feat: track accept header dimension

README.md

@@ -10,14 +10,14 @@ Track a request in your Next.js middleware (now named proxy.ts):
 
 ```typescript
 // proxy.ts
-import { NextResponse, type NextRequest } from "next/server"
+import { NextResponse, type NextRequest, after } from "next/server"
 import { AgentAnalytics } from "@upstash/agent-analytics"
 import { redis } from "./redis"
 
 const analytics = new AgentAnalytics({ redis })
 
 export const proxy = async (request: NextRequest) => {
-  await analytics.track(request)
+  after(() => analytics.track(request))
 
   return NextResponse.next()
 }

src/analytics.test.ts

@@ -130,7 +130,11 @@ describe("ingestion", () => {
 
   test("track(Request) infers dimensions and writes the event", async () => {
     const req = new Request("https://upstash.com/blog", {
-      headers: { "user-agent": "PerplexityBot/1.0", referer: "https://www.perplexity.ai/" },
+      headers: {
+        "user-agent": "PerplexityBot/1.0",
+        referer: "https://www.perplexity.ai/",
+        accept: "Text/Markdown, text/html;q=0.8",
+      },
     });
 
     expect(await analytics.track(req)).toBe(1);
@@ -146,6 +150,7 @@ describe("ingestion", () => {
     );
     expect(tracked).toBeDefined();
     expect(String(tracked!.provider)).toBe("perplexity");
+    expect(String(tracked!.accept)).toBe("text/markdown, text/html;q=0.8");
   });
 
   test("track(Request) from an unknown agent records nothing and resolves to null", async () => {
@@ -247,7 +252,7 @@ describe("querying without an index", () => {
 
 describe("getIndex schema reconciliation", () => {
   // The schema getIndex() should converge to, regardless of what existed before.
-  const EXPECTED_FIELDS = ["count", "hour", "path", "provider"];
+  const EXPECTED_FIELDS = ["accept", "count", "hour", "path", "provider"];
 
   /** A bare index handle for inspecting the server-side schema via describe(). */
   function indexHandle(name: string) {
@@ -256,6 +261,7 @@ describe("getIndex schema reconciliation", () => {
       schema: {
         count: { type: "U64" as const, fast: true as const },
         hour: { type: "U64" as const, fast: true as const },
+        accept: { type: "KEYWORD" as const },
         provider: { type: "KEYWORD" as const },
         path: { type: "KEYWORD" as const },
       },
@@ -311,6 +317,7 @@ describe("getIndex schema reconciliation", () => {
         schema: {
           count: { type: "U64", fast: true },
           hour: { type: "U64", fast: true },
+          accept: { type: "KEYWORD" },
           provider: { type: "KEYWORD" },
           path: { type: "KEYWORD" },
           sourceUrl: { type: "KEYWORD" },

src/analytics.ts

@@ -40,6 +40,7 @@ export class IndexNotFoundError extends Error {
 const EVENT_SCHEMA = {
   count: { type: "U64" as const, fast: true as const },
   hour: { type: "U64" as const, fast: true as const },
+  accept: { type: "KEYWORD" as const },
   provider: { type: "KEYWORD" as const },
   path: { type: "KEYWORD" as const },
 };
@@ -287,9 +288,8 @@ export class AgentAnalytics {
    * applies to the event form and defaults to now.
    *
    * Returns a promise resolving to the counter's new value. In a request
-   * handler you usually don't want to block the response on it — hand it to the
-   * runtime's `waitUntil` instead (see the README for the Vercel/Next.js
-   * pattern).
+   * handler you usually don't want to block the response on it — schedule it
+   * with Next.js `after()` instead (see the README proxy example).
    *
    * The request form resolves to `null` when the request can't be attributed
    * to a known agent — only known agents are recorded.

src/request.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, test } from "bun:test";
+
+import { eventFromRequest } from "./request.ts";
+
+describe("eventFromRequest", () => {
+  test("captures the normalized Accept header", () => {
+    const event = eventFromRequest(
+      new Request("https://upstash.com/blog#section", {
+        headers: {
+          "user-agent": "ClaudeBot/1.0",
+          accept: " Text/Markdown, text/html;q=0.8 ",
+        },
+      }),
+    );
+
+    expect(event).toEqual({
+      provider: "claude",
+      path: "https://upstash.com/blog",
+      accept: "text/markdown, text/html;q=0.8",
+    });
+  });
+
+  test("omits Accept when the header is missing", () => {
+    const event = eventFromRequest(
+      new Request("https://upstash.com/docs", {
+        headers: { "user-agent": "ClaudeBot/1.0" },
+      }),
+    );
+
+    expect(event?.accept).toBeUndefined();
+  });
+});

src/request.ts

@@ -21,6 +21,7 @@ export function eventFromRequest(req: Request): TrackedEvent | undefined {
   return {
     provider,
     path: normalizeUrl(request.nextUrl?.href ?? request.url),
+    accept: normalizeHeader(request.headers.get("accept")),
   };
 }
 
@@ -35,6 +36,10 @@ function normalizeUrl(url: string): string {
   }
 }
 
+function normalizeHeader(value: string | null): string | undefined {
+  return value?.trim().toLowerCase() || undefined;
+}
+
 /**
  * Infer the AI agent from the user-agent and referrer headers. Returns
  * `undefined` when no known agent matches — the request is then not recorded.

src/types.ts

@@ -22,6 +22,8 @@ export type TrackedEvent = {
   provider: Provider;
   /** The path on our site that was cited. */
   path: string;
+  /** The request's Accept header, when present. */
+  accept?: string;
 };
 
 /** The dimensions that can be grouped/filtered on. */