URI parser: fix percent-encoding and add ToString() method (#28485)

* fix URI percent-encoding character set

* clean up and fix edge cases

* add ToString() method to URI parser with appropriate percent-encoding logic

* clang-format

* fix ordering for URI::QueryParam

* fix decoding edge cases in parsing

* generate upper-case hex digits, as per the RFC

* clang-format

* reuse offset variable

src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc

@@ -91,9 +91,9 @@ bool ParseUri(const URI& uri,
   // Construct addresses.
   bool errors_found = false;
   for (absl::string_view ith_path : absl::StrSplit(uri.path(), ',')) {
-    URI ith_uri(uri.scheme(), "", std::string(ith_path), {}, "");
+    auto ith_uri = URI::Create(uri.scheme(), "", std::string(ith_path), {}, "");
     grpc_resolved_address addr;
-    if (!parse(ith_uri, &addr)) {
+    if (!ith_uri.ok() || !parse(*ith_uri, &addr)) {
       errors_found = true;
       break;
     }

src/core/ext/filters/client_channel/resolver/xds/xds_resolver.cc

@@ -81,11 +81,10 @@ class XdsResolver : public Resolver {
         uri_(std::move(args.uri)),
         data_plane_authority_(GetDataPlaneAuthority(*args.args, uri_)) {
     if (GRPC_TRACE_FLAG_ENABLED(grpc_xds_resolver_trace)) {
-      gpr_log(GPR_INFO,
-              "[xds_resolver %p] created for URI scheme %s path %s authority "
-              "%s data plane authority %s",
-              this, args.uri.scheme().c_str(), args.uri.path().c_str(),
-              args.uri.authority().c_str(), data_plane_authority_.c_str());
+      gpr_log(
+          GPR_INFO,
+          "[xds_resolver %p] created for URI %s; data plane authority is %s",
+          this, uri_.ToString().c_str(), data_plane_authority_.c_str());
     }
   }
 
@@ -738,7 +737,8 @@ void XdsResolver::StartLocked() {
                                    "/envoy.config.listener.v3.Listener/%s");
     }
     lds_resource_name_ = absl::StrReplaceAll(
-        name_template, {{"%s", URI::PercentEncode(resource_name_fragment)}});
+        name_template,
+        {{"%s", URI::PercentEncodePath(resource_name_fragment)}});
   } else {
     // target_uri.authority not set
     absl::string_view name_template =
@@ -748,7 +748,7 @@ void XdsResolver::StartLocked() {
       name_template = "%s";
     }
     if (absl::StartsWith(name_template, "xdstp:")) {
-      resource_name_fragment = URI::PercentEncode(resource_name_fragment);
+      resource_name_fragment = URI::PercentEncodePath(resource_name_fragment);
     }
     lds_resource_name_ =
         absl::StrReplaceAll(name_template, {{"%s", resource_name_fragment}});

src/core/lib/uri/uri_parser.cc

@@ -1,20 +1,18 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
+//
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 
 #include <grpc/support/port_platform.h>
 
@@ -37,48 +35,110 @@ namespace grpc_core {
 
 namespace {
 
-bool ShouldEscape(unsigned char c) {
-  // Unreserved characters RFC 3986 section 2.3 Unreserved Characters.
-  if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
-      (c >= '0' && c <= '9')) {
-    return false;
+// Returns true for any sub-delim character, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-2.2
+bool IsSubDelimChar(char c) {
+  switch (c) {
+    case '!':
+    case '$':
+    case '&':
+    case '\'':
+    case '(':
+    case ')':
+    case '*':
+    case '+':
+    case ',':
+    case ';':
+    case '=':
+      return true;
   }
+  return false;
+}
+
+// Returns true for any unreserved character, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-2.3
+bool IsUnreservedChar(char c) {
+  if (absl::ascii_isalnum(c)) return true;
   switch (c) {
     case '-':
-    case '_':
     case '.':
+    case '_':
     case '~':
-    case '/':
+      return true;
+  }
+  return false;
+}
+
+// Returns true for any character in scheme, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-3.1
+bool IsSchemeChar(char c) {
+  if (absl::ascii_isalnum(c)) return true;
+  switch (c) {
+    case '+':
+    case '-':
+    case '.':
+      return true;
+  }
+  return false;
+}
+
+// Returns true for any character in authority, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-3.2
+bool IsAuthorityChar(char c) {
+  if (IsUnreservedChar(c)) return true;
+  if (IsSubDelimChar(c)) return true;
+  switch (c) {
     case ':':
-      return false;
+    case '[':
+    case ']':
+    case '@':
+      return true;
   }
-  return true;
+  return false;
 }
 
