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Monorepo for the nibling.run platform
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217import { isCid, isDid, isNsid, isRecordKey, isResourceUri } from '@atcute/lexicons/syntax';import { parseActorIdentifier } from '@nibling/sdk/identifier';import { cached, POLICY, type CachePolicy } from './cache.ts';import { cacheKey, type Gateway } from './context.ts';import { miniDoc, resolveDid, resolveMiniDoc } from './identity.ts';import { CORS, failureResponse, fetchUpstream, MAX_BLOB_BYTES, MAX_JSON_BYTES, proxyJson, readLimited, xrpcError,} from './proxy.ts';
type Params = Record<string, string | undefined>;
/** What a valid request turns into: where it is cached, for how long, and how to load it. */interface Plan { key: string; policy: CachePolicy; load(): Promise<Response>;}
type Parsed = { ok: true; params: Params } | { ok: false; message: string };
/** One query param's rule: `required` or not, and a check on its value. */type Rule = { required: boolean; check(value: string): boolean; what: string };
const required = (check: Rule['check'], what: string): Rule => ({ required: true, check, what });const optional = (check: Rule['check'], what: string): Rule => ({ required: false, check, what });
const actor = (v: string) => parseActorIdentifier(v) !== undefined;const limit = (v: string) => /^\d{1,3}$/.test(v) && Number(v) >= 1 && Number(v) <= 100;const cursor = (v: string) => v.length > 0 && v.length <= 1024;const bool = (v: string) => v === 'true' || v === 'false';const subject = (v: string) => v.length > 0 && v.length <= 2048;const source = (v: string) => /^[a-zA-Z0-9.-]+:[a-zA-Z0-9_.[\]-]+$/.test(v) && v.length <= 512;
/** Parses the params a route takes. Anything else in the query string is dropped, so it can neither * reach the upstream nor split the cache. */function parse(query: URLSearchParams, rules: Record<string, Rule>): Parsed { const params: Params = {}; for (const [name, rule] of Object.entries(rules)) { const values = query.getAll(name); if (values.length > 1) return { ok: false, message: `${name} may be given once` }; const value = values[0]; if (value === undefined || value === '') { if (rule.required) return { ok: false, message: `${name} is required` }; continue; } if (!rule.check(value)) return { ok: false, message: `${name} must be ${rule.what}` }; params[name] = value; } return { ok: true, params };}
function upstreamUrl(base: string, nsid: string, params: Params): string { const url = new URL(`/xrpc/${nsid}`, base); for (const [name, value] of Object.entries(params)) if (value !== undefined) url.searchParams.set(name, value); return url.toString();}
/** Resolves `repo` to its DID and PDS, so a handle and its DID share one cache entry. */async function withPds(g: Gateway, identifier: string, plan: (did: string, pds: string) => Plan): Promise<Plan | Response> { try { const found = await miniDoc(g, parseActorIdentifier(identifier)!); if (!found.found) return xrpcError('RepoNotFound', found.message, 400); return plan(found.value.did, found.value.pds); } catch (error) { return failureResponse(error); }}
/** A record pinned by CID never changes, but a PDS asked for a CID it no longer holds answers with the * current version on some implementations. Only an answer that carries the asked-for CID is kept. */async function pinnedRecord(g: Gateway, url: string, cid: string): Promise<Response> { const res = await proxyJson(g.fetch, url); if (res.status !== 200) return res; const body = (await res.clone().json()) as { cid?: unknown }; return body.cid === cid ? res : xrpcError('RecordNotFound', `no version ${cid} of that record`, 400);}
async function blob(g: Gateway, url: string): Promise<Response> { try { const res = await fetchUpstream(g.fetch, url); if (res.status >= 500) { await res.body?.cancel(); return xrpcError('UpstreamFailure', `${new URL(url).host} answered ${res.status}`, 502); } if (res.status !== 200) return proxyJsonBody(res); const bytes = await readLimited(res, MAX_BLOB_BYTES); return new Response(bytes, { headers: { ...CORS, 'content-type': res.headers.get('content-type') ?? 'application/octet-stream', // A blob is whatever its uploader said it is. Served from our origin it must never run. 'content-security-policy': "default-src 'none'; sandbox", 'x-content-type-options': 'nosniff', }, }); } catch (error) { return failureResponse(error); }}
