feat: handle errors with prisma exception filter

src/main.ts

@@ -1,17 +1,24 @@
 import { createWriteStream } from "fs";
 import { get } from "http";
 import { ValidationPipe } from "@nestjs/common";
-import { NestFactory } from "@nestjs/core";
+import { HttpAdapterHost, NestFactory } from "@nestjs/core";
 import { DocumentBuilder, SwaggerModule } from "@nestjs/swagger";
 import { AppModule } from "./app.module";
+import { PrismaClientExceptionFilter } from "./prisma-client-exception/prisma-client-exception.filter";
 
 const DEFAULT_PORT = 3000;
 
 async function bootstrap(): Promise<void> {
   const app = await NestFactory.create(AppModule);
 
+  // Validation Pipe
   app.useGlobalPipes(new ValidationPipe({ whitelist: true }));
 
+  // Exception Filter
+  const { httpAdapter } = app.get(HttpAdapterHost);
+  app.useGlobalFilters(new PrismaClientExceptionFilter(httpAdapter));
+
+  // Swagger
   const config = new DocumentBuilder()
     .setTitle("Node + Nest + TypeScript starter project API")
     .setDescription("Basic User API generated with @nestjs/swagger")

src/prisma-client-exception/prisma-client-exception.filter.spec.ts

@@ -0,0 +1,7 @@
+import { PrismaClientExceptionFilter } from "./prisma-client-exception.filter";
+
+describe("PrismaClientExceptionFilter", () => {
+  it("should be defined", () => {
+    expect(new PrismaClientExceptionFilter()).toBeDefined();
+  });
+});

src/prisma-client-exception/prisma-client-exception.filter.ts

@@ -0,0 +1,36 @@
+import {
+  ArgumentsHost,
+  Catch,
+  HttpException,
+  HttpStatus,
+} from "@nestjs/common";
+import { BaseExceptionFilter } from "@nestjs/core";
+import { Prisma } from "@prisma/client";
+
+@Catch(Prisma.PrismaClientKnownRequestError)
+export class PrismaClientExceptionFilter extends BaseExceptionFilter {
+  catch(exception: Prisma.PrismaClientKnownRequestError, host: ArgumentsHost): void {
+    const { code, message } = exception;
+
+    // Log full error message on the server
+    console.error(message);
+
+    // Trim error message for the client
+    const trimmedMessage = message.substring(message.lastIndexOf("\n") + 1);
+
+    // Map Prisma Client exception codes to their corresponding HTTP status code
+    switch (code) {
+      case "P2000":
+        super.catch(new HttpException(trimmedMessage, HttpStatus.BAD_REQUEST), host);
+        break;
+      case "P2002":
+        super.catch(new HttpException(trimmedMessage, HttpStatus.CONFLICT), host);
+        break;
+      case "P2025":
+        super.catch(new HttpException(trimmedMessage, HttpStatus.NOT_FOUND), host);
+        break;
+      default:
+        super.catch(exception, host);
+    }
+  }
+}

src/users/users.controller.ts

@@ -9,7 +9,10 @@ import {
   ParseIntPipe,
 } from "@nestjs/common";
 import {
+  ApiBadRequestResponse,
+  ApiConflictResponse,
   ApiCreatedResponse,
+  ApiNotFoundResponse,
   ApiOkResponse,
   ApiOperation,
   ApiTags,
@@ -32,14 +35,12 @@ export class UsersController {
    *
    * @param user User to create.
    * @returns The created user entity.
-   * @throws If the user creation failed.
    */
   @Post()
   @ApiOperation({ description: "Create a new user." })
-  @ApiCreatedResponse({
-    type: UserEntity,
-    description: "Created. The user has been successfully created.",
-  })
+  @ApiCreatedResponse({ type: UserEntity, description: "Created. The user has been successfully created." })
+  @ApiConflictResponse({ description: "Conflict. Cannot update without corrupt the database." })
+  @ApiBadRequestResponse({ description: "Bad Request. Invalid body content." })
   async create(@Body() user: CreateUserDto): Promise<UserEntity> {
     return this.usersService.create(user);
   }
@@ -51,10 +52,7 @@ export class UsersController {
    */
   @Get()
   @ApiOperation({ description: "Fetch all users." })
-  @ApiOkResponse({
-    type: [UserEntity],
-    description: "OK. The users have been successfully fetched.",
-  })
+  @ApiOkResponse({ type: [UserEntity], description: "OK. The users have been successfully fetched." })
   async findAll(): Promise<UserEntity[]> {
     return this.usersService.findAll();
   }
@@ -64,15 +62,13 @@ export class UsersController {
    *
    * @param id ID of the user to fetch.
    * @returns The fetched user entity or null.
-   * @throws If the request failed.
    */
   @Get(":id")
   @ApiOperation({ description: "Fetch one user." })
-  @ApiOkResponse({
-    type: UserEntity,
-    description: "OK. The user has been successfully fetched.",
-  })
-  async findOne(@Param("id", ParseIntPipe) id: number): Promise<UserEntity | null> {
+  @ApiOkResponse({ type: UserEntity, description: "OK. The user has been successfully fetched." })
+  @ApiNotFoundResponse({ description: "Not Found. The user doesn't exist." })
+  @ApiBadRequestResponse({ description: "Bad Request. Invalid id param." })
+  async findOne(@Param("id", ParseIntPipe) id: number): Promise<UserEntity> {
     return this.usersService.findOne(id);
   }
 
