feat: track accept header dimension

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");
   });
 });
 
@@ -235,7 +240,7 @@ 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) {
@@ -244,6 +249,7 @@ 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 },
       },
@@ -299,6 +305,7 @@ 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 },
 };

src/request.test.ts

@@ -0,0 +1,28 @@
+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"));
+
+    expect(event.accept).toBeUndefined();
+  });
+});

src/request.ts

@@ -15,6 +15,7 @@ export function eventFromRequest(req: Request): TrackedEvent {
   return {
     provider: detectProvider(request),
     path: normalizeUrl(request.nextUrl?.href ?? request.url),
+    accept: normalizeHeader(request.headers.get("accept")),
   };
 }
 
@@ -29,6 +30,10 @@ 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. */
 export function detectProvider(req: Request): Provider {
   const userAgent = req.headers.get("user-agent")?.toLowerCase() ?? "";

src/types.ts

@@ -29,6 +29,8 @@ 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. */