feat: switch to Google Sheets as backend

.fly.yml

@@ -2,7 +2,9 @@ app-name: fly-shortener
 config:
   adminSecret:
     fromSecret: adminSecret
-  airtableApiKey:
-    fromSecret: airtableApiKey
-  airtableBase:
-    fromSecret: airtableBase
+  googleSheetDocId:
+    fromSecret: googleSheetDocId
+  googleServiceAccountEmail:
+    fromSecret: googleServiceAccountEmail
+  googleServiceAccountKey:
+    fromSecret: googleServiceAccountKey

index.ts

@@ -0,0 +1,3 @@
+import { route } from "./lib/router";
+
+fly.http.respondWith(route);

lib/google.ts

@@ -0,0 +1,52 @@
+import * as jwt from "jwt-simple";
+
+const SERVICE_ENDPOINT = "https://sheets.googleapis.com";
+
+// We only care about From, To, and Is Regex
+const A1_RANGE = "B2:D";
+
+export type LinkRecord = { from: string; to: string; isRegex: boolean };
+
+export const createAuthJwt = () => {
+  const claims = {
+    iss: app.config.googleServiceAccountEmail,
+    scope: "https://www.googleapis.com/auth/spreadsheets.readonly",
+    aud: "https://oauth2.googleapis.com/token",
+    exp: Math.floor(Date.now() / 1000) + 5 * 60,
+    iat: Math.floor(Date.now() / 1000)
+  };
+
+  return jwt.encode(claims, app.config.googleServiceAccountKey, "RS256");
+};
+
+export const getAccessToken = async () => {
+  const token = createAuthJwt();
+  const payload = {
+    grant_type: encodeURI("urn:ietf:params:oauth:grant-type:jwt-bearer"),
+    assertion: token
+  };
+  const auth = await fetch("https://oauth2.googleapis.com/token", {
+    method: "POST",
+    body: JSON.stringify(payload)
+  });
+  const { access_token } = await auth.json();
+  return access_token;
+};
+
+export const fetchEntries = async (): Promise<LinkRecord[]> => {
+  const accessToken = await getAccessToken();
+
+  const docId = app.config.googleSheetDocId;
+  const url = `${SERVICE_ENDPOINT}/v4/spreadsheets/${docId}/values/${A1_RANGE}?access_token=${accessToken}`;
+  const response = await fetch(url);
+  const { values: rows }: { values: string[] } = await response.json();
+
+  // Make sure that record has From and To values
+  return rows
+    .map(row => ({
+      from: row[0],
+      to: row[1],
+      isRegex: row[2] === "TRUE"
+    }))
+    .filter(({ from, to }) => !!from && !!to);
+};

lib/router.ts

@@ -0,0 +1,90 @@
+import * as Url from "url-parse";
+import * as queryString from "query-string";
+import cache from "@fly/cache";
+
+import {
+  clearCache,
+  refreshCache,
+  lookupPath,
+  CACHE_TAG,
+  TTL_404
+} from "./shortener";
+
+export const parseReq = (req: Request) => {
+  const url = new Url(req.url);
+  const { pathname } = url;
+  const params = queryString.parse(url.query);
+  return { url, pathname, params };
+};
+
+const normalize = (str: string) => str.toLowerCase().trim();
+
+/**
+ * Handle admin routing
+ * @param req The admin Request to be routed
+ */
+const routeAdmin = async (req: Request): Promise<Response> => {
+  const { pathname, params } = parseReq(req);
+
+  if (params.secret !== app.config.adminSecret) {
+    return new Response("Unauthorized", { status: 403 });
+  }
+
+  if (pathname.includes("/clear")) {
+    await clearCache();
+    return new Response("Cleared", { status: 200 });
+  }
+
+  if (pathname.includes("/refresh")) {
+    await clearCache();
+    await refreshCache();
+    return new Response("Refreshed", { status: 200 });
+  }
+
+  return new Response("Not Found", { status: 404 });
+};
+
+/**
+ * Handle short link redirects
+ * @param req The short link request to be routed
+ */
+const routeShortlink = async (req: Request): Promise<Response> => {
+  const { pathname } = parseReq(req);
+  const path = normalize(pathname);
+
+  // Check for existing match
+  let matchingResponse = await lookupPath(path);
+  if (matchingResponse) {
+    return matchingResponse;
+  }
+
+  // Refresh the cache if no match
+  await refreshCache();
+
+  // Re-check for match
+  matchingResponse = await lookupPath(path);
+  if (matchingResponse) {
+    return matchingResponse;
+  }
+
+  await cache.set(path, "404", { ttl: TTL_404, tags: [CACHE_TAG] });
+  return new Response("", { status: 404 });
+};
+
+/**
+ * Handle routing
+ * @param req The Request to be routed
+ */
+export const route = async (req: Request): Promise<Response> => {
+  const { pathname } = parseReq(req);
+
+  if (pathname === "/favicon.ico") {
+    return new Response("", { status: 404 });
+  }
+
+  if (pathname.includes("/admin")) {
+    return routeAdmin(req);
+  }
+
+  return routeShortlink(req);
+};