Gowee · April 1, 2024 07:17 · Gowee · Oct 1, 2019
diff --git a/cfapi-ddns-worker.js b/cfapi-ddns-worker.js
 // CloudFlare API token
 // for zone: example.com (Edit)
 const CLOUDFLARE_API_TOKEN = "TO_BE_FILLED";
 // Currently, there seems not to be a way to get zone ids with tokens. So hardcode it here.
 // https://community.cloudflare.com/t/bug-in-list-zones-endpoint-when-using-api-token/115048
 // Trailing dots CANNOT BE OMITTED.
 const ZONES = {
  "example.org.": {
    id: "TO_BE_FILLED"
  },
 };
 // Arbitrary API tokens, mapping domains to customizable tokens, which can be any text.
 // Tokens for a domain can always be used to access its direct or indirect subdomains.
 // Trailing dots CANNOT BE OMITTED.
 const TOKENS = /* TOKENS: */ {
  "example.org.": "b69541a8-0acd-4e14-aecf-053d5e1b923d",
  "foo.example.org.": "144e7c59-7c2b-4360-9d16-00bbad549fb9",
  "foo.bar.example.org.": "218fa52e-d3c9-419d-a800-d8510e899a30",
 } /* :TOKENS */;
 // Time To Live in DNS record. 1 indictes automatic.
 const TTL = 1;

 class Flare {
  constructor(api_token) {
    this.api_token = api_token;
  }

  async request(method, path, data) {
    const response = await fetch("https://api.cloudflare.com/client/v4/" + path, {
      method: method,
      headers: {
        "Authorization": `Bearer ${this.api_token}`,
        "Content-Type": "application/json"
      },
      body: JSON.stringify(data),
    });
    if (!response.ok) {
      throw new Error(`Upstream response error (status code: ${response.status})`);
    }
    try {
      return await response.json();
    }
    catch (e) {
      throw new Error("Upstream invalid response");
    }
  }

  get(path, data) {
    return this.request("GET", path, data);
  }

  post(path, data) {
    return this.request("POST", path, data);
  }

  put(path, data) {
    return this.request("PUT", path, data);
  }

  delete(path, data) {
    return this.request("delete", path, data);
  }
 }

 const flare = new Flare(CLOUDFLARE_API_TOKEN);

 class ClientError extends Error { }

 addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
 })

 /**
 * Respond to the request
 * @param {Request} request
 */
 async function handleRequest(request) {
  const url = new URL(request.url);
  if (url.pathname === "/") {
    return new Response("cfapi-ddns-worker.js is up");
  }
  try {
    const path = url.pathname.startsWith("/") ? url.pathname.substring(1) : url.pathname;
    const [action, token, domain, rtype, content] = path.split("/", 5);
    if (["update", "create", "delete", "upsert"].includes(action)) {
      if ([token, domain, rtype, content].some((e) => e === undefined)) {
        throw new ClientError("Parameters Missing");
      }
      return await handleAction(action, token, domain, rtype, content);
    }
    else {
      return new Response(`Unsupported action: ${action}`, { status: 404 });
    }
  }
  catch (e) {
    if (e instanceof ClientError) {
      return new Response(e, { status: 400 });
    }
    else {
      return new Response(e, { status: 500 });
    }
  }
 }

 async function handleAction(action, token, domain, rtype, content) {
  const canon_domain = canonicalizeDomain(domain);
  const effective_domain = getEffectiveDomain(token, canon_domain);
  if (effective_domain === undefined) {
    throw new ClientError("Invalid token");
  }
  let { id: zone_id } = getZoneByDomain(effective_domain);
  if (zone_id === undefined) {
    throw new ClientError(`Zone ID has not been specified for the domain ${effective_domain}`);
  }
  const records = (await flare.get(`zones/${zone_id}/dns_records?name=${simplifyDomain(domain)}&type=${rtype}`)).result;
  if (action === "upsert" && records.length === 0) {
    action = "create";
  }
  else {
    action = "update";
  }
  let result;
  switch (action) {
    case "create":
      if (records.length > 0) {
        throw new ClientError("Record Already Existing");
      }
      result = await flare.post(`zones/${zone_id}/dns_records`, { type: rtype, name: simplifyDomain(domain), content: content });
      break;
    case "update":
    case "delete":
      if (records.length > 1) {
        throw new ClientError("Record Not Unique");
      }
      else if (records.length == 0) {
        throw new ClientError("Record Not Found")
      }
      const record_id = records[0].id;
      if (action === "update") {
        result = await flare.put(`zones/${zone_id}/dns_records/${record_id}`, { type: rtype, name: simplifyDomain(domain), content: content });
      } else { // delete
        result = await flare.delete(`zones/${zone_id}/dns_records/${record_id}`);
      }
      break;
  }
  if (!result.success) {
    throw new Error(`Upstream erorr (${errors})`);
  }
  return new Response(`Successfully Updated at ${new Date()}`, { status: 200 });
 }

