Forum PHP 2017

header

(PHP 4, PHP 5, PHP 7)

header Отправка HTTP заголовка

Описание

void header ( string $string [, bool $replace = true [, int $http_response_code ]] )

header() используется для отправки HTTP заголовка. В » спецификации HTTP/1.1 есть подробное описание HTTP заголовков.

Помните, что функцию header() можно вызывать только если клиенту еще не передавались данные. То есть она должна идти первой в выводе, перед ее вызовом не должно быть никаких HTML тэгов, пустых строк и т.п. Довольно часто возникает ошибка, когда при чтении кода файловыми функциями, вроде include или require, в этом коде попадаются пробелы или пустые строки, которые выводятся до вызова header(). Те же проблемы могут возникать и при использовании одиночного PHP/HTML файла.

<html>
<?php
/* Этот пример приведет к ошибке. Обратите внимание
 * на тэг вверху, который будет выведен до вызова header() */
header('Location: http://www.example.com/');
exit;
?>

Список параметров

string

Строка заголовка.

Существует два специальных заголовка. Один из них начинается с "HTTP/" (регистр не важен) и используется для отправки кода состояния HTTP. Например, если веб-сервер Apache сконфигурирован таким образом, чтобы запросы к несуществующим файлам обрабатывались средствами PHP скрипта (используя директиву ErrorDocument), вы наверняка захотите быть уверенными что скрипт генерирует правильный код состояния.

<?php
header
("HTTP/1.0 404 Not Found");
?>

Другим специальным видом заголовков является "Location:". В этом случае функция не только отправляет этот заголовок браузеру, но также возвращает ему код состояния REDIRECT (302) (если ранее не был установлен код 201 или 3xx).

<?php
header
("Location: http://www.example.com/"); /* Перенаправление броузера */

/* Можно убедиться, что следующий за командой код не выполнится из-за
перенаправления.*/
exit;
?>

replace

Необязательный параметр replace определяет, надо ли заменять предыдущий аналогичный заголовок или заголовок того же типа. По умолчанию заголовок будет заменен, но если передать FALSE, можно задать несколько однотипных заголовков. Например:

<?php
header
('WWW-Authenticate: Negotiate');
header('WWW-Authenticate: NTLM'false);
?>

http_response_code

Принудительно задает код ответа HTTP. Следует учитывать, что это будет работать, только если строка string не является пустой.

Возвращаемые значения

Эта функция не возвращает значения после выполнения.

Список изменений

Версия Описание
5.1.2 Стало невозможно отправлять более одного заголовка за раз. Это сделано для защиты от атак, связанных с инъекцией заголовков.

Примеры

Пример #1 Диалог загрузки

Если нужно предупредить пользователя о необходимости сохранить пересылаемые данные, такие как сгенерированный PDF файл, можно воспользоваться заголовком » Content-Disposition, который подставляет рекомендуемое имя файла и заставляет броузер показать диалог загрузки.

<?php
// Будем передавать PDF
header('Content-Type: application/pdf');

// Который будет называться downloaded.pdf
header('Content-Disposition: attachment; filename="downloaded.pdf"');

// Исходный PDF файл original.pdf
readfile('original.pdf');
?>

Пример #2 Директивы для работы с кэшем

PHP скрипты часто генерируют динамический контент, который не должен кэшироваться клиентским броузером или какими-либо промежуточными обработчиками, вроде прокси серверов. Можно принудительно отключить кэширование на многих прокси серверах и броузерах, передав заголовки:

<?php
header
("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Дата в прошлом
?>

Замечание:

В некоторых случаях ваши страницы не будут кэшироваться броузером, даже если вы не передавали этих заголовков. В броузерах есть определенные настройки, с помощью которых пользователь может изменять обычный ход кэширования, отключать его. Вы должны перекрывать любые настройки, которые могут повлиять на кэширование скрипта, отправляя приведенные выше заголовки.

Дополнительно, для случаев когда используются сессии, можно задать настройки конфигурации session_cache_limiter() и session.cache_limiter. Эти настройки можно использовать для автоматической генерации заголовков управляющих кешированием.

Примечания

Замечание:

Доступ к заголовкам и их вывод будет осуществляться только в случае, если в используемом вами SAPI есть их поддержка.

