为什么要提供1x1像素的GIF（网络臭虫）数据呢？

问题描述

许多分析和跟踪工具正在为跨域事件存储/处理请求1x1 GIF图像（网络bug，用户不可见）。

为什么为什么要服务这个GIF图像？简单地返回一些错误代码，比如 Service Temporary Unavailable 或空文件 / p>

更新：为了更清楚一点，我问为什么在所有必需的信息已被发送时为GIF图像数据提供服务在请求标题中。 GIF图片本身并没有返回任何有用的信息。

解决方案

Doug的回答非常全面;我想我会添加一个附加说明（在OP的请求中，关于我的评论）

Doug的答案解释了为什么1x1像素信标被用于他们的目的用于;我想我会概述一种潜在的替代方法，即使用HTTP状态代码204，无内容作为响应，而不发送图像主体。

基本上，服务器接收到请求，并决定不发送一个正文（在这种情况下，不发送图像）。但它回复了一个代码，告知代理人这是一个有意识的决定;基本上，它只是一个较短的方式来回应肯定。

从：
$ b

我从来没有尝试过它，但理论上它应该达到相同的目的，而不需要传输gif本身，从而节省了35个字节，就Google而言Analytics（分析）。 （在这个计划中，除非您的Google Analytics每天提供数万亿次点击，否则35个字节实际上什么都没有。）

您可以使用此代码对其进行测试：

  var i = new Image（）; 
 i.src =http://httpstat.us/204; 
  

Many analytic and tracking tools are requesting 1x1 GIF image (web bug, invisible for the user) for cross-domain event storing/processing.

Why to serve this GIF image at all? Wouldn't it be more efficient to simply return some error code such as 503 Service Temporary Unavailable or empty file?

Update: To be more clear, I'm asking why to serve GIF image data when all information required has been already sent in request headers. The GIF image itself does not return any useful information.

解决方案

Doug's answer is pretty comprehensive; I thought I'd add in an additional note (at the OP's request, off of my comment)

Doug's answer explains why 1x1 pixel beacons are used for the purpose they are used for; I thought I'd outline a potential alternative approach, which is to use HTTP Status Code 204, No Content, for a response, and not send an image body.

Basically, the server receives the request, and decides to not send a body (in this case, to not send an image). But it replies with a code to inform the agent that this was a conscious decision; basically, its just a shorter way to respond affirmatively.

From Google's Page Speed documentation:

I've never tried it, but in theory it should serve the same purpose without requiring the gif itself to be transmitted, saving you 35 bytes, in the case of Google Analytics. (In the scheme of things, unless you're Google Analytics serving many trillions of hits per day, 35 bytes is really nothing.)

You can test it with this code:

var i = new Image();
i.src = "http://httpstat.us/204";

这篇关于为什么要提供1x1像素的GIF（网络臭虫）数据呢？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！