Start implementing an auth flow for platform apps to be able to do auth

chrome/browser/extensions/api/identity/extension_auth_flow.cc

+// Copyright (c) 2012 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 "chrome/browser/extensions/api/identity/extension_auth_flow.h"
+
+#include "base/location.h"
+#include "base/message_loop.h"
+#include "base/stringprintf.h"
+#include "base/string_util.h"
+#include "content/public/browser/invalidate_type.h"
+#include "content/public/browser/navigation_controller.h"
+#include "ipc/ipc_message.h"
+
+using content::BrowserContext;
+using content::WebContents;
+using content::WebContentsDelegate;
+using views::View;
+using views::WebView;
+using views::Widget;
+using views::WidgetDelegate;
+
+namespace {
+
+static const char kChromeExtensionSchemeUrlPattern[] =
+    "chrome-extension://%s/";
+static const char kChromiumDomainRedirectUrlPattern[] =
+    "https://%s.ext.chromium.org/";

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

I would prefer not use chromium.org, since it's still a valid domain. How about
chromiumapp.org?

Also (in a separate CL), there should be an API method for generating these
callback URLs, so that app authors don't have to be aware of the exact formats.
Something like chrome.identity.generateCallbackUrl with an optional "generate
HTTPS URL" boolean param.

[Munjal (Google), 2012/05/08 19:26:35]

Done.

+
+static void PopulateValidRedirectUrlPrefixes(

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

Not sure I see the benefit of making this into a static function (vs. a private
one that doesn't need to be passed in extension_id_  and valid_prefixes_).

[Munjal (Google), 2012/05/08 19:26:35]

Done.

+    const std::string& extension_id,
+    std::vector<std::string>* list) {
+  CHECK(list);
+  list->push_back(base::StringPrintf(kChromeExtensionSchemeUrlPattern,
+      extension_id.c_str()));
+  list->push_back(base::StringPrintf(kChromiumDomainRedirectUrlPattern,
+      extension_id.c_str()));
+}
+
+}  // namespace
+
+namespace extensions {
+
+ExtensionAuthFlow::ExtensionAuthFlow(
+    Delegate* delegate,
+    content::BrowserContext* browser_context,
+    const std::string& extension_id,
+    const GURL& provider_url)
+    : delegate_(delegate),
+      browser_context_(browser_context),
+      extension_id_(extension_id),

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

The extension_id_ member is otherwise unused, you could just pass in
extension_id to PopulateValidRedirectUrlPrefixes.

[Munjal (Google), 2012/05/08 19:26:35]

Done.

[Munjal (Google), 2012/05/08 19:26:35]

Done.

+      provider_url_(provider_url),
+      contents_(NULL),
+      widget_(NULL),
+      web_view_(NULL) {
+  PopulateValidRedirectUrlPrefixes(extension_id_, &valid_prefixes_);
+}
+
+ExtensionAuthFlow::~ExtensionAuthFlow() {
+  if (widget_)
+    widget_->Close();  // Close() deletes the widget also.
+  if (contents_) {
+    contents_->SetDelegate(NULL);
+    contents_->Stop();
+    // Tell message loop to delete contents_ instead of deleting it
+    // directly since destructor can run in response to a callback from
+    // contents_.
+    MessageLoop::current()->DeleteSoon(FROM_HERE, contents_);
+  }
+}
+
+void ExtensionAuthFlow::Start() {
+  contents_ = WebContents::Create(
+      browser_context_, NULL, MSG_ROUTING_NONE, NULL, NULL);
+  contents_->SetDelegate(this);
+  contents_->GetController().LoadURL(
+      provider_url_,
+      content::Referrer(),
+      content::PAGE_TRANSITION_START_PAGE,
+      std::string());
+}
+
+void ExtensionAuthFlow::LoadingStateChanged(WebContents* source) {
+  if (source->IsLoading())
+    return;
+  OnUrlLoaded();
+}
+
+void ExtensionAuthFlow::NavigationStateChanged(
+    const WebContents* source, unsigned changed_flags) {
+  // If the URL has not changed, do not perform the check again (for
+  // efficiency).
+  if ((changed_flags & content::INVALIDATE_TYPE_URL) == 0)
+    return;
+
+  const GURL& url = source->GetURL();
+
+  // If the URL being loaded is not from the provider host, then
+  // we are done with the flow.

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

I don't think this is quite true. If I'm not signed into a service, I might go
through several pages in the flow window before ending up at the callback URL.

