feat(dispatcher): local error handling

packages/client/src/types/messages/message.ts

@@ -786,6 +786,20 @@ export class Message {
         })
     }
 
+    /**
+     * Forward this message to some chat
+     *
+     * @param peer  Chat where to forward this message
+     * @param params
+     * @returns  Forwarded message
+     */
+    forwardTo(
+        peer: InputPeerLike,
+        params?: Parameters<TelegramClient['forwardMessages']>[3]
+    ): Promise<Message> {
+        return this.client.forwardMessages(peer, this.chat.inputPeer, this.id, params)
+    }
+
     /**
      * Send this message as a copy (i.e. send the same message,
      * but do not forward it).

packages/dispatcher/src/dispatcher.ts

@@ -31,6 +31,7 @@ import {
     PollVoteHandler,
     UserStatusUpdateHandler,
     UserTypingHandler,
+    UpdateInfoForError,
 } from './handler'
 // end-codegen-imports
 import { filters, UpdateFilter } from './filters'
@@ -169,6 +170,14 @@ export class Dispatcher<State = never, SceneName extends string = string> {
 
     private _handlersCount: Record<string, number> = {}
 
+    private _errorHandler?: <
+        T extends Exclude<UpdateHandler, RawUpdateHandler>
+    >(
+        err: Error,
+        update: UpdateInfoForError<T>,
+        state?: UpdateState<State, SceneName>
+    ) => MaybeAsync<void>
+
     /**
      * Create a new dispatcher, that will be used as a child,
      * optionally providing a custom key delegate
@@ -400,22 +409,37 @@ export class Dispatcher<State = never, SceneName extends string = string> {
                     RawUpdateHandler
                 >[]
 
-                for (const h of handlers) {
-                    let result: void | PropagationSymbol
+                try {
+                    for (const h of handlers) {
+                        let result: void | PropagationSymbol
 
-                    if (
-                        !h.check ||
-                        (await h.check(parsed, parsedState as never))
-                    ) {
-                        result = await h.callback(parsed, parsedState as never)
-                    } else continue
+                        if (
+                            !h.check ||
+                            (await h.check(parsed, parsedState as never))
+                        ) {
+                            result = await h.callback(
+                                parsed,
+                                parsedState as never
+                            )
+                        } else continue
 
-                    if (result === ContinuePropagation) continue
-                    if (result === StopPropagation) break outer
-                    if (result === StopChildrenPropagation) return
+                        if (result === ContinuePropagation) continue
+                        if (result === StopPropagation) break outer
+                        if (result === StopChildrenPropagation) return
 
-                    tryRaw = false
-                    break
+                        tryRaw = false
+                        break
+                    }
+                } catch (e) {
+                    if (this._errorHandler) {
+                        await this._errorHandler(
+                            e,
+                            { type: parsedType, data: parsed },
+                            parsedState as never
+                        )
+                    } else {
+                        throw e
+                    }
                 }
             }
 
@@ -542,6 +566,35 @@ export class Dispatcher<State = never, SceneName extends string = string> {
         }
     }
 
+    /**
+     * Register an error handler.
+     *
+     * This is used locally within this dispatcher
+     * (does not affect children/parent) whenever
+     * an error is thrown inside an update handler.
+     * Not used for raw update handlers
+     *
+     * When an error is thrown, but there is no error
+     * handler, it is propagated to `TelegramClient`.
+     *
+     * There can be at most one error handler.
+     * Pass `null` to remove it.
+     *
+     * @param handler  Error handler
+     */
+    onError(
+        handler:
+            | ((
+                  err: Error,
+                  update: UpdateInfoForError<UpdateHandler>,
+                  state?: UpdateState<State, SceneName>
+              ) => MaybeAsync<void>)
+            | null
+    ): void {
+        if (handler) this._errorHandler = handler
+        else this._errorHandler = undefined
+    }
+
     // children //
 
     /**

packages/dispatcher/src/handler.ts

@@ -30,6 +30,16 @@ type ParsedUpdateHandler<Type, Update, State = never> = BaseUpdateHandler<
     (update: Update, state: State) => MaybeAsync<boolean>
 >
 
+export type UpdateInfoForError<T> = T extends ParsedUpdateHandler<
+    infer K,
+    infer Q
+>
+    ? {
+          type: K
+          data: Q
+      }
+    : never
+
 export type RawUpdateHandler = BaseUpdateHandler<
     'raw',
     (

packages/node/index.ts

@@ -1,6 +1,6 @@
 import { TelegramClient, User } from '@mtcute/client'
 import { BaseTelegramClient } from '@mtcute/core'
-import { NodeNativeCryptoProvider } from '@mtcute/crypto-node'
+import type { NodeNativeCryptoProvider } from '@mtcute/crypto-node'
 import { HtmlMessageEntityParser } from '@mtcute/html-parser'
 import { MarkdownMessageEntityParser } from '@mtcute/markdown-parser'
 import { SqliteStorage } from '@mtcute/sqlite'
@@ -9,6 +9,11 @@ import { createInterface, Interface as RlInterface } from 'readline'
 export * from '@mtcute/dispatcher'
 export { SqliteStorage }
 
+let nativeCrypto: typeof NodeNativeCryptoProvider | null
+try {
+    nativeCrypto = require('@mtcute/crypto-node').NodeNativeCryptoProvider
+} catch (e) {}
+
 export namespace NodeTelegramClient {
     export interface Options
         extends Omit<BaseTelegramClient.Options, 'storage'> {
@@ -63,7 +68,7 @@ export const input = (text: string): Promise<string> => {
 export class NodeTelegramClient extends TelegramClient {
     constructor(opts: NodeTelegramClient.Options) {
         super({
-            crypto: () => new NodeNativeCryptoProvider(),
+            crypto: nativeCrypto ? () => new nativeCrypto!() : undefined,
             ...opts,
             storage:
                 typeof opts.storage === 'string'

packages/node/package.json

@@ -16,7 +16,6 @@
         "@mtcute/sqlite": "^1.0.0",
         "@mtcute/markdown-parser": "^1.0.0",
         "@mtcute/html-parser": "^1.0.0",
-        "@mtcute/dispatcher": "^1.0.0",
-        "@mtcute/crypto-node": "^1.0.0"
+        "@mtcute/dispatcher": "^1.0.0"
     }
 }