Added feature flags via KV

Author: nora-soderlund

src/controllers/getUserAgentGroups.ts

@@ -0,0 +1,22 @@
+export default function getUserAgentGroups(userAgent: string | null) {
+    if(!userAgent)
+        return null;
+
+    const match = userAgent.match(/(?<client>[\w]+)\-(?<major>[0-9v]+)\.(?<minor>[0-9]+)\.(?<patch>[0-9]+)/);
+
+    if(!match?.groups)
+        return null;
+
+    return {
+        client: match.groups.client,
+        version: {
+            major: match.groups.major,
+            minor: match.groups.minor,
+            patch: match.groups.patch,
+
+            toString: () => {
+                return `${match.groups?.major}.${match.groups?.minor}.${match.groups?.patch}`;
+            }
+        }
+    };
+};

src/global.d.ts

@@ -4,6 +4,7 @@ declare type Env = {
     DATABASE: D1Database;
     BUCKET: R2Bucket;
     ACTIVITY_DURABLE_OBJECT: DurableObjectNamespace;
+    FEATURE_FLAGS: KVNamespace;
 
     ENVIRONMENT: "production" | "staging" | "dev";
     CLOUDFLARE_ACCOUNT_ID: string;

src/index.ts

@@ -7,11 +7,13 @@ import { createActivitySummary } from "./controllers/activities/summary/createAc
 import { updatePersonalBestActivitySummary } from "./controllers/activities/summary/updatePersonalBestActivitySummary";
 import { getActivitySummaryById } from "./controllers/activities/summary/getActivitySummaryById";
 import { getActivitiesWithoutSummary } from "./controllers/activities/getActivitiesWithoutSummary";
+import getUserAgentGroups from "./controllers/getUserAgentGroups";
+import { FeatureFlags, VersionFeatureFlags } from "./models/FeatureFlags";
 
 const router = createRouter();
 
-async function getRequest(request: any, env: any, context: any) {
-    const response: Response = await router.handle(request, env, context);
+async function getRequest(request: Request, env: Env, context: EventContext<Env, string, null>, featureFlags: VersionFeatureFlags) {
+    const response: Response = await router.handle(request, env, context, featureFlags);
 
     if(!response) {
         return new Response(undefined, {
@@ -23,8 +25,6 @@ async function getRequest(request: any, env: any, context: any) {
     return response;
 }
 
-const acceptedAgents = [ "RideTrackerService", "RideTrackerApp" ];
-
 export default {
     async scheduled(controller: ScheduledController, env: Env, context: EventContext<Env, string, null>) {
         switch(controller.cron) {
@@ -51,25 +51,36 @@ export default {
 
     async fetch(request: Request, env: Env, context: EventContext<Env, string, null>) {
         try {
-            const userAgent = request.headers.get("User-Agent");
+            const userAgent = getUserAgentGroups(request.headers.get("User-Agent"));
 
-            if(!userAgent || !userAgent.match(/\w+\-([0-9]+)\.([0-9]+)\.([0-9]+)/)) {
+            if(!userAgent) {
                 return new Response(undefined, {
                     status: 400,
                     statusText: "Bad Request"
                 });
             }
 
-            if(!acceptedAgents.includes(userAgent.substring(0, userAgent.indexOf('-')))) {
+            const featureFlags = await env.FEATURE_FLAGS.get<FeatureFlags | null>(`${userAgent.client}`, "json");
+
+            if(!featureFlags) {
                 context.waitUntil(triggerAlarm(env, "User Agent Alarm", `An unrecognized user agent was detected.\n \n\`\`\`\n${userAgent}\n\`\`\`\n${request.method} ${request.url}\nRemote Address: || ${request.headers.get("CF-Connecting-IP")} ||`));
 
                 return new Response(undefined, {
-                    status: 403,
-                    statusText: "Forbidden"
+                    status: 400,
+                    statusText: "Bad Request"
+                });
+            }
+
+            const versionFeatureFlags = featureFlags.versions[userAgent.version.toString()];
+
+            if(versionFeatureFlags.status === "UNSUPPORTED") {
+                return new Response(undefined, {
+                    status: 410,
+                    statusText: "Gone"
                 });
             }
 
-            const response = await getRequest(request, env, context);
+            const response = await getRequest(request, env, context, versionFeatureFlags);
 
             if(response.status < 200 || response.status > 299) { 
                 context.waitUntil(new Promise<void>(async (resolve) => {

src/models/FeatureFlags.ts

@@ -0,0 +1,13 @@
+export type VersionFeatureFlags = {
+    uses: string;
+    
+    status: "SUPPORTED" | "UNSUPPORTED" | "DEPRECATED";
+    
+    supersededBy?: string;
+};
+
+export type FeatureFlags = {
+    versions: {
+        [key: string]: VersionFeatureFlags;
+    };
+};

wrangler.toml

@@ -26,6 +26,10 @@ bindings = [
     { name = "ACTIVITY_DURABLE_OBJECT", class_name = "ActivityDurableObject" }
 ]
 
+[[ kv_namespaces ]]
+binding = "FEATURE_FLAGS"
+id = "e4051aac3f97408eb005e85eb81bdc97"
+
 [triggers]
 crons = [ "0 * * * *" ]
 
@@ -46,6 +50,10 @@ bindings = [
     { name = "ACTIVITY_DURABLE_OBJECT", class_name = "ActivityDurableObject" }
 ]
 
+[[ env.production.kv_namespaces ]]
+binding = "FEATURE_FLAGS"
+id = "e9e05d97db9c4e0f8fa1e3784dc4d0ad"
+
 [env.production.triggers]
 crons = [ "0 * * * *" ]
 
@@ -66,5 +74,9 @@ bindings = [
     { name = "ACTIVITY_DURABLE_OBJECT", class_name = "ActivityDurableObject" }
 ]
 
+[[ env.staging.kv_namespaces ]]
+binding = "FEATURE_FLAGS"
+id = "225cf6788c7447079e5f8dc7b9f1be18"
+
 [env.staging.triggers]
 crons = [ "0 * * * *" ]