Question

我试图打造一个文字,作为本地人的替代/交换器,XMLHttpRequest,使我能够拦截该文本,修改复方复原地改变活动。

如果当地储存已经提供数据,则该数据试图接收,便可浏览XMLHttpRequest,并将当地储存的数据反馈到数据的成功/反馈方法中。 Assume I对AJAX现有备用方法没有控制。

I had originally tried the following idea..

var send = XMLHttpRequest.prototype.send;
XMLHttpRequest.prototype.send = function(data){
   //Do some stuff in here to modify the responseText
   send.call(this, data);
};

但是,正如我现在已经确定的那样,复文仅读。

然后,我尝试退一步,写上我自己的全本土代理人,以XMLHttpRequest,最终完成我自己版本的本土方法。类似于这里讨论的内容......

http://www.ilinsky.com/articles/XMLHttpRequest/#implementation-wrapping

但是,它迅速混淆,仍然难以将修改后的数据退回到原来的方法中。

任何建议? 这样做是否可行?

Answer 1

//
// firefox, ie8+ 
//
var accessor = Object.getOwnPropertyDescriptor(XMLHttpRequest.prototype,  responseText );

Object.defineProperty(XMLHttpRequest.prototype,  responseText , {
	get: function() {
		console.log( get responseText );
		return accessor.get.call(this);
	},
	set: function(str) {
		console.log( set responseText: %s , str);
		//return accessor.set.call(this, str);
	},
	configurable: true
});


//
// chrome, safari (accessor == null)
//
var rawOpen = XMLHttpRequest.prototype.open;

XMLHttpRequest.prototype.open = function() {
	if (!this._hooked) {
		this._hooked = true;
		setupHook(this);
	}
	rawOpen.apply(this, arguments);
}

function setupHook(xhr) {
	function getter() {
		console.log( get responseText );

		delete xhr.responseText;
		var ret = xhr.responseText;
		setup();
		return ret;
	}

	function setter(str) {
		console.log( set responseText: %s , str);
	}

	function setup() {
		Object.defineProperty(xhr,  responseText , {
			get: getter,
			set: setter,
			configurable: true
		});
	}
	setup();
}

Answer 2

The following script perfectly intercept the data before sending via XMLHttpRequest.prototype.send

<script>
(function(send) { 

        XMLHttpRequest.prototype.send = function(data) { 

            this.addEventListener( readystatechange , function() { 

            }, false); 

            console.log(data); 
            alert(data); 

        }; 

})(XMLHttpRequest.prototype.send);
</script>

Answer 3

我认为,为了拦截<条码>XMLHttpRequest的回复,将采用一种更现代的解决办法,将原XMLHttpRequest和在<条码>>>>上将其搁置。反对:

const { interceptXhrResponse } = (function () {
  let interceptionRules = [];

  /**
   * Function to intercept responses for given URL patterns
   * @param {RegExp} urlPattern - Regular expression to match the (canonicalized) URL
   * @param {Function} responseHandler - Function to handle the intercepted response
   */
  function interceptXhrResponse(urlPattern, responseHandler) {
    interceptionRules.push({ urlPattern, responseHandler });
  }

  // Function to find specific handler for the URL and return modified response
  function handleInterceptedResponse(response, url) {
    const interceptionRule = interceptionRules.find(({ urlPattern }) =>
      urlPattern.test(url)
    );

    if (interceptionRule) {
      const { responseHandler } = interceptionRule;
      return responseHandler(response, url);
    }

    return response;
  }

  const OriginalXMLHttpRequest = window.XMLHttpRequest;

  class XMLHttpRequest extends OriginalXMLHttpRequest {
    get responseText() {
      // If the request is not done, return the original responseText
      if (this.readyState !== 4) {
        return super.responseText;
      }

      return handleInterceptedResponse(super.responseText, this.responseURL);
    }

    get response() {
      // If the request is not done, return the original response
      if (this.readyState !== 4) {
        return super.response;
      }

      return handleInterceptedResponse(super.response, this.responseURL);
    }
  }

  window.XMLHttpRequest = XMLHttpRequest;

  return { interceptXhrResponse };
})();

上限代码显示<代码>interceptXhrResponse<>code>功能,使您能够以定期表述和相应的回复手写明URL型号。你可以把你想要的手里的东西回去,改变对策。

例如:

interceptXhrResponse(/.+/, (response, url) => {
  return `Response of ${url}: Intercepted. Original response length: ${String(response).length}`
})

然后,我们可以尝试启动XMLHttpRequest:

const xhr = new XMLHttpRequest()
xhr.open( GET ,  https://stackoverflow.com/404 )
xhr.send()
xhr.onloadend = () => {
  console.log(xhr.responseText)
}

产出:

Response of https://stackoverflow.com/404: Intercepted. Original response length: 63486

Answer 4

你的退步是一种超高技能:你可以在XMLHttpRequest上添加自己的内容:(more about property

Object.defineProperty(XMLHttpRequest.prototype,"myResponse",{
  get: function() {
    return this.responseText+"my update"; // anything you want
  }
});

使用:

var xhr = new XMLHttpRequest();
...
console.log(xhr.myResponse); // xhr.responseText+"my update"

。 XMLHttpRequest2 tips

Answer 5

被接受的回答是,直到最近,由于某种原因,我才在Twitter上工作。这里是另一个行之有效的:

        var open_prototype = XMLHttpRequest.prototype.open
        unsafeWindow.XMLHttpRequest.prototype.open = function() {
            this.addEventListener( readystatechange , function(event) {
                if ( this.readyState === 4 ) {
                    var response = event.target.responseText.replaceAll("a", "b");
                    Object.defineProperty(this,  response , {writable: true});
                    Object.defineProperty(this,  responseText , {writable: true});
                    this.response = this.responseText = response;
                }
            });
            return open_prototype.apply(this, arguments);
        };

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