github-webhook-filter/lib/filter.ts

107 lines
3.6 KiB
TypeScript

import { commentManager } from "./manager.ts";
import { UrlConfig } from "./types.d.ts";
import { requestLog } from "./util.ts";
export default async function filter(
headers: Headers,
json: any,
config: UrlConfig,
): Promise<string | null> {
const reqLog = requestLog(headers);
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 '${json.action}'`;
// if comment (not approval or changes requested), ignore empty review body
if (json.review?.state === "commented" && !json.review?.body) return "empty PR review";
}
// ignore some PR comment events
if (event === "pull_request_review_comment") {
// ignore edit/delete actions
if (json.action !== "created") return `no-op PR comment action '${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}`;
reqLog.debug(`filter: checking cache key ${cacheKey}`);
const curr = await commentManager.getAndIncrement(cacheKey);
reqLog.debug(`filter: current value: ${curr}`);
if (curr && curr >= config.commentBurstLimit) {
return `exceeded comment burst limit (${config.commentBurstLimit}) for review ${reviewId}`;
}
}
}
// ignore bots
if (
login &&
["coveralls[bot]", "netlify[bot]", "pre-commit-ci[bot]"].some((n) => login.includes(n))
) {
return "bot";
}
// ignore branch/tag push
const refMatch = /^refs\/([^\/]+)\/(.+)$/.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]}'`;
}
}
// ignore creation of branch/tag
if (event === "create") {
// check if branch is allowed
if (
json.ref_type === "branch" && config.allowBranches !== undefined &&
!config.allowBranches.includes(json.ref)
) {
return `branch '${json.ref}' not in ${JSON.stringify(config.allowBranches)}`;
}
// check if it's a tag
if (json.ref_type == "tag" && config.hideTags === true) {
return `tag '${json.ref}'`;
}
}
return null;
}