-// Checks if this string is made up of pchars, '/', '?', and '%' exclusively.
+// Returns true for any character in pchar, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-3.3
+bool IsPChar(char c) {
+  if (IsUnreservedChar(c)) return true;
+  if (IsSubDelimChar(c)) return true;
+  switch (c) {
+    case ':':
+    case '@':
+      return true;
+  }
+  return false;
+}
+
+// Returns true for any character allowed in a URI path, as defined in:
+// https://datatracker.ietf.org/doc/html/rfc3986#section-3.3
+bool IsPathChar(char c) { return IsPChar(c) || c == '/'; }
+
+// Returns true for any character allowed in a URI query or fragment,
+// as defined in:
 // See https://tools.ietf.org/html/rfc3986#section-3.4
-bool IsPCharString(absl::string_view str) {
-  return (str.find_first_not_of("ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-                                "abcdefghijklmnopqrstuvwxyz"
-                                "0123456789"
-                                "?/:@\\-._~!$&'()*+,;=%") ==
-          absl::string_view::npos);
+bool IsQueryOrFragmentChar(char c) {
+  return IsPChar(c) || c == '/' || c == '?';
 }
 
-absl::Status MakeInvalidURIStatus(absl::string_view part_name,
-                                  absl::string_view uri,
-                                  absl::string_view extra) {
-  return absl::InvalidArgumentError(absl::StrFormat(
-      "Could not parse '%s' from uri '%s'. %s", part_name, uri, extra));
+// Same as IsQueryOrFragmentChar(), but excludes '&' and '='.
+bool IsQueryKeyOrValueChar(char c) {
+  return c != '&' && c != '=' && IsQueryOrFragmentChar(c);
 }
-}  // namespace
 
-std::string URI::PercentEncode(absl::string_view str) {
+// Returns a copy of str, percent-encoding any character for which
+// is_allowed_char() returns false.
+std::string PercentEncode(absl::string_view str,
+                          std::function<bool(char)> is_allowed_char) {
   std::string out;
-  for (const char c : str) {
-    if (ShouldEscape(c)) {
+  for (char c : str) {
+    if (!is_allowed_char(c)) {
       std::string hex = absl::BytesToHexString(absl::string_view(&c, 1));
       GPR_ASSERT(hex.size() == 2);
+      // BytesToHexString() returns lower case, but
+      // https://datatracker.ietf.org/doc/html/rfc3986#section-6.2.2.1 says
+      // to prefer upper-case.
+      absl::AsciiStrToUpper(&hex);
       out.push_back('%');
       out.append(hex);
     } else {
@@ -88,6 +148,28 @@ std::string URI::PercentEncode(absl::string_view str) {
   return out;
 }
 
