Add SenderError

Author: coolreader18

crates/bindings-typescript/src/server/errors.ts

@@ -1,20 +1,22 @@
 /**
- * Base class for all Spacetime errors.
- * Each subclass must define a static CODE and MESSAGE property.
+ * Base class for all Spacetime host errors (i.e. errors that may be thrown
+ * by database functions).
+ *
  * Instances of SpacetimeError can be created with just an error code,
  * which will return the appropriate subclass instance.
  */
-export class SpacetimeError {
+export class SpacetimeHostError extends Error {
   public readonly code: number;
   public readonly message: string;
   constructor(code: number) {
+    super();
     const proto = Object.getPrototypeOf(this);
     let cls;
     if (errorProtoypes.has(proto)) {
       cls = proto.constructor;
       if (code !== cls.CODE)
         throw new TypeError(`invalid error code for ${cls.name}`);
-    } else if (proto === SpacetimeError.prototype) {
+    } else if (proto === SpacetimeHostError.prototype) {
       cls = errnoToClass.get(code);
       if (!cls) throw new RangeError(`unknown error code ${code}`);
     } else {
@@ -24,12 +26,30 @@ export class SpacetimeError {
     this.code = cls.CODE;
     this.message = cls.MESSAGE;
   }
+  get name(): string {
+    return errnoToClass.get(this.code)?.name ?? 'SpacetimeHostError';
+  }
+}
+
+/**
+ * An error thrown by a reducer that indicates a problem to the sender.
+ *
+ * When this error is thrown by a reducer, the sender will be notified
+ * that the reducer failed gracefully with the given message.
+ */
+export class SenderError extends Error {
+  constructor(message: string) {
+    super(message);
+  }
+  get name() {
+    return 'SenderError';
+  }
 }
 
 /**
  * A generic error class for unknown error codes.
  */
-export class HostCallFailure extends SpacetimeError {
+export class HostCallFailure extends SpacetimeHostError {
   static CODE = 1;
   static MESSAGE = 'ABI called by host returned an error';
   constructor() {
@@ -40,7 +60,7 @@ export class HostCallFailure extends SpacetimeError {
 /**
  * Error indicating that an ABI call was made outside of a transaction.
  */
-export class NotInTransaction extends SpacetimeError {
+export class NotInTransaction extends SpacetimeHostError {
   static CODE = 2;
   static MESSAGE = 'ABI call can only be made while in a transaction';
   constructor() {
@@ -52,7 +72,7 @@ export class NotInTransaction extends SpacetimeError {
  * Error indicating that BSATN decoding failed.
  * This typically means that the data could not be decoded to the expected type.
  */
-export class BsatnDecodeError extends SpacetimeError {
+export class BsatnDecodeError extends SpacetimeHostError {
   static CODE = 3;
   static MESSAGE = "Couldn't decode the BSATN to the expected type";
   constructor() {
@@ -63,7 +83,7 @@ export class BsatnDecodeError extends SpacetimeError {
 /**
  * Error indicating that a specified table does not exist.
  */
-export class NoSuchTable extends SpacetimeError {
+export class NoSuchTable extends SpacetimeHostError {
   static CODE = 4;
   static MESSAGE = 'No such table';
   constructor() {
@@ -74,7 +94,7 @@ export class NoSuchTable extends SpacetimeError {
 /**
  * Error indicating that a specified index does not exist.
  */
-export class NoSuchIndex extends SpacetimeError {
+export class NoSuchIndex extends SpacetimeHostError {
   static CODE = 5;
   static MESSAGE = 'No such index';
   constructor() {
@@ -85,7 +105,7 @@ export class NoSuchIndex extends SpacetimeError {
 /**
  * Error indicating that a specified row iterator is not valid.
  */
-export class NoSuchIter extends SpacetimeError {
+export class NoSuchIter extends SpacetimeHostError {
   static CODE = 6;
   static MESSAGE = 'The provided row iterator is not valid';
   constructor() {
@@ -96,7 +116,7 @@ export class NoSuchIter extends SpacetimeError {
 /**
  * Error indicating that a specified console timer does not exist.
  */
-export class NoSuchConsoleTimer extends SpacetimeError {
+export class NoSuchConsoleTimer extends SpacetimeHostError {
   static CODE = 7;
   static MESSAGE = 'The provided console timer does not exist';
   constructor() {
@@ -107,7 +127,7 @@ export class NoSuchConsoleTimer extends SpacetimeError {
 /**
  * Error indicating that a specified bytes source or sink is not valid.
  */
-export class NoSuchBytes extends SpacetimeError {
+export class NoSuchBytes extends SpacetimeHostError {
   static CODE = 8;
   static MESSAGE = 'The provided bytes source or sink is not valid';
   constructor() {
@@ -118,7 +138,7 @@ export class NoSuchBytes extends SpacetimeError {
 /**
  * Error indicating that a provided sink has no more space left.
  */
-export class NoSpace extends SpacetimeError {
+export class NoSpace extends SpacetimeHostError {
   static CODE = 9;
   static MESSAGE = 'The provided sink has no more space left';
   constructor() {
@@ -129,7 +149,7 @@ export class NoSpace extends SpacetimeError {
 /**
  * Error indicating that there is no more space in the database.
  */
-export class BufferTooSmall extends SpacetimeError {
+export class BufferTooSmall extends SpacetimeHostError {
   static CODE = 11;
   static MESSAGE = 'The provided buffer is not large enough to store the data';
   constructor() {
@@ -140,7 +160,7 @@ export class BufferTooSmall extends SpacetimeError {
 /**
  * Error indicating that a value with a given unique identifier already exists.
  */
-export class UniqueAlreadyExists extends SpacetimeError {
+export class UniqueAlreadyExists extends SpacetimeHostError {
   static CODE = 12;
   static MESSAGE = 'Value with given unique identifier already exists';
   constructor() {
@@ -151,7 +171,7 @@ export class UniqueAlreadyExists extends SpacetimeError {
 /**
  * Error indicating that the specified delay in scheduling a row was too long.
  */
-export class ScheduleAtDelayTooLong extends SpacetimeError {
+export class ScheduleAtDelayTooLong extends SpacetimeHostError {
   static CODE = 13;
   static MESSAGE = 'Specified delay in scheduling row was too long';
   constructor() {
@@ -162,7 +182,7 @@ export class ScheduleAtDelayTooLong extends SpacetimeError {
 /**
  * Error indicating that an index was not unique when it was expected to be.
  */
-export class IndexNotUnique extends SpacetimeError {
+export class IndexNotUnique extends SpacetimeHostError {
   static CODE = 14;
   static MESSAGE = 'The index was not unique';
   constructor() {
@@ -173,7 +193,7 @@ export class IndexNotUnique extends SpacetimeError {
 /**
  * Error indicating that an index was not unique when it was expected to be.
  */
-export class NoSuchRow extends SpacetimeError {
+export class NoSuchRow extends SpacetimeHostError {
   static CODE = 15;
   static MESSAGE = 'The row was not found, e.g., in an update call';
   constructor() {
@@ -184,7 +204,7 @@ export class NoSuchRow extends SpacetimeError {
 /**
  * Error indicating that an auto-increment sequence has overflowed.
  */
-export class AutoIncOverflow extends SpacetimeError {
+export class AutoIncOverflow extends SpacetimeHostError {
   static CODE = 16;
   static MESSAGE = 'The auto-increment sequence overflowed';
   constructor() {

