example.ts

import fastify from 'fastify';
import { ServerResponse } from 'http';
const S = require('sanctuary');

const healthCheckRoutes = (fastify: fastify.FastifyInstance) => {
  fastify.get(
    '/ping',
    {
      schema: {
        response: {
          200: {
            type: 'object',
            properties: {
              ok: {
                type: 'boolean',
              },
            },
          },
        },
      },
    },
    async () => {
      return { ok: true };
    },
  );

  const validateHeaders = request => {
    request.log.info(request.headers, 'headers');
    if (!request.headers['x-open-sesame']) {
      return S.Left({ err: 'Unauthorized', status: 401 });
    }

    return S.Right(request);
  };

  const greet = (request: fastify.FastifyRequest) => {
    return S.Right({
      ok: true,
      message: `Hello, ${request.query.name || 'world'}!`,
    });
  };

  const respond = (reply: fastify.FastifyReply<ServerResponse>) => what => {
    if (what.value.status) {
      reply.code(what.value.status);
    }
    if (S.isLeft(what)) {
      return { ok: false, err: what.value.err };
    } else {
      return what.value;
    }
  };

  fastify.get(
    '/protected',
    {
      schema: {
        headers: {
          type: 'object',
          properties: {
            'x-open-sesame': { type: 'boolean' },
          },
        },
        querystring: {
          type: 'object',
          properties: {
            name: { type: 'string' },
          },
        },
        response: {
          200: {
            type: 'object',
            properties: {
              ok: {
                type: 'boolean',
              },
              err: {
                type: 'string',
              },
              message: {
                type: 'string',
              },
            },
          },
        },
      },
    },
    async (
      request: fastify.FastifyRequest,
      reply: fastify.FastifyReply<ServerResponse>,
    ) => {
      // return S.compose(respond(reply))(greet)(validateHeaders)(request);
      return S.pipe([validateHeaders, S.chain(greet), respond(reply)])(request);
    },
  );
};

export default healthCheckRoutes;