+// Checks if this string is made up of query/fragment chars and '%' exclusively.
+// See https://tools.ietf.org/html/rfc3986#section-3.4
+bool IsQueryOrFragmentString(absl::string_view str) {
+  for (char c : str) {
+    if (!IsQueryOrFragmentChar(c) && c != '%') return false;
+  }
+  return true;
+}
+
+absl::Status MakeInvalidURIStatus(absl::string_view part_name,
+                                  absl::string_view uri,
+                                  absl::string_view extra) {
+  return absl::InvalidArgumentError(absl::StrFormat(
+      "Could not parse '%s' from uri '%s'. %s", part_name, uri, extra));
+}
+
+}  // namespace
+
+std::string URI::PercentEncodePath(absl::string_view str) {
+  return PercentEncode(str, IsPathChar);
+}
+
 // Similar to `grpc_permissive_percent_decode_slice`, this %-decodes all valid
 // triplets, and passes through the rest verbatim.
 std::string URI::PercentDecode(absl::string_view str) {
@@ -99,18 +181,14 @@ std::string URI::PercentDecode(absl::string_view str) {
   out.reserve(str.size());
   for (size_t i = 0; i < str.length(); i++) {
     unescaped = "";
-    if (str[i] != '%') {
-      out += str[i];
-      continue;
-    }
-    if (i + 3 >= str.length() ||
-        !absl::CUnescape(absl::StrCat("\\x", str.substr(i + 1, 2)),
-                         &unescaped) ||
-        unescaped.length() > 1) {
-      out += str[i];
-    } else {
+    if (str[i] == '%' && i + 3 <= str.length() &&
+        absl::CUnescape(absl::StrCat("\\x", str.substr(i + 1, 2)),
+                        &unescaped) &&
+        unescaped.length() == 1) {
       out += unescaped[0];
       i += 2;
+    } else {
+      out += str[i];
     }
   }
   return out;
@@ -120,11 +198,11 @@ absl::StatusOr<URI> URI::Parse(absl::string_view uri_text) {
   absl::StatusOr<std::string> decoded;
   absl::string_view remaining = uri_text;
   // parse scheme
-  size_t idx = remaining.find(':');
-  if (idx == remaining.npos || idx == 0) {
+  size_t offset = remaining.find(':');
+  if (offset == remaining.npos || offset == 0) {
     return MakeInvalidURIStatus("scheme", uri_text, "Scheme not found.");
   }
-  std::string scheme(remaining.substr(0, idx));
+  std::string scheme(remaining.substr(0, offset));
   if (scheme.find_first_not_of("ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                "abcdefghijklmnopqrstuvwxyz"
                                "0123456789+-.") != std::string::npos) {
@@ -136,30 +214,38 @@ absl::StatusOr<URI> URI::Parse(absl::string_view uri_text) {
         "scheme", uri_text,
         "Scheme must begin with an alpha character [A-Za-z].");
   }
-  remaining.remove_prefix(scheme.length() + 1);
+  remaining.remove_prefix(offset + 1);
   // parse authority
   std::string authority;
-  if (absl::StartsWith(remaining, "//")) {
-    remaining.remove_prefix(2);
-    authority =
-        PercentDecode(remaining.substr(0, remaining.find_first_of("/?#")));
-    remaining.remove_prefix(authority.length());
+  if (absl::ConsumePrefix(&remaining, "//")) {
+    offset = remaining.find_first_of("/?#");
+    authority = PercentDecode(remaining.substr(0, offset));
+    if (offset == remaining.npos) {
+      remaining = "";
+    } else {
+      remaining.remove_prefix(offset);
+    }
   }
   // parse path
   std::string path;
   if (!remaining.empty()) {
-    path = PercentDecode(remaining.substr(0, remaining.find_first_of("?#")));
-    remaining.remove_prefix(path.length());
+    offset = remaining.find_first_of("?#");
+    path = PercentDecode(remaining.substr(0, offset));
+    if (offset == remaining.npos) {
+      remaining = "";
+    } else {
+      remaining.remove_prefix(offset);
+    }
   }
   // parse query
   std::vector<QueryParam> query_param_pairs;
-  if (!remaining.empty() && remaining[0] == '?') {
-    remaining.remove_prefix(1);
-    absl::string_view tmp_query = remaining.substr(0, remaining.find('#'));
+  if (absl::ConsumePrefix(&remaining, "?")) {
+    offset = remaining.find('#');
+    absl::string_view tmp_query = remaining.substr(0, offset);
     if (tmp_query.empty()) {
       return MakeInvalidURIStatus("query", uri_text, "Invalid query string.");
     }
-    if (!IsPCharString(tmp_query)) {
+    if (!IsQueryOrFragmentString(tmp_query)) {
       return MakeInvalidURIStatus("query string", uri_text,
                                   "Query string contains invalid characters.");
     }
@@ -170,12 +256,15 @@ absl::StatusOr<URI> URI::Parse(absl::string_view uri_text) {
       query_param_pairs.push_back({PercentDecode(possible_kv.first),
                                    PercentDecode(possible_kv.second)});
     }
-    remaining.remove_prefix(tmp_query.length());
+    if (offset == remaining.npos) {
+      remaining = "";
+    } else {
+      remaining.remove_prefix(offset);
+    }
   }
   std::string fragment;
-  if (!remaining.empty() && remaining[0] == '#') {
-    remaining.remove_prefix(1);
-    if (!IsPCharString(remaining)) {
+  if (absl::ConsumePrefix(&remaining, "#")) {
+    if (!IsQueryOrFragmentString(remaining)) {
       return MakeInvalidURIStatus("fragment", uri_text,
                                   "Fragment contains invalid characters.");
     }
@@ -185,6 +274,18 @@ absl::StatusOr<URI> URI::Parse(absl::string_view uri_text) {
              std::move(query_param_pairs), std::move(fragment));
 }
 
+absl::StatusOr<URI> URI::Create(std::string scheme, std::string authority,
+                                std::string path,
+                                std::vector<QueryParam> query_parameter_pairs,
+                                std::string fragment) {
+  if (!authority.empty() && !path.empty() && path[0] != '/') {
+    return absl::InvalidArgumentError(
+        "if authority is present, path must start with a '/'");
+  }
+  return URI(std::move(scheme), std::move(authority), std::move(path),
+             std::move(query_parameter_pairs), std::move(fragment));
+}
+
 URI::URI(std::string scheme, std::string authority, std::string path,
          std::vector<QueryParam> query_parameter_pairs, std::string fragment)
     : scheme_(std::move(scheme)),
@@ -222,4 +323,39 @@ URI& URI::operator=(const URI& other) {
   }
   return *this;
 }
+
+namespace {
+
+// A pair formatter for use with absl::StrJoin() for formatting query params.
+struct QueryParameterFormatter {
+  void operator()(std::string* out, const URI::QueryParam& query_param) const {
+    out->append(
+        absl::StrCat(PercentEncode(query_param.key, IsQueryKeyOrValueChar), "=",
+                     PercentEncode(query_param.value, IsQueryKeyOrValueChar)));
+  }
+};
+
+}  // namespace
+
+std::string URI::ToString() const {
+  std::vector<std::string> parts = {PercentEncode(scheme_, IsSchemeChar), ":"};
+  if (!authority_.empty()) {
+    parts.emplace_back("//");
+    parts.emplace_back(PercentEncode(authority_, IsAuthorityChar));
+  }
+  if (!path_.empty()) {
+    parts.emplace_back(PercentEncode(path_, IsPathChar));
+  }
+  if (!query_parameter_pairs_.empty()) {
+    parts.push_back("?");
+    parts.push_back(
+        absl::StrJoin(query_parameter_pairs_, "&", QueryParameterFormatter()));
+  }
+  if (!fragment_.empty()) {
+    parts.push_back("#");
+    parts.push_back(PercentEncode(fragment_, IsQueryOrFragmentChar));
+  }
+  return absl::StrJoin(parts, "");
+}
+
 }  // namespace grpc_core

