Generics Support

import { Post, Param, Delete, Put, Get, Res, Body, HttpStatus } from "@nestjs/common";
import { ApiResponse, ApiOperation } from "@nestjs/swagger";
import { Response } from 'express';
import { CRUDService } from "./crud.service";
import { Document } from 'mongoose';

export abstract class CRUDController<M extends Document, C, U, T extends CRUDService<M, C, U>> {
  constructor ( protected readonly service: T ) { }

  @Post()
  @ApiOperation( { title: 'Create' } )
  @ApiResponse( { status: 201, description: 'Object created.' } )
  @ApiResponse( { status: 400, description: 'Validation failed.' } )
  async create ( @Body() post: C, @Res() res: Response ): Promise<void> {
    const result = await this.service.create( post );
    res.status( result ? HttpStatus.OK : HttpStatus.NOT_FOUND ).send( result );
  }

  @Get()
  @ApiOperation( { title: 'Find All' } )
  @ApiResponse( { status: 200, description: 'Objects returned.' } )
  @ApiResponse( { status: 400, description: 'Validation failed.' } )
  async findAll ( @Res() res: Response ): Promise<void> {
    const result = await this.service.findAll();
    res.status( result ? HttpStatus.OK : HttpStatus.NOT_FOUND ).send( result );
  }

  @Get( ':id' )
  @ApiOperation( { title: 'Find by Id' } )
  @ApiResponse( { status: 200, description: 'Object found.' } )
  @ApiResponse( { status: 400, description: 'Validation failed.' } )
  @ApiResponse( { status: 404, description: 'Object not found.' } )
  async findById ( @Param( 'id' ) id: string, @Res() res: Response ): Promise<void> {
    const result = await this.service.findById( id );
    res.status( result ? HttpStatus.OK : HttpStatus.NOT_FOUND ).send( result );
  }

  @Put( ':id' )
  @ApiOperation( { title: 'Update' } )
  @ApiResponse( { status: 200, description: 'Post updated.' } )
  @ApiResponse( { status: 400, description: 'Validation failed.' } )
  @ApiResponse( { status: 404, description: 'Post not found.' } )
  async update ( @Param( 'id' ) id: string, @Body() updatePostDto: U, @Res() res: Response ): Promise<void> {
    const result = await this.service.update( id, updatePostDto );
    res.status( result ? HttpStatus.OK : HttpStatus.NOT_FOUND ).send( result );
  }

  @Delete( ':id' )
  @ApiOperation( { title: 'Remove' } )
  @ApiResponse( { status: 204, description: 'Object removed.' } )
  @ApiResponse( { status: 400, description: 'Validation failed.' } )
  @ApiResponse( { status: 404, description: 'Object not found.' } )
  async remove ( @Param( 'id' ) id: string, @Res() res: Response ): Promise<void> {
    const result = await this.service.remove( id );
    res.status( result ? HttpStatus.NO_CONTENT : HttpStatus.NOT_FOUND ).send( result );
  }
}

This will produce the following error in the console of the browser.

swagger-ui-init.js:30 Uncaught SyntaxError: Unexpected identifier

Here is swagger-ui-init.js:

