feat: initial release

1 files changed, 118 insertions, 0 deletions

diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..74c9317
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,118 @@
+/*
+ ** We support the GET, POST, HEAD, and OPTIONS methods from any origin, and accept the Content-Type header on requests.
+ ** These headers must be present on all responses to all CORS requests.
+ ** In practice, this means all responses to OPTIONS requests.
+ **
+ ** Modified by Alejandro Akbal (VoidlessSeven7)
+ */
+
+/**
+ * Fetches the request content and returns it
+ * @param {*} request
+ */
+async function handleRequest(request) {
+	// Initialize url and query
+	const url = new URL(request.url);
+	const query = url.search.split('?q=')[1];
+	const origin = request.headers.get('Origin');
+
+	/*
+	 * Rewrite request to point to API url. This also makes the request mutable
+	 * so we can add the correct Origin header to make the API server think
+	 * that this request isn't cross-site.
+	 */
+
+	request = new Request(query, request);
+
+	/*
+	 * Set headers to make the endpoint think it's itself
+	 */
+	request.headers.set('Host', new URL(query).origin);
+	request.headers.set('Referer', new URL(query));
+	// request.headers.set('Origin', new URL(query))
+
+	// Fetch it
+	let response = await fetch(request);
+
+	// Recreate the response so we can modify the headers
+	response = new Response(response.body, response);
+
+	// Set CORS headers
+	response.headers.set('Access-Control-Allow-Origin', origin.includes('localhost') ? '*' : 'https://due.moe');
+
+	// Append to/Add Vary header so browser will cache response correctly
+	response.headers.append('Vary', 'Origin');
+
+	response.headers.append('max-age', '300');
+
+	// Return it
+	return response;
+}
+
+/**
+ * Makes sure that the necessary headers are present for this to be a valid pre-flight request
+ * @param {*} request
+ */
+async function handleOptions(request) {
+	/*
+	 * Handle CORS pre-flight request.
+	 * If you want to check the requested method + headers you can do that here.
+	 */
+	if (
+		request.headers.get('Origin') !== null &&
+		request.headers.get('Access-Control-Request-Method') !== null &&
+		request.headers.get('Access-Control-Request-Headers') !== null
+	) {
+		return new Response(null, {
+			headers: {
+				'Access-Control-Allow-Origin': '*',
+				'Access-Control-Allow-Methods': 'GET, HEAD, POST, OPTIONS',
+				'Access-Control-Allow-Headers': 'Content-Type',
+			},
+		});
+
+		/*
+		 * Handle standard OPTIONS request.
+		 * If you want to allow other HTTP Methods, you can do that here.
+		 */
+	} else {
+		return new Response(null, {
+			headers: {
+				Allow: 'GET, HEAD, POST, OPTIONS',
+			},
+		});
+	}
+}
+
+/*
+ ** Event listener for fetching content (What starts everything)
+ */
+addEventListener('fetch', (event) => {
+	// Initialize
+	const request = event.request;
+
+	// Handle CORS preflight requests
+	switch (request.method) {
+		case 'OPTIONS':
+			event.respondWith(handleOptions(request));
+			break;
+
+		// Handle requests
+		case 'GET':
+		case 'HEAD':
+		case 'POST':
+			event.respondWith(handleRequest(request));
+			break;
+
+		// If no good option then return error
+		default:
+			event.respondWith(async () => {
+				return new Response(null, {
+					status: 405,
+
+					statusText: 'Method Not Allowed',
+				});
+			});
+			break;
+	}
+});