Замечание:

Чтобы обойти эту проблему, можно буферизовать вывод скрипта. В этом случае все выводимые данные будут буферизоваться на сервере, пока не будет дана явная команда на пересылку данных. Управлять буферизацией можно вручную функциями ob_start() и ob_end_flush(), либо задав директиву output_buffering в конфигурационном файле php.ini, или же настроив соответствующим образом конфигурацию сервера.

Замечание:

Строка заголовка задающая состояние HTTP всегда будет отсылаться клиенту первой, вне зависимости от того был соответствующий вызов функции header() первым или нет. Это состояние можно перезаписать, вызывая header() с новой строкой состояния в любое время, когда можно отправлять HTTP заголовки.

Замечание:

В Microsoft Internet Explorer 4.01 есть баг, из-за которого это не работает. Обойти его никак нельзя. В Microsoft Internet Explorer 5.5 также есть этот баг, но его уже можно устранить установкой Service Pack 2 или выше.

Замечание: Если включен безопасный режим, то uid скрипта будет добавляться к realm части WWW-Authenticate заголовка (используется для HTTP аутентификации).

Замечание:

Спецификация HTTP/1.1 требует указывать абсолютный URI в качестве аргумента » Location:, включающий схему, имя хоста и абсолютный путь, хотя некоторые клиенты способны принимать и относительные URI. Абсолютный URI можно построить самостоятельно с помощью $_SERVER['HTTP_HOST'], $_SERVER['PHP_SELF'] и dirname():

<?php
/* Перенаправление броузера на другую страницу в той же директории, что и
изначально запрошенная */
$host  $_SERVER['HTTP_HOST'];
$uri   rtrim(dirname($_SERVER['PHP_SELF']), '/\\');
$extra 'mypage.php';
header("Location: http://$host$uri/$extra");
exit;
?>

Замечание:

ID сессии не будет передаваться вместе с заголовком Location, даже если включена настройка session.use_trans_sid. Его нужно передавать вручную, используя константу SID.

Смотрите также

add a note add a note

User Contributed Notes 29 notes

up
146
mjt at jpeto dot net
7 years ago
I strongly recommend, that you use

header($_SERVER["SERVER_PROTOCOL"]." 404 Not Found");

instead of

header("HTTP/1.1 404 Not Found");

I had big troubles with an Apache/2.0.59 (Unix) answering in HTTP/1.0 while I (accidentially) added a "HTTP/1.1 200 Ok" - Header.

Most of the pages were displayed correct, but on some of them apache added weird content to it:

A 4-digits HexCode on top of the page (before any output of my php script), seems to be some kind of checksum, because it changes from page to page and browser to browser. (same code for same page and browser)

"0" at the bottom of the page (after the complete output of my php script)

It took me quite a while to find out about the wrong protocol in the HTTP-header.
up
71
Marcel G
7 years ago
Several times this one is asked on the net but an answer could not be found in the docs on php.net ...

If you want to redirect an user and tell him he will be redirected, e. g. "You will be redirected in about 5 secs. If not, click here." you cannot use header( 'Location: ...' ) as you can't sent any output before the headers are sent.

So, either you have to use the HTML meta refresh thingy or you use the following:

<?php
  header
( "refresh:5;url=wherever.php" );
  echo
'You\'ll be redirected in about 5 secs. If not, click <a href="wherever.php">here</a>.';
?>

Hth someone
up
55
Dylan at WeDefy dot com
9 years ago
A quick way to make redirects permanent or temporary is to make use of the $http_response_code parameter in header().

<?php
// 301 Moved Permanently
header("Location: /foo.php",TRUE,301);

// 302 Found
header("Location: /foo.php",TRUE,302);
header("Location: /foo.php");

// 303 See Other
header("Location: /foo.php",TRUE,303);

// 307 Temporary Redirect
header("Location: /foo.php",TRUE,307);
?>

The HTTP status code changes the way browsers and robots handle redirects, so if you are using header(Location:) it's a good idea to set the status code at the same time.  Browsers typically re-request a 307 page every time, cache a 302 page for the session, and cache a 301 page for longer, or even indefinitely.  Search engines typically transfer "page rank" to the new location for 301 redirects, but not for 302, 303 or 307. If the status code is not specified, header('Location:') defaults to 302.
up
32
mandor at mandor dot net
11 years ago
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.

Here's how:

<?php

   
// Test image.
   
