Initial commit

.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+.pnpm-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Snowpack dependency directory (https://snowpack.dev/)
+web_modules/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional stylelint cache
+.stylelintcache
+
+# Microbundle cache
+.rpt2_cache/
+.rts2_cache_cjs/
+.rts2_cache_es/
+.rts2_cache_umd/
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variable files
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+.parcel-cache
+
+# Next.js build output
+.next
+out
+
+# Nuxt.js build / generate output
+.nuxt
+dist
+
+# Gatsby files
+.cache/
+# Comment in the public line in if your project uses Gatsby and not Next.js
+# https://nextjs.org/blog/next-9-1#public-directory-support
+# public
+
+# vuepress build output
+.vuepress/dist
+
+# vuepress v2.x temp and cache directory
+.temp
+.cache
+
+# Docusaurus cache and generated files
+.docusaurus
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# TernJS port file
+.tern-port
+
+# Stores VSCode versions used for testing VSCode extensions
+.vscode-test
+
+# yarn v2
+.yarn/cache
+.yarn/unplugged
+.yarn/build-state.yml
+.yarn/install-state.gz
+.pnp.*
+
+
+.vscode

.pre-commit-config.yaml

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+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.2.0
+    hooks:
+      - id: check-case-conflict
+      - id: check-toml
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+        args: [--markdown-linebreak-ext=md]
+
+  - repo: local
+    hooks:
+      - id: deno-fmt
+        name: deno-fmt
+        entry: deno fmt -q
+        language: system
+        types_or: [javascript, jsx, ts, tsx, json, markdown]
+      - id: deno-lint
+        name: deno-lint
+        entry: deno lint -q
+        language: system
+        types_or: [javascript, jsx, ts, tsx, json, markdown]

deno.json

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+{
+    "fmt": {
+        "options": {
+            "indentWidth": 4,
+            "lineWidth": 100
+        },
+        "files": {
+            "exclude": [
+                ".vscode"
+            ]
+        }
+    },
+    "lint": {
+        "rules": {
+            "exclude": ["no-explicit-any"]
+        }
+    }
+}

deps.ts

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+export * as http from "https://deno.land/std@0.154.0/http/mod.ts";
+export * as log from "https://deno.land/std@0.154.0/log/mod.ts";
+export * as hex from "https://deno.land/std@0.154.0/encoding/hex.ts";

lib/config.ts

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+function get(key: string, def?: string): string {
+    const value = Deno.env.get(key) ?? def;
+    if (value !== undefined) {
+        return value;
+    }
+    throw new Error(`Missing environment variable '${key}'.`);
+}
+
+export default {
+    debug: !!parseInt(get("DEBUG", "0")),
+    hostname: get("HOSTNAME", "127.0.0.1"),
+    port: parseInt(get("PORT", "8080")),
+    signKey: get("SIGN_KEY"),
+};

lib/crypto.ts

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+import config from "./config.ts";
+import { hex } from "../deps.ts";
+
+const signKey = await crypto.subtle.importKey(
+    "raw",
+    hex.decode(new TextEncoder().encode(config.signKey)),
+    { name: "HMAC", hash: "SHA-256" },
+    false,
+    ["sign", "verify"],
+);
+
+const encoder = new TextEncoder();
+
+export async function verify(input: string, signature: string): Promise<boolean> {
+    const signatureData = hex.decode(encoder.encode(signature));
+    const inputData = encoder.encode(input);
+    return await crypto.subtle.verify("HMAC", signKey, signatureData, inputData);
+}
+
+export async function sign(input: string): Promise<string> {
+    const inputData = encoder.encode(input);
+    const sig = await crypto.subtle.sign("HMAC", signKey, inputData);
+    return new TextDecoder().decode(hex.encode(new Uint8Array(sig)));
+}

