How to add file and other inputs in a POST api into swagger properly?

Question

I am trying to create swagger documentation for a file upload API with NestJS.

This is what I currently have in my controller:

@ApiTags('files')
@Controller('files')
export class FilesController {

    @ApiConsumes('multipart/form-data')
    @ApiCreatedResponse({description: "This api creates a file in the system"})
    @Post('upload')
    @UseInterceptors(FileInterceptor('file'))
    uploadFile(@UploadedFile() file, @Body() fileInfo: UploadFileDto) {
        console.log(file);
        console.log(fileInfo);  
    }
}

and in my DTO file:

import { IsString } from 'class-validator'
import { ApiProperty } from '@nestjs/swagger'

export class UploadFileDto {
    @IsString()
    communityName: string

    @IsString()
    type: string

    @ApiProperty({type:"file"})
    file: any;
}

This way, it shows everything in swagger (and works) properly. However, as you can see there is a redundant "file" variable in my DTO class and function variable. If I remove the "file" attribute from the DTO, then the swagger UI doesn't recognize this parameter as the file input. If I remove it from the function parameter, then it shows up in swagger UI but the controller doesn't receive the uploaded file. Is there a way to correct this?

Thanks.

Answer 1

I just encountered the same problem and thanks to you, I actually solved my issue.

My controller looks as following

@Controller('files')
@ApiTags('files')
export class FilesController
{
    @Post('import')
    @ApiConsumes("multipart/form-data")
    @UseInterceptors(FileInterceptor('file',
        {
            storage: diskStorage({
                destination: './tmp', 
                filename: (req, file, cb) => {
                    const randomName = Array(32).fill(null).map(() => (Math.round(Math.random() * 16)).toString(16)).join('')
                    return cb(null, `${randomName}${extname(file.originalname)}`)
                }
            })
        }
    ))
    async upload(
        @Body() uploadDto: UploadDto,
        @UploadedFile() file: Express.Multer.File
    ): Promise<void>
    {
        console.log(importDto);
        console.log(file);
    }
}

And my DTO

import { IsString } from 'class-validator';
import { ApiProperty } from '@nestjs/swagger';

export class ImportDto {

    @IsString()
    name: string;

    @ApiProperty({ type:'string', format:'binary' })
    file: any;
}

Notice the only real change is in the @ApiProperty() in the DTO. That did the trick.