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index.ts
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// Request [MessageType, Id, Method, Params]
// Response [MessageType, Id, Result]
// Error Response [MessageType, Id, ErrorResult]
// Notification [MessageType, Method, Params]
const generateRandomNumber = function () {
return Math.round(Math.random() * 10000000);
};
export const enum MessageType {
Request,
Notification,
Response,
ErrorResponse,
}
type MethodReturnType<Method> = Method extends (...args: any) => infer R ? R : any;
type MethodParameters<Method> = Method extends (...args: infer T) => any ? T : never;
type ToTransportCb<AppDataType> = AppDataType extends undefined ?
(message: string) => void :
(message: string, appData: AppDataType) => void;
type FromTransportParams<AppDataType> = AppDataType extends undefined ?
[message: string] :
[message: string, appData: AppDataType];
type AppendAppData<I, T extends unknown[]> = [...args: T, appData: I];
type AnyFunction = (...args: any) => any | Promise<any>;
type GuardFn<Method extends keyof Handlers, Handlers, AppDataType> =
AppDataType extends undefined
? (...args: MethodParameters<Handlers[Method]>) => void
: (...args: [...MethodParameters<Handlers[Method]>, AppDataType]) => void;
type KissMethod = string;
type KissRequestId = number;
type KissParams = any[];
type KissError = { code: number, message: string, errorMessage?: string }
const enum GuardType {
Guard,
ParamGuard,
AppData
}
type Guards = {
type: GuardType.Guard
fn: AnyFunction
} | {
type: GuardType.ParamGuard
fn: AnyFunction
} | {
type: GuardType.AppData
fn: AnyFunction
}
type KissRpcOptions = {
requestTimeout: number,
}
type KissPendingRequest<T> = {
id: number,
resolve: (value: MethodReturnType<T>) => void,
reject: (value: unknown) => void
}
export type KissRequest = [MessageType.Request, KissRequestId, KissMethod, KissParams];
export type KissResponse = [MessageType.Response, KissRequestId, any];
export type KissNotification = [MessageType.Notification, KissMethod, KissParams];
export type KissErrorResponse = [MessageType.ErrorResponse, KissRequestId, KissError];
export type KissMessage = KissRequest | KissResponse | KissNotification | KissErrorResponse;
export function getMessageType(message: KissMessage): MessageType {
return message[0];
}
export function getMessageMethod(message: KissMessage): KissMethod {
switch (getMessageType(message)) {
case MessageType.Request:
return message[2];
case MessageType.Notification:
return <string>message[1];
case MessageType.Response:
case MessageType.ErrorResponse:
return ''
}
}
export function getMessageParams(message: KissMessage): KissParams {
switch (getMessageType(message)) {
case MessageType.Request:
return message[3] || [];
case MessageType.Notification:
return message[2];
default:
return [];
}
}
export function getMessageId(message: KissMessage): KissRequestId {
switch (getMessageType(message)) {
case MessageType.Request:
case MessageType.Response:
case MessageType.ErrorResponse:
return <number>message[1];
case MessageType.Notification:
return -1;
}
}
export function getMessageResult(message: KissMessage): any {
switch (getMessageType(message)) {
case MessageType.Response:
case MessageType.ErrorResponse:
return message[2];
default:
return;
}
}
export function getMessageError(message: KissMessage): KissError {
switch (getMessageType(message)) {
case MessageType.ErrorResponse:
return message[2];
default:
return new KissRpcError(0, '');
}
}
export function isRequest(message: KissMessage): message is KissRequest {
