Create node-smartcdn-sig.ts

Author: kvz

tests/node-smartcdn-sig.ts

@@ -0,0 +1,91 @@
+#!/usr/bin/env tsx
+// Reference Smart CDN (https://transloadit.com/services/content-delivery/) Signature implementation
+// And CLI tester to see if our SDK's implementation
+// matches Node's
+
+/// <reference types="node" />
+
+import { createHash, createHmac } from 'crypto'
+
+interface SmartCDNParams {
+  workspace: string
+  template: string
+  input: string
+  expire_at_ms?: number
+  auth_key?: string
+  auth_secret?: string
+  url_params?: Record<string, any>
+}
+
+function signSmartCDNUrl(params: SmartCDNParams): string {
+  const {
+    workspace,
+    template,
+    input,
+    expire_at_ms,
+    auth_key,
+    auth_secret,
+    url_params = {},
+  } = params
+
+  if (!workspace) throw new Error('workspace is required')
+  if (!template) throw new Error('template is required')
+  if (input === null || input === undefined)
+    throw new Error('input must be a string')
+  if (!auth_key) throw new Error('auth_key is required')
+  if (!auth_secret) throw new Error('auth_secret is required')
+
+  const workspaceSlug = encodeURIComponent(workspace)
+  const templateSlug = encodeURIComponent(template)
+  const inputField = encodeURIComponent(input)
+
+  const expireAt = expire_at_ms ?? Date.now() + 60 * 60 * 1000 // 1 hour default
+
+  const queryParams: Record<string, string[]> = {}
+
+  // Handle url_params
+  Object.entries(url_params).forEach(([key, value]) => {
+    if (value === null || value === undefined) return
+    if (Array.isArray(value)) {
+      value.forEach((val) => {
+        if (val === null || val === undefined) return
+        ;(queryParams[key] ||= []).push(String(val))
+      })
+    } else {
+      queryParams[key] = [String(value)]
+    }
+  })
+
+  queryParams.auth_key = [auth_key]
+  queryParams.exp = [String(expireAt)]
+
+  // Sort parameters to ensure consistent ordering
+  const sortedParams = Object.entries(queryParams)
+    .sort()
+    .map(([key, values]) =>
+      values.map((v) => `${encodeURIComponent(key)}=${encodeURIComponent(v)}`)
+    )
+    .flat()
+    .join('&')
+
+  const stringToSign = `${workspaceSlug}/${templateSlug}/${inputField}?${sortedParams}`
+  const signature = createHmac('sha256', auth_secret)
+    .update(stringToSign)
+    .digest('hex')
+
+  const finalParams = `${sortedParams}&sig=${encodeURIComponent(
+    `sha256:${signature}`
+  )}`
+  return `https://${workspaceSlug}.tlcdn.com/${templateSlug}/${inputField}?${finalParams}`
+}
+
+// Read JSON from stdin
+let jsonInput = ''
+process.stdin.on('data', (chunk) => {
+  jsonInput += chunk
+})
+
+process.stdin.on('end', () => {
+  const params = JSON.parse(jsonInput)
+  console.log(signSmartCDNUrl(params))
+})