$fn = '/test/foo.png';

   
// Getting headers sent by the client.
   
$headers = apache_request_headers();

   
// Checking if the client is validating his cache and if it is current.
   
if (isset($headers['If-Modified-Since']) && (strtotime($headers['If-Modified-Since']) == filemtime($fn))) {
       
// Client's cache IS current, so we just respond '304 Not Modified'.
       
header('Last-Modified: '.gmdate('D, d M Y H:i:s', filemtime($fn)).' GMT', true, 304);
    } else {
       
// Image not cached or cache outdated, we respond '200 OK' and output the image.
       
header('Last-Modified: '.gmdate('D, d M Y H:i:s', filemtime($fn)).' GMT', true, 200);
       
header('Content-Length: '.filesize($fn));
       
header('Content-Type: image/png');
        print
file_get_contents($fn);
    }

?>

That way foo.png will be properly cached by the client and you'll save bandwith. :)
up
26
bebertjean at yahoo dot fr
8 years ago
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.

So instead of typing:

<?php
  header
("Content-Disposition: attachment; filename=" . basename($filename));
?>

you should type:

<?php
  header
("Content-Disposition: attachment; filename=\"" . basename($filename) . "\"");
?>

If you don't do this then when the user clicks on the link for a file named "Example file with spaces.txt", then Firefox's Save As dialog box will give it the name "Example", and it will have no extension.

See the page called "Filenames_with_spaces_are_truncated_upon_download" at
http://kb.mozillazine.org/ for more information. (Sorry, the site won't let me post such a long link...)
up
18
ben at indietorrent dot org
5 years ago
Be aware that sending binary files to the user-agent (browser) over an encrypted connection (SSL/TLS) will fail in IE (Internet Explorer) versions 5, 6, 7, and 8 if any of the following headers is included:

Cache-control:no-store
Cache-control:no-cache

See: http://support.microsoft.com/kb/323308

Workaround: do not send those headers.

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.

Workaround: disable compression (beyond text/html) for these particular versions of IE, e.g., using Apache's "BrowserMatch" directive. The following example disables compression in all versions of IE:

BrowserMatch ".*MSIE.*" gzip-only-text/html
up
17
shutout2730 at yahoo dot com
8 years ago
It is important to note that headers are actually sent when the first byte is output to the browser. If you are replacing headers in your scripts, this means that the placement of echo/print statements and output buffers may actually impact which headers are sent. 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.html since the second header replaces the first.

<?php
header
("location: 1.html");
header("location: 2.html"); //replaces 1.html
?>

This redirects to 1.html since the header is sent as soon as the echo happens. You also won't see any "headers already sent" errors because the browser follows the redirect before it can display the error.

<?php
header
("location: 1.html");
echo
"send data";
header("location: 2.html"); //1.html already sent
?>

Wrapping the previous example in an output buffer actually changes the behavior of the script! This is because headers aren't sent until the output buffer is flushed.

<?php
ob_start
();
header("location: 1.html");
echo
"send data";
header("location: 2.html"); //replaces 1.html
ob_end_flush(); //now the headers are sent
?>
up
5
Refugnic
7 years ago
My files are in a compressed state (bz2). When the user clicks the link, I want them to get the uncompressed version of the file.

After decompressing the file, I ran into the problem, that the download dialog would always pop up, even when I told the dialog to 'Always perform this operation with this file type'.

As I found out, the problem was in the header directive 'Content-Disposition', namely the 'attachment' directive.

If you want your browser to simulate a plain link to a file, either change 'attachment' to 'inline' or omit it alltogether and you'll be fine.

This took me a while to figure out and I hope it will help someone else out there, who runs into the same problem.
up
5
bMindful at fleetingiamge dot org
14 years ago
If you haven't used, HTTP Response 204 can be very convenient. 204 tells the server to immediately termiante this request. This is helpful if you want a javascript (or similar) client-side function to execute a server-side function without refreshing or changing the current webpage. Great for updating database, setting global variables, etc.

     header("status: 204");  (or the other call)
     header("HTTP/1.0 204 No Response");
up
4
mzheng[no-spam-thx] at ariba dot com
8 years ago
For large files (100+ MBs), I found that it is essential to flush the file content ASAP, otherwise the download dialog doesn't show until a long time or never.