async function proxyJsonBody(res: Response): Promise<Response> { const bytes = await readLimited(res, MAX_JSON_BYTES); return new Response(bytes, { status: res.status, headers: { ...CORS, 'content-type': 'application/json' } });}
type Route = { rules: Record<string, Rule>; plan(g: Gateway, params: Params): Plan | Response | Promise<Plan | Response> };
/** Every read the gateway answers, by NSID. Each validates its params, then names a cache policy. */const ROUTES: Record<string, Route> = { 'com.atproto.repo.getRecord': { rules: { repo: required(actor, 'a handle or DID'), collection: required(isNsid, 'an NSID'), rkey: required(isRecordKey, 'a record key'), cid: optional(isCid, 'a CID'), }, plan: (g, p) => withPds(g, p.repo!, (did, pds) => { const params = { ...p, repo: did }; const url = upstreamUrl(pds, 'com.atproto.repo.getRecord', params); return p.cid ? { key: cacheKey(g, '/xrpc/com.atproto.repo.getRecord', params), policy: POLICY.immutable, load: () => pinnedRecord(g, url, p.cid!) } : { key: cacheKey(g, '/xrpc/com.atproto.repo.getRecord', params), policy: POLICY.repo, load: () => proxyJson(g.fetch, url) }; }), }, 'com.atproto.repo.listRecords': { rules: { repo: required(actor, 'a handle or DID'), collection: required(isNsid, 'an NSID'), limit: optional(limit, 'an integer from 1 to 100'), cursor: optional(cursor, 'at most 1024 characters'), reverse: optional(bool, 'true or false'), }, plan: (g, p) => withPds(g, p.repo!, (did, pds) => { const params = { ...p, repo: did }; return { key: cacheKey(g, '/xrpc/com.atproto.repo.listRecords', params), policy: POLICY.repo, load: () => proxyJson(g.fetch, upstreamUrl(pds, 'com.atproto.repo.listRecords', params)) }; }), }, 'com.atproto.repo.describeRepo': { rules: { repo: required(actor, 'a handle or DID') }, plan: (g, p) => withPds(g, p.repo!, (did, pds) => { const params = { repo: did }; return { key: cacheKey(g, '/xrpc/com.atproto.repo.describeRepo', params), policy: POLICY.repo, load: () => proxyJson(g.fetch, upstreamUrl(pds, 'com.atproto.repo.describeRepo', params)) }; }), }, 'com.atproto.sync.getBlob': { rules: { did: required(isDid, 'a DID'), cid: required(isCid, 'a CID') }, plan: (g, p) => withPds(g, p.did!, (did, pds) => ({ key: cacheKey(g, '/xrpc/com.atproto.sync.getBlob', p), policy: POLICY.immutable, load: () => blob(g, upstreamUrl(pds, 'com.atproto.sync.getBlob', { did, cid: p.cid })), })), }, 'com.atproto.identity.resolveDid': { rules: { did: required(isDid, 'a DID') }, // Cached inside, where the gateway's own lookups share the entry. plan: (g, p) => resolveDid(g, p.did!), }, 'blue.microcosm.identity.resolveMiniDoc': { rules: { identifier: required(actor, 'a handle or DID') }, plan: (g, p) => resolveMiniDoc(g, parseActorIdentifier(p.identifier!)!), }, 'blue.microcosm.links.getBacklinks': { rules: { subject: required(subject, 'at most 2048 characters'), source: required(source, 'a <collection>:<path> source'), limit: optional(limit, 'an integer from 1 to 100'), cursor: optional(cursor, 'at most 1024 characters'), }, plan: (g, p) => ({ key: cacheKey(g, '/xrpc/blue.microcosm.links.getBacklinks', p), policy: POLICY.backlinks, load: () => proxyJson(g.fetch, upstreamUrl(g.constellation, 'blue.microcosm.links.getBacklinks', p)), }), }, 'blue.microcosm.links.getBacklinksCount': { rules: { subject: required(subject, 'at most 2048 characters'), source: required(source, 'a <collection>:<path> source') }, plan: (g, p) => ({ key: cacheKey(g, '/xrpc/blue.microcosm.links.getBacklinksCount', p), policy: POLICY.backlinks, load: () => proxyJson(g.fetch, upstreamUrl(g.constellation, 'blue.microcosm.links.getBacklinksCount', p)), }), }, 'blue.microcosm.repo.getRecordByUri': { rules: { at_uri: required(isResourceUri, 'an AT-URI'), cid: optional(isCid, 'a CID') }, plan: (g, p) => ({ key: cacheKey(g, '/xrpc/blue.microcosm.repo.getRecordByUri', p), policy: p.cid ? POLICY.immutable : POLICY.repo, load: () => { const url = upstreamUrl(g.slingshot, 'blue.microcosm.repo.getRecordByUri', p); return p.cid ? pinnedRecord(g, url, p.cid) : proxyJson(g.fetch, url); }, }), },};
/** Answers `/xrpc/<nsid>` when the gateway serves that NSID, else undefined. */export async function handleXrpc(g: Gateway, nsid: string, query: URLSearchParams, bypass: boolean): Promise<Response | undefined> { const route = ROUTES[nsid]; if (!route) return undefined; const parsed = parse(query, route.rules); if (!parsed.ok) return xrpcError('InvalidRequest', parsed.message, 400); const plan = await route.plan(g, parsed.params); if (plan instanceof Response) return plan; return cached(g, plan.key, plan.policy, bypass, plan.load);}