github-webhook-filter/lib/filter.ts

84 lines
3.1 KiB
TypeScript

import { log, TTL } from "../deps.ts";
import { UrlConfig } from "./types.d.ts";
const reviewComments = new TTL<number>(2 * 1000);
export default function filter(headers: Headers, json: any, config: UrlConfig): string | null {
const event = headers.get("x-github-event") || "unknown";
const login: string | undefined = json.sender?.login?.toLowerCase();
// ignore events that Discord won't render anyway
if (["status", "pull_request_review_thread"].includes(event)) {
return event;
}
// ignore all PR actions except "opened", "closed", "reopened"
if (
event === "pull_request" && json.action &&
!["opened", "closed", "reopened"].includes(json.action)
) {
return `no-op PR action '${json.action}'`;
}
// ignore all issue actions except "opened", "deleted", "closed", "reopened", "transferred"
if (
event === "issues" && json.action &&
!["opened", "deleted", "closed", "reopened", "transferred"].includes(json.action)
) {
return `no-op issue action '${json.action}'`;
}
// ignore some PR review actions
if (event === "pull_request_review") {
// ignore edit/dismiss actions
if (json.action !== "submitted") return `no-op PR review action '${json.action}'`;
// if comment (not approval or changes requested), ignore empty review body
else if (json.review?.state === "commented" && !json.review?.body) return "empty PR review";
}
// ignore some PR comment events
if (event === "pull_request_review_comment") {
// ignore edit/delete actions
if (json.action !== "created") return `no-op PR comment action '${json.action}'`;
// check if more than x comments on a PR review in a short timespan
const reviewId: number = json.comment?.pull_request_review_id;
if (config.commentBurstLimit && reviewId) {
const cacheKey = `${reviewId}-${login}`;
log.debug(`filter: checking cache key ${cacheKey}`);
log.debug(`filter: full comment cache ${JSON.stringify(Array.from(reviewComments))}`);
const curr = reviewComments.get(cacheKey);
if (curr && curr >= config.commentBurstLimit) {
return `exceeded comment burst limit (${config.commentBurstLimit}) for review ${reviewId}`;
}
reviewComments.set(cacheKey, (curr ?? 0) + 1);
}
}
// ignore bots
if (
login &&
["coveralls[bot]", "netlify[bot]", "pre-commit-ci[bot]"].some((n) => login.includes(n))
) {
return "bot";
}
// ignore branch/tag if configured
const refMatch = /^refs\/([^\/]+)\/(.+)$/.exec(json.ref);
if (event === "push" && refMatch) {
// check if branch is allowed
if (
refMatch[1] == "heads" && config.allowBranches !== undefined &&
!config.allowBranches.includes(refMatch[2])
) {
return `branch '${refMatch[2]}' not in ${JSON.stringify(config.allowBranches)}`;
}
// check if it's a tag
if (refMatch[1] == "tags" && config.hideTags === true) {
return `tag '${refMatch[2]}'`;
}
}
return null;
}