src/core/lib/uri/uri_parser.h

@@ -1,20 +1,18 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
+//
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 
 #ifndef GRPC_CORE_LIB_URI_URI_PARSER_H
 #define GRPC_CORE_LIB_URI_URI_PARSER_H
@@ -40,15 +38,23 @@ class URI {
     bool operator==(const QueryParam& other) const {
       return key == other.key && value == other.value;
     }
+    bool operator<(const QueryParam& other) const {
+      int c = key.compare(other.key);
+      if (c != 0) return c < 0;
+      return value < other.value;
+    }
   };
 
-  // Creates an instance of GrpcURI by parsing an rfc3986 URI string. Returns
-  // an IllegalArgumentError on failure.
+  // Creates a URI by parsing an rfc3986 URI string. Returns an
+  // InvalidArgumentError on failure.
   static absl::StatusOr<URI> Parse(absl::string_view uri_text);
-  // Explicit construction by individual URI components
-  URI(std::string scheme, std::string authority, std::string path,
+  // Creates a URI from components. Returns an InvalidArgumentError on failure.
+  static absl::StatusOr<URI> Create(
+      std::string scheme, std::string authority, std::string path,
       std::vector<QueryParam> query_parameter_pairs, std::string fragment);
+
   URI() = default;
+
   // Copy construction and assignment
   URI(const URI& other);
   URI& operator=(const URI& other);
@@ -56,7 +62,8 @@ class URI {
   URI(URI&&) = default;
   URI& operator=(URI&&) = default;
 
-  static std::string PercentEncode(absl::string_view str);
+  static std::string PercentEncodePath(absl::string_view str);
+
   static std::string PercentDecode(absl::string_view str);
 
   const std::string& scheme() const { return scheme_; }
@@ -77,7 +84,12 @@ class URI {
   }
   const std::string& fragment() const { return fragment_; }
 
+  std::string ToString() const;
+
  private:
+  URI(std::string scheme, std::string authority, std::string path,
+      std::vector<QueryParam> query_parameter_pairs, std::string fragment);
+
   std::string scheme_;
   std::string authority_;
   std::string path_;
@@ -87,4 +99,4 @@ class URI {
 };
 }  // namespace grpc_core
 
-#endif /* GRPC_CORE_LIB_URI_URI_PARSER_H */
+#endif  // GRPC_CORE_LIB_URI_URI_PARSER_H

test/core/uri/uri_parser_test.cc

@@ -1,20 +1,18 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
+//
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 
 #include "src/core/lib/uri/uri_parser.h"
 
@@ -34,28 +32,33 @@ using ::testing::Contains;
 using ::testing::ElementsAre;
 using ::testing::Pair;
 
-static void TestSucceeds(
-    absl::string_view uri_text, absl::string_view scheme,
-    absl::string_view authority, absl::string_view path,
-    const std::map<absl::string_view, absl::string_view>& query_param_map,
-    const std::vector<grpc_core::URI::QueryParam>& query_param_pairs,
-    absl::string_view fragment) {
-  absl::StatusOr<grpc_core::URI> uri = grpc_core::URI::Parse(uri_text);
-  ASSERT_TRUE(uri.ok());
-  EXPECT_EQ(scheme, uri->scheme());
-  EXPECT_EQ(authority, uri->authority());
-  EXPECT_EQ(path, uri->path());
-  EXPECT_THAT(uri->query_parameter_map(), ContainerEq(query_param_map));
-  EXPECT_THAT(uri->query_parameter_pairs(), ContainerEq(query_param_pairs));
-  EXPECT_EQ(fragment, uri->fragment());
-}
-
-static void TestFails(absl::string_view uri_text) {
-  absl::StatusOr<grpc_core::URI> uri = grpc_core::URI::Parse(uri_text);
-  ASSERT_FALSE(uri.ok());
-}
+namespace grpc_core {
+
+class URIParserTest : public testing::Test {
+ protected:
+  static void TestSucceeds(
+      absl::string_view uri_text, absl::string_view scheme,
+      absl::string_view authority, absl::string_view path,
+      const std::map<absl::string_view, absl::string_view>& query_param_map,
+      const std::vector<URI::QueryParam>& query_param_pairs,
+      absl::string_view fragment) {
+    absl::StatusOr<URI> uri = URI::Parse(uri_text);
+    ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+    EXPECT_EQ(scheme, uri->scheme());
+    EXPECT_EQ(authority, uri->authority());
+    EXPECT_EQ(path, uri->path());
+    EXPECT_THAT(uri->query_parameter_map(), ContainerEq(query_param_map));
+    EXPECT_THAT(uri->query_parameter_pairs(), ContainerEq(query_param_pairs));
+    EXPECT_EQ(fragment, uri->fragment());
+  }
 
