graphql-sse/lib/use/fastify.mjs

Zero-dependency, HTTP/1 safe, simple, GraphQL over Server-Sent Events Protocol server and client

import { createHandler as createRawHandler, } from '../handler.mjs';
/**
 * The ready-to-use handler for [fastify](https://www.fastify.io).
 *
 * Errors thrown from the provided options or callbacks (or even due to
 * library misuse or potential bugs) will reject the handler or bubble to the
 * returned iterator. They are considered internal errors and you should take care
 * of them accordingly.
 *
 * For production environments, its recommended not to transmit the exact internal
 * error details to the client, but instead report to an error logging tool or simply
 * the console.
 *
 * ```ts
 * import Fastify from 'fastify'; // yarn add fastify
 * import { createHandler } from 'graphql-sse/lib/use/fastify';
 *
 * const handler = createHandler({ schema });
 *
 * const fastify = Fastify();
 *
 * fastify.all('/graphql/stream', async (req, reply) => {
 *   try {
 *     await handler(req, reply);
 *   } catch (err) {
 *     console.error(err);
 *     reply.code(500).send();
 *   }
 * });
 *
 * fastify.listen({ port: 4000 });
 * console.log('Listening to port 4000');
 * ```
 *
 * @category Server/fastify
 */
export function createHandler(options) {
    const handler = createRawHandler(options);
    return async function handleRequest(req, reply) {
        const [body, init] = await handler({
            method: req.method,
            url: req.url,
            headers: {
                get(key) {
                    var _a;
                    const header = (_a = reply.getHeader(key)) !== null && _a !== void 0 ? _a : req.headers[key];
                    return Array.isArray(header) ? header.join('\n') : String(header);
                },
            },
            body: () => new Promise((resolve, reject) => {
                if (req.body) {
                    // body was parsed by middleware
                    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- even if fastify incorrectly parsed the body, we cannot re-read it
                    return resolve(req.body);
                }
                let body = '';
                req.raw.on('data', (chunk) => (body += chunk));
                req.raw.once('error', reject);
                req.raw.once('end', () => {
                    req.raw.off('error', reject);
                    resolve(body);
                });
            }),
            raw: req,
            context: { reply },
        });
        const middlewareHeaders = {};
        for (const [key, val] of Object.entries(reply.getHeaders())) {
            middlewareHeaders[key] = Array.isArray(val)
                ? val.join('\n')
                : String(val);
        }
        reply.raw.writeHead(init.status, init.statusText, {
            ...middlewareHeaders,
            ...init.headers,
        });
        if (!body || typeof body === 'string') {
            return new Promise((resolve) => reply.raw.end(body, () => resolve()));
        }
        reply.raw.once('close', body.return);
        for await (const value of body) {
            const closed = await new Promise((resolve, reject) => {
                if (!reply.raw.writable) {
                    // response's close event might be late
                    resolve(true);
                }
                else {
                    reply.raw.write(value, (err) => (err ? reject(err) : resolve(false)));
                }
            });
            if (closed) {
                break;
            }
        }
        reply.raw.off('close', body.return);
        return new Promise((resolve) => reply.raw.end(resolve));
    };
}