Functions to create and manipulate x-callback-url URLs.

ios/chrome/common/x_callback_url.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 "ios/chrome/common/x_callback_url.h"
+
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "net/base/escape.h"
+#include "net/base/url_util.h"
+
+namespace {
+
+const char kXCallbackURLHost[] = "x-callback-url";
+const char kSuccessURLParameterName[] = "x-success";
+const char kErrorURLParameterName[] = "x-error";
+const char kCancelURLParameterName[] = "x-cancel";
+
+}  // namespace
+
+bool IsXCallbackURL(const GURL& url) {
+  return url.is_valid() && url.host_piece() == kXCallbackURLHost;
+}
+
+GURL CreateXCallbackURL(base::StringPiece scheme, base::StringPiece action) {
+  return CreateXCallbackURLWithParameters(scheme, action, GURL(), GURL(),
+                                          GURL(),
+                                          std::map<std::string, std::string>());
+}
+
+GURL CreateXCallbackURLWithParameters(
+    base::StringPiece scheme,
+    base::StringPiece action,
+    const GURL& success_url,
+    const GURL& error_url,
+    const GURL& cancel_url,
+    const std::map<std::string, std::string>& parameters) {
+  DCHECK(!scheme.empty());
+  GURL url(base::StringPrintf("%s://%s/%s", scheme.data(), kXCallbackURLHost,

[rohitrao (ping after 24h), 2016/11/07 17:58:17]

Is there any way to do this using GURL primitives, without using StringPrintf?

[sdefresne, 2016/11/08 07:15:28]

I've tried the following:

GURL url;
GURL::Replacements replacements;
replacements.SetSchemeStr(scheme);
replacements.SetHostStr(kXCallbackURLHost);
....
return url.ReplaceComponents(replacements);

But the returned GURL still return false to is_valid (as is using replacements
does not change the is_valid state of the default constructed GURL), so I don't
really know which GURL primitives can be used here.

+                              !action.empty() ? action.data() : ""));
+
+  if (success_url.is_valid()) {
+    url = net::AppendQueryParameter(url, kSuccessURLParameterName,

[rohitrao (ping after 24h), 2016/11/07 17:58:17]

Does AppendQueryParameter handle escaping?

[mef, 2016/11/07 18:42:10]

Yes,  Unsafe characters in the name and the value are escaped like %XX%XX. 

+                                    success_url.spec());
+  }
+
+  if (error_url.is_valid()) {
+    url = net::AppendQueryParameter(url, kErrorURLParameterName,
+                                    error_url.spec());
+  }
+
+  if (cancel_url.is_valid()) {
+    url = net::AppendQueryParameter(url, kCancelURLParameterName,
+                                    cancel_url.spec());
+  }
+
+  if (!parameters.empty()) {
+    for (const auto& pair : parameters) {
+      url = net::AppendQueryParameter(url, pair.first, pair.second);
+    }
+  }
+
+  return url;
+}
+
+std::map<std::string, std::string> ExtractQueryParametersFromXCallbackURL(
+    const GURL& x_callback_url) {
+  DCHECK(IsXCallbackURL(x_callback_url));
+  std::map<std::string, std::string> parameters;
+
+  net::QueryIterator query_iterator(x_callback_url);
+  while (!query_iterator.IsAtEnd()) {
+    parameters.insert(std::make_pair(query_iterator.GetKey(),
+                                     query_iterator.GetUnescapedValue()));
+    query_iterator.Advance();
+  }
+
+  return parameters;
+}