return getMessageType(message) === MessageType.Request;
}
export function isResponse(message: KissMessage): message is KissResponse {
return getMessageType(message) === MessageType.Response;
}
export function isErrorResponse(message: KissMessage): message is KissErrorResponse {
return getMessageType(message) === MessageType.ErrorResponse;
}
export function isNotification(message: KissMessage): message is KissNotification {
return getMessageType(message) === MessageType.Notification;
}
export function isMessage(message: any): message is KissMessage {
if (!Array.isArray(message)) return false;
if (message.length > 4 || message.length < 2) return false;
if (typeof message[0] !== 'number') return false;
if (message[0] < 0 || message[0] > 3) return false;
switch (getMessageType(message as KissMessage)) {
case MessageType.Request:
if (typeof message[1] !== 'number') return false;
if (typeof message[2] !== 'string') return false;
break;
case MessageType.Response:
if (typeof message[1] !== 'number') return false;
break;
case MessageType.ErrorResponse:
if (typeof message[1] !== 'number') return false;
if (typeof message[2] !== 'object') return false;
if (typeof message[2].code !== 'number') return false;
if (typeof message[2].message !== 'string') return false;
break;
case MessageType.Notification:
if (typeof message[1] !== 'string') return false;
break;
default:
return false;
}
return true;
}
export class KissRpcError extends Error {
code: number
message: string
id?: number
errorMessage?: string
constructor(code: number, message: string, id: number = -1, errorMessage: string = '') {
super();
this.code = code;
this.message = message;
this.id = id;
this.errorMessage = errorMessage;
}
}
export const KISS_RPC_ERRORS = {
PARSE_ERROR: {
code: 1000,
message: "Invalid JSON was received by the server. An error occurred on the server while parsing the JSON text."
},
INVALID_REQUEST: {
code: 1001,
message: "Invalid Request. The JSON sent is not a valid Request object."
},
METHOD_NOT_FOUND: {
code: 1002,
message: "Method not found. The method does not exist / is not available."
},
INTERNAL_ERROR: {
code: 1004,
message: "Internal error. Internal JSON-RPC error."
},
REQUEST_TIMEOUT: {
code: 1005,
message: 'Request has timed-out'
},
GUARD_ERROR: {
code: 1006,
message: 'Guard error'
},
APPLICATION_ERROR: {
code: 1007,
message: 'Application error'
},
TRANSPORT_ERROR: {
code: 1008,
message: 'Underlying transport issue'
}
};
export class DispatcherHandler<Method extends keyof Handlers, Handlers, AppDataType = undefined> {
fn: AnyFunction
guards: Array<Guards> = []
method: Method
constructor(fn: AnyFunction, method: Method) {
this.fn = fn;
this.method = method;
}
addGuard(fn: GuardFn<Method, Handlers, AppDataType>): this {
this.guards.push({
type: GuardType.Guard,
fn
});
return this
}
addParamsGuard(fn: (...args: MethodParameters<Handlers[Method]>) => void): this {
this.guards.push({
type: GuardType.ParamGuard,
fn
});
return this
}
addAppDataGuard(fn: (appData: AppDataType) => void): this {
this.guards.push({
type: GuardType.AppData,
fn
});
return this
}
}
export class KissRpc<RequestMethods, HandlersMethods = RequestMethods, AppDataType = undefined> {
requestTimeout: number
toTransport: ToTransportCb<AppDataType> | null = null;
dispatcher: Map<KissMethod, DispatcherHandler<any, HandlersMethods, AppDataType>>
pendingRequests: Map<KissRequestId, KissPendingRequest<keyof RequestMethods>>
static parse(raw: string): KissMessage {
let message: KissMessage;
try {
message = JSON.parse(raw);
} catch (error) {
throw new KissRpcError(
