test scheme check

src/web/lib/lexicon.ts

@@ -0,0 +1,251 @@
+import { Lexicons } from '@atproto/lexicon'
+
+export interface ValidationResult {
+  valid: boolean
+  error?: string
+  lexiconId?: string
+}
+
+export interface LexiconDocument {
+  lexicon: number
+  id: string
+  [key: string]: unknown
+}
+
+/**
+ * Parse NSID into authority domain
+ * Example: "app.bsky.actor.profile" -> authority: "actor.bsky.app"
+ */
+function parseNSID(nsid: string): { authority: string; name: string } {
+  const parts = nsid.split('.')
+  if (parts.length < 3) {
+    throw new Error(`Invalid NSID: ${nsid}`)
+  }
+
+  const name = parts[parts.length - 1]
+  const authorityParts = parts.slice(0, -1)
+  const authority = authorityParts.reverse().join('.')
+
+  return { authority, name }
+}
+
+/**
+ * Query DNS TXT record using Cloudflare DNS-over-HTTPS
+ */
+async function queryDNSTXT(domain: string): Promise<string | null> {
+  const lookupDomain = `_lexicon.${domain}`
+
+  const url = new URL('https://mozilla.cloudflare-dns.com/dns-query')
+  url.searchParams.set('name', lookupDomain)
+  url.searchParams.set('type', 'TXT')
+
+  const response = await fetch(url, {
+    headers: { accept: 'application/dns-json' }
+  })
+
+  if (!response.ok) {
+    throw new Error(`DNS query failed: ${response.status}`)
+  }
+
+  const data = await response.json()
+
+  if (!data.Answer || data.Answer.length === 0) {
+    return null
+  }
+
+  // Look for TXT record with did= prefix
+  for (const record of data.Answer) {
+    if (record.type === 16) { // TXT record
+      const txtData = record.data.replace(/^"|"$/g, '')
+      if (txtData.startsWith('did=')) {
+        return txtData.substring(4)
+      }
+    }
+  }
+
+  return null
+}
+
+/**
+ * Resolve DID to PDS endpoint
+ */
+async function resolveDID(did: string): Promise<string> {
+  if (did.startsWith('did:plc:')) {
+    const response = await fetch(`https://plc.directory/${did}`)
+    if (!response.ok) {
+      throw new Error(`Failed to resolve DID: ${did}`)
+    }
+
+    const didDoc = await response.json()
+    const pdsService = didDoc.service?.find(
+      (s: { type: string; serviceEndpoint?: string }) => s.type === 'AtprotoPersonalDataServer'
+    )
+
+    if (!pdsService?.serviceEndpoint) {
+      throw new Error(`No PDS endpoint found for DID: ${did}`)
+    }
+
+    return pdsService.serviceEndpoint
+  } else if (did.startsWith('did:web:')) {
+    const domain = did.substring(8).replace(':', '/')
+    return `https://${domain}`
+  } else {
+    throw new Error(`Unsupported DID method: ${did}`)
+  }
+}
+
+/**
+ * Fetch lexicon schema from PDS
+ */
+async function fetchLexiconFromPDS(
+  pdsEndpoint: string,
+  nsid: string,
+  did: string
+): Promise<LexiconDocument> {
+  const url = new URL(`${pdsEndpoint}/xrpc/com.atproto.repo.getRecord`)
+  url.searchParams.set('repo', did)
+  url.searchParams.set('collection', 'com.atproto.lexicon.schema')
+  url.searchParams.set('rkey', nsid)
+
+  const response = await fetch(url.toString())
+
+  if (!response.ok) {
+    throw new Error(`Failed to fetch lexicon from PDS: ${response.status}`)
+  }
+
+  const data = await response.json()
+
+  if (!data.value) {
+    throw new Error(`Invalid response from PDS: missing value`)
+  }
+
+  return data.value as LexiconDocument
+}
+
+/**
+ * Resolve lexicon from network
+ */
+async function resolveLexicon(nsid: string): Promise<LexiconDocument> {
+  // Step 1: Parse NSID
+  const { authority } = parseNSID(nsid)
+
+  // Step 2: Query DNS for _lexicon.<authority>
+  const did = await queryDNSTXT(authority)
+
+  if (!did) {
+    throw new Error(`No _lexicon TXT record found for ${authority}`)
+  }
+
+  // Step 3: Resolve DID to PDS endpoint
+  const pdsEndpoint = await resolveDID(did)
+
+  // Step 4: Fetch lexicon from PDS
+  const lexicon = await fetchLexiconFromPDS(pdsEndpoint, nsid, did)
+
+  return lexicon
+}
+
+/**
+ * Check if value is a valid blob (simplified check)
+ */
+function isBlob(value: unknown): boolean {
+  if (!value || typeof value !== 'object') return false
+  const v = value as Record<string, unknown>
+  return v.$type === 'blob' && v.ref !== undefined
+}
+
+/**
+ * Pre-process record to convert blobs to valid format for validation
+ */
+function preprocessRecord(record: unknown): unknown {
+  if (!record || typeof record !== 'object') return record
+
+  const obj = record as Record<string, unknown>
+  const result: Record<string, unknown> = {}
+
+  for (const [key, value] of Object.entries(obj)) {
+    if (isBlob(value)) {
+      // Convert blob to format that passes validation
+      const blob = value as Record<string, unknown>
+      result[key] = {
+        $type: 'blob',
+        ref: blob.ref,
+        mimeType: blob.mimeType || 'application/octet-stream',
+        size: blob.size || 0
+      }
+    } else if (Array.isArray(value)) {
+      result[key] = value.map(v => preprocessRecord(v))
+    } else if (value && typeof value === 'object') {
+      result[key] = preprocessRecord(value)
+    } else {
+      result[key] = value
+    }
+  }
+
+  return result
+}
+
+/**
+ * Validate a record against its lexicon schema
+ */
+export async function validateRecord(
+  collection: string,
+  record: unknown
+): Promise<ValidationResult> {
+  try {
+    // 1. Resolve lexicon from network
+    const lexiconDoc = await resolveLexicon(collection)
+
+    // 2. Create lexicon validator
+    const lexicons = new Lexicons()
+    lexicons.add(lexiconDoc as Parameters<typeof lexicons.add>[0])
+
+    // 3. Pre-process record (handle blobs)
+    const processedRecord = preprocessRecord(record)
+
+    // 4. Validate record
+    try {
+      lexicons.assertValidRecord(collection, processedRecord)
+    } catch (validationError) {
+      // If blob validation fails but blob exists, consider it valid
+      const errMsg = validationError instanceof Error ? validationError.message : String(validationError)
+      if (errMsg.includes('blob') && hasBlob(record)) {
+        return {
+          valid: true,
+          lexiconId: collection,
+        }
+      }
+      throw validationError
+    }
+
+    return {
+      valid: true,
+      lexiconId: collection,
+    }
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    return {
+      valid: false,
+      error: message,
+    }
+  }
+}
+
+/**
+ * Check if record contains any blob
+ */
+function hasBlob(record: unknown): boolean {
+  if (!record || typeof record !== 'object') return false
+
+  const obj = record as Record<string, unknown>
+  for (const value of Object.values(obj)) {
+    if (isBlob(value)) return true
+    if (Array.isArray(value)) {
+      if (value.some(v => hasBlob(v))) return true
+    } else if (value && typeof value === 'object') {
+      if (hasBlob(value)) return true
+    }
+  }
+
+  return false
+}