Add AffiliationFetcher to fetch authoritative affiliation information regarding facets.

components/password_manager/core/browser/affiliation_fetcher.cc

+// Copyright 2014 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/password_manager/core/browser/affiliation_fetcher.h"
+
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/values.h"
+#include "components/password_manager/core/browser/affiliation_api.pb.h"
+#include "components/password_manager/core/browser/affiliation_utils.h"
+#include "google_apis/google_api_keys.h"
+#include "net/base/load_flags.h"
+#include "net/base/url_util.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_context_getter.h"
+#include "url/gurl.h"
+
+namespace password_manager {
+
+AffiliationFetcher::AffiliationFetcher(
+    net::URLRequestContextGetter* request_context_getter,
+    const std::vector<FacetURI>& facet_uris,
+    AffiliationFetcherDelegate* delegate)
+    : request_context_getter_(request_context_getter),
+      requested_facet_uris_(facet_uris),
+      delegate_(delegate) {
+  for (const FacetURI& uri : requested_facet_uris_)
+    DCHECK(uri.is_valid());

[Ryan Sleevi, 2014/12/12 23:02:19]

BUG/DANGER: Whenever using debugging macros and conditionals, you should ensure
the conditional has appropriate braces around it, in the event the macros is
optimized out.

While DCHECK is a "safe" macro for this construct, it encourages safe coding
around potentially dangerous idioms, and isolates you from any future changes to
DCHECK.

[engedy, 2014/12/15 13:54:51]

Done.

+}
+
+AffiliationFetcher::~AffiliationFetcher() {
+}
+
+// static
+AffiliationFetcher* AffiliationFetcher::Create(
+    net::URLRequestContextGetter* context_getter,
+    const std::vector<FacetURI>& facet_uris,
+    AffiliationFetcherDelegate* delegate) {
+  return new AffiliationFetcher(context_getter, facet_uris, delegate);
+}
+
+void AffiliationFetcher::StartRequest() {
+  DCHECK(!fetcher_);
+
+  fetcher_.reset(
+      net::URLFetcher::Create(BuildQueryURL(), net::URLFetcher::POST, this));
+  fetcher_->SetRequestContext(request_context_getter_.get());
+  fetcher_->SetUploadData("application/x-protobuf", PreparePayload());
+  fetcher_->SetLoadFlags(
+      net::LOAD_DO_NOT_SAVE_COOKIES | net::LOAD_DO_NOT_SEND_COOKIES |
+      net::LOAD_DO_NOT_SEND_AUTH_DATA | net::LOAD_BYPASS_CACHE |
+      net::LOAD_DISABLE_CACHE | net::LOAD_DO_NOT_PROMPT_FOR_LOGIN);
+  fetcher_->SetAutomaticallyRetryOn5xx(false);
+  fetcher_->SetAutomaticallyRetryOnNetworkChanges(0);
+  fetcher_->Start();
+}
+
+GURL AffiliationFetcher::BuildQueryURL() const {
+  return net::AppendQueryParameter(
+      GURL("https://www.googleapis.com/affiliation/v1/affiliation:lookup"),
+      "key", google_apis::GetAPIKey());
+}
+
+std::string AffiliationFetcher::PreparePayload() const {
+  affiliation_pb::LookupAffiliationRequest lookup_request;
+  for (const FacetURI& uri : requested_facet_uris_)
+    lookup_request.add_facet(uri.canonical_spec());
+
+  std::string serialized_request;
+  bool success = lookup_request.SerializeToString(&serialized_request);
+  DCHECK(success);
+  return serialized_request;
+}
+
+bool AffiliationFetcher::ParseResponse(

[Ryan Sleevi, 2014/12/12 23:02:19]

DOCUMENTATION: I think it'd be helpful for future readers/maintainers of this
code to provide a bit of a design-level comment in this file about the
transformation/sanitization that you're doing here (similar to what you
mentioned in the code review).

Just clarifying the facet cleanups in more detail (that is, your comments on 98,
104, and 110 are all good, but perhaps a high level view of inputs and outputs
and why, and then leave the code to show & comment the how)

[engedy, 2014/12/15 13:54:51]

Done.

+    AffiliationFetcherDelegate::Result* result) const {
+  std::string serialized_response;
+  if (!fetcher_->GetResponseAsString(&serialized_response))
+    NOTREACHED();
+
+  affiliation_pb::LookupAffiliationResponse response;
+  if (!response.ParseFromString(serialized_response))
+    return false;
+
+  result->reserve(requested_facet_uris_.size());
+
+  std::map<FacetURI, size_t> facet_uri_to_class_index;
+  for (int i = 0; i < response.affiliation_size(); ++i) {
+    const affiliation_pb::Affiliation& equivalence_class(
+        response.affiliation(i));
+
+    AffiliatedFacets affiliated_uris;
+    for (int j = 0; j < equivalence_class.facet_size(); ++j) {
+      const std::string uri_spec(equivalence_class.facet(j));

[Ryan Sleevi, 2014/12/12 23:02:19]

Should this be "const std::string&" ?

I didn't dig into the protobuf generator, but given line 91, I suspect it does
return a const-ref? If not, no worries.

[engedy, 2014/12/15 13:54:51]

Argh, of course. Done.

+      FacetURI uri = FacetURI::FromPotentiallyInvalidSpec(uri_spec);
+      // Ignore potential future kinds of facet URIs (e.g. for new platforms).
+      if (!uri.is_valid())
+        continue;
+      affiliated_uris.push_back(uri);
+    }
+
+    // Be lenient and ignore empty (after filtering) equivalence classes.
+    if (affiliated_uris.empty())
+      continue;
+
+    // Ignore equivalence classes that are duplicates of earlier ones. However,
+    // fail in the case of a partial overlap, which violates the invariant that
+    // affiliations must form an equivalence relation.
+    for (const FacetURI& uri : affiliated_uris) {
+      if (!facet_uri_to_class_index.count(uri))
+        facet_uri_to_class_index[uri] = result->size();
+      if (facet_uri_to_class_index[uri] !=
+          facet_uri_to_class_index[affiliated_uris[0]]) {
+        return false;
+      }
+    }
+
+    // Filter out duplicate equivalence classes in the response.
+    if (facet_uri_to_class_index[affiliated_uris[0]] == result->size())
+      result->push_back(affiliated_uris);
+  }
+
+  // The API contract of this class is to return an equivalence class for all
+  // requested facets; however, the server will not return anything for facets
+  // that are not affiliated with any other facet. Synthesize an equivalence
+  // class (of size one) for each of the missing facets.
+  for (const FacetURI& uri : requested_facet_uris_) {
+    if (!facet_uri_to_class_index.count(uri))
+      result->push_back(AffiliatedFacets(1, uri));
+  }
+
+  return true;
+}
+
+void AffiliationFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK_EQ(source, fetcher_.get());
+
+  scoped_ptr<AffiliationFetcherDelegate::Result> result(
+      new AffiliationFetcherDelegate::Result);
+  if (fetcher_->GetStatus().status() == net::URLRequestStatus::SUCCESS &&
+      fetcher_->GetResponseCode() == net::HTTP_OK) {
+    if (ParseResponse(result.get()))
+      delegate_->OnFetchSucceeded(result.Pass());
+    else
+      delegate_->OnMalformedResponse();
+  } else {
+    delegate_->OnFetchFailed();
+  }
+}
+
+}  // namespace password_manager