anyproxy學習3-修改返回內容(beforeSendResponse)

前言

fiddler能夠抓包打斷點後，修改返回的內容，便於模擬各類返回結果。anyproxy也能夠經過寫rule模塊規則，模擬返回狀態碼、頭部、body

beforeSendResponse

beforeSendResponse(requestDetail, responseDetail)

• AnyProxy向客戶端發送請求前，會調用beforeSendResponse，並帶上參數requestDetail responseDetail
• requestDetail 同beforeSendRequest中的參數
• responseDetail
  response {object} 服務端的返回信息，包括statusCode header body三個字段
  _res {object} 原始的服務端返回對象

舉例，請求 http://httpbin.org/get 時，responseDetail參數內容大體以下

{
  response: {
    statusCode: 200,
    header: {
      'Content-Type': 'image/gif',
      Connection: 'close',
      'Cache-Control': '...'
    },
    body: '...'
  },
  _res: { /* ... */ }
}

修改返回內容

如下幾種返回都是合法的

不作任何處理，返回null

return null;

修改返回的狀態碼

var newResponse = Object.assign({}, responseDetail.response);
newResponse.statusCode = 404;
return {
  response: newResponse
};

修改返回的內容

var newResponse = Object.assign({}, responseDetail.response);
newResponse.body += '--from anyproxy--';
return {
  response: newResponse
};

rule案例

這裏提供一些樣例，來說解規則模塊的常見用法
你能夠經過 anyproxy --rule http://....js 來加載模塊並體驗

用curl發請求測試的方法以下

• 直接請求服務器：curl http://httpbin.org/
• 經過代理服務器請求：curl http://httpbin.org/ --proxy http://127.0.0.1:8001

返回本地json格式body

使用本地數據，攔截髮送到 http://httpbin.org 的請求，使用本地數據代替服務端返回，sample_use_local_response.js規則

/* 
  sample: 
    intercept all requests toward httpbin.org, use a local response
  test:
    curl http://httpbin.org/user-agent --proxy http://127.0.0.1:8001
*/
module.exports = {
  *beforeSendRequest(requestDetail) {
    const localResponse = {
      statusCode: 200,
      header: { 'Content-Type': 'application/json' },
      body: '{"hello": "this is local response"}'
    };
    if (requestDetail.url.indexOf('http://httpbin.org') === 0) {
      return {
        response: localResponse
      };
    }
  },
};

加載rule規則的js文件

anyproxy -i --rule sample_use_local_response.js

使用curl測試http://httpbin.org

C:\Users\dell>curl http://httpbin.org/user-agent --proxy http://127.0.0.1:8001
{"hello": "this is local response"}

模擬返回狀態碼

模擬返回404狀態碼,sample_modify_response_statuscode.js規則以下

/* 
  sample: 
    modify all status code of http://httpbin.org/ to 404
  test:
    curl -I 'http://httpbin.org/user-agent' --proxy http://127.0.0.1:8001
  expected response:
    HTTP/1.1 404 Not Found
*/
module.exports = {
  *beforeSendResponse(requestDetail, responseDetail) {
    if (requestDetail.url.indexOf('http://httpbin.org') === 0) {
      const newResponse = responseDetail.response;
      newResponse.statusCode = 404;
      return {
        response: newResponse
      };
    }
  }
};

模擬返回頭部

修改返回的頭部，sample_modify_response_header.js規則以下

/* 
  sample: 
    modify response header of http://httpbin.org/user-agent
  test:
    curl -I 'http://httpbin.org/user-agent' --proxy http://127.0.0.1:8001
  expected response:
    X-Proxy-By: AnyProxy
*/
module.exports = {
  *beforeSendResponse(requestDetail, responseDetail) {
    if (requestDetail.url.indexOf('http://httpbin.org/user-agent') === 0) {
      const newResponse = responseDetail.response;
      newResponse.header['X-Proxy-By'] = 'AnyProxy';
      return {
        response: newResponse
      };
    }
  }
};

修改返回body

修改返回的body裏面部份內容，sample_modify_response_data.js規則以下

/* 
  sample: 
    modify response data of http://httpbin.org/user-agent
  test:
    curl 'http://httpbin.org/user-agent' --proxy http://127.0.0.1:8001
  expected response:
    { "user-agent": "curl/7.43.0" } -- AnyProxy Hacked! --
*/

module.exports = {
  *beforeSendResponse(requestDetail, responseDetail) {
    if (requestDetail.url === 'http://httpbin.org/user-agent') {
      const newResponse = responseDetail.response;
      newResponse.body += '-- AnyProxy Hacked! --';
      return new Promise((resolve, reject) => {
        setTimeout(() => { // delay the response for 5s
          resolve({ response: newResponse });
        }, 5000);
      });
    }
  },
};

更多學習資料參考https://github.com/alibaba/anyproxy/blob/master/docs/cn/src_doc.md