-TEST(URIParserTest, BasicExamplesAreParsedCorrectly) {
+  static void TestFails(absl::string_view uri_text) {
+    absl::StatusOr<URI> uri = URI::Parse(uri_text);
+    ASSERT_FALSE(uri.ok());
+  }
+};
+
+TEST_F(URIParserTest, BasicExamplesAreParsedCorrectly) {
   TestSucceeds("http://www.google.com", "http", "www.google.com", "", {}, {},
                "");
   TestSucceeds("dns:///foo", "dns", "", "/foo", {}, {}, "");
@@ -75,7 +78,7 @@ TEST(URIParserTest, BasicExamplesAreParsedCorrectly) {
                "buckle/my/shoe");
 }
 
-TEST(URIParserTest, UncommonValidExamplesAreParsedCorrectly) {
+TEST_F(URIParserTest, UncommonValidExamplesAreParsedCorrectly) {
   TestSucceeds("scheme:path//is/ok", "scheme", "", "path//is/ok", {}, {}, "");
   TestSucceeds("http:?legit", "http", "", "", {{"legit", ""}}, {{"legit", ""}},
                "");
@@ -84,15 +87,18 @@ TEST(URIParserTest, UncommonValidExamplesAreParsedCorrectly) {
   TestSucceeds("http:?legit#twice", "http", "", "", {{"legit", ""}},
                {{"legit", ""}}, "twice");
   TestSucceeds("fake:///", "fake", "", "/", {}, {}, "");
+  TestSucceeds("http://local%25host:8080/whatz%25it?1%25=2%25#fragment", "http",
+               "local%host:8080", "/whatz%it", {{"1%", "2%"}}, {{"1%", "2%"}},
+               "fragment");
 }
 
-TEST(URIParserTest, VariousKeyValueAndNonKVQueryParamsAreParsedCorrectly) {
+TEST_F(URIParserTest, VariousKeyValueAndNonKVQueryParamsAreParsedCorrectly) {
   TestSucceeds("http://foo/path?a&b=B&c=&#frag", "http", "foo", "/path",
                {{"c", ""}, {"a", ""}, {"b", "B"}},
                {{"a", ""}, {"b", "B"}, {"c", ""}}, "frag");
 }
 
-TEST(URIParserTest, ParserTreatsFirstEqualSignAsKVDelimiterInQueryString) {
+TEST_F(URIParserTest, ParserTreatsFirstEqualSignAsKVDelimiterInQueryString) {
   TestSucceeds(
       "http://localhost:8080/?too=many=equals&are=present=here#fragged", "http",
       "localhost:8080", "/", {{"are", "present=here"}, {"too", "many=equals"}},
@@ -102,52 +108,48 @@ TEST(URIParserTest, ParserTreatsFirstEqualSignAsKVDelimiterInQueryString) {
                {{"foo", "bar=baz"}, {"foobar", "=="}}, "");
 }
 
-TEST(URIParserTest,
-     RepeatedQueryParamsAreSupportedInOrderedPairsButDeduplicatedInTheMap) {
-  absl::StatusOr<grpc_core::URI> uri =
-      grpc_core::URI::Parse("http://foo/path?a=2&a=1&a=3");
-  ASSERT_TRUE(uri.ok());
+TEST_F(URIParserTest,
+       RepeatedQueryParamsAreSupportedInOrderedPairsButDeduplicatedInTheMap) {
+  absl::StatusOr<URI> uri = URI::Parse("http://foo/path?a=2&a=1&a=3");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
   // The map stores the last found value.
   ASSERT_THAT(uri->query_parameter_map(), ElementsAre(Pair("a", "3")));
   // Order matters for query parameter pairs
   ASSERT_THAT(uri->query_parameter_pairs(),
-              ElementsAre(grpc_core::URI::QueryParam{"a", "2"},
-                          grpc_core::URI::QueryParam{"a", "1"},
-                          grpc_core::URI::QueryParam{"a", "3"}));
+              ElementsAre(URI::QueryParam{"a", "2"}, URI::QueryParam{"a", "1"},
+                          URI::QueryParam{"a", "3"}));
 }
 
-TEST(URIParserTest, QueryParamMapRemainsValiditAfterMovingTheURI) {
-  grpc_core::URI uri_copy;
+TEST_F(URIParserTest, QueryParamMapRemainsValiditAfterMovingTheURI) {
+  URI uri_copy;
   {
-    absl::StatusOr<grpc_core::URI> uri =
-        grpc_core::URI::Parse("http://foo/path?a=2&b=1&c=3");
-    ASSERT_TRUE(uri.ok());
+    absl::StatusOr<URI> uri = URI::Parse("http://foo/path?a=2&b=1&c=3");
+    ASSERT_TRUE(uri.ok()) << uri.status().ToString();
     uri_copy = std::move(*uri);
   }
   // ASSERT_EQ(uri_copy.query_parameter_map().find("a")->second, "2");
   ASSERT_THAT(uri_copy.query_parameter_map(), Contains(Pair("a", "2")));
 }
 
