Apollo Rest utils

Encoura's solution to integrating rest APIs with Apollo and Apollo Client.

These utils build on top of the great work of apollo-link-rest.

This library provides helper functions and generators for making integration with REST apis and Apollo in a TypeScript application.

Features

• A command line utiltity that takes a swagger file/url, and automatically generates input and output types, and endpoint definitions that can be used to make integration with apollo-link-rest much easier.
• Wrapper functions for common GraphQL operations that allow you to pass in pure GraphQL, and enables the input variables and the result to be strongly typed based on the swagger definition.
• Automatically checks your GraphQL at runtime and will throw exceptions if your GraphQL fields do not match the endpoint definition.
• Custom apollo links to cover REST API edge cases, such as using the headersLink to retrieve data from REST response headers.

Usage

From the command line you can generate definitions for endpoints:

npx apollo-rest-utils <path_to_swagger_file_or_url> <output_directory_where_you_want_the_files> [optional_endpoint_id_to_use] 

Then you can use those definitions to make GraphQL calls within an Apollo context:

import { wrapRestQuery } from '@encoura/apollo-rest-utils';

import ROUTES from 'path/to/directory_specified_in_cli_call/__generatedRestEndpoints';

const userSearch = (searchPattern: string) => {
  const wrappedRestQuery = wrapRestQuery<'users'>();

  const { data, loading } = wrappedRestQuery(
    gql`
      query RenderUserSearchQuery($search: String!) {
        user(search: $search) {
          id
          name
          city
          state
        }
      }
    `,
    {
      endpoint: ROUTES.GET.USER_SEARCH,
      skip: !searchPattern,
      variables: {
        search: searchPattern,
      },
    },
  );

  return data?.users ?? [];
}

Endpoint IDs

To facilitate using this with multiple endpoints, you must specify an endpoint id per endpoint. See https://www.apollographql.com/docs/react/api/link/apollo-link-rest/#multiple-endpoints

Custom Links

HeadersLink

This link allows you to access the REST API's response headers within the data object that comes back from Apollo Client.

NOTE: Since GraphQL only accepts field names written in camelCase, the headers should be requested in camel case format. I.e. if your REST API returns a total-count header, you'll want to ask for it using totalCount.

HeadersLink Setup

import { HeadersLink } from '@encoura/apollo-rest-utils';
import { RestLink } from 'apollo-link-rest';

const headersLink = new HeadersLink();
const restLink = new RestLink({ ... });

new ApolloClient({
  ...
  cache: new InMemoryCache({ ... }),
  link: ApolloLink.from([headersLink, restLink]),
  ...
});

HeadersLink Usage

const { data } = wrapRestQuery<'something'>()(
  gql`
    query SomethingQuery($id: String!) {
      something(id: $id) {
        _id
        fieldA
        fieldB
        fieldC
      }
      headers {
        nextOffset
        totalCount
        totalPages
      }
    }
  `,
  {
    endpoint: REST.GET.SOMETHING,
    variables: {
      id,
    },
  },
);

console.log(data?.something); // response data
console.log(data?.headers); // response headers

Releasing

Checking in the dist folder is not necessary as it will be built upon npm install by the downstream project.

After making any changes and merging them to main, please do the following:

• Create a new branch from main and run npm run update:version
• Verify the CHANGELOG.md generated changes
• Commit, push, and merge to main.
• Create a new release using the tag generated in the previous steps
• Use the Auto-generate release notes button to generate the release notes, and add any context you may deem necessary.