KISS_RPC_ERRORS.PARSE_ERROR.code,
KISS_RPC_ERRORS.PARSE_ERROR.message
);
}
if (!isMessage(message)) {
throw new KissRpcError(
KISS_RPC_ERRORS.INVALID_REQUEST.code,
KISS_RPC_ERRORS.INVALID_REQUEST.message
);
}
return message;
}
static createRequest(method: string, params: any[] | undefined): KissRequest {
return [MessageType.Request, generateRandomNumber(), method, params || []];
}
static createResponse(id: number, data: any): KissResponse {
return [MessageType.Response, id, data];
}
static createErrorResponse(id: number, errorCode: number, errorReason: string, errorMessage?: string): KissErrorResponse {
return [MessageType.ErrorResponse, id, {code: errorCode, message: errorReason, errorMessage: errorMessage}];
}
static createNotification(method: string, params: any[]): KissNotification {
return [MessageType.Notification, method, params];
}
constructor(options?: KissRpcOptions) {
this.requestTimeout = options?.requestTimeout || 5000;
this.dispatcher = new Map<KissMethod, DispatcherHandler<any, HandlersMethods, AppDataType>>();
this.pendingRequests = new Map<KissRequestId, KissPendingRequest<keyof RequestMethods>>();
}
private appDataIsDefined(appData?: AppDataType): appData is NonNullable<AppDataType> {
return appData !== undefined && appData !== null;
}
private rejectPendingRequests(error: KissRpcError) {
for (const request of this.pendingRequests.values()) {
request.reject(error);
}
this.pendingRequests.clear();
}
private resetDispatcher() {
for (const handler of this.dispatcher.values()) {
handler.guards.length = 0;
}
this.dispatcher.clear();
}
registerToTransportCallback(cb: ToTransportCb<AppDataType>) {
this.toTransport = cb;
}
registerHandler<Method extends keyof HandlersMethods>(
method: Method,
handler: (
...params: AppDataType extends undefined ?
MethodParameters<HandlersMethods[Method]> :
AppendAppData<AppDataType, MethodParameters<HandlersMethods[Method]>>
) => MethodReturnType<HandlersMethods[Method]> | Promise<MethodReturnType<HandlersMethods[Method]>>,
): DispatcherHandler<Method, HandlersMethods, AppDataType> {
const dispatcherHandler = new DispatcherHandler<Method, HandlersMethods, AppDataType>(handler, method)
this.dispatcher.set(method.toString(), dispatcherHandler);
return dispatcherHandler
}
request<Method extends keyof RequestMethods>(
...args: AppDataType extends undefined ?
[method: Method, params: MethodParameters<RequestMethods[Method]>] :
[method: Method, params: MethodParameters<RequestMethods[Method]>, appData: AppDataType]
): Promise<MethodReturnType<RequestMethods[Method]>> {
const requestMessage = KissRpc.createRequest(args[0].toString(), args[1]);
return Promise.race([
new Promise<MethodReturnType<RequestMethods[Method]>>((resolve, reject) => {
this.pendingRequests.set(requestMessage[1], {
id: requestMessage[1],
resolve,
reject
});
this.callToTransport(requestMessage, args[2]);
}),
new Promise<never>((resolve, reject) => {
setTimeout(() => {
this.pendingRequests.delete(requestMessage[1])
reject(new KissRpcError(
KISS_RPC_ERRORS.REQUEST_TIMEOUT.code,
KISS_RPC_ERRORS.REQUEST_TIMEOUT.message
))
}, this.requestTimeout);
})
])
}
notify<Method extends keyof RequestMethods>(
...args: AppDataType extends undefined ?
[method: Method, params: MethodParameters<RequestMethods[Method]>] :
[method: Method, params: MethodParameters<RequestMethods[Method]>, appData: AppDataType]
): void {
this.callToTransport(KissRpc.createNotification(args[0].toString(), args[1]), args[2]);
}
callToTransport(message: KissMessage, appData?: AppDataType) {
if (!this.toTransport) return;
this.appDataIsDefined(appData) ?
