shumengya

functions/api/favicon.js

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+/**
+ * Favicon 代理 API
+ * 通过 Google、DuckDuckGo、直连 /favicon.ico 与解析页面 <link rel="icon"> 多路竞速获取 favicon（支持 ico/png/jpg/webp）
+ * 注：Bing 无公开 favicon API，故使用 DuckDuckGo 作为第二源
+ */
+
+function parseDomain(input) {
+  if (!input || typeof input !== 'string') return null
+  const trimmed = input.trim()
+  if (!trimmed) return null
+  try {
+    let url = trimmed
+    if (!/^https?:\/\//i.test(trimmed)) url = `https://${trimmed}`
+    const u = new URL(url)
+    return u.hostname
+  } catch {
+    return null
+  }
+}
+
+/** 从 HTML 中解析 <link rel="icon"> 的 href，支持 png/jpg/webp/svg 等 */
+function parseFaviconFromHtml(html, baseUrl) {
+  const linkRegex = /<link[^>]+>/gi
+  const links = html.match(linkRegex) || []
+  for (const tag of links) {
+    const relMatch = tag.match(/\brel\s*=\s*["']([^"']+)["']/i)
+    if (!relMatch) continue
+    const rel = relMatch[1].toLowerCase()
+    if (!rel.includes('icon')) continue
+    const hrefMatch = tag.match(/\bhref\s*=\s*["']([^"']+)["']/i)
+    if (!hrefMatch) continue
+    const href = hrefMatch[1].trim()
+    if (!href || href.startsWith('data:')) continue
+    try {
+      return new URL(href, baseUrl).href
+    } catch {
+      continue
+    }
+  }
+  return null
+}
+
+function firstSuccess(promises) {
+  return new Promise((resolve, reject) => {
+    let rejectedCount = 0
+    const total = promises.length
+    const onFulfill = (value) => {
+      if (!resolve.done) {
+        resolve.done = true
+        resolve(value)
+      }
+    }
+    const onReject = () => {
+      if (++rejectedCount === total && !resolve.done) reject(new Error('All sources failed'))
+    }
+    promises.forEach((p) => p.then(onFulfill, onReject))
+  })
+}
+
+export async function onRequestGet(context) {
+  const { request } = context
+  const url = new URL(request.url)
+  const domainParam = url.searchParams.get('domain') ?? url.searchParams.get('url') ?? url.searchParams.get('u')
+
+  const domain = parseDomain(domainParam)
+  if (!domain) {
+    return new Response(
+      JSON.stringify({
+        error: 'missing_domain',
+        message: '请提供 domain、url 或 u 参数，例如: ?url=https://twitter.com 或 ?domain=github.com',
+      }),
+      {
+        status: 400,
+        headers: {
+          'Content-Type': 'application/json; charset=utf-8',
+          'Access-Control-Allow-Origin': '*',
+        },
+      }
+    )
+  }
+
+  const size = Math.min(256, Math.max(16, parseInt(url.searchParams.get('size') || '128', 10) || 128))
+
+  const fetchOpts = {
+    headers: {
+      'User-Agent': 'Mozilla/5.0 (compatible; FaviconProxy/1.0)',
+    },
+  }
+
+  // 多路：Google、DuckDuckGo、直连 /favicon.ico、解析页面 <link rel="icon">（支持 png/jpg/webp）
+  const googleUrl = `https://www.google.com/s2/favicons?domain=${encodeURIComponent(domain)}&sz=${size}`
+  const ddgUrl = `https://icons.duckduckgo.com/ip3/${encodeURIComponent(domain)}.ico`
+  const directUrl = `https://${domain}/favicon.ico`
+
+  // 四路竞速：任一路成功即返回，都不参与 fallback
+  const googlePromise = fetch(googleUrl, fetchOpts).then((r) =>
+    r.ok ? r : Promise.reject(new Error('Google non-OK'))
+  )
+  const ddgPromise = fetch(ddgUrl, fetchOpts).then((r) =>
+    r.ok ? r : Promise.reject(new Error('DDG non-OK'))
+  )
+  const directPromise = fetch(directUrl, fetchOpts).then((r) =>
+    r.ok ? r : Promise.reject(new Error('Direct non-OK'))
+  )
+
+  // 抓取首页 HTML，解析 <link rel="icon" href="...">，支持 png/jpg/webp/svg 等
+  const fromHtmlPromise = (async () => {
+    const pageRes = await fetch(`https://${domain}/`, { ...fetchOpts, redirect: 'follow' })
+    if (!pageRes.ok) throw new Error('Page non-OK')
+    const html = await pageRes.text()
+    const baseUrl = pageRes.url || `https://${domain}/`
+    const iconUrl = parseFaviconFromHtml(html, baseUrl)
+    if (!iconUrl) throw new Error('No icon in HTML')
+    const iconRes = await fetch(iconUrl, fetchOpts)
+    if (!iconRes.ok) throw new Error('Icon fetch non-OK')
+    return iconRes
+  })()
+
+  // 仅当以上四路全部失败时，才尝试 public/favicon.ico（最后才用，不参与竞速）
+  try {
+    const response = await firstSuccess([googlePromise, ddgPromise, directPromise, fromHtmlPromise])
+    const contentType = response.headers.get('Content-Type') || 'image/x-icon'
+    const body = await response.arrayBuffer()
+
+    return new Response(body, {
+      status: 200,
+      headers: {
+        'Content-Type': contentType,
+        'Cache-Control': 'public, max-age=86400',
+        'Access-Control-Allow-Origin': '*',
+        'X-Favicon-Domain': domain,
+      },
+    })
+  } catch (e) {
+    // 仅当四路（Google、DDG、直连 ico、页面解析）全部失败后，才用 public/favicon.ico
+    const fallbackUrl = `${url.origin}/public/favicon.ico`
+    const fallbackRes = await fetch(fallbackUrl, fetchOpts)
+    if (fallbackRes.ok) {
+      const contentType = fallbackRes.headers.get('Content-Type') || 'image/x-icon'
+      const body = await fallbackRes.arrayBuffer()
+      return new Response(body, {
+        status: 200,
+        headers: {
+          'Content-Type': contentType,
+          'Cache-Control': 'public, max-age=86400',
+          'Access-Control-Allow-Origin': '*',
+          'X-Favicon-Domain': domain,
+          'X-Favicon-Fallback': 'true',
+        },
+      })
+    }
+    return new Response(
+      JSON.stringify({
+        error: 'fetch_failed',
+        message: '无法从多路源获取该域名的 favicon，且未找到 public/favicon.ico 作为回退',
+        domain,
+      }),
+      {
+        status: 502,
+        headers: {
+          'Content-Type': 'application/json; charset=utf-8',
+          'Access-Control-Allow-Origin': '*',
+        },
+      }
+    )
+  }
+}