-TEST(URIParserTest, QueryParamMapRemainsValidAfterCopyingTheURI) {
+TEST_F(URIParserTest, QueryParamMapRemainsValidAfterCopyingTheURI) {
   // Since the query parameter map points to objects stored in the param pair
   // vector, this test checks that the param map pointers remain valid after
   // a copy. Ideally {a,m}san will catch this if there's a problem.
   // testing copy operator=:
-  grpc_core::URI uri_copy;
+  URI uri_copy;
   {
-    absl::StatusOr<grpc_core::URI> del_uri =
-        grpc_core::URI::Parse("http://foo/path?a=2&b=1&c=3");
-    ASSERT_TRUE(del_uri.ok());
+    absl::StatusOr<URI> del_uri = URI::Parse("http://foo/path?a=2&b=1&c=3");
+    ASSERT_TRUE(del_uri.ok()) << del_uri.status().ToString();
     uri_copy = *del_uri;
   }
   ASSERT_THAT(uri_copy.query_parameter_map(), Contains(Pair("a", "2")));
-  grpc_core::URI* del_uri2 = new grpc_core::URI(uri_copy);
-  grpc_core::URI uri_copy2(*del_uri2);
+  URI* del_uri2 = new URI(uri_copy);
+  URI uri_copy2(*del_uri2);
   delete del_uri2;
   ASSERT_THAT(uri_copy2.query_parameter_map(), Contains(Pair("a", "2")));
 }
 
-TEST(URIParserTest, AWSExternalAccountRegressionTest) {
+TEST_F(URIParserTest, AWSExternalAccountRegressionTest) {
   TestSucceeds(
       "https://foo.com:5555/v1/"
       "token-exchange?subject_token=eyJhbGciO&subject_token_type=urn:ietf:"
@@ -160,20 +162,21 @@ TEST(URIParserTest, AWSExternalAccountRegressionTest) {
       "");
 }
 
-TEST(URIParserTest, NonKeyValueQueryStringsWork) {
+TEST_F(URIParserTest, NonKeyValueQueryStringsWork) {
   TestSucceeds("http://www.google.com?yay-i'm-using-queries", "http",
                "www.google.com", "", {{"yay-i'm-using-queries", ""}},
                {{"yay-i'm-using-queries", ""}}, "");
 }
 
-TEST(URIParserTest, IPV6StringsAreParsedCorrectly) {
+TEST_F(URIParserTest, IPV6StringsAreParsedCorrectly) {
   TestSucceeds("ipv6:[2001:db8::1%252]:12345", "ipv6", "",
                "[2001:db8::1%2]:12345", {}, {}, "");
   TestSucceeds("ipv6:[fe80::90%eth1.sky1]:6010", "ipv6", "",
                "[fe80::90%eth1.sky1]:6010", {}, {}, "");
 }
 
-TEST(URIParserTest, PreviouslyReservedCharactersInUnrelatedURIPartsAreIgnored) {
+TEST_F(URIParserTest,
+       PreviouslyReservedCharactersInUnrelatedURIPartsAreIgnored) {
   // The '?' and '/' characters are not reserved delimiter characters in the
   // fragment. See http://go/rfc/3986#section-3.5
   TestSucceeds("http://foo?bar#lol?", "http", "foo", "", {{"bar", ""}},
@@ -182,30 +185,30 @@ TEST(URIParserTest, PreviouslyReservedCharactersInUnrelatedURIPartsAreIgnored) {
                {{"bar", ""}}, "lol?/");
 }
 
-TEST(URIParserTest, EncodedCharactersInQueryStringAreParsedCorrectly) {
+TEST_F(URIParserTest, EncodedCharactersInQueryStringAreParsedCorrectly) {
   TestSucceeds("https://www.google.com/?a=1%26b%3D2&c=3", "https",
                "www.google.com", "/", {{"c", "3"}, {"a", "1&b=2"}},
                {{"a", "1&b=2"}, {"c", "3"}}, "");
 }
 
-TEST(URIParserTest, InvalidPercentEncodingsArePassedThrough) {
+TEST_F(URIParserTest, InvalidPercentEncodingsArePassedThrough) {
   TestSucceeds("x:y?%xx", "x", "", "y", {{"%xx", ""}}, {{"%xx", ""}}, "");
   TestSucceeds("http:?dangling-pct-%0", "http", "", "",
                {{"dangling-pct-%0", ""}}, {{"dangling-pct-%0", ""}}, "");
 }
 
-TEST(URIParserTest, NullCharactersInURIStringAreSupported) {
+TEST_F(URIParserTest, NullCharactersInURIStringAreSupported) {
   // Artificial examples to show that embedded nulls are supported.
   TestSucceeds(std::string("unix-abstract:\0should-be-ok", 27), "unix-abstract",
                "", std::string("\0should-be-ok", 13), {}, {}, "");
 }
 
-TEST(URIParserTest, EncodedNullsInURIStringAreSupported) {
+TEST_F(URIParserTest, EncodedNullsInURIStringAreSupported) {
   TestSucceeds("unix-abstract:%00x", "unix-abstract", "", std::string("\0x", 2),
                {}, {}, "");
 }
 