this.toTransport(JSON.stringify(message), appData) :
// @ts-ignore because we know that appData is undefined
// and also because we know that toTransport is defined
// and because fuck you typescript
this.toTransport(JSON.stringify(message));
}
handleMessage(message: KissMessage, appData?: AppDataType) {
switch (getMessageType(message)) {
case MessageType.Request:
case MessageType.Notification:
const handler = this.dispatcher.get(getMessageMethod(message));
if (!handler)
return this.callToTransport(KissRpc.createErrorResponse(
isRequest(message) ? getMessageId(message) : -1,
KISS_RPC_ERRORS.METHOD_NOT_FOUND.code,
KISS_RPC_ERRORS.METHOD_NOT_FOUND.message
), appData);
// Execute guards attached to the handler
try {
if (handler.guards.length) {
for (const guard of handler.guards) {
switch (guard.type) {
case GuardType.Guard:
guard.fn.apply(
null,
this.appDataIsDefined(appData) ?
[...getMessageParams(message), appData] :
[getMessageParams(message)]);
break;
case GuardType.ParamGuard:
guard.fn.apply(null, getMessageParams(message));
break;
case GuardType.AppData:
if (this.appDataIsDefined(appData)) {
guard.fn.apply(null, [appData])
}
break;
}
}
}
} catch (e) {
const err = e as Error
if (isNotification(message)) return
return this.callToTransport(KissRpc.createErrorResponse(
getMessageId(message),
KISS_RPC_ERRORS.GUARD_ERROR.code,
KISS_RPC_ERRORS.GUARD_ERROR.message,
err.toString()
), appData);
}
// Guard passed, execute handler
try {
let result
if (this.appDataIsDefined(appData)) {
result = handler.fn.apply(null, [...getMessageParams(message), appData]);
} else {
result = handler.fn.apply(null, getMessageParams(message));
}
// Notifications don't have any response
if (isNotification(message)) return;
if (result && result.then) {
result.then((res: any) => {
this.callToTransport(KissRpc.createResponse(getMessageId(message), res), appData);
}).catch((e: Error) => {
this.callToTransport(KissRpc.createErrorResponse(
getMessageId(message),
KISS_RPC_ERRORS.APPLICATION_ERROR.code,
KISS_RPC_ERRORS.APPLICATION_ERROR.message,
e.message
), appData);
})
} else {
this.callToTransport(
KissRpc.createResponse(getMessageId(message), result),
appData
);
}
} catch (e) {
const err = e as Error
if (isNotification(message)) return;
this.callToTransport(KissRpc.createErrorResponse(
getMessageId(message),
KISS_RPC_ERRORS.APPLICATION_ERROR.code,
KISS_RPC_ERRORS.APPLICATION_ERROR.message,
err.message
), appData);
}
break;
case MessageType.Response:
case MessageType.ErrorResponse:
const pendingRequest = this.pendingRequests.get(getMessageId(message));
if (pendingRequest) {
this.pendingRequests.delete(getMessageId(message));
if (isResponse(message)) {
pendingRequest.resolve(getMessageResult(message));
} else if (isErrorResponse(message)) {
const error = getMessageError(message);
pendingRequest.reject(
new KissRpcError(
error.code,
error.message,
getMessageId(message),
error.errorMessage
)
)
}
}
}
}
fromTransport(...args: FromTransportParams<AppDataType>) {
let message: KissMessage;
try {
message = KissRpc.parse(args[0]);
// handleMessage will call toTransport if it's defined for any errors,
// so we don't need to check it here the only thing we care if message
// was parsed correctly and is valid
this.appDataIsDefined(args[1]) ?
this.handleMessage(message, args[1]) :
this.handleMessage(message)
} catch (e) {
if (e instanceof KissRpcError) {
this.callToTransport(
KissRpc.createErrorResponse(
-1,
e.code,
e.message,
e.errorMessage || ''
),
args[1]);
}
}
}
clean(reason: string) {
this.rejectPendingRequests(new KissRpcError(
KISS_RPC_ERRORS.INTERNAL_ERROR.code,
KISS_RPC_ERRORS.INTERNAL_ERROR.message,
-1,
reason
));
this.resetDispatcher();
this.toTransport = null;
}
}