etag | 易学教程

How to use shell magic to create a recursive etags using GNU etags?

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问题 The standard GNU etags does not support a recursive walk of directories as done by exuberant ctags -R . If I only have access to the GNU etags, how can I use bash shell magic to get etags to produce a TAGS table for all the C++ files *.cpp and *.h files in the current directory and all directories below the current one recursively to create a TAGS table in the current directory which has the proper path name for emacs to resolve the TAGS table entries. 回答1: The Emacs Wiki is often a good

how does a etag work in expressjs

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问题 Expressjs automatically send etags. I would like to know how the etag is generated..is it based on the content that is generated dynamically by the get routine. or is there way I can mainpulate it, by not even going through the process of generating the content(dynamic content - from DB) and pass back etag as same. may be a middleware which start with just checking if it is valid session id and pass back the same etag that the client gives or may be based of the url + session id..that way it

How do I remove eTag headers from IIS7?

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问题 Per Yahoo's best practices for high performance web sites, I'd like to remove Etags from my headers (I'm manually managing all my caching and have no need for Etags... and when/if I need to scale to a farm, I'd really like them gone). I'm running IIS7 on Windows Server 2008. Anyone know how I can do this? 回答1: Under IIS7 the Etag change number (the part of the Etag following : ) is always set to 0. Hence the Etag from the server no longer varies from server to server for the same file and

ETag vs Header Expires

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问题 I've looked around but haven't been able to figure out if I should use both an ETag and an Expires Header or one or the other. What I'm trying to do is make sure that my flash files (and other images and what not only get updated when there is a change to those files. I don't want to do anything special like changing the filename or putting some weird chars on the end of the url to make it not get cached. Also, is there anything I need to do programatically on my end in my PHP scripts to

面试官：如果 http 响应头中 ETag 值改变了，是否意味着文件内容一定已经更改

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本篇文章由我的一日一题中的四个 Issue 组合而成【Q111】http 响应头中的 ETag 值是如何生成的【Q112】如果 http 响应头中 ETag 值改变了，是否意味着文件内容一定已经更改【Q115】文件系统中 mtime 和 ctime 指什么，都有什么不同【Q116】http 服务中静态文件的 Last-Modified 是根据什么生成的不一定，由服务器中 ETag 的生成算法决定。详见 #112 比如 nginx 中的 etag 由 last_modified 与 content_length 组成，而 last_modified 又由 mtime 组成当编辑文件却未更改文件内容时， mtime 也会改变，此时 etag 改变，但是文件内容没有更改。 http 服务中静态文件的 Last-Modified 根据什么生成比奇小说网 m.biqi.org 一般会选文件的 mtime ，表示文件内容的修改时间 nginx 也是这样处理的，源码见: ngx_http_static_module.c r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = of.size; r->headers_out.last_modified_time = of.mtime;

Set ETag for FileResult - MVC 3

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问题 MVC 3 RTM. I have an action that returns a file (image/jpeg). I am trying to set the ETag for a file with no success (the etag doesn't come through on header). I have tried both Response.Cache.SetETag and Response.AppenderHeader. If I add my own custom header tag, it works as expected, it just seems to be ETag that I can't set. Here is the source. [HttpGet, OutputCache(Location= OutputCacheLocation.Client, VaryByParam="userId", Duration=3600, NoStore=true)] public ActionResult GetImage(string

Does the ETag header make the Cache-Control header obsolete? How to make sure Cache-Control is not harmful then?

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问题 Definition of ETag header (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag): The ETag HTTP response header is an identifier for a specific version of a resource. It allows caches to be more efficient, and saves bandwidth, as a web server does not need to send a full response if the content has not changed. On the other side, if the content has changed, etags are useful to help prevent simultaneous updates of a resource from overwriting each other ("mid-air collisions").

HTTP头信息总结

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本文为多篇“HTTP请求头相关文章”及《HTTP权威指南》一书的阅读后个人汇总整理版，以便于理解。　　通常HTTP消息包括客户机向服务器的请求消息和服务器向客户机的响应消息。客户端向服务器发送一个请求，请求头包含请求的方法、URI、协议版本、以及包含请求修饰符、客户信息和内容的类似于MIME的消息结构。服务器以一个状态行作为响应，相应的内容包括消息协议的版本，成功或者错误编码加上包含服务器信息、实体元信息以及可能的实体内容。 Http协议定义了很多与服务器交互的方法，最基本的有4种，分别是GET、POST、PUT、DELETE。一个URL地址用于描述一个网络上的资源，而HTTP中的GET、POST、PUT、 DELETE就对应着对这个资源的查、改、增、删4个操作，我们最常见的就是GET和POST了。GET一般用于获取/查询资源信息，而POST一般用于更新资源信息。 HTTP头信息解读　　HTTP的头域包括通用头、请求头、响应头和实体头四个部分。每个头域由一个域名，冒号（:）和域值三部分组成。　　通用头部是客户端和服务器都可以使用的头部，可以在客户端、服务器和其他应用程序之间提供一些非常有用的通用功能，如Date头部。　　请求头部是请求报文特有的，它们为服务器提供了一些额外信息，比如客户端希望接收什么类型的数据，如Accept头部。　　响应头部便于客户端提供信息，比如

How can I find the references of a class, method, variable in Emacs with Etags?

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问题 I'd like to find all the references to a class, method, variable in Emacs, the same way I'm able to do it in Eclipse with Ctrl+Shift+G (or Cmd+Shift+G on the Mac) once I've setup my project's ETags. I can navigate the code fine, but finding references to things is key to understanding large code bases, I'm sure this must be possible in Emacs but I can't find anything about it, maybe an Emacs expert will know right away. Thanks. 回答1: I think your best bet is an M-x rgrep . The TAGS file lists

Why would ETags set to a MUST requirement if you already have the resource?

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问题 Why would you set ETags to a "MUST requirement level"? You obtains the resource before the ETags returned... I'm working on a project where I am the client that sends HTTP requests to a server that returns an HTTP Cache-Control header with ETags to cache response (where in each addition request it gets compared to the If-None-Match header to determine if the data is stale and if a new request should be made). In my current project the ETags parameter is using the conditional GET architecture