window.onload = function() {
  // Build a system
  var url = window.location.search.match(/url=([^&]+)/);
  if (url && url.length > 1) {
    url = decodeURIComponent(url[1]);
  } else {
    url = window.location.origin;
  }
  var options = {
  "swaggerDoc": {
    "swagger": "2.0",
    "info": {
      "description": "Bitea API",
      "version": "1.0",
      "title": "Bitea API"
    },
    "basePath": "/",
    "tags": [],
    "schemes": [
      "http"
    ],
    "securityDefinitions": {},
    "paths": {
      "/posts": {
        "post": {
          "summary": "Create",
          "parameters": [
            {
              "type": function Object() { [native code] },
              "name": "Object",
              "required": true,
              "in": "body",
              "schema": {
                "$ref": "#/definitions/Object"
              }
            }
          ],
          "responses": {
            "201": {
              "description": "Object created."
            },
            "400": {
              "description": "Validation failed."
            }
          },
          "tags": [
            "Posts"
          ],
          "produces": [
            "application/json"
          ],
          "consumes": [
            "application/json"
          ]
        },
        "get": {
          "summary": "Find All",
          "responses": {
            "200": {
              "description": "Objects returned."
            },
            "400": {
              "description": "Validation failed."
            }
          },
          "tags": [
            "Posts"
          ],
          "produces": [
            "application/json"
          ],
          "consumes": [
            "application/json"
          ]
        }
      },
      "/posts/{id}": {
        "get": {
          "summary": "Find by Id",
          "parameters": [
            {
              "type": "string",
              "name": "id",
              "required": true,
              "in": "path"
            }
          ],
          "responses": {
            "200": {
              "description": "Object found."
            },
            "400": {
              "description": "Validation failed."
            },
            "404": {
              "description": "Object not found."
            }
          },
          "tags": [
            "Posts"
          ],
          "produces": [
            "application/json"
          ],
          "consumes": [
            "application/json"
          ]
        },
        "put": {
          "summary": "Update",
          "parameters": [
            {
              "type": function Object() { [native code] },
              "name": "Object",
              "required": true,
              "in": "body",
              "schema": {
                "$ref": "#/definitions/Object"
              }
            },
            {
              "type": "string",
              "name": "id",
              "required": true,
              "in": "path"
            }
          ],
          "responses": {
            "200": {
              "description": "Post updated."
            },
            "400": {
              "description": "Validation failed."
            },
            "404": {
              "description": "Post not found."
            }
          },
          "tags": [
            "Posts"
          ],
          "produces": [
            "application/json"
          ],
          "consumes": [
            "application/json"
          ]
        },
        "delete": {
          "summary": "Remove",
          "parameters": [
            {
              "type": "string",
              "name": "id",
              "required": true,
              "in": "path"
            }
          ],
          "responses": {
            "204": {
              "description": "Object removed."
            },
            "400": {
              "description": "Validation failed."
            },
            "404": {
              "description": "Object not found."
            }
          },
          "tags": [
            "Posts"
          ],
          "produces": [
            "application/json"
          ],
          "consumes": [
            "application/json"
          ]
        }
      }
    },
    "definitions": {
      "Object": {
        "type": "object",
        "properties": {}
      }
    }
  },
  "customOptions": {}
};
  url = options.swaggerUrl || url
  var customOptions = options.customOptions
  var spec1 = options.swaggerDoc
  var swaggerOptions = {
    spec: spec1,
    url: url,
    dom_id: '#swagger-ui',
    deepLinking: true,
    presets: [
      SwaggerUIBundle.presets.apis,
      SwaggerUIStandalonePreset
    ],
    plugins: [
      SwaggerUIBundle.plugins.DownloadUrl
    ],
    layout: "StandaloneLayout"
  }
  for (var attrname in customOptions) {
    swaggerOptions[attrname] = customOptions[attrname];
  }
  var ui = SwaggerUIBundle(swaggerOptions)

  if (customOptions.oauth) {
    ui.initOAuth(customOptions.oauth)
  }

  if (customOptions.authAction) {
    ui.authActions.authorize(customOptions.authAction)
  }

  window.ui = ui
}

[XBeg9]

Solution using Mixin:

export type ClassType<T = any> = new (...args: any[]) => T;

interface IPaginated {
  limit?: number;
  offset?: number;
}

export function PaginatedRequestDto<T extends ClassType>(ResourceCls: T) {
  class Paginated extends ResourceCls implements IPaginated {
    @ApiModelPropertyOptional({ default: 100 })
    public limit?: number;

    @ApiModelPropertyOptional({ default: 0 })
    public offset?: number;
  }

  return Paginated;
}

and then use it like this:

class PaginatedSearchRequestDto extends PaginatedRequestDto(SearchRequestDto) {}

I’ve also verified this with swagger docs shows both definitions from SearchRequestDto and Paginated.

[cojack]

@kamilmysliwiec so maybe we’ll add some additional decorator for class definition that will cover generic output, something like:

@ApiInputOutput(Class)

fe Im using TypeORM, and using generic RestController with methods like:

@Post()
public async update(partial: DataPartial<T>): Promise<T> {
  return this.service.update(partial);
}

This produce and empty POST params in swagger, by this, swagger is useless.