-TEST(URIParserTest, InvalidURIsResultInFailureStatuses) {
+TEST_F(URIParserTest, InvalidURIsResultInFailureStatuses) {
   TestFails("xyz");
   TestFails("http://foo?[bar]");
   TestFails("http://foo?x[bar]");
@@ -215,13 +218,253 @@ TEST(URIParserTest, InvalidURIsResultInFailureStatuses) {
   TestFails("0invalid_scheme:must_start/with?alpha");
 }
 
-TEST(URIParserTest, PercentEncode) {
-  // Ensure "?" and "=" are percent encoded; and ":" is escaped.
-  std::string input = "127.0.0.1:22222?psm_project_id=1234";
-  EXPECT_EQ("127.0.0.1:22222%3fpsm_project_id%3d1234",
-            grpc_core::URI::PercentEncode(input));
+TEST(URITest, PercentEncodePath) {
+  EXPECT_EQ(URI::PercentEncodePath(
+                // These chars are allowed.
+                "abcdefghijklmnopqrstuvwxyz"
+                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                "0123456789"
+                "/:@-._~!$&'()*+,;="
+                // These chars will be escaped.
+                "\\?%#[]^"),
+            "abcdefghijklmnopqrstuvwxyz"
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+            "0123456789"
+            "/:@-._~!$&'()*+,;="
+            "%5C%3F%25%23%5B%5D%5E");
+}
+
+TEST(URITest, Basic) {
+  auto uri =
+      URI::Create("http", "server.example.com", "/path/to/file.html", {}, "");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "server.example.com");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(uri->query_parameter_pairs(), testing::ElementsAre());
+  EXPECT_THAT(uri->query_parameter_map(), testing::ElementsAre());
+  EXPECT_EQ(uri->fragment(), "");
+  EXPECT_EQ("http://server.example.com/path/to/file.html", uri->ToString());
+}
+
+TEST(URITest, NoAuthority) {
+  auto uri = URI::Create("http", "", "/path/to/file.html", {}, "");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(uri->query_parameter_pairs(), testing::ElementsAre());
+  EXPECT_THAT(uri->query_parameter_map(), testing::ElementsAre());
+  EXPECT_EQ(uri->fragment(), "");
+  EXPECT_EQ("http:/path/to/file.html", uri->ToString());
+}
+
+TEST(URITest, NoAuthorityRelativePath) {
+  auto uri = URI::Create("http", "", "path/to/file.html", {}, "");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "");
+  EXPECT_EQ(uri->path(), "path/to/file.html");
+  EXPECT_THAT(uri->query_parameter_pairs(), testing::ElementsAre());
+  EXPECT_THAT(uri->query_parameter_map(), testing::ElementsAre());
+  EXPECT_EQ(uri->fragment(), "");
+  EXPECT_EQ("http:path/to/file.html", uri->ToString());
+}
+
+TEST(URITest, AuthorityRelativePath) {
+  auto uri =
+      URI::Create("http", "server.example.com", "path/to/file.html", {}, "");
+  ASSERT_FALSE(uri.ok());
+  EXPECT_EQ(uri.status().code(), absl::StatusCode::kInvalidArgument);
+  EXPECT_EQ(uri.status().message(),
+            "if authority is present, path must start with a '/'");
+}
+
+TEST(URITest, QueryParams) {
+  auto uri = URI::Create("http", "server.example.com", "/path/to/file.html",
+                         {{"key", "value"}, {"key2", "value2"}}, "");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "server.example.com");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(
+      uri->query_parameter_pairs(),
+      testing::ElementsAre(
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key"),
+                         testing::Field(&URI::QueryParam::value, "value")),
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key2"),
+                         testing::Field(&URI::QueryParam::value, "value2"))));
+  EXPECT_THAT(uri->query_parameter_map(),
+              testing::ElementsAre(testing::Pair("key", "value"),
+                                   testing::Pair("key2", "value2")));
+  EXPECT_EQ(uri->fragment(), "");
+  EXPECT_EQ("http://server.example.com/path/to/file.html?key=value&key2=value2",
+            uri->ToString());
 }
 
