diff --git a/protos/google/api/annotations.proto b/protos/google/api/annotations.proto
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+++ b/protos/google/api/annotations.proto
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+// Copyright (c) 2015, Google Inc.
+//
+// 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.
+
+syntax = "proto3";
+
+package google.api;
+
+import "google/api/http.proto";
+import "google/protobuf/descriptor.proto";
+
+option go_package = "google.golang.org/genproto/googleapis/api/annotations;annotations";
+option java_multiple_files = true;
+option java_outer_classname = "AnnotationsProto";
+option java_package = "com.google.api";
+option objc_class_prefix = "GAPI";
+
+extend google.protobuf.MethodOptions {
+  // See `HttpRule`.
+  HttpRule http = 72295728;
+}
diff --git a/protos/google/api/http.proto b/protos/google/api/http.proto
new file mode 100644
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+++ b/protos/google/api/http.proto
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+// Copyright 2018 Google LLC.
+//
+// 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.
+//
+
+syntax = "proto3";
+
+package google.api;
+
+option cc_enable_arenas = true;
+option go_package = "google.golang.org/genproto/googleapis/api/annotations;annotations";
+option java_multiple_files = true;
+option java_outer_classname = "HttpProto";
+option java_package = "com.google.api";
+option objc_class_prefix = "GAPI";
+
+// Defines the HTTP configuration for an API service. It contains a list of
+// [HttpRule][google.api.HttpRule], each specifying the mapping of an RPC method
+// to one or more HTTP REST API methods.
+message Http {
+  // A list of HTTP configuration rules that apply to individual API methods.
+  //
+  // **NOTE:** All service configuration rules follow "last one wins" order.
+  repeated HttpRule rules = 1;
+
+  // When set to true, URL path parmeters will be fully URI-decoded except in
+  // cases of single segment matches in reserved expansion, where "%2F" will be
+  // left encoded.
+  //
+  // The default behavior is to not decode RFC 6570 reserved characters in multi
+  // segment matches.
+  bool fully_decode_reserved_expansion = 2;
+}
+
+// # gRPC Transcoding
+//
+// gRPC Transcoding is a feature for mapping between a gRPC method and one or
+// more HTTP REST endpoints. It allows developers to build a single API service
+// that supports both gRPC APIs and REST APIs. Many systems, including [Google
+// APIs](https://github.com/googleapis/googleapis),
+// [Cloud Endpoints](https://cloud.google.com/endpoints), [gRPC
+// Gateway](https://github.com/grpc-ecosystem/grpc-gateway),
+// and [Envoy](https://github.com/envoyproxy/envoy) proxy support this feature
+// and use it for large scale production services.
+//
+// `HttpRule` defines the schema of the gRPC/REST mapping. The mapping specifies
+// how different portions of the gRPC request message are mapped to the URL
+// path, URL query parameters, and HTTP request body. It also controls how the
+// gRPC response message is mapped to the HTTP response body. `HttpRule` is
+// typically specified as an `google.api.http` annotation on the gRPC method.
+//
+// Each mapping specifies a URL path template and an HTTP method. The path
+// template may refer to one or more fields in the gRPC request message, as long
+// as each field is a non-repeated field with a primitive (non-message) type.
+// The path template controls how fields of the request message are mapped to
+// the URL path.
+//
+// Example:
+//
+//     service Messaging {
+//       rpc GetMessage(GetMessageRequest) returns (Message) {
+//         option (google.api.http) = {
+//             get: "/v1/{name=messages/*}"
+//         };
+//       }
+//     }
+//     message GetMessageRequest {
+//       string name = 1; // Mapped to URL path.
+//     }
+//     message Message {
+//       string text = 1; // The resource content.
+//     }
+//
+// This enables an HTTP REST to gRPC mapping as below:
+//
+// HTTP | gRPC
+// -----|-----
+// `GET /v1/messages/123456`  | `GetMessage(name: "messages/123456")`
+//
+// Any fields in the request message which are not bound by the path template
+// automatically become HTTP query parameters if there is no HTTP request body.
