Pushing errors back to frontend

backend/src/album/album.controller.ts

@@ -31,7 +31,9 @@ export class AlbumController {
 
   @Post()
   @UsePipes(new ValidationPipe({ transform: true }))
-  async create(@Body() createAlbumDto: CreateAlbumDto): Promise<Album | string | null> {
+  async create(
+    @Body() createAlbumDto: CreateAlbumDto,
+  ): Promise<Album | string | null> {
     return this.albumService.create(createAlbumDto);
   }
 

backend/src/album/album.service.ts

@@ -13,21 +13,24 @@ export class AlbumService {
   ) {}
 
   findAll(): Promise<Album[] | string | null> {
-    return this.albumRepository.find({
+    return this.albumRepository
+      .find({
         order: {
           artist: 'ASC',
           title: 'ASC',
         },
-    }).then((albums) => {
+      })
+      .then((albums) => {
         return albums;
       })
       .catch((error) => {
-      return `There was a problem getting the list of albums: ${error}`
+        return `There was a problem getting the list of albums: ${error}`;
       });
   }
 
   findOneById(id: number): Promise<Album | string | null> {
-    return this.albumRepository.findOne({
+    return this.albumRepository
+      .findOne({
         where: {
           id: id,
         },
@@ -39,13 +42,15 @@ export class AlbumService {
             trackNumber: 'ASC',
           },
         },
-    }).then((album) => {
+      })
+      .then((album) => {
         return album;
       })
       .catch((error) => {
-      return `There was a problem creating the Album identified by ID ${id}: ${error}`
+        return `There was a problem creating the Album identified by ID ${id}: ${error}`;
-    }).finally(() => {
+      })
-      return `There was a problem creating the Album identified by ID ${id}`
+      .finally(() => {
+        return `There was a problem creating the Album identified by ID ${id}`;
       });
   }
 
@@ -55,12 +60,13 @@ export class AlbumService {
       artist: createAlbumDto.artist,
       genre: createAlbumDto.genre,
     });
-    return await this.albumRepository.save(album)
+    return await this.albumRepository
+      .save(album)
       .then((savedAlbum) => {
         return savedAlbum;
       })
       .catch((error) => {
-        return `There was a problem creating the Album (${createAlbumDto.title} by ${createAlbumDto.artist} (${createAlbumDto.genre})): ${error}`
+        return `There was a problem creating the Album (${createAlbumDto.title} by ${createAlbumDto.artist} (${createAlbumDto.genre})): ${error}`;
       });
   }
 
@@ -100,12 +106,13 @@ export class AlbumService {
   }
 
   async remove(id: number): Promise<DeleteResult | string | null> {
-    return await this.albumRepository.delete(id)
+    return await this.albumRepository
+      .delete(id)
       .then((deleteResult) => {
         return deleteResult;
       })
       .catch((error) => {
-      return `There was a problem deleting the Album identified by ID ${id}: ${error}`
+        return `There was a problem deleting the Album identified by ID ${id}: ${error}`;
       });
   }
 }

backend/src/album/dto/create-album.dto.ts

@@ -1,3 +1,5 @@
+import { IsNotEmpty, IsString } from 'class-validator';
+
 export class CreateAlbumDto {
   @IsString()
   @IsNotEmpty()

backend/src/album/dto/update-album.dto.ts

@@ -1,5 +1,6 @@
+import { IsNotEmpty, IsNumber, IsString } from 'class-validator';
+
 export class UpdateAlbumDto {
-  @Column()
   @IsNumber()
   id: number;
 
@@ -13,7 +14,6 @@ export class UpdateAlbumDto {
 
   @IsString()
   @IsNotEmpty()
-
   @IsString()
   @IsNotEmpty()
   genre: string;

backend/src/main.ts

@@ -1,5 +1,5 @@
 import { NestFactory } from '@nestjs/core';
-import { ValidationPipe } from '@nestjs/common';
+import { UnprocessableEntityException, ValidationError, ValidationPipe } from '@nestjs/common';
 import { AppModule } from './app.module';
 
 async function bootstrap() {
@@ -13,16 +13,53 @@ async function bootstrap() {
     allowedHeaders:
       'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept, Observe',
   });
-  app.useGlobalPipes(new ValidationPipe({
+  app.useGlobalPipes(
+    new ValidationPipe({
       transform: true,
-    exceptionFactory: (errors) => {
+      whitelist: true,
-        const result = errors.map((error) => ({
+      exceptionFactory: (validationErrors: ValidationError[] = []) => {
-          property: error.property,
+        const getPrettyClassValidatorErrors = (
-          message: error.constraints[Object.keys(error.constraints)[0]],
+          validationErrors: ValidationError[],
-        }));
+          parentProperty = '',
-        return new UnprocessableEntityException(result);
+        ): Array<{ property: string; errors: string[] }> => {
+          const errors : any[] = [];
+
+          const getValidationErrorsRecursively = (
+            validationErrors: ValidationError[],
+            parentProperty = '',
+          ) => {
+            for (const error of validationErrors) {
+              const propertyPath = parentProperty
+                ? `${parentProperty}.${error.property}`
+                : error.property;
+
+              if (error.constraints) {
+                errors.push({
+                  property: propertyPath,
+                  errors: Object.values(error.constraints),
+                });
+              }
+
+              if (error.children?.length) {
+                getValidationErrorsRecursively(error.children, propertyPath);
+              }
+            }
+          };
+
+          getValidationErrorsRecursively(validationErrors, parentProperty);
+
+          return errors;
+        };
+
+        const errors = getPrettyClassValidatorErrors(validationErrors);
+
+        return new UnprocessableEntityException({
+          message: 'validation error',
+          errors: errors,
+        });
       },
-  }));
+    }),
+  );
   await app.listen(process.env.PORT ?? 3000);
 }
 bootstrap();

