@bakaat/grpc-mock

grpc-mock

[!NOTE] Main requirement was to allow modification of routes/rules on a working server of what looks to be mostly a dead repo.

Runs on node 18.x, 20.x, and updated packages.

A simple mock gRPC server on Node.js.

const {createMockServer} = require("grpc-mock");
const mockServer = createMockServer({
  protoPath: "/path/to/greeter.proto",
  packageName: "greeter",
  serviceName: "Greeter",
  rules: [
    { method: "Hello", input: { message: "test" }, output: { message: "Hello" } },
    { method: "Goodbye", input: ".*", output: { message: "Goodbye" } },
    
    {
      method: "HowAreYou",
      streamType: "client",
      stream: [
        { input: { message: "Hi" } },
        { input: { message: "How are you?" } },
      ],
      output: { message: "I'm fine, thank you" }
    },
    
    {
      method: "NiceToMeetYou",
      streamType: "server",
      stream: [
        { output: { message: "Hi, I'm Sana" } },
        { output: { message: "Nice to meet you too" } },
      ],
      input: { message: "Hi. I'm John. Nice to meet you" }
    },
    
    {
      method: "Chat",
      streamType: "mutual",
      stream: [
        { input: { message: "Hi" }, output: { message: "Hi there" } },
        { input: { message: "How are you?" }, output: { message: "I'm fine, thank you." } },
      ]
    },
    
    { method: "ReturnsError", input: { }, error: { code: 3, message: "Message text is required"} },
    
    {
      method: "ReturnsErrorWithMetadata",
      streamType: "server",
      input: { },
      error: { code: 3, message: "Message text is required", metadata: { key: "value"}}
    }
  ]
});
await mockServer.listen("0.0.0.0:50051");

syntax="proto3";

package greeter;

service Greeter {
  rpc Hello (RequestGreet) returns (ResponseGreet) {}
  rpc Goodbye (RequestGreet) returns (ResponseGreet) {}
  rpc HowAreYou (stream RequestGreet) returns (ResponseGreet) {}
  rpc NiceToMeetYou (RequestGreet) returns (stream ResponseGreet) {}
  rpc Chat (stream RequestGreet) returns (stream ResponseGreet) {}
}

message RequestGreet {
  string message = 1;
}

message ResponseGreet {
  string message = 1;
}

api

createMockServer({protoPath,packageName,serviceName,options,rules}): utils.GrpcServer

arg name	type	required/optional	description
protoPath	String	Required	path to .proto file
packageName	String	Required	name of package
serviceName	String	Required	name of service
options	@grpc/proto-loader.Options	Optional	options for @grpc/proto-loader to load .proto file. In detail, please check here out. Default is null
rules	Array<Rule>	Required	Array of Rules

Rule

prop name	type	required/optional	description
method	String	Required	path to .proto file
streamType	Enum<"client"|"server"|"mutual">	Optional	Type of stream. Set client if only using client side stream, set server if only using server side stream, and set mutual if using both of client and server side stream. Set null/undefined if not using stream. Default is null
input	Object|String	Required when streamType is null or server	Specifying an expected input. Raw object or pattern string(RegExp) is available
output	String	Required when streamType is null or client	Specifying an output to an expected input
stream	Array<Chunk>	Required when streamType is client, server and mutual	Array of Chunks
error	Object	Optional	If provided, server will respond with this error object

Chunk

prop name	type	required/optional	description
input	Object|String	Required when streamType is client. Optional when streamType is mutual	Specifying an expected input. Raw object or pattern string(RegExp) is available.
output	Object	Required when streamType is server. Optional when streamType is mutual	Specifying an output to an expected input