writeWebResponse() — astro Function Reference

Architecture documentation for the writeWebResponse() function in response.ts from the astro codebase.

Function typescript CoreAstro RenderingEngine called by 1

Entity Profile

CoreAstro→ RenderingEngine→ writeWebResponse() — astro Function Reference

Dependency Diagram

graph TD
  2320f1f4_bad3_72be_6b18_c52ec324e612["writeWebResponse()"]
  4611d913_9978_903f_46fc_e5961ccf4da7["response.ts"]
  2320f1f4_bad3_72be_6b18_c52ec324e612 -->|defined in| 4611d913_9978_903f_46fc_e5961ccf4da7
  108bcb8c_9076_0822_7c6e_8e40a396e1a0["writeSSRResult()"]
  108bcb8c_9076_0822_7c6e_8e40a396e1a0 -->|calls| 2320f1f4_bad3_72be_6b18_c52ec324e612
  style 2320f1f4_bad3_72be_6b18_c52ec324e612 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/astro/src/vite-plugin-astro-server/response.ts lines 58–103

async function writeWebResponse(res: http.ServerResponse, webResponse: Response) {
	const { status, headers, body, statusText } = webResponse;

	// Attach any set-cookie headers added via Astro.cookies.set()
	const setCookiesFromResponse = Array.from(getSetCookiesFromResponse(webResponse));
	const setCookieHeaders = [...setCookiesFromResponse, ...headers.getSetCookie()];

	const _headers: http.OutgoingHttpHeaders = Object.fromEntries(headers.entries());

	if (setCookieHeaders.length) {
		_headers['set-cookie'] = setCookieHeaders;
	}
	// HTTP/2 doesn't support statusMessage
	if (!(res instanceof Http2ServerResponse)) {
		res.statusMessage = statusText;
	}
	res.writeHead(status, _headers);
	if (body) {
		if (Symbol.for('astro.responseBody') in webResponse) {
			let stream = (webResponse as any)[Symbol.for('astro.responseBody')];
			for await (const chunk of stream) {
				res.write(chunk.toString());
			}
		} else if (body instanceof Readable) {
			body.pipe(res);
			return;
		} else if (typeof body === 'string') {
			res.write(body);
		} else {
			const reader = body.getReader();
			res.on('close', () => {
				reader.cancel().catch(() => {
					// Don't log here, or errors will get logged twice in most cases
				});
			});
			while (true) {
				const { done, value } = await reader.read();
				if (done) break;
				if (value) {
					res.write(value);
				}
			}
		}
	}
	res.end();
}