+// For example:
+//
+//     service Messaging {
+//       rpc GetMessage(GetMessageRequest) returns (Message) {
+//         option (google.api.http) = {
+//             get:"/v1/messages/{message_id}"
+//         };
+//       }
+//     }
+//     message GetMessageRequest {
+//       message SubMessage {
+//         string subfield = 1;
+//       }
+//       string message_id = 1; // Mapped to URL path.
+//       int64 revision = 2;    // Mapped to URL query parameter `revision`.
+//       SubMessage sub = 3;    // Mapped to URL query parameter `sub.subfield`.
+//     }
+//
+// This enables a HTTP JSON to RPC mapping as below:
+//
+// HTTP | gRPC
+// -----|-----
+// `GET /v1/messages/123456?revision=2&sub.subfield=foo` |
+// `GetMessage(message_id: "123456" revision: 2 sub: SubMessage(subfield:
+// "foo"))`
+//
+// Note that fields which are mapped to URL query parameters must have a
+// primitive type or a repeated primitive type or a non-repeated message type.
+// In the case of a repeated type, the parameter can be repeated in the URL
+// as `...?param=A&param=B`. In the case of a message type, each field of the
+// message is mapped to a separate parameter, such as
+// `...?foo.a=A&foo.b=B&foo.c=C`.
+//
+// For HTTP methods that allow a request body, the `body` field
+// specifies the mapping. Consider a REST update method on the
+// message resource collection:
+//
+//     service Messaging {
+//       rpc UpdateMessage(UpdateMessageRequest) returns (Message) {
+//         option (google.api.http) = {
+//           patch: "/v1/messages/{message_id}"
+//           body: "message"
+//         };
+//       }
+//     }
+//     message UpdateMessageRequest {
+//       string message_id = 1; // mapped to the URL
+//       Message message = 2;   // mapped to the body
+//     }
+//
+// The following HTTP JSON to RPC mapping is enabled, where the
+// representation of the JSON in the request body is determined by
+// protos JSON encoding:
+//
+// HTTP | gRPC
+// -----|-----
+// `PATCH /v1/messages/123456 { "text": "Hi!" }` | `UpdateMessage(message_id:
+// "123456" message { text: "Hi!" })`
+//
+// The special name `*` can be used in the body mapping to define that
+// every field not bound by the path template should be mapped to the
+// request body.  This enables the following alternative definition of
+// the update method:
+//
+//     service Messaging {
+//       rpc UpdateMessage(Message) returns (Message) {
+//         option (google.api.http) = {
+//           patch: "/v1/messages/{message_id}"
+//           body: "*"
+//         };
+//       }
+//     }
+//     message Message {
+//       string message_id = 1;
+//       string text = 2;
+//     }
+//
+//
+// The following HTTP JSON to RPC mapping is enabled:
+//
+// HTTP | gRPC
+// -----|-----
+// `PATCH /v1/messages/123456 { "text": "Hi!" }` | `UpdateMessage(message_id:
+// "123456" text: "Hi!")`
+//
+// Note that when using `*` in the body mapping, it is not possible to
+// have HTTP parameters, as all fields not bound by the path end in
+// the body. This makes this option more rarely used in practice when
+// defining REST APIs. The common usage of `*` is in custom methods
+// which don't use the URL at all for transferring data.
