fix(cli): use correct subpath during setup slack app for self hosted

packages/blink/src/cli/setup-slack-app.test.ts

@@ -11,6 +11,7 @@ import {
 } from "./lib/in-memory-cli";
 import { makeTmpDir } from "./lib/terminal";
 import {
+  appendSubpath,
   setupSlackApp,
   updateEnvCredentials,
   verifySlackSignature,
@@ -111,6 +112,44 @@ describe("verifySlackSignature", () => {
   });
 });
 
+describe("appendSubpath", () => {
+  it("should append a subpath to a simple URL", () => {
+    expect(appendSubpath("https://example.com", "/slack")).toBe(
+      "https://example.com/slack"
+    );
+  });
+
+  it("should append a subpath to a URL with an existing path", () => {
+    expect(appendSubpath("https://example.com/devhook/abc", "/slack")).toBe(
+      "https://example.com/devhook/abc/slack"
+    );
+  });
+
+  it("should handle trailing slashes on the base URL", () => {
+    expect(appendSubpath("https://example.com/devhook/", "/slack")).toBe(
+      "https://example.com/devhook/slack"
+    );
+  });
+
+  it("should handle subpath without leading slash", () => {
+    expect(appendSubpath("https://example.com/devhook", "slack")).toBe(
+      "https://example.com/devhook/slack"
+    );
+  });
+
+  it("should handle both trailing and leading slashes", () => {
+    expect(appendSubpath("https://example.com/devhook///", "///slack")).toBe(
+      "https://example.com/devhook/slack"
+    );
+  });
+
+  it("should preserve query parameters", () => {
+    expect(
+      appendSubpath("https://example.com/devhook?token=abc", "/slack")
+    ).toBe("https://example.com/devhook/slack?token=abc");
+  });
+});
+
 describe("updateEnvCredentials", () => {
   it("should add credentials to an empty env file", async () => {
     await using tempDir = await makeTmpDir();

packages/blink/src/cli/setup-slack-app.ts

@@ -97,6 +97,12 @@ export function verifySlackSignature(
   );
 }
 
+export function appendSubpath(baseUrl: string, subpath: string): string {
+  const url = new URL(baseUrl);
+  url.pathname = `${url.pathname.replace(/\/+$/, "")}/${subpath.replace(/^\/+/, "")}`;
+  return url.toString();
+}
+
 const makeDisposable = (value: unknown): Disposable => {
   if (!(typeof value === "object" && value !== null)) {
     throw new Error("Unable to make value disposable, it's not an object");
@@ -234,7 +240,10 @@ export async function setupSlackApp(
       baseURL: host,
       authToken: getAuthToken(),
     });
-  const webhookUrl = await client.devhook.getUrl(devhookId);
+  const webhookUrl = appendSubpath(
+    await client.devhook.getUrl(devhookId),
+    "/slack"
+  );
 
   log.info("Starting webhook listener...");