+TEST(URITest, DuplicateQueryParams) {
+  auto uri = URI::Create(
+      "http", "server.example.com", "/path/to/file.html",
+      {{"key", "value"}, {"key2", "value2"}, {"key", "other_value"}}, "");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "server.example.com");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(
+      uri->query_parameter_pairs(),
+      testing::ElementsAre(
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key"),
+                         testing::Field(&URI::QueryParam::value, "value")),
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key2"),
+                         testing::Field(&URI::QueryParam::value, "value2")),
+          testing::AllOf(
+              testing::Field(&URI::QueryParam::key, "key"),
+              testing::Field(&URI::QueryParam::value, "other_value"))));
+  EXPECT_THAT(uri->query_parameter_map(),
+              testing::ElementsAre(testing::Pair("key", "other_value"),
+                                   testing::Pair("key2", "value2")));
+  EXPECT_EQ(uri->fragment(), "");
+  EXPECT_EQ(
+      "http://server.example.com/path/to/file.html"
+      "?key=value&key2=value2&key=other_value",
+      uri->ToString());
+}
+
+TEST(URITest, Fragment) {
+  auto uri = URI::Create("http", "server.example.com", "/path/to/file.html", {},
+                         "fragment");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "server.example.com");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(uri->query_parameter_pairs(), testing::ElementsAre());
+  EXPECT_THAT(uri->query_parameter_map(), testing::ElementsAre());
+  EXPECT_EQ(uri->fragment(), "fragment");
+  EXPECT_EQ("http://server.example.com/path/to/file.html#fragment",
+            uri->ToString());
+}
+
+TEST(URITest, QueryParamsAndFragment) {
+  auto uri = URI::Create("http", "server.example.com", "/path/to/file.html",
+                         {{"key", "value"}, {"key2", "value2"}}, "fragment");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(), "http");
+  EXPECT_EQ(uri->authority(), "server.example.com");
+  EXPECT_EQ(uri->path(), "/path/to/file.html");
+  EXPECT_THAT(
+      uri->query_parameter_pairs(),
+      testing::ElementsAre(
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key"),
+                         testing::Field(&URI::QueryParam::value, "value")),
+          testing::AllOf(testing::Field(&URI::QueryParam::key, "key2"),
+                         testing::Field(&URI::QueryParam::value, "value2"))));
+  EXPECT_THAT(uri->query_parameter_map(),
+              testing::ElementsAre(testing::Pair("key", "value"),
+                                   testing::Pair("key2", "value2")));
+  EXPECT_EQ(uri->fragment(), "fragment");
+  EXPECT_EQ(
+      "http://server.example.com/path/to/"
+      "file.html?key=value&key2=value2#fragment",
+      uri->ToString());
+}
+
+TEST(URITest, ToStringPercentEncoding) {
+  auto uri = URI::Create(
+      // Scheme allowed chars.
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+-."
+      // Scheme escaped chars.
+      "%:/?#[]@!$&'()*,;=",
+      // Authority allowed chars.
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-.+~!$&'()*+,;=:[]@"
+      // Authority escaped chars.
+      "%/?#",
+      // Path allowed chars.
+      "/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$&'()*+,;=:@"
+      // Path escaped chars.
+      "%?#[]",
+      {{// Query allowed chars.
+        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+        "-._~!$'()*+,;:@/?"
+        // Query escaped chars.
+        "%=&#[]",
+        // Query allowed chars.
+        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+        "-._~!$'()*+,;:@/?"
+        // Query escaped chars.
+        "%=&#[]"}},
+      // Fragment allowed chars.
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$'()*+,;:@/?=&"
+      // Fragment escaped chars.
+      "%#[]");
+  ASSERT_TRUE(uri.ok()) << uri.status().ToString();
+  EXPECT_EQ(uri->scheme(),
+            "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+-."
+            "%:/?#[]@!$&'()*,;=");
+  EXPECT_EQ(uri->authority(),
+            "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+            "-.+~!$&'()*+,;=:[]@"
+            "%/?#");
+  EXPECT_EQ(uri->path(),
+            "/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+            "-._~!$&'()*+,;=:@"
+            "%?#[]");
+  EXPECT_THAT(
+      uri->query_parameter_pairs(),
+      testing::ElementsAre(testing::AllOf(
+          testing::Field(
+              &URI::QueryParam::key,
+              "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+              "-._~!$'()*+,;:@/?"
+              "%=&#[]"),
+          testing::Field(
+              &URI::QueryParam::value,
+              "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+              "-._~!$'()*+,;:@/?"
+              "%=&#[]"))));
+  EXPECT_THAT(
+      uri->query_parameter_map(),
+      testing::ElementsAre(testing::Pair(
+          "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+          "-._~!$'()*+,;:@/?"
+          "%=&#[]",
+          "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+          "-._~!$'()*+,;:@/?"
+          "%=&#[]")));
+  EXPECT_EQ(uri->fragment(),
+            "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+            "-._~!$'()*+,;:@/?=&"
+            "%#[]");
+  EXPECT_EQ(
+      // Scheme
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+-."
+      "%25%3A%2F%3F%23%5B%5D%40%21%24%26%27%28%29%2A%2C%3B%3D"
+      // Authority
+      "://abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-.+~!$&'()*+,;=:[]@"
+      "%25%2F%3F%23"
+      // Path
+      "/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$&'()*+,;=:@"
+      "%25%3F%23%5B%5D"
+      // Query
+      "?abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$'()*+,;:@/?"
+      "%25%3D%26%23%5B%5D"
+      "=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$'()*+,;:@/?"
+      "%25%3D%26%23%5B%5D"
+      // Fragment
+      "#abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+      "-._~!$'()*+,;:@/?=&"
+      "%25%23%5B%5D",
+      uri->ToString());
+}
+
+}  // namespace grpc_core
+
 int main(int argc, char** argv) {
   testing::InitGoogleTest(&argc, argv);
   grpc::testing::TestEnvironment env(argc, argv);