
| return false; |
| } |
| ScriptEditor::Type first_type = first_editor->GetType(); |
| CHECK(first_type == ScriptEditor::kGaJsScriptSrcLoad || |
| first_type == ScriptEditor::kGaJsDocWriteLoad); |
| |
| GoogleString replacement_script; |
| for (int i = script_editors_.size() - 1; i > 0; --i) { |
| ScriptEditor* editor = script_editors_[i]; |
| HtmlElement* script = editor->GetScriptElement(); |
| if (editor->GetType() == ScriptEditor::kGaJsScriptSrcLoad) { |
| html_parse_->DeleteNode(script); |
| html_parse_->InfoHere("Deleted script src load"); |
| } else if (editor->GetType() == ScriptEditor::kGaJsDocWriteLoad) { |
| editor->NewContents("", &replacement_script); |
| html_parse_->ReplaceNode( |
| editor->GetScriptCharactersNode(), |
| html_parse_->NewCharactersNode(script, replacement_script)); |
| html_parse_->InfoHere("Deleted document.write load"); |
| } else if (editor->GetType() == ScriptEditor::kGaJsInit) { |
| editor->NewContents(kGaSnippetGetTracker, &replacement_script); |
| html_parse_->ReplaceNode( |
| editor->GetScriptCharactersNode(), |
| html_parse_->NewCharactersNode(script, replacement_script)); |
| html_parse_->InfoHere("Replaced init"); |
| } |
| } |
| |
| GoogleString glue_script; |
| GetSyncToAsyncScript(&glue_script); |
| if (first_type == ScriptEditor::kGaJsScriptSrcLoad) { |
| html_parse_->PrependChild( |
| first_script, |
| html_parse_->NewCharactersNode(first_script, glue_script)); |
| first_script->DeleteAttribute(HtmlName::kSrc); |
| html_parse_->InfoHere("Replaced script src load"); |
| } else { |
| first_editor->NewContents(glue_script, &replacement_script); |
| html_parse_->ReplaceNode( |
| first_editor->GetScriptCharactersNode(), |
| html_parse_->NewCharactersNode(first_script, replacement_script)); |
| html_parse_->InfoHere("Replaced document.write load"); |
| } |
| return true; |
| } |
| |
| } // namespace net_instaweb |
