Retrieved Hostlist information from Directory service.

remoting/test/chromoting_host_list_fetcher.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 "remoting/test/chromoting_host_list_fetcher.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/json/json_reader.h"
+#include "base/logging.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/values.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "remoting/base/url_request_context_getter.h"
+
+namespace remoting {
+namespace test {
+
+ChromotingHostListFetcher::ChromotingHostListFetcher() {
+}
+
+ChromotingHostListFetcher::~ChromotingHostListFetcher() {
+}
+
+bool ChromotingHostListFetcher::RetrieveHostlist(
+    const std::string& access_token,
+    const HostlistCallback& callback) {
+
+  DVLOG(2) << "ChromotingHostListFetcher::RetrieveHostlist() called";
+
+  DCHECK(!access_token.empty());
+  DCHECK(!callback.is_null());
+  DCHECK(hostlist_callback_.is_null());
+
+  hostlist_callback_ = callback;
+
+  request_context_getter_ = new remoting::URLRequestContextGetter(
+      base::ThreadTaskRunnerHandle::Get(),   // network_runner
+      base::ThreadTaskRunnerHandle::Get());  // file_runner
+
+  request_ = net::URLFetcher::Create(
+      GURL(kChromotingHostListProdRequestUrl),
+      net::URLFetcher::GET, this);

[joedow, 2015/07/06 22:19:13]

Will this line fit on the line above?

[tonychun, 2015/07/08 03:12:13]

Done.

+  request_->SetRequestContext(request_context_getter_.get());
+  request_->AddExtraRequestHeader("Authorization: OAuth " + access_token);
+  request_->Start();
+
+  return true;

[joedow, 2015/07/06 22:19:13]

Why return a value here if it is always true?  I'd update this so it is void and
simplify the calling pattern.

[tonychun, 2015/07/08 03:12:14]

Done.

+}
+
+void ChromotingHostListFetcher::OnURLFetchComplete(
+    const net::URLFetcher* source) {
+  DCHECK(source);
+  DVLOG(2) << "URL Fetch Completed for: " << source->GetOriginalURL();
+
+  std::vector<ChromotingHostInfo> hostlist_;

[joedow, 2015/07/06 22:19:13]

no trailing underscore is used for local vars, only for class members.

[tonychun, 2015/07/08 03:12:13]

Done.

+
+  // Allows executing a callback after the original callback is Reset().

[joedow, 2015/07/06 22:19:12]

Can you update the comment a bit, basically state that you are saving off the
object's stored callback so you can use a ScopedClosureRunner to ensure the
callback is run regardless of when the function returns.

[tonychun, 2015/07/08 03:12:14]

The ScopedClosureRunner has been removed.

+  HostlistCallback reset_hostlist_callback(hostlist_callback_);

[joedow, 2015/07/06 22:19:13]

Can you rename reset_hostlist_callback?  You could just use 'hostlist_callback'
without the trailing underscore since it is a local var.

[tonychun, 2015/07/08 03:12:13]

Done.

+  hostlist_callback_.Reset();
+

[joedow, 2015/07/06 22:19:12]

remove newline

[tonychun, 2015/07/08 03:12:14]

Done.

+  base::Closure cb = base::Bind(reset_hostlist_callback, &hostlist_);

[joedow, 2015/07/06 22:19:12]

rename cb, something like bound_hostlist_callback would be good.  You could also
just do this inline in the ScopedClosureRunner which would probably be cleaner.

[joedow, 2015/07/06 22:19:13]

You can use base::ConstRef(hostlist) here instead of a raw pointer.  Raw
pointers are used for out params, in params are passed by const ref.

[tonychun, 2015/07/08 03:12:14]

Done.

[tonychun, 2015/07/08 03:12:14]

Acknowledged.

+  base::ScopedClosureRunner runner(cb);

[Sergey Ulanov, 2015/07/07 00:01:46]

I don't think this is a good way to use ScopedClosureRunner. It makes error
handling very confusing here.

Another problem here is that the callback can'd distinguish list being empty
from failed request. I suggest adding another argument in the callback to solve
this problem.

I suggest separating parsing from calling the callback. E.g. this function could
look as follows:
 std::vector<ChromotingHostInfo> hostlist;
 if (!ProcessResponse(&hostlist)) {
   hostlist.clear();
   base::ResetAndReturnCallback(false, hostlist_callback_).Run(hostlist);
   return;
 }
 base::ResetAndReturnCallback(true, hostlist_callback_).Run(hostlist);

[tonychun, 2015/07/08 03:12:14]

Done.

+
+  int response_code = request_->GetResponseCode();
+  if (response_code != net::HTTP_OK) {
+    LOG(ERROR) << "Hostlist request failed with error code: " << response_code;
+    return;
+  }
+
+  std::string response_string;
+  if (!request_->GetResponseAsString(&response_string)) {
+    LOG(ERROR) << "Failed to retrieve Hostlist response data";
+    return;
+  }
+
+  scoped_ptr<base::Value> response_value(
+      base::JSONReader::Read(response_string));
+  if (!response_value ||
+      !response_value->IsType(base::Value::TYPE_DICTIONARY)) {
+    LOG(ERROR) << "Failed to parse response string to JSON";
+    return;
+  }
+
+  const base::DictionaryValue* response;
+  if (!response_value->GetAsDictionary(&response)) {
+    LOG(ERROR) << "Failed to convert parsed JSON to a dictionary object";
+    return;
+  }
+
+  const base::DictionaryValue* data = nullptr;
+  response->GetDictionary("data", &data);
+

[joedow, 2015/07/06 22:19:13]

remove newline

[tonychun, 2015/07/08 03:12:14]

Done.

+  if (!data) {

[Sergey Ulanov, 2015/07/07 00:01:46]

use GetDictionary() result here

[tonychun, 2015/07/08 03:12:13]

Done.

+    LOG(ERROR) << "Hostlist response data is empty";
+    return;
+  }
+
+  const base::ListValue* items = nullptr;

[joedow, 2015/07/06 22:19:13]

would hosts be a better name?  items is pretty generic

[tonychun, 2015/07/08 03:12:14]

Done.

+  data->GetList("items", &items);
+

[joedow, 2015/07/06 22:19:13]

remove newline

[tonychun, 2015/07/08 03:12:13]

Done.

+  if (!items) {

[Sergey Ulanov, 2015/07/07 00:01:46]

See my comment in chromoting_host_info.cc: DictionaryValue::GetList() returns a
bool value and you can use it here

[tonychun, 2015/07/08 03:12:14]

Done.

+    LOG(ERROR) << "Failed to find hosts in Hostlist response data";
+    return;
+  }
+
+  int size = items->GetSize();
+  const base::DictionaryValue* item = nullptr;

[joedow, 2015/07/06 22:19:12]

host_info instead of item?

[tonychun, 2015/07/08 03:12:14]

Done.

+  for (int i = 0; i < size; ++i) {

[Sergey Ulanov, 2015/07/07 00:01:46]

List values support iterators, use them here, i.e.:
  for (base::Value* item : *items) {
    hostlist_.push_back(ChromotingHostInfo(*item));
  }

[tonychun, 2015/07/08 03:12:14]

Done.

+    items->GetDictionary(i, &item);
+    hostlist_.push_back(ChromotingHostInfo(*item));
+  }
+}
+
+}  // namespace test
+}  // namespace remoting