HTTP Cache Control

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Cache-Control defines how, and for how long the individual response can be cached by the browser and other intermediate caches.

Cache-Control header was defined as part of the HTTP/1.1 specification and supersedes previous headers (e.g. Expires) used to define response caching policies.

The correct minimum set of headers that works across the most important browsers:

Cache-Control: no-cache, no-store, must-revalidate
Pragma: no-cache
Expires: 0

Add the following <meta> HTML tags to the page(s) you want to keep browsers from caching (the code must be in the <head> section of your page, for example right after <title> tag):

<meta http-equiv=”Cache-Control” content=”no-cache, no-store, must-revalidate” />
<meta http-equiv=”Pragma” content=”no-cache” />
<meta http-equiv=”Expires” content=”0″ />

.htaccess (Apache)

<IfModule mod_headers.c>
Header set Cache-Control “no-cache, no-store, must-revalidate”
Header set Pragma “no-cache”
Header set Expires 0
</IfModule>

Java Servlet

response.setHeader(“Cache-Control”, “no-cache, no-store, must-revalidate”);
response.setHeader(“Pragma”, “no-cache”);
response.setDateHeader(“Expires”, 0);

PHP

header(‘Cache-Control: no-cache, no-store, must-revalidate’); // HTTP 1.1.
header(‘Pragma: no-cache’); // HTTP 1.0.
header(‘Expires: 0’); // Proxies.

ASP.NET

Response.AppendHeader(“Cache-Control”, “no-cache, no-store, must-revalidate”);
Response.AppendHeader(“Pragma”, “no-cache”);
Response.AppendHeader(“Expires”, “0”);

ASP

Response.addHeader “Cache-Control”, “no-cache, no-store, must-revalidate”
Response.addHeader “Pragma”, “no-cache”
Response.addHeader “Expires”, “0”

Ruby on Rails

response.headers[‘Cache-Control’] = ‘no-cache, no-store, must-revalidate’
response.headers[‘Pragma’] = ‘no-cache’
response.headers[‘Expires’] = ‘0’

Python on Flask

resp.headers[“Cache-Control”] = “no-cache, no-store, must-revalidate”
resp.headers[“Pragma”] = “no-cache”
resp.headers[“Expires”] = “0”

Google Go

responseWriter.Header().Set(“Cache-Control”, “no-cache, no-store, must-revalidate”)
responseWriter.Header().Set(“Pragma”, “no-cache”)
responseWriter.Header().Set(“Expires”, “0”)

 

 

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