A Nest interceptor to display the Link and the Content Range in the response headers.

# NestJS Request Pagination A simple NestJS interceptor catching query parameters and format a Link Header, based on [GitHub](https://developer.github.com/v3/guides/traversing-with-pagination/) pagination API. This module uses [format-link-header](https://github.com/jonathansamines/format-link-header) node module to build the response Link Header. ## Installation ```bash npm install --save @algoan/nestjs-pagination ``` ## Requirements - On this version, the API attached with this interceptor needs to return an object: ```json { "totalResources": 1530, "resources": [ { ... }, ..., { ... }] } ``` - The resource has to be specified in the interceptor constructor ## Limits - This module does not take into account what is returned in the `resources` property. It may be inconsistent with headers set by the interceptor. ## Quick Start Import `LinkHeaderInterceptor` next to a controller method. ```typescript import { LinkHeaderInterceptor } from '@algoan/nestjs-pagination'; import { Controller, Get, UseInterceptors } from '@nestjs/common'; @Controller() /** * Controller returning a lot of documents */ class AppController { /** * Find all documents */ @UseInterceptors(new LinkHeaderInterceptor({ resource: 'data' })) @Get('/data') public async findAll(): Promise<{ totalResources: number; resources: DataToReturn[] }> { const data: DataToReturn = await model.find(...); const count: number = await model.count(); return { totalResources: count, resources: data }; } } ``` For instance, if you have 1015 resources, calling `GET /data?page=4&per_page=100` will return: ``` Content-Range: data 300-399/1015 Link: ; rel="first", ; rel="last", ; rel="next", ; rel="prev" ``` If you use MongoDB as your database, we also provide a `ParamDecorator` you can use to convert the request to a mongo query parameter. ```typescript import { LinkHeaderInterceptor, MongoPaginationParamDecorator, MongoPagination, Pageable } from '@algoan/nestjs-pagination'; import { Controller, Get, UseInterceptors } from '@nestjs/common'; @Controller() /** * Controller returning a lot of documents */ class AppController { /** * Find all documents */ @UseInterceptors(new LinkHeaderInterceptor({ resource: 'data' })) @Get('/data') public async findAll(@MongoPaginationParamDecorator() pagination: MongoPagination ): Promise> { const data: DataToReturn[] = await model.find(pagination); const count: number = await model.count(pagination.filter); return { totalResources: count, resources: data }; } } ``` ## Usage By default, the interceptor and the decorator will look for the query parameters `page` and `per_page` (which is 100 by default). You can also change the name of those parameters and the default per page limit if you want, by passing a configuration object. Beware that if you use both the interceptor and the decorator, you need to pass the configuration to both of them. ```typescript new LinkHeaderInterceptor({ resource: 'data', pageName: '_page', perPageName: 'numberPerPage', defaultLimit: 50 }) @MongoPaginationParamDecorator({ pageName: '_page', perPageName: 'numberPerPage', defaultLimit: 50 }) ``` You can also have the pagination in the response body by using the PaginationBodyInterceptor. By using this interceptor, the pagination is included in the response body instead of the header. A paginated data response is returned. ```json { "resources": [], "pagination": { "next": null, "previous": null, "first": null, "last": null, "totalPages": 1, "totalResources": 0, } } ``` Import the `PaginationBodyInterceptor` next to a controller method. ```typescript import { PaginationBodyInterceptor } from '@algoan/nestjs-pagination'; import { Controller, Get, UseInterceptors } from '@nestjs/common'; @Controller() /** * Controller returning a lot of documents */ class AppController { /** * Find all documents */ @UseInterceptors(new PaginationBodyInterceptor({pageName: 'page', perPageName: 'limit'})) @Get('/data') public async findAll(@MongoPaginationParamDecorator({pageName: 'page', perPageName: 'limit'}) pagination: MongoPagination): Promise<{ totalResources: number; resources: DataToReturn[] }> { const data: DataToReturn = await model.find(...); const count: number = await model.count(); return { totalResources: count, resources: data }; } } ```