refactor: move isGitHubEvent to util

Author: shiftinv

src/filter/index.ts

@@ -1,27 +1,17 @@
-import { WebhookEvent, WebhookEventMap, WebhookEventName } from "@octokit/webhooks-types";
+import { WebhookEvent } from "@octokit/webhooks-types";
 
 import { getAndIncrementKV } from "./kv.ts";
 import { getRequestLog } from "../server/context.ts";
 import { UrlConfig } from "../types.d.ts";
-import { wildcardMatch } from "../util.ts";
+import { isGitHubEvent, wildcardMatch } from "../util.ts";
 
 const COMMON_CI_BOTS = ["coveralls[bot]", "netlify[bot]", "pre-commit-ci[bot]", "dependabot[bot]"];
 
-function isGitHubEvent<T extends WebhookEventName>(
-    _data: WebhookEvent,
-    eventType: string,
-    expected: T,
-): _data is WebhookEventMap[T] {
-    return eventType === expected;
-}
-
 export default async function filter(
-    headers: Record<string, string>,
     json: WebhookEvent,
+    event: string,
     config: UrlConfig,
 ): Promise<string | null> {
-    const event = headers["x-github-event"] || "unknown";
-
     if (!("sender" in json)) {
         // Discord always requires a sender (most events have this, but a handful of them don't)
         return "missing sender";

src/handler.ts

@@ -17,8 +17,13 @@ export default async function handle(
 ): Promise<[Response, Record<string, string>]> {
     const urlConfig = getUrlConfig(queryParams);
 
+    const eventType = headers["x-github-event"];
+    if (!eventType) {
+        throw new HTTPException(418, { message: `Missing x-github-event` });
+    }
+
     // do the thing
-    const filterReason = await filterWebhook(headers, json, urlConfig);
+    const filterReason = await filterWebhook(json, eventType, urlConfig);
     if (filterReason !== null) {
         const reqLog = getRequestLog();
         reqLog.debug(`handler: ignored due to '${filterReason}'`);

src/util.ts

@@ -1,4 +1,5 @@
 import type { Context } from "@hono/hono";
+import { WebhookEvent, WebhookEventMap, WebhookEventName } from "@octokit/webhooks-types";
 
 export function parseBool(s: string, strict: false): boolean | undefined;
 export function parseBool(s: string, strict?: true): boolean;
@@ -54,3 +55,11 @@ export type RequestLog = ReturnType<typeof requestLog>;
 export function setMetaHeader(c: Context, key: string, value: string): void {
     c.res.headers.set(`x-webhook-filter-${key}`, value);
 }
+
+export function isGitHubEvent<T extends WebhookEventName>(
+    _data: WebhookEvent,
+    eventType: string,
+    expected: T,
+): _data is WebhookEventMap[T] {
+    return eventType === expected;
+}