电子邮件跟踪 - GMail

我正在为电子邮件营销跟踪创建自己的电子邮件跟踪系统.我已经能够通过使用 http 引荐来源网址来确定他们正在使用的每个人的电子邮件客户端，但由于某种原因，GMAIL 根本不发送 HTTP_REFERRER！

I am creating my own email tracking system for email marketing tracking. I have been able to determine each persons email client they are using by using the http referrer but for some reason GMAIL does not send a HTTP_REFERRER at all!

所以我试图找到另一种方法来识别 gmail 何时从我的服务器请求透明图像.我得到以下标题 print_r($_SERVER);:

So I am trying to find another way of identifying when gmail requests a transparent image from my server. I get the following headers print_r($_SERVER);:

DOCUMENT_ROOT  =  /usr/local/apache/htdocs

GATEWAY_INTERFACE  =  CGI/1.1

HTTP_ACCEPT  =  */*

HTTP_ACCEPT_CHARSET  =  ISO-8859-1,utf-8;q=0.7,*;q=0.3

HTTP_ACCEPT_ENCODING  =  gzip,deflate,sdch

HTTP_ACCEPT_LANGUAGE  =  en-GB,en-US;q=0.8,en;q=0.6

HTTP_CONNECTION  =  keep-alive

HTTP_COOKIE  =  __utmz=156230011.1290976484.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=156230011.422791272.1290976484.1293034866.1293050468.7

HTTP_HOST  =  xx.xxx.xx.xxx

HTTP_USER_AGENT  =  Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.237 Safari/534.10

PATH  =  /bin:/usr/bin

QUERY_STRING  =  i=MTA=

REDIRECT_STATUS  =  200

REMOTE_ADDR  =  xx.xxx.xx.xxx

REMOTE_PORT  =  61296

REQUEST_METHOD  =  GET

该列表中有什么有用的吗?或者我还能做些什么来真正获得 http 引荐来源网址，如果不是其他 ESP 是如何设法找到是否使用 gmail 来查看电子邮件的?

Is there anything of use in that list? Or is there something else I can do to actually get the http referrer, if not how are other ESPs managing to find whether gmail was used to view an email?

顺便说一句，如果我们能阻止这是否合乎道德，我将不胜感激，因为许多 ESP 已经这样做了，我只是不想为他们的服务付费，我想在内部进行.

Btw, I appreciate it if we can hold back on whether this is ethical or not as many ESPs do this already, I just don't want to pay for their service and I want to do it internally.

感谢大家的任何实施建议.

Thanks all for any implementation advice.

只是想我会更新这个问题并根据赏金更清楚地说明.

Just thought I would update this question and make it clearer in light of the bounty.

我想知道用户何时打开我发送到 GMail 收件箱的电子邮件.假设，我有通常的透明图像跟踪，并且用户没有阻止图像.

I would like to find out when a user opens my email when sent to a GMail inbox. Assume, I have the usual transparent image tracking and the user does not block images.

我想使用单个请求和请求透明图像时获得的标头详细信息来执行此操作.

I would like to do this with the single request and the header details I get when the transparent image is requested.