backend/src/song/dto/create-song.dto.ts

@@ -1,21 +1,16 @@
-import { Entity, Column, ManyToOne, PrimaryGeneratedColumn } from 'typeorm';
 import { IsNotEmpty, IsNumber, IsString } from 'class-validator';
 
 export class CreateSongDto {
-  @Column({ unique: true })
   @IsString()
   @IsNotEmpty()
   title: string;
 
-  @Column()
   @IsNumber()
   duration: number;
 
-  @Column()
   @IsNumber()
   trackNumber: number;
 
-  @Column()
   @IsNumber()
   albumId: number;
 }

backend/src/song/dto/update-song.dto.ts

@@ -1,22 +1,19 @@
+import { IsNotEmpty, IsNumber, IsString } from 'class-validator';
+
 export class UpdateSongDto {
-  @Column()
   @IsNumber()
   id: number;
 
-  @Column({ unique: true })
   @IsString()
   @IsNotEmpty()
   title: string;
 
-  @Column()
   @IsNumber()
   duration: number;
 
-  @Column()
   @IsNumber()
   trackNumber: number;
 
-  @Column()
   @IsNumber()
   albumId: number;
 }

backend/src/song/song.controller.ts

@@ -31,7 +31,9 @@ export class SongController {
 
   @Post()
   @UsePipes(new ValidationPipe({ transform: true }))
-  async create(@Body() createSongDto: CreateSongDto): Promise<Song | string | null> {
+  async create(
+    @Body() createSongDto: CreateSongDto,
+  ): Promise<Song | string | null> {
     return this.songService.create(createSongDto);
   }
 

backend/src/song/song.service.ts

@@ -16,24 +16,28 @@ export class SongService {
   ) {}
 
   findAll(): Promise<Song[] | string | null> {
-    return this.songRepository.find({
+    return this.songRepository
+      .find({
         order: {
           trackNumber: 'ASC',
         },
-    }).then((songs) => {
+      })
+      .then((songs) => {
         return songs;
       })
       .catch((error) => {
-      return `There was a problem getting the list of songs: ${error}`
+        return `There was a problem getting the list of songs: ${error}`;
       });
   }
 
   findOneById(id: number): Promise<Song | string | null> {
-    return this.songRepository.findOneBy({ id: id }).then((albums) => {
+    return this.songRepository
+      .findOneBy({ id: id })
+      .then((albums) => {
         return albums;
       })
       .catch((error) => {
-      return `There was a problem getting the song identified by ID ${id}: ${error}`
+        return `There was a problem getting the song identified by ID ${id}: ${error}`;
       });
   }
 
@@ -47,18 +51,23 @@ export class SongService {
       song.duration = createSongDto.duration;
       song.trackNumber = createSongDto.trackNumber;
       song.album = album;
-      return this.songRepository.save(song).then((albums) => {
+      return this.songRepository
+        .save(song)
+        .then((albums) => {
           return albums;
         })
         .catch((error) => {
-        return `There was a problem creating the song (${createSongDto.trackNumber} ${createSongDto.title} (${createSongDto.duration}s) on the Album ${album.title} by ${album.artist}): ${error}`
+          return `There was a problem creating the song (${createSongDto.trackNumber} ${createSongDto.title} (${createSongDto.duration}s) on the Album ${album.title} by ${album.artist}): ${error}`;
         });
     } else {
       throw new Error(`Unable to find Album with ID ${createSongDto.albumId}`);
     }
   }
 
-  async update(id: number, updateSongDto: UpdateSongDto): Promise<Song | string | null> {
+  async update(
+    id: number,
+    updateSongDto: UpdateSongDto,
+  ): Promise<Song | string | null> {
     if (id == updateSongDto.id) {
       const album = await this.albumRepository.findOneBy({
         id: updateSongDto.albumId,
@@ -91,12 +100,13 @@ export class SongService {
   }
 
   async remove(id: number): Promise<DeleteResult | string | null> {
-    return await this.songRepository.delete(id)
+    return await this.songRepository
+      .delete(id)
       .then((deleteResult) => {
         return deleteResult;
       })
       .catch((error) => {
-      return `There was a problem deleting the Song identified by ID ${id}: ${error}`
+        return `There was a problem deleting the Song identified by ID ${id}: ${error}`;
       });
   }
 }