fix(repository): Move backend code into subdirectory

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

backend/src/errors/error-mapping.ts

@@ -0,0 +1,100 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import {
+  ArgumentsHost,
+  BadRequestException,
+  Catch,
+  ConflictException,
+  InternalServerErrorException,
+  NotFoundException,
+  PayloadTooLargeException,
+  UnauthorizedException,
+} from '@nestjs/common';
+import { HttpException } from '@nestjs/common/exceptions/http.exception';
+import { BaseExceptionFilter } from '@nestjs/core';
+
+import {
+  buildHttpExceptionObject,
+  HttpExceptionObject,
+} from './http-exception-object';
+
+type HttpExceptionConstructor = (object: HttpExceptionObject) => HttpException;
+
+const mapOfHedgeDocErrorsToHttpErrors: Map<string, HttpExceptionConstructor> =
+  new Map([
+    ['NotInDBError', (object): HttpException => new NotFoundException(object)],
+    [
+      'AlreadyInDBError',
+      (object): HttpException => new ConflictException(object),
+    ],
+    [
+      'ForbiddenIdError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    ['ClientError', (object): HttpException => new BadRequestException(object)],
+    [
+      'PermissionError',
+      (object): HttpException => new UnauthorizedException(object),
+    ],
+    [
+      'TokenNotValidError',
+      (object): HttpException => new UnauthorizedException(object),
+    ],
+    [
+      'TooManyTokensError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    [
+      'PermissionsUpdateInconsistentError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    [
+      'MediaBackendError',
+      (object): HttpException => new InternalServerErrorException(object),
+    ],
+    [
+      'PrimaryAliasDeletionForbiddenError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    [
+      'InvalidCredentialsError',
+      (object): HttpException => new UnauthorizedException(object),
+    ],
+    [
+      'NoLocalIdentityError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    [
+      'PasswordTooWeakError',
+      (object): HttpException => new BadRequestException(object),
+    ],
+    [
+      'MaximumDocumentLengthExceededError',
+      (object): HttpException => new PayloadTooLargeException(object),
+    ],
+  ]);
+
+@Catch()
+export class ErrorExceptionMapping extends BaseExceptionFilter<Error> {
+  catch(error: Error, host: ArgumentsHost): void {
+    super.catch(ErrorExceptionMapping.transformError(error), host);
+  }
+
+  private static transformError(error: Error): Error {
+    const httpExceptionConstructor = mapOfHedgeDocErrorsToHttpErrors.get(
+      error.name,
+    );
+    if (httpExceptionConstructor === undefined) {
+      // We don't know how to map this error and just leave it be
+      return error;
+    }
+    const httpExceptionObject = buildHttpExceptionObject(
+      error.name,
+      error.message,
+    );
+    return httpExceptionConstructor(httpExceptionObject);
+  }
+}

backend/src/errors/errors.ts

@@ -0,0 +1,61 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export class NotInDBError extends Error {
+  name = 'NotInDBError';
+}
+
+export class AlreadyInDBError extends Error {
+  name = 'AlreadyInDBError';
+}
+
+export class ForbiddenIdError extends Error {
+  name = 'ForbiddenIdError';
+}
+
+export class ClientError extends Error {
+  name = 'ClientError';
+}
+
+export class PermissionError extends Error {
+  name = 'PermissionError';
+}
+
+export class TokenNotValidError extends Error {
+  name = 'TokenNotValidError';
+}
+
+export class TooManyTokensError extends Error {
+  name = 'TooManyTokensError';
+}
+
+export class PermissionsUpdateInconsistentError extends Error {
+  name = 'PermissionsUpdateInconsistentError';
+}
+
+export class MediaBackendError extends Error {
+  name = 'MediaBackendError';
+}
+
+export class PrimaryAliasDeletionForbiddenError extends Error {
+  name = 'PrimaryAliasDeletionForbiddenError';
+}
+
+export class InvalidCredentialsError extends Error {
+  name = 'InvalidCredentialsError';
+}
+
+export class NoLocalIdentityError extends Error {
+  name = 'NoLocalIdentityError';
+}
+
+export class PasswordTooWeakError extends Error {
+  name = 'PasswordTooWeakError';
+}
+
+export class MaximumDocumentLengthExceededError extends Error {
+  name = 'MaximumDocumentLengthExceededError';
+}

backend/src/errors/http-exception-object.ts

@@ -0,0 +1,20 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export interface HttpExceptionObject {
+  name: string;
+  message: string;
+}
+
+export function buildHttpExceptionObject(
+  name: string,
+  message: string,
+): HttpExceptionObject {
+  return {
+    name: name,
+    message: message,
+  };
+}