You can perhaps let the client of this class (and thus the app developer) pass
in a set of URLPatterns that shouldn't trigger response, but should let the flow
keep going. That way, if I'm doing a Facebook flow, I would say that
https://facebook.com/* is OK, but if the user somehow clicks on a non-Facebook
link, then the flow should be aborted.

[Munjal (Google), 2012/05/08 19:26:35]

I put in some thought into this but not enough to decide what to do exactly
here.

The way I have it here, it works fine if the user is not logged in etc. as long
as the URLs being loaed are in the same domain as the provider. I already tested
it with Google and Facebook.

But what you said is probably useful to do in cases where the app is
communicating with its own server to do auth and then the app server can
delegate it to another provider to do th real sign in. In fact, this is what
Google tells mobile app developers to do auth. So I changed the logis to as
follows:
- Get done with the flow when either the user closes the window OR
- Redirect to a valid extension redirect URL happens.

I think the complexity of letting the developer specify a list of URLs is
probably not worth it.

+  if (url.host() != provider_url_.host()) {
+    // The URL is either a valid extension redirect URL or an
+    // invalid URL.
+    if (IsValidExtensionRedirectUrl(url))
+      result_ = url;

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

I don't think result_ should be a member, instead you can just pass the result
into ReturnResult as a parameter.

[Munjal (Google), 2012/05/08 19:26:35]

Done.

+
+    ReportResult();
+    return;
+  }
+}
+
+void ExtensionAuthFlow::OnUrlLoaded() {
+  const GURL& url = contents_->GetURL();
+  CHECK_EQ(url.host(), provider_url_.host());
+
+  if (!widget_) {
+    web_view_ = new WebView(browser_context_);
+    web_view_->SetWebContents(contents_);
+    widget_ = Widget::CreateWindow(this);

[Avi (use Gerrit), 2012/05/07 23:31:13]

This is just a floating window, popup-like without being a popup?

[Munjal (Google), 2012/05/08 19:26:35]

I am not aware of what is the difference between a floating window and a popup.
Regardless of terminology, this seems to produce the UI we need (on Windows).

+    widget_->CenterWindow(gfx::Size(1024, 768));

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

TODO about making this configurable?

[Munjal (Google), 2012/05/08 19:26:35]

Done.
I suppose you meant the size of the window.
By configurable do you mean the app can specify it?

+    widget_->Show();

[Mihai Parparita -not on Chrome, 2012/05/04 22:37:18]

So we only show the window once the initial URL has loaded? It seems like we'd
want some kind of progress indicator as soon as the API is called.

This can be a TODO, but consider something like showing the window straightaway,
filled with a "Loading.." message, and swapping that with the WebView once it
loads.

[Munjal (Google), 2012/05/08 19:26:35]

Yes, this is actually intentional. We will not show any UI if the auth flow
results in a silent redirect back to the app (in cases when the user is signed
in and the approval is already done). If we show "Loading" UI, then in such
cases the Loading window will come up and go away, which can be very jarring.

+  }
+}
+
+View* ExtensionAuthFlow::GetContentsView() {
+  CHECK(web_view_);
+  return web_view_;
+}
+
+Widget* ExtensionAuthFlow::GetWidget() {
+  CHECK(widget_);
+  return widget_;
+}
+
+const Widget* ExtensionAuthFlow::GetWidget() const {
+  CHECK(widget_);
+  return widget_;
+}
+
+View* ExtensionAuthFlow::GetInitiallyFocusedView() {
+  CHECK(web_view_);
+  return web_view_;
+}
+
+void ExtensionAuthFlow::DeleteDelegate() {
+  ReportResult();
+}
+
+void ExtensionAuthFlow::ReportResult() {
+  if (!delegate_)
+    return;
+
+  if (result_.is_empty()) {
+    delegate_->OnAuthFlowFailed();
+  } else {
+    // TODO(munjal): Consider adding code to parse out access token
+    // from some common places (e.g. URL fragment) so the apps don't
+    // have to do that work.
+    delegate_->OnAuthFlowCompleted(result_.spec());
+  }
+
+  // IMPORTANT: Do not access any members after calling the delegate
+  // since the delegate can destroy |this| in the callback and hence
+  // all data members are invalid after that.
+}
+
+bool ExtensionAuthFlow::IsValidExtensionRedirectUrl(const GURL& url) const {
+  std::vector<std::string>::const_iterator iter;
+  for (iter = valid_prefixes_.begin(); iter != valid_prefixes_.end(); ++iter) {
+    if (StartsWithASCII(url.spec(), *iter, false))
+      return true;
+  }
+  return false;
+}
+
+}  // namespace extensions