Class: Google::Apis::ServiceusageV1::HttpRule
- Inherits:
-
Object
- Object
- Google::Apis::ServiceusageV1::HttpRule
- Includes:
- Core::Hashable, Core::JsonObjectSupport
- Defined in:
- lib/google/apis/serviceusage_v1/classes.rb,
lib/google/apis/serviceusage_v1/representations.rb,
lib/google/apis/serviceusage_v1/representations.rb
Overview
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, Cloud
Endpoints, gRPC Gateway, and 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: GET /v1/messages/123456
- gRPC:
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: GET /v1/messages/123456?
revision=2&sub.subfield=foo
- gRPC: 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¶m=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: PATCH /v1/messages/123456
"text": "Hi!" `- gRPC:
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:
PATCH /v1/messages/123456 "text": "Hi!"
- gRPC:
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:
GET /
v1/messages/123456- gRPC:
GetMessage(message_id: "123456")- HTTP:
GET /
v1/users/me/messages/123456- gRPC:
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. 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 is "*", there is no URL query parameter, all fields are passed
via URL path and HTTP request body. 3. If 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
Variablematches 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
LITERALmatches
literal text in the URL path. If the
LITERALcontains 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.Serviceproto 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
HttpRulethat 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. The following example selects a gRPC method and applies an
HttpRuleto it: http: rules: - selector: example.v1.Messaging.GetMessage get:
/v1/messages/
message_id/
sub.subfieldSpecial 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.
Instance Attribute Summary collapse
-
#additional_bindings ⇒ Array<Google::Apis::ServiceusageV1::HttpRule>
Additional HTTP bindings for the selector.
-
#body ⇒ String
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. -
#custom ⇒ Google::Apis::ServiceusageV1::CustomHttpPattern
A custom pattern is used for defining custom HTTP verb.
-
#delete ⇒ String
Maps to HTTP DELETE.
-
#get ⇒ String
Maps to HTTP GET.
-
#patch ⇒ String
Maps to HTTP PATCH.
-
#post ⇒ String
Maps to HTTP POST.
-
#put ⇒ String
Maps to HTTP PUT.
-
#response_body ⇒ String
Optional.
-
#selector ⇒ String
Selects a method to which this rule applies.
Instance Method Summary collapse
-
#initialize(**args) ⇒ HttpRule
constructor
A new instance of HttpRule.
-
#update!(**args) ⇒ Object
Update properties of this object.
Constructor Details
#initialize(**args) ⇒ HttpRule
Returns a new instance of HttpRule.
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3042 def initialize(**args) update!(**args) end |
Instance Attribute Details
#additional_bindings ⇒ Array<Google::Apis::ServiceusageV1::HttpRule>
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).
Corresponds to the JSON property additionalBindings
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 2988 def additional_bindings @additional_bindings end |
#body ⇒ String
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.
Corresponds to the JSON property body
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 2996 def body @body end |
#custom ⇒ Google::Apis::ServiceusageV1::CustomHttpPattern
A custom pattern is used for defining custom HTTP verb.
Corresponds to the JSON property custom
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3001 def custom @custom end |
#delete ⇒ String
Maps to HTTP DELETE. Used for deleting a resource.
Corresponds to the JSON property delete
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3006 def delete @delete end |
#get ⇒ String
Maps to HTTP GET. Used for listing and getting information about resources.
Corresponds to the JSON property get
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3011 def get @get end |
#patch ⇒ String
Maps to HTTP PATCH. Used for updating a resource.
Corresponds to the JSON property patch
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3016 def patch @patch end |
#post ⇒ String
Maps to HTTP POST. Used for creating a resource or performing an action.
Corresponds to the JSON property post
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3021 def post @post end |
#put ⇒ String
Maps to HTTP PUT. Used for replacing a resource.
Corresponds to the JSON property put
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3026 def put @put end |
#response_body ⇒ String
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.
Corresponds to the JSON property responseBody
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3034 def response_body @response_body end |
#selector ⇒ String
Selects a method to which this rule applies. Refer to selector for syntax
details.
Corresponds to the JSON property selector
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3040 def selector @selector end |
Instance Method Details
#update!(**args) ⇒ Object
Update properties of this object
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# File 'lib/google/apis/serviceusage_v1/classes.rb', line 3047 def update!(**args) @additional_bindings = args[:additional_bindings] if args.key?(:additional_bindings) @body = args[:body] if args.key?(:body) @custom = args[:custom] if args.key?(:custom) @delete = args[:delete] if args.key?(:delete) @get = args[:get] if args.key?(:get) @patch = args[:patch] if args.key?(:patch) @post = args[:post] if args.key?(:post) @put = args[:put] if args.key?(:put) @response_body = args[:response_body] if args.key?(:response_body) @selector = args[:selector] if args.key?(:selector) end |