+//
+// It is possible to define multiple HTTP methods for one RPC by using
+// the `additional_bindings` option. Example:
+//
+//     service Messaging {
+//       rpc GetMessage(GetMessageRequest) returns (Message) {
+//         option (google.api.http) = {
+//           get: "/v1/messages/{message_id}"
+//           additional_bindings {
+//             get: "/v1/users/{user_id}/messages/{message_id}"
+//           }
+//         };
+//       }
+//     }
+//     message GetMessageRequest {
+//       string message_id = 1;
+//       string user_id = 2;
+//     }
+//
+// This enables the following two alternative HTTP JSON to RPC mappings:
+//
+// HTTP | gRPC
+// -----|-----
+// `GET /v1/messages/123456` | `GetMessage(message_id: "123456")`
+// `GET /v1/users/me/messages/123456` | `GetMessage(user_id: "me" message_id:
+// "123456")`
+//
+// ## Rules for HTTP mapping
+//
+// 1. Leaf request fields (recursive expansion nested messages in the request
+//    message) are classified into three categories:
+//    - Fields referred by the path template. They are passed via the URL path.
+//    - Fields referred by the [HttpRule.body][google.api.HttpRule.body]. They
+//    are passed via the HTTP
+//      request body.
+//    - All other fields are passed via the URL query parameters, and the
+//      parameter name is the field path in the request message. A repeated
+//      field can be represented as multiple query parameters under the same
+//      name.
+//  2. If [HttpRule.body][google.api.HttpRule.body] is "*", there is no URL
+//  query parameter, all fields
+//     are passed via URL path and HTTP request body.
+//  3. If [HttpRule.body][google.api.HttpRule.body] is omitted, there is no HTTP
+//  request body, all
+//     fields are passed via URL path and URL query parameters.
+//
+// ### Path template syntax
+//
+//     Template = "/" Segments [ Verb ] ;
+//     Segments = Segment { "/" Segment } ;
+//     Segment  = "*" | "**" | LITERAL | Variable ;
+//     Variable = "{" FieldPath [ "=" Segments ] "}" ;
+//     FieldPath = IDENT { "." IDENT } ;
+//     Verb     = ":" LITERAL ;
+//
+// The syntax `*` matches a single URL path segment. The syntax `**` matches
+// zero or more URL path segments, which must be the last part of the URL path
+// except the `Verb`.
+//
+// The syntax `Variable` matches part of the URL path as specified by its
+// template. A variable template must not contain other variables. If a variable
+// matches a single path segment, its template may be omitted, e.g. `{var}`
+// is equivalent to `{var=*}`.
+//
+// The syntax `LITERAL` matches literal text in the URL path. If the `LITERAL`
+// contains any reserved character, such characters should be percent-encoded
+// before the matching.
+//
+// If a variable contains exactly one path segment, such as `"{var}"` or
+// `"{var=*}"`, when such a variable is expanded into a URL path on the client
+// side, all characters except `[-_.~0-9a-zA-Z]` are percent-encoded. The
+// server side does the reverse decoding. Such variables show up in the
+// [Discovery
+// Document](https://developers.google.com/discovery/v1/reference/apis) as
+// `{var}`.
+//
+// If a variable contains multiple path segments, such as `"{var=foo/*}"`
+// or `"{var=**}"`, when such a variable is expanded into a URL path on the
+// client side, all characters except `[-_.~/0-9a-zA-Z]` are percent-encoded.
+// The server side does the reverse decoding, except "%2F" and "%2f" are left
+// unchanged. Such variables show up in the
+// [Discovery
+// Document](https://developers.google.com/discovery/v1/reference/apis) as
+// `{+var}`.
+//
+// ## Using gRPC API Service Configuration
+//
+// gRPC API Service Configuration (service config) is a configuration language
+// for configuring a gRPC service to become a user-facing product. The
+// service config is simply the YAML representation of the `google.api.Service`
+// proto message.
+//
+// As an alternative to annotating your proto file, you can configure gRPC
+// transcoding in your service config YAML files. You do this by specifying a
+// `HttpRule` that maps the gRPC method to a REST endpoint, achieving the same
+// effect as the proto annotation. This can be particularly useful if you
+// have a proto that is reused in multiple services. Note that any transcoding
+// specified in the service config will override any matching transcoding
+// configuration in the proto.
