chrome://snippets-internals page for debugging NTP snippets.

chrome/browser/ui/webui/snippets_internals_message_handler.cc

+// Copyright 2015 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 "snippets_internals_message_handler.h"
+
+#include <set>
+#include <sstream>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/command_line.h"
+#include "base/feature_list.h"
+#include "base/i18n/time_formatting.h"
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_split.h"
+#include "base/values.h"
+#include "chrome/browser/android/chrome_feature_list.h"
+#include "chrome/browser/ntp_snippets/ntp_snippets_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/ntp_snippets/ntp_snippet.h"
+#include "components/ntp_snippets/switches.h"
+#include "content/public/browser/web_ui.h"
+
+namespace {
+
+scoped_ptr<base::DictionaryValue> PrepareSnippet(
+    const ntp_snippets::NTPSnippet& snippet,
+    int index,
+    bool discarded) {
+  scoped_ptr<base::DictionaryValue> entry(new base::DictionaryValue);
+  entry->SetString("title", snippet.title());
+  entry->SetString("siteTitle", snippet.site_title());
+  entry->SetString("snippet", snippet.snippet());
+  entry->SetString("published",
+                   TimeFormatShortDateAndTime(snippet.publish_date()));
+  entry->SetString("expires",
+                   TimeFormatShortDateAndTime(snippet.expiry_date()));
+  entry->SetString("url", snippet.url().spec());
+  entry->SetString("faviconUrl", snippet.favicon_url().spec());
+  entry->SetString("salientImageUrl", snippet.salient_image_url().spec());
+
+  if (discarded)
+    entry->SetString("id", "discarded-snippet-" + base::IntToString(index));
+  else
+    entry->SetString("id", "snippet-" + base::IntToString(index));
+
+  return entry;
+}
+
+} // namespace
+
+SnippetsInternalsMessageHandler::SnippetsInternalsMessageHandler() {}
+
+SnippetsInternalsMessageHandler::~SnippetsInternalsMessageHandler() {}
+
+void SnippetsInternalsMessageHandler::NTPSnippetsServiceShutdown() {}
+
+void SnippetsInternalsMessageHandler::NTPSnippetsServiceLoaded() {
+  ntp_snippets::NTPSnippetsService* ntp_snippets_service =
+        NTPSnippetsServiceFactory::GetInstance()->GetForProfile(
+            Profile::FromWebUI(web_ui()));
+
+  SendSnippets(ntp_snippets_service);
+  SendDiscardedSnippets(ntp_snippets_service);
+}
+
+void SnippetsInternalsMessageHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback(
+      "loaded",
+      base::Bind(&SnippetsInternalsMessageHandler::HandleLoaded,
+                 base::Unretained(this)));
+
+  web_ui()->RegisterMessageCallback(
+      "clear", base::Bind(&SnippetsInternalsMessageHandler::HandleClear,
+                          base::Unretained(this)));
+
+  web_ui()->RegisterMessageCallback(
+      "download", base::Bind(&SnippetsInternalsMessageHandler::HandleDownload,
+                             base::Unretained(this)));
+
+  web_ui()->RegisterMessageCallback(
+      "clearDiscarded",
+      base::Bind(&SnippetsInternalsMessageHandler::HandleClearDiscarded,
+                 base::Unretained(this)));
+}
+
+void SnippetsInternalsMessageHandler::HandleLoaded(
+    const base::ListValue* args) {
+  DCHECK(args->empty());
+
+  ntp_snippets::NTPSnippetsService* ntp_snippets_service =
+      NTPSnippetsServiceFactory::GetInstance()->GetForProfile(
+          Profile::FromWebUI(web_ui()));
+
+  // On page reloads it is necessary to first remove the observer.

[Marc Treib, 2016/04/13 08:45:51]

Why?
Also: On the initial load, you're trying to remove an observer that isn't there.
(Probably not really a problem, but not nice either.)
And you never remove the observer when this page is closed. That might cause
use-after-free crashes.

[jkrcal, 2016/04/14 15:27:00]

Done.

On page reload, nothing is destroyed, HandleLoaded is called again on the same
object. I added a check into NTPSnippetsService::AddObserver so that we do not
do it twice.

[Marc Treib, 2016/04/14 15:43:44]

IMO this class should handle not adding itself twice.

+  ntp_snippets_service->RemoveObserver(this);
+  ntp_snippets_service->AddObserver(this);
+
+  ntp_snippets_service->FetchSnippets();
+
+  SendInitialData(ntp_snippets_service);
+}
+
+void SnippetsInternalsMessageHandler::HandleClear(const base::ListValue* args) {
+  DCHECK_EQ(0u, args->GetSize());
+
+  ntp_snippets::NTPSnippetsService* ntp_snippets_service =
+      NTPSnippetsServiceFactory::GetInstance()->GetForProfile(
+          Profile::FromWebUI(web_ui()));
+
+  ntp_snippets_service->ClearSnippets();
+}
+
+void SnippetsInternalsMessageHandler::HandleClearDiscarded(
+    const base::ListValue* args) {
+  DCHECK_EQ(0u, args->GetSize());
+
+  ntp_snippets::NTPSnippetsService* ntp_snippets_service =
+      NTPSnippetsServiceFactory::GetInstance()->GetForProfile(
+          Profile::FromWebUI(web_ui()));
+
+  ntp_snippets_service->ClearDiscardedSnippets();
+  SendDiscardedSnippets(ntp_snippets_service);
+}
+
+void SnippetsInternalsMessageHandler::HandleDownload(
+    const base::ListValue* args) {
+  DCHECK_EQ(1u, args->GetSize());
+
+  std::string hosts_string;
+  args->GetString(0, &hosts_string);
+  base::StringPiece hosts_piece(hosts_string);

