Fetch snippets from ChromeReader and show them on the NTP

components/ntp_snippets/ntp_snippets_fetcher.cc

+// Copyright 2016 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 "components/ntp_snippets/ntp_snippets_fetcher.h"
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/path_service.h"
+#include "base/strings/stringprintf.h"
+#include "base/task_runner_util.h"
+#include "components/signin/core/browser/profile_oauth2_token_service.h"
+#include "components/signin/core/browser/signin_manager.h"
+#include "components/signin/core/browser/signin_tracker.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_request_headers.h"
+#include "net/http/http_response_headers.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+
+using net::URLFetcher;
+using net::URLRequestContextGetter;
+using net::HttpRequestHeaders;
+using net::URLRequestStatus;
+
+namespace ntp_snippets {
+
+const char kSnippetSuggestionsFilename[] = "ntp_snippets.json";
+const char kApiScope[] = "https://www.googleapis.com/auth/webhistory";
+const char kContentSnippetsServer[] =
+    "https://chromereader-pa.googleapis.com/v1/fetch";
+const char kAuthorizationRequestHeaderFormat[] = "Bearer %s";
+
+const char kUnpersonalizedRequestParameters[] =
+    "{ \"response_detail_level\": \"FULL_DEBUG\", \"advanced_options\": { "
+    "\"local_scoring_params\": {\"content_params\" : { "
+    "\"only_return_personalized_results\": false } }, "
+    "\"global_scoring_params\": { \"num_to_return\": 10 } } }";
+
+base::FilePath GetSnippetsSuggestionsPath() {
+  base::FilePath dir;
+#if defined(OS_ANDROID)
+  DCHECK(PathService::Get(base::DIR_ANDROID_APP_DATA, &dir));
+  return dir.AppendASCII(kSnippetSuggestionsFilename);
+#else
+  NOTIMPLEMENTED();

[noyau (Ping after 24h), 2016/02/17 20:19:47]

Use PathService::Get(ios::FILE_LOCAL_STATE, &dir)) to put the data in some
installation dependent folder. But should you use a profile dependent path
instead? Is there different snippets returned to different users, or do you
expect all users to get the same snippets?

Anyway this would be probably better if the difference was handled in the
factory and the path passed in instead of using a #if, and this would make
testing simpler.

[May, 2016/02/19 14:49:01]

Done.