lib/handler.ts

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+import { verify } from "./crypto.ts";
+import { http, log } from "../deps.ts";
+
+function filter(headers: Headers, json: any, config: UrlConfig): string | null {
+    const event = headers.get("x-github-event");
+    const login: string = json.sender?.login?.toLowerCase() || "";
+    if (["coveralls[bot]", "netlify[bot]", "pre-commit-ci[bot]"].some((n) => login.includes(n))) {
+        return "bot";
+    }
+
+    const branchMatch = /^refs\/heads\/(.*)$/.exec(json.ref);
+    if (
+        event === "push" && branchMatch &&
+        config.allowBranches && !config.allowBranches.includes(branchMatch[1])
+    ) {
+        return `branch '${branchMatch[1]}' not in ${JSON.stringify(config.allowBranches)}`;
+    }
+
+    return null;
+}
+
+async function sendWebhook(
+    id: string,
+    token: string,
+    headers: HeadersInit,
+    body: string,
+): Promise<Response> {
+    const url = `https://discord.com/api/webhooks/${id}/${token}/github?wait=1`;
+    log.info(`Sending webhook request to ${url}`);
+    const req = new Request(url, {
+        method: "POST",
+        headers: headers,
+        body: body,
+    });
+    return await fetch(req);
+}
+
+interface UrlConfig {
+    allowBranches?: string[];
+}
+
+function getUrlConfig(params: URLSearchParams): UrlConfig {
+    const config: UrlConfig = {};
+    for (const [key, value] of params) {
+        switch (key) {
+            case "sig":
+                continue;
+            case "allowBranches":
+                config.allowBranches = value.split(",");
+                break;
+            default:
+                throw http.createHttpError(418, `Unknown config option: ${key}`);
+        }
+    }
+    return config;
+}
+
+export default async function handle(req: Request): Promise<Response> {
+    if (req.method !== "POST") {
+        throw http.createHttpError(405);
+    }
+
+    // split url into parts
+    const url = new URL(req.url);
+    const [, id, token] = url.pathname.split("/");
+    const signature = url.searchParams.get("sig");
+    if (!id || !token || !signature) {
+        throw http.createHttpError(400);
+    }
+
+    // verify signature
+    if (!(await verify(`${id}/${token}`, signature))) {
+        throw http.createHttpError(403);
+    }
+
+    // extract data
+    const urlConfig = getUrlConfig(url.searchParams);
+    const data = await req.text();
+    const json = JSON.parse(data);
+
+    // do the thing
+    const filterReason = filter(req.headers, json, urlConfig);
+    if (filterReason !== null) {
+        return new Response(`Ignored by webhook filter (reason: ${filterReason})`, { status: 203 });
+    }
+
+    return await sendWebhook(id, token, req.headers, data);
+}

main.ts

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+import { http, log } from "./deps.ts";
+import config from "./lib/config.ts";
+import handler from "./lib/handler.ts";
+
+await log.setup({
+    handlers: {
+        console: new log.handlers.ConsoleHandler("DEBUG", {
+            formatter: (rec) => `${rec.datetime.toISOString()} [${rec.levelName}] ${rec.msg}`,
+        }),
+    },
+    loggers: {
+        default: {
+            level: config.debug ? "DEBUG" : "INFO",
+            handlers: ["console"],
+        },
+    },
+});
+
+async function handleRequest(req: Request, connInfo: http.ConnInfo): Promise<Response> {
+    let resp: Response;
+    try {
+        resp = await handler(req);
+    } catch (err) {
+        if (http.isHttpError(err) && err.expose) {
+            log.warning(`http error: ${err.message}`);
+            resp = new Response(err.message, { status: err.status });
+        } else {
+            log.critical(err);
+            resp = new Response("Internal Server Error", { status: 500 });
+        }
+    }
+
+    const respLen = resp.headers.get("content-length") || 0;
+    const addr = connInfo.remoteAddr as Deno.NetAddr;
+    log.info(
+        `http: ${addr.hostname}:${addr.port} - ${req.method} ${req.url} ${resp.status} ${respLen}`,
+    );
+
+    return resp;
+}
+
+log.info(`Starting webserver on ${config.hostname}:${config.port}`);
+http.serve(handleRequest, {
+    hostname: config.hostname,
+    port: config.port,
+});