[Marc Treib, 2016/04/13 08:45:51]

I think this conversion happens automatically, i.e. you can just pass
hosts_string to SplitString.

[jkrcal, 2016/04/14 15:27:00]

Done.

+
+  std::vector<std::string> hosts_vector = base::SplitString(
+      hosts_piece, " ", base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  std::set<std::string> hosts(hosts_vector.begin(), hosts_vector.end());
+
+  ntp_snippets::NTPSnippetsService* ntp_snippets_service =
+      NTPSnippetsServiceFactory::GetInstance()->GetForProfile(
+          Profile::FromWebUI(web_ui()));
+
+  ntp_snippets_service->FetchSnippetsFromHosts(hosts);
+}
+
+void SnippetsInternalsMessageHandler::SendInitialData(
+    ntp_snippets::NTPSnippetsService* service){
+  SendHosts(service);
+
+  SendBoolean("flag-snippets", base::FeatureList::IsEnabled(
+                                   chrome::android::kNTPSnippetsFeature));
+
+  bool restricted = !base::CommandLine::ForCurrentProcess()->HasSwitch(
+      ntp_snippets::switches::kDontRestrict);
+  SendBoolean("switch-restrict-to-hosts", restricted);
+  const std::string help(restricted ? "cannot be empty"
+                                    : "unrestricted if empty");
+  SendString("hosts-help", help);
+}
+
+void SnippetsInternalsMessageHandler::SendSnippets(
+    ntp_snippets::NTPSnippetsService* service) {
+  scoped_ptr<base::ListValue> snippets_list(new base::ListValue);
+
+  int index = 0;
+  for (auto& snippet : *service)
+    snippets_list->Append(PrepareSnippet(snippet, index++, false));
+
+  base::DictionaryValue result;
+  result.Set("list", std::move(snippets_list));
+  web_ui()->CallJavascriptFunction("chrome.snippets_internals.receiveSnippets",
+                                   result);
+}
+
+void SnippetsInternalsMessageHandler::SendDiscardedSnippets(
+    ntp_snippets::NTPSnippetsService* service) {
+  scoped_ptr<base::ListValue> snippets_list(new base::ListValue);
+
+  int index = 0;
+  for (auto& snippet : service->GetDiscardedSnippets())
+    snippets_list->Append(PrepareSnippet(*snippet, index++, true));
+
+  base::DictionaryValue result;
+  result.Set("list", std::move(snippets_list));
+  web_ui()->CallJavascriptFunction(
+      "chrome.snippets_internals.receiveDiscardedSnippets", result);
+}
+
+void SnippetsInternalsMessageHandler::SendHosts(
+    ntp_snippets::NTPSnippetsService* service) {
+  scoped_ptr<base::ListValue> hosts_list(new base::ListValue);
+
+  std::set<std::string> hosts = service->GetSuggestionsHosts();
+  std::ostringstream hosts_imploded;
+
+  for (const std::string& host : hosts) {
+    scoped_ptr<base::DictionaryValue> entry(new base::DictionaryValue);
+    entry->SetString("url", host);
+
+    hosts_list->Append(std::move(entry));
+    hosts_imploded << host << " ";
+  }
+
+  base::DictionaryValue result;
+  result.Set("list", std::move(hosts_list));
+  web_ui()->CallJavascriptFunction("chrome.snippets_internals.receiveHosts",
+                                   result);
+
+  base::StringValue hosts_value(hosts_imploded.str());
+  web_ui()->CallJavascriptFunction(
+      "chrome.snippets_internals.receiveHostsInput", hosts_value);

[Marc Treib, 2016/04/13 08:45:51]

Any particular reason for sending this separately? Should be trivial to just
build the "imploded" string in js, right?

[jkrcal, 2016/04/14 15:27:00]

Done.

+}
+
+void SnippetsInternalsMessageHandler::SendBoolean(const std::string& name,
+                                                  bool value) {
+  const std::string string_value(value ? "True" : "False");

[Marc Treib, 2016/04/13 08:45:51]

Might as well just inline this below.

[jkrcal, 2016/04/14 15:27:00]

Done.

+  SendString(name, string_value);
+}
+
+void SnippetsInternalsMessageHandler::SendString(const std::string& name,
+                                                 const std::string& value) {
+  base::StringValue string_name(name);
+  base::StringValue string_value(value);
+
+  web_ui()->CallJavascriptFunction("chrome.snippets_internals.receiveProperty",
+                                   string_name, string_value);
+}