@@ -82,14 +78,13 @@ export class UsersController {
    * @param id ID of the user to update.
    * @param user User data to update.
    * @returns The updated user entity.
-   * @throw If the update failed.
    */
   @Patch(":id")
   @ApiOperation({ description: "Update one user." })
-  @ApiOkResponse({
-    type: UserEntity,
-    description: "OK. The user has been successfully updated.",
-  })
+  @ApiOkResponse({ type: UserEntity, description: "OK. The user has been successfully updated." })
+  @ApiNotFoundResponse({ description: "Not Found. The user to update doesn't exist." })
+  @ApiConflictResponse({ description: "Conflict. Cannot update without corrupt the database." })
+  @ApiBadRequestResponse({ description: "Bad Request. Invalid body content and/or id param." })
   async update(@Param("id", ParseIntPipe) id: number, @Body() user: UpdateUserDto): Promise<UserEntity> {
     return this.usersService.update(id, user);
   }
@@ -99,14 +94,12 @@ export class UsersController {
    *
    * @param id ID of the user to delete.
    * @returns The deleted user entity.
-   * @throws If the deletion failed.
    */
   @Delete(":id")
   @ApiOperation({ description: "Delete one user." })
-  @ApiOkResponse({
-    type: UserEntity,
-    description: "OK. The user has been successfully deleted.",
-  })
+  @ApiOkResponse({ type: UserEntity, description: "OK. The user has been successfully deleted." })
+  @ApiNotFoundResponse({ description: "Not Found. The user to delete doesn't exist." })
+  @ApiBadRequestResponse({ description: "Bad Request. Invalid id param." })
   remove(@Param("id", ParseIntPipe) id: number): Promise<UserEntity> {
     return this.usersService.remove(id);
   }

src/users/users.service.ts

@@ -39,8 +39,8 @@ export class UsersService {
    * @returns The fetched user entity or null.
    * @throws If the query failed.
    */
-  async findOne(id: number): Promise<UserEntity | null> {
-    return this.prismaService.user.findUnique({ where: { id } });
+  async findOne(id: number): Promise<UserEntity> {
+    return this.prismaService.user.findUniqueOrThrow({ where: { id } });
   }
 
   /**

swagger-static/swagger-ui-init.js

@@ -37,6 +37,12 @@ window.onload = function() {
                   }
                 }
               }
+            },
+            "400": {
+              "description": "Bad Request. Invalid body content."
+            },
+            "409": {
+              "description": "Conflict. Cannot update without corrupt the database."
             }
           },
           "tags": [
@@ -93,6 +99,12 @@ window.onload = function() {
                   }
                 }
               }
+            },
+            "400": {
+              "description": "Bad Request. Invalid id param."
+            },
+            "404": {
+              "description": "Not Found. The user doesn't exist."
             }
           },
           "tags": [
@@ -133,6 +145,15 @@ window.onload = function() {
                   }
                 }
               }
+            },
+            "400": {
+              "description": "Bad Request. Invalid body content and/or id param."
+            },
+            "404": {
+              "description": "Not Found. The user to update doesn't exist."
+            },
+            "409": {
+              "description": "Conflict. Cannot update without corrupt the database."
             }
           },
           "tags": [
@@ -163,6 +184,12 @@ window.onload = function() {
                   }
                 }
               }
+            },
+            "400": {
+              "description": "Bad Request. Invalid id param."
+            },
+            "404": {
+              "description": "Not Found. The user to delete doesn't exist."
             }
           },
           "tags": [