feature: 新增 `response` 拦截器，目前暂时只支持替换响应头 (#295)

packages/mitmproxy/src/lib/interceptor/impl/res/response.js

@@ -0,0 +1,69 @@
+const lodash = require('lodash')
+
+function replaceHeaders (newHeaders, res, proxyRes) {
+  if (newHeaders && !lodash.isEmpty(newHeaders)) {
+    // 响应头Key统一转小写
+    for (const headerKey in newHeaders) {
+      if (headerKey === headerKey.toLowerCase()) {
+        continue
+      }
+
+      const value = newHeaders[headerKey]
+      delete newHeaders[headerKey]
+      newHeaders[headerKey.toLowerCase()] = value
+    }
+
+    // 原先响应头
+    const preHeaders = {}
+
+    // 替换响应头
+    for (let i = 0; i < proxyRes.rawHeaders.length; i += 2) {
+      const headerKey = proxyRes.rawHeaders[i]
+      const headerKeyLower = headerKey.toLowerCase()
+
+      const newHeaderValue = newHeaders[headerKeyLower]
+      if (newHeaderValue) {
+        preHeaders[headerKeyLower] = proxyRes.rawHeaders[i + 1] // 先保存原先响应头
+
+        proxyRes.rawHeaders[i + 1] = newHeaderValue
+        delete newHeaders[headerKeyLower]
+      }
+    }
+    // 新增响应头
+    for (const headerKey in newHeaders) {
+      res.setHeader(headerKey, newHeaders[headerKey])
+      preHeaders[headerKey] = null // 标记原先响应头为null
+    }
+
+    // 返回原先响应头
+    return preHeaders
+  }
+
+  return null
+}
+
+module.exports = {
+  name: 'response',
+  priority: 203,
+  replaceHeaders,
+  responseIntercept (context, interceptOpt, req, res, proxyReq, proxyRes, ssl, next) {
+    const { log } = context
+
+    const responseConfig = interceptOpt.response
+
+    let actions = ''
+
+    // 替换响应头
+    if (replaceHeaders(responseConfig.headers, res, proxyRes)) {
+      actions += 'headers'
+    }
+
+    if (actions) {
+      res.setHeader('DS-Response-Interceptor', actions)
+      log.info('response intercept: ' + actions)
+    }
+  },
+  is (interceptOpt) {
+    return !!interceptOpt.response
+  }
+}

packages/mitmproxy/src/lib/interceptor/index.js

@@ -13,6 +13,7 @@ const sni = require('./impl/req/sni')
 // response interceptor impls
 const cacheRes = require('./impl/res/cacheRes')
 const script = require('./impl/res/script')
+const response = require('./impl/res/response')
 
 module.exports = [
   // request interceptor impls
@@ -22,5 +23,5 @@ module.exports = [
   proxy, sni,
 
   // response interceptor impls
-  cacheRes, script
+  cacheRes, script, response
 ]