NestJS swagger module not working properly with generic crud controller

user_1286787 0
Viewed 2278

I'm trying to create a generic crud controller that use a generic crud service in a NestJS application. It works properly but the swagger module doesn't generate the documentation about the REST services parameters correctly.

This is the service:

import { Model, Document } from "mongoose";

export abstract class CrudService<CrudModel extends Document, CreateDto, UpdateDto> {

    constructor(protected readonly model: Model<CrudModel>) {}

    async findAll(): Promise<CrudModel[]> {
        return this.model.find().exec();
    }

    async create(dto: CreateDto): Promise<CrudModel> {
        const createdDto = new this.model(dto);
        return createdDto.save();
    }

    async update(id: any, dto: UpdateDto): Promise<CrudModel> {
        return this.model.findOneAndUpdate({ _id: id }, dto, { new: true });
    }

    async delete(id: any): Promise<boolean> {
        const deleteResult = await this.model.deleteOne({ _id: id });
        return deleteResult.ok === 1 && deleteResult.deletedCount === 1;
    }

}

This is the controller:

import { Body, Delete, Get, Param, Post, Put } from "@nestjs/common";
import { Document } from "mongoose";
import { CrudService } from "./crud-service.abstract";

export abstract class CrudController<CrudModel extends Document, CreateDto, UpdateDto> {

    constructor(protected readonly service: CrudService<CrudModel, CreateDto, UpdateDto>) {}

    @Get()
    async findAll(): Promise<CrudModel[]> {
        return this.service.findAll();
    }

    @Post()
    async create(@Body() dto: CreateDto): Promise<CrudModel> {
        return this.service.create(dto);
    }
    
    @Put(':id')
    async update(@Param('id') id: string, @Body() dto: UpdateDto): Promise<CrudModel> {
        return this.service.update(id, dto);
    }

    @Delete(':id')
    async delete(@Param('id') id: string): Promise<boolean> {
        return this.service.delete(id);
    }

}

I found this issue on Github repo: https://github.com/nestjs/swagger/issues/86

The last comment mentions a solution using mixins but I can't figure it out how to adapt it to my needs

nestjs typescript node.js
2 Answers

I eventually went to describing my own schema.

Here is the custom decorator (NestJs example)

import { applyDecorators } from '@nestjs/common';
import { ApiOkResponse, getSchemaPath } from '@nestjs/swagger';

export const OpenApiPaginationResponse = (model: any) => {
  return applyDecorators(
    ApiOkResponse({
      schema: {
        properties: {
          totalPages: {
            type: 'number'
          },
          currentPage: {
            type: 'number'
          },
          itemsPerPage: {
            type: 'number'
          },
          data: {
            type: 'array',
            items: { $ref: getSchemaPath(model) }
          }
        }
      }
    })
  );
};

And here is a example of how it is applied to a controller

@OpenApiPaginationResponse(DTOHere)
public async controllerMethod() {}

Hope this helps you out

user_44103940

I had the same problem recently, I found the solution with Decorators in Nestjs because for native properties Swagger can't recognize our Generic Type Class < T >.

I will show you how I could implement my solution with a Parameterized Pagination Class.

  1. Specify our Pagination Class

     export class PageDto<T> {
   @IsArray()
   readonly data: T[];

   @ApiProperty({ type: () => PageMetaDto })
   readonly meta: PageMetaDto;

    constructor(data: T[], meta: PageMetaDto) {
     this.data = data;
     this.meta = meta;
   }
}

Our parametrized type is data.

  1. Create our Decorator class, that will map our parametrized type data

     export const ApiOkResponsePaginated = <DataDto extends Type<unknown>>(
     dataDto: DataDto,
 ) =>
     applyDecorators(
     ApiExtraModels(PageDto, dataDto),
     ApiOkResponse({
         schema: {
         allOf: [
             { $ref: getSchemaPath(PageDto) },
             {
             properties: {
                 data: {
                 type: 'array',
                 items: { $ref: getSchemaPath(dataDto) },
                 },
             },
             },
         ],
         },
     }),
     );

In this decorator we used the definition of SwaggerDocumentation for specify what will be our class that Swagger will be mapped.

  1. Add our Decorator ApiOkResponsePaginated class in our Controller.

     @Get('/invoices')
 @ApiOkResponsePaginated(LightningInvoice)
 async getAllInvoices(
 @Auth() token: string,
 @Query() pageOptionsDto: any,
 ): Promise<any> {
 return this.client.send('get_invoices', {
     token,
     pageOptionsDto,
 });
 }

And that's how you can visualize in Swagger the representation of PageDto<LightningInvoice> response.

enter image description here

I hope this answer help you in your code.

user_60426530
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