Implement GET method for idempotent methods

packages/jsonrpc/src/express.ts

@@ -1,7 +1,7 @@
 import express, {ErrorRequestHandler} from 'express'
 import {FunctionPropertyNames} from './types'
 import {IDEMPOTENT_METHOD_REGEX} from './idempotent'
-import {IErrorResponse} from './jsonrpc'
+import {IErrorResponse} from './error'
 import {ILogger} from '@rondo/common'
 import {ISuccessResponse} from './jsonrpc'
 import {NextFunction, Request, Response, Router} from 'express'

packages/jsonrpc/src/jsonrpc.ts

@@ -1,7 +1,7 @@
 export type TId = number | string
 import {ArgumentTypes, FunctionPropertyNames, RetType} from './types'
 import {isPromise} from './isPromise'
-import {createError, IErrorWithData} from './error'
+import {createError, IErrorResponse, IErrorWithData} from './error'
 
 export const ERROR_PARSE = {
   code: -32700,
@@ -43,7 +43,7 @@ export function pick<T, K extends FunctionPropertyNames<T>>(t: T, keys: K[])
   }, {} as Pick<T, K>)
 }
 
-export interface IRequest<M extends string | symbol | number = any, A = any[]> {
+export interface IRequest<M extends string = any, A = any[]> {
   jsonrpc: '2.0'
   id: TId | null
   method: M
@@ -57,13 +57,6 @@ export interface ISuccessResponse<T> {
   error: null
 }
 
-export interface IErrorResponse<T> {
-  jsonrpc: '2.0'
-  id: TId | null
-  result: null
-  error: IErrorWithData<T>
-}
-
 export type IResponse<T = any> = ISuccessResponse<T> | IErrorResponse<T>
 
 export function createSuccessResponse<T>(id: number | string, result: T)
@@ -76,19 +69,6 @@ export function createSuccessResponse<T>(id: number | string, result: T)
   }
 }
 
-export function createErrorResponse<T>(
-  id: number | string | null, error: IErrorWithData<T>)
-  : IErrorResponse<T> {
-  return {
-    jsonrpc: '2.0',
-    id,
-    result: null,
-    error,
-  }
-}
-
-export type TGetContext<Context> = (req: Request) => Context
-
 export const createRpcService =
   <T, M extends FunctionPropertyNames<T>>(
     service: T,

packages/jsonrpc/src/remote.test.ts

@@ -15,6 +15,7 @@ describe('remote', () => {
 
   interface IService {
     add(a: number, b: number): number
+    fetchItem(id: number): Promise<string>
   }
   const IServiceKeys = keys<IService>()
 
@@ -22,6 +23,9 @@ describe('remote', () => {
     add(a: number, b: number) {
       return a + b
     }
+    async fetchItem(id: number): Promise<string> {
+      return Promise.resolve('id:' + id)
+    }
   }
 
   const service = new Service()
@@ -52,11 +56,20 @@ describe('remote', () => {
     })
   })
 
-  describe('method invocation', () => {
+  describe('idempotent method invocation (GET)', () => {
     it('creates a proxy for remote service', async () => {
-      const s = createRemoteClient<IService>(
+      const rpc = createRemoteClient<IService>(
         baseUrl, '/myService', IServiceKeys)
-      const result = await s.add(3, 7)
+      const result = await rpc.fetchItem(5)
+      expect(result).toBe('id:5')
+    })
+  })
+
+  describe('method invocation (POST)', () => {
+    it('creates a proxy for remote service', async () => {
+      const rpc = createRemoteClient<IService>(
+        baseUrl, '/myService', IServiceKeys)
+      const result = await rpc.add(3, 7)
       expect(result).toBe(3 + 7)
     })
   })

packages/jsonrpc/src/remote.ts

@@ -1,37 +1,51 @@
 import Axios from 'axios'
 import {FunctionPropertyNames, TAsyncified} from './types'
+import {IDEMPOTENT_METHOD_REGEX} from './idempotent'
+
+export type TRequestIdGenerator<T extends string | number> = () => T
+
+export const createNumberGenerator = (val: number) => () => ++val
+export const constantId = (val: string) => () => val
 
 export function createRemoteClient<T>(
   baseUrl: string,
   url: string,
   methods: Array<FunctionPropertyNames<T>>,
+  getNextRequestId: TRequestIdGenerator<string | number> = constantId('c'),
+  idempotentMethodRegex = IDEMPOTENT_METHOD_REGEX,
 ) {
   const axios = Axios.create({
     baseURL: baseUrl,
   })
 
-  let id = 0
+  async function createRequest(
+    id: string | number | null,
+    method: string,
+    params: any[],
+  ) {
+    const reqMethod = IDEMPOTENT_METHOD_REGEX.test(method) ? 'get' : 'post'
+    const payloadKey = reqMethod === 'post' ? 'data' : 'params'
+
+    const response = await axios({
+      method: reqMethod,
+      url,
+      [payloadKey]: {
+        id,
+        jsonrpc: '2.0',
+        method,
+        params,
+      },
+    })
+    if (response.data.error) {
+      // TODO create an actual error
+      throw response.data.error
+    }
+    return response.data.result
+  }
+
   const service = methods.reduce((obj, method) => {
     obj[method] = async function makeRequest(...args: any[]) {
-      id++
-      const response = await axios({
-        method: 'post',
-        url,
-        headers: {
-          'content-type': 'application/json',
-        },
-        data: {
-          id,
-          jsonrpc: '2.0',
-          method,
-          params: args,
-        },
-      })
-      if (response.data.error) {
-        // TODO create an actual error
-        throw response.data.error
-      }
-      return response.data.result
+      return createRequest(getNextRequestId(), method, args)
     }
     return obj
   }, {} as any)

packages/jsonrpc/src/types.ts

@@ -10,7 +10,11 @@ type PromisifyReturnType<T> = (...a: ArgumentTypes<T>) =>
   RetProm<UnwrapHOC<RetType<T>>>
 
 export type FunctionPropertyNames<T> = {
-  [K in keyof T]: T[K] extends (...args: any[]) => any ? K : never
+  [K in keyof T]: K extends string
+    ? T[K] extends (...args: any[]) => any
+      ? K
+      : never
+    : never
 }[keyof T]
 
 export type TAsyncified<T> = {