 // Search predefined ZONES for matching domain, returning the matched zone.
 function getZoneByDomain(domain) {
  let zone;
  for (const parent_domain of parentDomains(domain)) {
    if (ZONES[parent_domain] !== undefined) {
      zone = ZONES[parent_domain];
      break;
    }
  }
  return zone;
 }

 // Search TOKENS for matching token, serving as authentication process.
 function getEffectiveDomain(token, domain) {
  let effective_domain;
  for (const parent_domain of parentDomains(domain)) {
    console.log(parent_domain, TOKENS[parent_domain]);
    if (TOKENS[parent_domain] && TOKENS[parent_domain] === token) {
      effective_domain = parent_domain;
      break;
    }
  }
  return effective_domain;
 }

 // Generator function yielding a canonicalized domain and all of its parent-domains.
 // e.g. parentDomains("www.example.org.") -> ["www.example.org.", example.org., org.]*
 function* parentDomains(domain) {
  if (domain !== ".") {
    let dot = -1;
    do {
      domain = domain.substring(dot + 1);
      yield domain;
      dot = domain.indexOf(".");
    }
    while (dot != domain.length - 1)
  }
  yield ".";
 }

 // Strip the trailing dot indicating root domain, if it is present.
 // Necessary because the poor CloudFlare cannot understand canonicalized domains.
 function simplifyDomain(domain) {
  if (domain.endsWith(".")) {
    domain = domain.substring(0, domain.length - 1);
  }
  return domain;
 }

 // Canonicalize the domain by add trailing dot indicating root domain, if it is not present. 
 function canonicalizeDomain(domain) {
  if (!domain.endsWith(".")) {
    domain += ".";
  }
  return domain;
 }
	// CloudFlare API token
	// for zone: example.com (Edit)
	const CLOUDFLARE_API_TOKEN = "TO_BE_FILLED";
	// Currently, there seems not to be a way to get zone ids with tokens. So hardcode it here.
	// https://community.cloudflare.com/t/bug-in-list-zones-endpoint-when-using-api-token/115048
	// Trailing dots CANNOT BE OMITTED.
	const ZONES = {
	"example.org.": {
	id: "TO_BE_FILLED"
	},
	};
	// Arbitrary API tokens, mapping domains to customizable tokens, which can be any text.
	// Tokens for a domain can always be used to access its direct or indirect subdomains.
	// Trailing dots CANNOT BE OMITTED.
	const TOKENS = /* TOKENS: */ {
	"example.org.": "b69541a8-0acd-4e14-aecf-053d5e1b923d",
	"foo.example.org.": "144e7c59-7c2b-4360-9d16-00bbad549fb9",
	"foo.bar.example.org.": "218fa52e-d3c9-419d-a800-d8510e899a30",
	} /* :TOKENS */;
	// Time To Live in DNS record. 1 indictes automatic.
	const TTL = 1;

	class Flare {
	constructor(api_token) {
	this.api_token = api_token;
	}

	async request(method, path, data) {
	const response = await fetch("https://api.cloudflare.com/client/v4/" + path, {
	method: method,
	headers: {
	"Authorization": `Bearer ${this.api_token}`,
	"Content-Type": "application/json"
	},
	body: JSON.stringify(data),
	});
	if (!response.ok) {
	throw new Error(`Upstream response error (status code: ${response.status})`);
	}
	try {
	return await response.json();
	}
	catch (e) {
	throw new Error("Upstream invalid response");
	}
	}

	get(path, data) {
	return this.request("GET", path, data);
	}

	post(path, data) {
	return this.request("POST", path, data);
	}

	put(path, data) {
	return this.request("PUT", path, data);
	}

	delete(path, data) {
	return this.request("delete", path, data);
	}
	}

	const flare = new Flare(CLOUDFLARE_API_TOKEN);

	class ClientError extends Error { }

	addEventListener('fetch', event => {
	event.respondWith(handleRequest(event.request));
	})

