backend.cfworker.js

addEventListener('fetch', (event) => {
	const request = event.request;
	if (request.method === 'POST') {
		event.respondWith(handleShortUrlGenerator(request));
	} else if (request.method === 'GET') {
		event.respondWith(handleShortUrlRedirector(request));
	} else {
		event.respondWith(
			new Response('Method not allowed', {
				status: 405,
				headers: {
					'Access-Control-Allow-Origin': 'https://short-url.yuameshi.top',
				},
			})
		);
	}
});

async function handleShortUrlGenerator(request) {
	// 解析请求体中的长链接
	let longUrl = await request.text();
	try {
		new URL(longUrl);
	} catch (e) {
		return new Response('Not a valid URL', {
			status: 400,
			headers: {
				'Access-Control-Allow-Origin': 'https://short-url.yuameshi.top',
			},
		});
	}
	longUrl = new URL(longUrl).href; // 标准化长链接
	// 使用 KV 存储来存储长链接和短链接之间的映射关系
	const shortId = SHA256(longUrl).slice(0, 8); // 生成随机的短链接
	const shortUrl = `https://${new URL(request.url).host.replace('xn--xrra.top', '呃呃.top')}/${shortId}`;
	await SHORT_URL_DATABASE.put(shortId, longUrl);

	// 返回短链接
	return new Response(shortUrl, {
		status: 200,
		headers: {
			'Access-Control-Allow-Origin': 'https://short-url.yuameshi.top',
		},
	});
}

async function handleShortUrlRedirector(request) {
	// 解析短链接的 ID
	const shortId = new URL(request.url).pathname.slice(1);

	// 使用 KV 存储来查询长链接
	try {
		const longUrl = await SHORT_URL_DATABASE.get(shortId);
		return Response.redirect(longUrl, 302);
	} catch (error) {
		// 如果找不到对应的长链接，则返回 404 错误
		// return new Response('404 Not found', {
		// 	status: 404,
		// });
		// 否则，返回一个重定向响应
		return Response.redirect('https://short-url.yuameshi.top/', 302);
	}
}

function SHA256(s) {
	const chrsz = 8;
	const hexcase = 0;

	function safe_add(x, y) {
		const lsw = (x & 0xffff) + (y & 0xffff);
		const msw = (x >> 16) + (y >> 16) + (lsw >> 16);
		return (msw << 16) | (lsw & 0xffff);
	}

	function S(X, n) {
		return (X >>> n) | (X << (32 - n));
	}

	function R(X, n) {
		return X >>> n;
	}

	function Ch(x, y, z) {
		return (x & y) ^ (~x & z);
	}

	function Maj(x, y, z) {
		return (x & y) ^ (x & z) ^ (y & z);
	}

	function Sigma0256(x) {
		return S(x, 2) ^ S(x, 13) ^ S(x, 22);
	}

	function Sigma1256(x) {
		return S(x, 6) ^ S(x, 11) ^ S(x, 25);
	}

	function Gamma0256(x) {
		return S(x, 7) ^ S(x, 18) ^ R(x, 3);
	}

	function Gamma1256(x) {
		return S(x, 17) ^ S(x, 19) ^ R(x, 10);
	}

	function core_sha256(m, l) {
		const K = [
			0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0xfc19dc6, 0x240ca1cc,
			0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x6ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
			0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
			0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
		];
		const HASH = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19];
		const W = new Array(64);
		let a, b, c, d, e, f, g, h, i, j;
		let T1, T2;
		m[l >> 5] |= 0x80 << (24 - (l % 32));
		m[(((l + 64) >> 9) << 4) + 15] = l;
		for (i = 0; i < m.length; i += 16) {
			a = HASH[0];
			b = HASH[1];
			c = HASH[2];
			d = HASH[3];
			e = HASH[4];
			f = HASH[5];
			g = HASH[6];
			h = HASH[7];
			for (j = 0; j < 64; j++) {
				if (j < 16) {
					W[j] = m[j + i];
				} else {
					W[j] = safe_add(safe_add(safe_add(Gamma1256(W[j - 2]), W[j - 7]), Gamma0256(W[j - 15])), W[j - 16]);
				}
				T1 = safe_add(safe_add(safe_add(safe_add(h, Sigma1256(e)), Ch(e, f, g)), K[j]), W[j]);
				T2 = safe_add(Sigma0256(a), Maj(a, b, c));
				h = g;
				g = f;
				f = e;
				e = safe_add(d, T1);
				d = c;
				c = b;
				b = a;
				a = safe_add(T1, T2);
			}
			HASH[0] = safe_add(a, HASH[0]);
			HASH[1] = safe_add(b, HASH[1]);
			HASH[2] = safe_add(c, HASH[2]);
			HASH[3] = safe_add(d, HASH[3]);
			HASH[4] = safe_add(e, HASH[4]);
			HASH[5] = safe_add(f, HASH[5]);
			HASH[6] = safe_add(g, HASH[6]);
			HASH[7] = safe_add(h, HASH[7]);
		}
		return HASH;
	}

	function str2binb(str) {
		const bin = [];
		const mask = (1 << chrsz) - 1;
		for (let i = 0; i < str.length * chrsz; i += chrsz) {
			bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - (i % 32));
		}
		return bin;
	}

	function Utf8Encode(string) {
		string = string.replace(/\r\n/g, '\n');
		let utfText = '';
		for (let n = 0; n < string.length; n++) {
			const c = string.charCodeAt(n);
			if (c < 128) {
				utfText += String.fromCharCode(c);
			} else if (c > 127 && c < 2048) {
				utfText += String.fromCharCode((c >> 6) | 192);
				utfText += String.fromCharCode((c & 63) | 128);
			} else {
				utfText += String.fromCharCode((c >> 12) | 224);
				utfText += String.fromCharCode(((c >> 6) & 63) | 128);
				utfText += String.fromCharCode((c & 63) | 128);
			}
		}
		return utfText;
	}

	function binb2hex(binarray) {
		const hex_tab = hexcase ? '0123456789ABCDEF' : '0123456789abcdef';
		let str = '';
		for (let i = 0; i < binarray.length * 4; i++) {
			str += hex_tab.charAt((binarray[i >> 2] >> ((3 - (i % 4)) * 8 + 4)) & 0xf) + hex_tab.charAt((binarray[i >> 2] >> ((3 - (i % 4)) * 8)) & 0xf);
		}
		return str;
	}

	s = Utf8Encode(s);
	return binb2hex(core_sha256(str2binb(s), s.length * chrsz));
}