+//
+// Example:
+//
+//     http:
+//       rules:
+//         # Selects a gRPC method and applies HttpRule to it.
+//         - selector: example.v1.Messaging.GetMessage
+//           get: /v1/messages/{message_id}/{sub.subfield}
+//
+// ## Special notes
+//
+// When gRPC Transcoding is used to map a gRPC to JSON REST endpoints, the
+// proto to JSON conversion must follow the [proto3
+// specification](https://developers.google.com/protocol-buffers/docs/proto3#json).
+//
+// While the single segment variable follows the semantics of
+// [RFC 6570](https://tools.ietf.org/html/rfc6570) Section 3.2.2 Simple String
+// Expansion, the multi segment variable **does not** follow RFC 6570 Section
+// 3.2.3 Reserved Expansion. The reason is that the Reserved Expansion
+// does not expand special characters like `?` and `#`, which would lead
+// to invalid URLs. As the result, gRPC Transcoding uses a custom encoding
+// for multi segment variables.
+//
+// The path variables **must not** refer to any repeated or mapped field,
+// because client libraries are not capable of handling such variable expansion.
+//
+// The path variables **must not** capture the leading "/" character. The reason
+// is that the most common use case "{var}" does not capture the leading "/"
+// character. For consistency, all path variables must share the same behavior.
+//
+// Repeated message fields must not be mapped to URL query parameters, because
+// no client library can support such complicated mapping.
+//
+// If an API needs to use a JSON array for request or response body, it can map
+// the request or response body to a repeated field. However, some gRPC
+// Transcoding implementations may not support this feature.
+message HttpRule {
+  // Selects a method to which this rule applies.
+  //
+  // Refer to [selector][google.api.DocumentationRule.selector] for syntax
+  // details.
+  string selector = 1;
+
+  // Determines the URL pattern is matched by this rules. This pattern can be
+  // used with any of the {get|put|post|delete|patch} methods. A custom method
+  // can be defined using the 'custom' field.
+  oneof pattern {
+    // Maps to HTTP GET. Used for listing and getting information about
+    // resources.
+    string get = 2;
+
+    // Maps to HTTP PUT. Used for replacing a resource.
+    string put = 3;
+
+    // Maps to HTTP POST. Used for creating a resource or performing an action.
+    string post = 4;
+
+    // Maps to HTTP DELETE. Used for deleting a resource.
+    string delete = 5;
+
+    // Maps to HTTP PATCH. Used for updating a resource.
+    string patch = 6;
+
+    // The custom pattern is used for specifying an HTTP method that is not
+    // included in the `pattern` field, such as HEAD, or "*" to leave the
+    // HTTP method unspecified for this rule. The wild-card rule is useful
+    // for services that provide content to Web (HTML) clients.
+    CustomHttpPattern custom = 8;
+  }
+
+  // The name of the request field whose value is mapped to the HTTP request
+  // body, or `*` for mapping all request fields not captured by the path
+  // pattern to the HTTP body, or omitted for not having any HTTP request body.
+  //
+  // NOTE: the referred field must be present at the top-level of the request
+  // message type.
+  string body = 7;
+
+  // Optional. The name of the response field whose value is mapped to the HTTP
+  // response body. When omitted, the entire response message will be used
+  // as the HTTP response body.
+  //
+  // NOTE: The referred field must be present at the top-level of the response
+  // message type.
+  string response_body = 12;
+
+  // Additional HTTP bindings for the selector. Nested bindings must
+  // not contain an `additional_bindings` field themselves (that is,
+  // the nesting may only be one level deep).
+  repeated HttpRule additional_bindings = 11;
+}
+
+// A custom pattern is used for defining custom HTTP verb.
+message CustomHttpPattern {
+  // The name of this custom HTTP verb.
+  string kind = 1;
+
+  // The path matched by this custom verb.
+  string path = 2;
+}