crates/bindings-typescript/src/server/index.ts

@@ -1,6 +1,8 @@
 export * from './type_builders';
 export { schema } from './schema';
 export { table } from './table';
+export * as errors from './errors';
+export { SenderError } from './errors';
 
 import './polyfills'; // Ensure polyfills are loaded
 import './register_hooks'; // Ensure module hooks are registered

crates/bindings-typescript/src/server/runtime.ts

@@ -7,7 +7,12 @@ import { ConnectionId } from '../lib/connection_id';
 import { Identity } from '../lib/identity';
 import { Timestamp } from '../lib/timestamp';
 import { BinaryReader, BinaryWriter } from '../sdk';
-import { AutoIncOverflow, SpacetimeError, UniqueAlreadyExists } from './errors';
+import {
+  AutoIncOverflow,
+  SenderError,
+  SpacetimeHostError,
+  UniqueAlreadyExists,
+} from './errors';
 import { Range, type Bound } from './range';
 import {
   type Index,
@@ -56,7 +61,14 @@ export const hooks: ModuleHooks = {
       connectionId: ConnectionId.nullIfZero(new ConnectionId(connId)),
       db: getDbView(),
     });
-    return REDUCERS[reducerId](ctx, args) ?? { tag: 'ok' };
+    try {
+      return REDUCERS[reducerId](ctx, args) ?? { tag: 'ok' };
+    } catch (e) {
+      if (e instanceof SenderError) {
+        return { tag: 'err', value: e.message };
+      }
+      throw e;
+    }
   },
 };
 
@@ -423,7 +435,7 @@ function wrapSyscall<F extends (...args: any[]) => any>(
           hasOwn(e, '__code_error__') &&
           typeof e.__code_error__ == 'number'
         ) {
-          throw new SpacetimeError(e.__code_error__);
+          throw new SpacetimeHostError(e.__code_error__);
         }
         throw e;
       }

modules/quickstart-chat-ts/src/index.ts

@@ -1,7 +1,7 @@
 // ─────────────────────────────────────────────────────────────────────────────
 // IMPORTS
 // ─────────────────────────────────────────────────────────────────────────────
-import { schema, t, table } from 'spacetimedb/server';
+import { schema, t, table, SenderError } from 'spacetimedb/server';
 
 const User = table(
   { name: 'user', public: true },
@@ -19,31 +19,27 @@ const Message = table(
 
 const spacetimedb = schema(User, Message);
 
-function validateName(name: string): { tag: 'err'; value: string } | null {
-  if (!name) return { tag: 'err', value: 'Names must not be empty' };
-  return null;
+function validateName(name: string) {
+  if (!name) throw new SenderError('Names must not be empty');
 }
 
 spacetimedb.reducer('set_name', { name: t.string() }, (ctx, { name }) => {
-  let err = validateName(name);
-  if (err) return err;
+  validateName(name);
   const user = ctx.db.user.identity.find(ctx.sender);
-  if (!user) return { tag: 'err', value: 'Cannot set name for unknown user' };
+  if (!user) throw new SenderError('Cannot set name for unknown user');
   console.info(`User ${ctx.sender} sets name to ${name}`);
   ctx.db.user.identity.update({ ...user, name });
 });
 
-function validateMessage(text: string): { tag: 'err'; value: string } | null {
-  if (!text) return { tag: 'err', value: 'Messages must not be empty' };
-  return null;
+function validateMessage(text: string) {
+  if (!text) throw new SenderError('Messages must not be empty');
 }
 
 spacetimedb.reducer('send_message', { text: t.string() }, (ctx, { text }) => {
   // Things to consider:
   // - Rate-limit messages per-user.
   // - Reject messages from unnamed user.
-  const err = validateMessage(text);
-  if (err) return err;
+  validateMessage(text);
   console.info(`User ${ctx.sender}: ${text}`);
   ctx.db.message.insert({
     sender: ctx.sender,