Tutorial – Published REST API

Goal for this step 🏁: Add a REST API to the backend for published client.

Similarly we can setup the published REST API. In backend/main.ts we expose a GET endpoint at /api/published/:operationName:

import {
  executePublishedClientOperationFromJson,
  type PublishedClientJsonOperationArgs,
} from '@dossierhq/core';

app.get(
  '/api/published/:operationName',
  asyncHandler(async (req, res) => {
    const publishedClient = getPublishedClientForRequest(server, req);
    const { operationName } = req.params;
    const operationArgs = decodeURLSearchParamsParam<PublishedClientJsonOperationArgs>(
      req.query as Record<string, string>,
      'args'
    );
    if (!operationArgs) {
      sendResult(res, notOk.BadRequest('Missing args'));
    } else {
      sendResult(
        res,
        await executePublishedClientOperationFromJson(publishedClient, operationName, operationArgs)
      );
    }
  })
);

And to create a published client in the frontend we add this to src/ClientUtils.ts:

import {
  convertJsonPublishedClientResult,
  createBasePublishedClient,
  type PublishedClientOperation,
} from '@dossierhq/core';
import type { AppPublishedClient } from './SchemaTypes.js';

export function usePublishedClient(): AppPublishedClient | null {
  return useMemo(
    () =>
      createBasePublishedClient<ClientContext, AppPublishedClient>({
        context: { logger },
        pipeline: [createPublishedBackendMiddleware()],
      }),
    []
  );
}

function createPublishedBackendMiddleware() {
  return async (context: ClientContext, operation: PublishedClientOperation): Promise<void> => {
    const response = await fetch(
      `/api/published/${operation.name}?${encodeObjectToURLSearchParams(
        { args: operation.args },
        { keepEmptyObjects: true }
      )}`
    );
    const result = await getBodyAsJsonResult(response);
    operation.resolve(convertJsonPublishedClientResult(operation.name, result));
  };
}

In the next step we'll use the published client in the web interface.