+  return dir;
+#endif
+}
+
+NTPSnippetsFetcher::NTPSnippetsFetcher(
+    scoped_refptr<base::SequencedTaskRunner> file_task_runner,
+    SigninManager* signin_manager,
+    OAuth2TokenService* token_service,
+    URLRequestContextGetter* url_request_context_getter)
+    : OAuth2TokenService::Consumer("NTP_snippets"),
+      file_task_runner_(file_task_runner),
+      url_request_context_getter_(url_request_context_getter),
+      signin_manager_(signin_manager),
+      token_service_(token_service),
+      waiting_for_refresh_token_(false),
+      weak_ptr_factory_(this) {}
+
+NTPSnippetsFetcher::~NTPSnippetsFetcher() {
+  if (waiting_for_refresh_token_)
+    token_service_->RemoveObserver(this);
+}
+
+scoped_ptr<NTPSnippetsFetcher::SnippetsAvailableCallbackList::Subscription>
+NTPSnippetsFetcher::AddCallback(const SnippetsAvailableCallback& callback) {
+  return callback_list_.Add(callback);
+}
+
+void NTPSnippetsFetcher::FetchSnippets(bool overwrite) {
+  if (overwrite) {
+    StartFetch();
+  } else {
+    base::PostTaskAndReplyWithResult(
+        file_task_runner_.get(), FROM_HERE,
+        base::Bind(&base::PathExists, GetSnippetsSuggestionsPath()),
+        base::Bind(&NTPSnippetsFetcher::OnFileExistsCheckDone,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+}
+
+void NTPSnippetsFetcher::OnFileExistsCheckDone(bool exists) {
+  if (exists) {
+    NotifyObservers();
+  } else {
+    StartFetch();
+  }
+}
+
+void NTPSnippetsFetcher::StartFetch() {
+  if (signin_manager_->IsAuthenticated()) {
+    StartTokenRequest();
+  } else {
+    if (!waiting_for_refresh_token_) {
+      // Wait until we get a refresh token.
+      waiting_for_refresh_token_ = true;
+      token_service_->AddObserver(this);
+    }
+  }
+}
+
+void NTPSnippetsFetcher::StartTokenRequest() {
+  OAuth2TokenService::ScopeSet scopes;
+  scopes.insert(kApiScope);
+  oauth_request_ = token_service_->StartRequest(
+      signin_manager_->GetAuthenticatedAccountId(), scopes, this);
+}
+
+void NTPSnippetsFetcher::NotifyObservers() {
+  callback_list_.Notify(GetSnippetsSuggestionsPath());
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// OAuth2TokenService::Consumer overrides
+void NTPSnippetsFetcher::OnGetTokenSuccess(
+    const OAuth2TokenService::Request* request,
+    const std::string& access_token,
+    const base::Time& expiration_time) {
+  oauth_request_.reset();
+  url_fetcher_ =
+      URLFetcher::Create(GURL(kContentSnippetsServer), URLFetcher::POST, this);
+  url_fetcher_->SetRequestContext(url_request_context_getter_);
+  url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                             net::LOAD_DO_NOT_SAVE_COOKIES);
+  HttpRequestHeaders headers;
+  headers.SetHeader("Authorization",
+                    base::StringPrintf(kAuthorizationRequestHeaderFormat,
+                                       access_token.c_str()));
+  headers.SetHeader("Content-Type", "application/json; charset=UTF-8");
+  url_fetcher_->SetExtraRequestHeaders(headers.ToString());
+  url_fetcher_->SetUploadData("application/json",
+                              kUnpersonalizedRequestParameters);
+  url_fetcher_->SaveResponseToTemporaryFile(file_task_runner_.get());
+  url_fetcher_->Start();
+}
+
+void NTPSnippetsFetcher::OnGetTokenFailure(
+    const OAuth2TokenService::Request* request,
+    const GoogleServiceAuthError& error) {
+  oauth_request_.reset();
+  DLOG(ERROR) << "Unable to get token: " << error.ToString();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// OAuth2TokenService::Observer overrides
+void NTPSnippetsFetcher::OnRefreshTokenAvailable(
+    const std::string& account_id) {
+  token_service_->RemoveObserver(this);
+  waiting_for_refresh_token_ = false;
+  StartTokenRequest();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// URLFetcherDelegate overrides
+void NTPSnippetsFetcher::OnURLFetchComplete(const URLFetcher* source) {
+  DCHECK_EQ(url_fetcher_.get(), source);
+
+  const URLRequestStatus& status = source->GetStatus();
+  if (!status.is_success()) {
+    DLOG(WARNING) << "URLRequestStatus error " << status.error()
+                  << " while trying to download " << source->GetURL().spec();
+    return;
+  }
+
+  int response_code = source->GetResponseCode();
+  if (response_code != net::HTTP_OK) {
+    DLOG(WARNING) << "HTTP error " << response_code
+                  << " while trying to download " << source->GetURL().spec();
+    return;
+  }
+
+  base::FilePath response_path;
+  source->GetResponseAsFilePath(false, &response_path);
+
+  base::PostTaskAndReplyWithResult(
+      file_task_runner_.get(), FROM_HERE,
+      base::Bind(&base::Move, response_path, GetSnippetsSuggestionsPath()),
+      base::Bind(&NTPSnippetsFetcher::OnFileMoveDone,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void NTPSnippetsFetcher::OnFileMoveDone(bool success) {
+  if (!success) {
+    DLOG(WARNING) << "Could not move file to "
+                  << GetSnippetsSuggestionsPath().LossyDisplayName();
+    return;
+  }
+
+  NotifyObservers();
+}
+
+}  // namespace ntp_snippets