@grpc/proto-loader
v0.7.13
Published
gRPC utility library for loading .proto files
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gRPC Protobuf Loader
A utility package for loading .proto
files for use with gRPC, using the latest Protobuf.js package.
Please refer to protobuf.js' documentation
to understands its features and limitations.
Installation
npm install @grpc/proto-loader
Usage
const protoLoader = require('@grpc/proto-loader');
const grpcLibrary = require('grpc');
// OR
const grpcLibrary = require('@grpc/grpc-js');
protoLoader.load(protoFileName, options).then(packageDefinition => {
const packageObject = grpcLibrary.loadPackageDefinition(packageDefinition);
});
// OR
const packageDefinition = protoLoader.loadSync(protoFileName, options);
const packageObject = grpcLibrary.loadPackageDefinition(packageDefinition);
The options parameter is an object that can have the following optional properties:
| Field name | Valid values | Description
|------------|--------------|------------
| keepCase
| true
or false
| Preserve field names. The default is to change them to camel case.
| longs
| String
or Number
| The type to use to represent long
values. Defaults to a Long
object type.
| enums
| String
| The type to use to represent enum
values. Defaults to the numeric value.
| bytes
| Array
or String
| The type to use to represent bytes
values. Defaults to Buffer
.
| defaults
| true
or false
| Set default values on output objects. Defaults to false
.
| arrays
| true
or false
| Set empty arrays for missing array values even if defaults
is false
Defaults to false
.
| objects
| true
or false
| Set empty objects for missing object values even if defaults
is false
Defaults to false
.
| oneofs
| true
or false
| Set virtual oneof properties to the present field's name. Defaults to false
.
| json
| true
or false
| Represent Infinity
and NaN
as strings in float
fields, and automatically decode google.protobuf.Any
values. Defaults to false
| includeDirs
| An array of strings | A list of search paths for imported .proto
files.
The following options object closely approximates the existing behavior of grpc.load
:
const options = {
keepCase: true,
longs: String,
enums: String,
defaults: true,
oneofs: true
}
Generating TypeScript types
The proto-loader-gen-types
script distributed with this package can be used to generate TypeScript type information for the objects loaded at runtime. More information about how to use it can be found in the @grpc/proto-loader TypeScript Type Generator CLI Tool proposal document. The arguments mostly match the load
function's options; the full usage information is as follows:
proto-loader-gen-types.js [options] filenames...
Options:
--help Show help [boolean]
--version Show version number [boolean]
--keepCase Preserve the case of field names
[boolean] [default: false]
--longs The type that should be used to output 64 bit integer
values. Can be String, Number[string] [default: "Long"]
--enums The type that should be used to output enum fields. Can
be String [string] [default: "number"]
--bytes The type that should be used to output bytes fields.
Can be String, Array [string] [default: "Buffer"]
--defaults Output default values for omitted fields
[boolean] [default: false]
--arrays Output default values for omitted repeated fields even
if --defaults is not set [boolean] [default: false]
--objects Output default values for omitted message fields even
if --defaults is not set [boolean] [default: false]
--oneofs Output virtual oneof fields set to the present field's
name [boolean] [default: false]
--json Represent Infinity and NaN as strings in float fields.
Also decode google.protobuf.Any automatically
[boolean] [default: false]
--includeComments Generate doc comments from comments in the original
files [boolean] [default: false]
-I, --includeDirs Directories to search for included files [array]
-O, --outDir Directory in which to output files [string] [required]
--grpcLib The gRPC implementation library that these types will
be used with. If not provided, some types will not be
generated [string]
--inputTemplate Template for mapping input or "permissive" type names
[string] [default: "%s"]
--outputTemplate Template for mapping output or "restricted" type names
[string] [default: "%s__Output"]
--inputBranded Output property for branded type for "permissive"
types with fullName of the Message as its value
[boolean] [default: false]
--outputBranded Output property for branded type for "restricted"
types with fullName of the Message as its value
[boolean] [default: false]
Example Usage
Generate the types:
$(npm bin)/proto-loader-gen-types --longs=String --enums=String --defaults --oneofs --grpcLib=@grpc/grpc-js --outDir=proto/ proto/*.proto
Consume the types:
import * as grpc from '@grpc/grpc-js';
import * as protoLoader from '@grpc/proto-loader';
import type { ProtoGrpcType } from './proto/example.ts';
import type { ExampleHandlers } from './proto/example_package/Example.ts';
const exampleServer: ExampleHandlers = {
// server handlers implementation...
};
const packageDefinition = protoLoader.loadSync('./proto/example.proto');
const proto = (grpc.loadPackageDefinition(
packageDefinition
) as unknown) as ProtoGrpcType;
const server = new grpc.Server();
server.addService(proto.example_package.Example.service, exampleServer);