	/**
	* Respond to the request
	* @param {Request} request
	*/
	async function handleRequest(request) {
	const url = new URL(request.url);
	if (url.pathname === "/") {
	return new Response("cfapi-ddns-worker.js is up");
	}
	try {
	const path = url.pathname.startsWith("/") ? url.pathname.substring(1) : url.pathname;
	const [action, token, domain, rtype, content] = path.split("/", 5);
	if (["update", "create", "delete", "upsert"].includes(action)) {
	if ([token, domain, rtype, content].some((e) => e === undefined)) {
	throw new ClientError("Parameters Missing");
	}
	return await handleAction(action, token, domain, rtype, content);
	}
	else {
	return new Response(`Unsupported action: ${action}`, { status: 404 });
	}
	}
	catch (e) {
	if (e instanceof ClientError) {
	return new Response(e, { status: 400 });
	}
	else {
	return new Response(e, { status: 500 });
	}
	}
	}

	async function handleAction(action, token, domain, rtype, content) {
	const canon_domain = canonicalizeDomain(domain);
	const effective_domain = getEffectiveDomain(token, canon_domain);
	if (effective_domain === undefined) {
	throw new ClientError("Invalid token");
	}
	let { id: zone_id } = getZoneByDomain(effective_domain);
	if (zone_id === undefined) {
	throw new ClientError(`Zone ID has not been specified for the domain ${effective_domain}`);
	}
	const records = (await flare.get(`zones/${zone_id}/dns_records?name=${simplifyDomain(domain)}&type=${rtype}`)).result;
	if (action === "upsert" && records.length === 0) {
	action = "create";
	}
	else {
	action = "update";
	}
	let result;
	switch (action) {
	case "create":
	if (records.length > 0) {
	throw new ClientError("Record Already Existing");
	}
	result = await flare.post(`zones/${zone_id}/dns_records`, { type: rtype, name: simplifyDomain(domain), content: content });
	break;
	case "update":
	case "delete":
	if (records.length > 1) {
	throw new ClientError("Record Not Unique");
	}
	else if (records.length == 0) {
	throw new ClientError("Record Not Found")
	}
	const record_id = records[0].id;
	if (action === "update") {
	result = await flare.put(`zones/${zone_id}/dns_records/${record_id}`, { type: rtype, name: simplifyDomain(domain), content: content });
	} else { // delete
	result = await flare.delete(`zones/${zone_id}/dns_records/${record_id}`);
	}
	break;
	}
	if (!result.success) {
	throw new Error(`Upstream erorr (${errors})`);
	}
	return new Response(`Successfully Updated at ${new Date()}`, { status: 200 });
	}

	// Search predefined ZONES for matching domain, returning the matched zone.
	function getZoneByDomain(domain) {
	let zone;
	for (const parent_domain of parentDomains(domain)) {
	if (ZONES[parent_domain] !== undefined) {
	zone = ZONES[parent_domain];
	break;
	}
	}
	return zone;
	}

	// Search TOKENS for matching token, serving as authentication process.
	function getEffectiveDomain(token, domain) {
	let effective_domain;
	for (const parent_domain of parentDomains(domain)) {
	console.log(parent_domain, TOKENS[parent_domain]);
	if (TOKENS[parent_domain] && TOKENS[parent_domain] === token) {
	effective_domain = parent_domain;
	break;
	}
	}
	return effective_domain;
	}

	// Generator function yielding a canonicalized domain and all of its parent-domains.
	// e.g. parentDomains("www.example.org.") -> ["www.example.org.", example.org., org.]*
	function* parentDomains(domain) {
	if (domain !== ".") {
	let dot = -1;
	do {
	domain = domain.substring(dot + 1);
	yield domain;
	dot = domain.indexOf(".");
	}
	while (dot != domain.length - 1)
	}
	yield ".";
	}

	// Strip the trailing dot indicating root domain, if it is present.
	// Necessary because the poor CloudFlare cannot understand canonicalized domains.
	function simplifyDomain(domain) {
	if (domain.endsWith(".")) {
	domain = domain.substring(0, domain.length - 1);
	}
	return domain;
	}

	// Canonicalize the domain by add trailing dot indicating root domain, if it is not present.
	function canonicalizeDomain(domain) {
	if (!domain.endsWith(".")) {
	domain += ".";
	}
	return domain;
	}