If you want to redirect an user and tell him he will be redirected, e. If not, click here. Browsers typically re-request a page every time, cache a page for the session, and cache a page for longer, or even indefinitely.
If the status code is not specified, header 'Location:' defaults to When using PHP to output an image, it won't be cached by the client so if you don't want them to download the image each time they reload the page, you will need to emulate part of the HTTP protocol. It seems the note saying the URI must be absolute is obsolete. The header call can be misleading to novice php users. If using the 'header' function for the downloading of files, especially if you're passing the filename as a variable, remember to surround the filename with double quotes, otherwise you'll have problems in Firefox as soon as there's a space in the filename.
Sorry, the site won't let me post such a long link Since PHP 5. Also, be aware that IE versions 5, 6, 7, and 8 double-compress already-compressed files and do not reverse the process correctly, so ZIP files and similar are corrupted on download. The following example disables compression in all versions of IE: BrowserMatch ". PageRank may be transferred. The new URI is not a substitute reference for the originally requested resource and is not cached. It is important to note that headers are actually sent when the first byte is output to the browser.
In the case of redirects, if you forget to terminate your script after sending the header, adding a buffer or sending a character may change which page your users are sent to. This redirects to 2. You also won't see any "headers already sent" errors because the browser follows the redirect before it can display the error. This is because headers aren't sent until the output buffer is flushed. Just to inform you all, do not get confused between Content-Transfer-Encoding and Content-Encoding Content-Transfer-Encoding specifies the encoding used to transfer the data within the HTTP protocol, like raw binary or base Eg Use:- header 'Content-Encoding: gzip' ;.
You can use HTTP's etags and last modified dates to ensure that you're not sending the browser data it already has cached. Thanks Rasmus Lerdorf and his team to wrap off parts of unusual php functionality ,php 7 roolez!!!!!
I made a script that generates an optimized image for use on web pages using a script to resize and reduce original images, but on some servers it was generating the image but then not using it due to some kind of cache somewhere of the status.
It will tell the PHP session code to not do any cache header changes of its own. Otherwise you will face problem of headers not being properly sent eg. After lots of research and testing, I'd like to share my findings about my problems with Internet Explorer and file downloads. User may change settings. The Content-Length header is required by some browsers to activate download box. I use it here to make sure the box opens. Anyway, I set the Content-Disposition to attachment because I already know that the box will appear.
Then I have the Content-Length again. I didn't see any difference with or without this head information yet. Add a comment. Active Oldest Votes. Define "necessary". AnthumChris 6, 2 2 gold badges 22 22 silver badges 44 44 bronze badges. Jeremy Logan Jeremy Logan I don't disagree, just searching for official documentation stating such.
Search your php. Not sure why, but they don't actually state it in the manual. This is dangerous advice. It does really matter. The original question didn't specify that though, so I just answered the question.
Show 1 more comment. Kristoffer Bohmann Kristoffer Bohmann 3, 2 2 gold badges 25 25 silver badges 34 34 bronze badges. There's a small mistake in that code. Angel: Fixed. An attacker just needs to convince a user to click on a link. Alan Storm Alan Storm k 86 86 gold badges silver badges bronze badges. Ashish Agarwal Ashish Agarwal 5, 12 12 gold badges 54 54 silver badges 87 87 bronze badges. Well sure, you can do selective compression based on MIME type at least you can in Apache , but there's no reason to ever NOT compress text-based entities unless the requesting party can't handle it.
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