etag registration

Smart developers will use the HTTP header for Last-modified and ETAGS requests, which can take advantage of caching by clients such as browsers. Because the server first generates the LAST-MODIFIED/ETAG tag, the server can later use it to determine if the page has been modified. Essentially, the client requires the server to validate its (client) cache by passing the token back to the server.The process is as follows: The client requests a

First time request Request: Copy Code code as follows: Get/pic/201408/102.jpg http/1.1 Host:www.jb51.net Connection:keep-alive Cache-control:no-cache accept:image/webp,*/*;q=0.8 Pragma:no-cache user-agent:mozilla/5.0 (Windows NT 6.1) applewebkit/537.36 (khtml, like Gecko) chrome/29.0.1547.66 safari/537.36 referer:http://www.jb51.net/ Accept-encoding:gzip,deflate,sdch accept-language:zh-cn,zh;q=0.8 Response: Copy Code code as follows: http

Browser cache, also known as HTTP cache, refers to when we browse the site, the browser will store a copy locally, so that the next time you visit the same URL can no longer connect to the server, directly from the browser local cache to obtain resources. The server-side program can control the cache behavior through HTTP cache headers, reduce the burden on the server, shorten the response time, and significantly improve the performance of the website. HTTP Cache related head has Last-modified/

Address: http://blog.chinaunix.net/uid-20614434-id-2999833.html Author: finalbsdDate: 2008-07-08Previously, etag only provided the simplest description of resumable upload without further research. I studied for a while today, hoping to answer the question of Laurence, haha :) 1. Concept of resumable uploadResumable upload can be divided into two parts: one is a breakpoint and the other is a resumable upload. BreakpointThe reason is that during the d

This series of articles will discuss how to optimize client caching policies through ASP.net server-side technology, and make this strategy configurable and extensible. We want to understand the impact of the relevant attributes on the client cache from the HTTP protocol, to how ASP.net controls these properties to implement our caching strategy.HTTP basic knowledgeSince the discussion involves client-side caching, it is a simple introduction to how the HTTP protocol controls client caching, whi

return a special HTTP status code of 304, which means "this data has not changed since the last request". What progress does this make? When the server sends a status code of 304, the data is no longer resent. You only get this status code. So when the data is not updated, you don't need to download the same data again and again; The server assumes you have local cache data.All modern browsers support recently modified (last-modified) data checks. If you've ever visited a page, re-visited the s

Apache turns off the Etag and Last-Modified methods, and only boring people like me will do this. Haha, what will happen if we turn off etag and last-modified. Do not ask me what these two parameters are. The Etag is disabled as follows: add an noneFileETagnone to disable the Last-Modified Apache disables Etag and Las

Etag: "5d8c72a5edda8d6a:3239″The client's query update format is like this:If-none-match: "5d8c72a5edda8d6a:3239″If the etag does not change, the status 304 is returned.That is, after the client makes a request, the Http reponse header contains Etag: "5d8c72a5edda8d6a:3239″The identity is equal to telling the client that the resources you get are id:5d8c72a5edda8

.111cn.net/Accept-Encoding: gzip, deflate, sdchAccept-Language: zh-CN, zh; q = 0.8Response:Reference contentHTTP/1.1 304 Not ModifiedLast-Modified: Tue, 19 Aug 2014 12:23:54 GMTAccept-Ranges: bytesETag: "029e570a8bbcf1: 1ae2"Server: Microsoft-Microsoft IIS/6.0X-Powered-By: ASP. NETDate: Wed, 20 Aug 2014 00:29:54 GMTHTTP cache is used to save the amount of data transmitted over the network. If the server resources do not change, 304 is returned and the content is blank. Last-Modified an

002 $file _path = './download/download_cn.rar '; 003 004//How to use 005 Downfile ($file _path); 006 007//server file path, download file name (default is server file name), whether to license user download method (default), speed limit (default automatic), file type (default all) 008 function Downfile ($fileName, $fancyName = ', $forceDownload = true, $speedLimit = 0, $contentType = ') { 009 if (!is_readable ($fileName)) 010 { 011 header ("http/1.1 404 Not Found"); 012 return false; 013} 014 01