<?php
header
("Content-Disposition: attachment; filename=" . urlencode($file));   
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Description: File Transfer");            
header("Content-Length: " . filesize($file));
flush(); // this doesn't really matter.

$fp = fopen($file, "r");
while (!
feof($fp))
{
    echo
fread($fp, 65536);
   
flush(); // this is essential for large downloads

fclose($fp);
?>
up
0
chris at ocproducts dot com
5 months ago
Note that 'session_start' may overwrite your custom cache headers.
To remedy this you need to call:

session_cache_limiter('');

...after you set your custom cache headers. It will tell the PHP session code to not do any cache header changes of its own.
up
1
dev at omikrosys dot com
7 years ago
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 base64. (binary is more compact than base64. base64 having 33% overhead).
Eg Use:- header('Content-Transfer-Encoding: binary');

Content-Encoding is used to apply things like gzip compression to the content/data.
Eg Use:- header('Content-Encoding: gzip');
up
0
DC
2 years ago
In the bottom note:
<?php
$uri  
= rtrim(dirname($_SERVER['REQUEST_URI']), '/\\');
?>
not $_SERVER['PHP_SELF']!

(But the strange behaviour of dirname is a problem for URL ending by a directory without file name!)
up
0
Vinay Kotekar
2 years ago
Saving php file in ANSI  no isuess but when saving the file in UTF-8 format for various reasons remember to save the file without any BOM ( byte-order mark) support.
Otherwise you will face problem of headers not being properly sent
eg.
<?php header("Set-Cookie: name=user");?>

Would give something like this :-

Warning: Cannot modify header information - headers already sent by (output started at C:\www\info.php:1) in C:\www\info.php on line 1
up
1
sk89q
8 years ago
You can use HTTP's etags and last modified dates to ensure that you're not sending the browser data it already has cached.

<?php
$last_modified_time
= filemtime($file);
$etag = md5_file($file);

header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
header("Etag: $etag");

if (@
strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $last_modified_time ||
   
trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
   
header("HTTP/1.1 304 Not Modified");
    exit;
}
?>
up
0
Cody G.
6 years ago
After lots of research and testing, I'd like to share my findings about my problems with Internet Explorer and file downloads.

  Take a look at this code, which replicates the normal download of a Javascript:

<?php
if(strstr($_SERVER["HTTP_USER_AGENT"],"MSIE")==false) {
 
header("Content-type: text/javascript");
 
header("Content-Disposition: inline; filename=\"download.js\"");
 
header("Content-Length: ".filesize("my-file.js"));
} else {
 
header("Content-type: application/force-download");
 
header("Content-Disposition: attachment; filename=\"download.js\"");
 
header("Content-Length: ".filesize("my-file.js"));
}
header("Expires: Fri, 01 Jan 2010 05:00:00 GMT");
if(
strstr($_SERVER["HTTP_USER_AGENT"],"MSIE")==false) {
 
header("Cache-Control: no-cache");
 
header("Pragma: no-cache");
}
include(
"my-file.js");
?>

Now let me explain:

  I start out by checking for IE, then if not IE, I set Content-type (case-sensitive) to JS and set Content-Disposition (every header is case-sensitive from now on) to inline, because most browsers outside of IE like to display JS inline. (User may change settings). The Content-Length header is required by some browsers to activate download box. Then, if it is IE, the "application/force-download" Content-type is sometimes required to show the download box. Use this if you don't want your PDF to display in the browser (in IE). 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.

  Now, here's my big point. I have the Cache-Control and Pragma headers sent only if not IE. THESE HEADERS WILL PREVENT DOWNLOAD ON IE!!! Only use the Expires header, after all, it will require the file to be downloaded again the next time. This is not a bug! IE stores downloads in the Temporary Internet Files folder until the download is complete. I know this because once I downloaded a huge file to My Documents, but the Download Dialog box put it in the Temp folder and moved it at the end. Just think about it. If IE requires the file to be downloaded to the Temp folder, setting the Cache-Control and Pragma headers will cause an error!

I hope this saves someone some time!
~Cody G.
up
0
Anonymous
7 years ago
I just want to add, becuase I see here lots of wrong formated headers.

1. All used headers have first letters uppercase, so you MUST follow this. For example:

Location, not location
Content-Type, not content-type, nor CONTENT-TYPE

2. Then there MUST be colon and space, like

good: header("Content-Type: text/plain");
wrong: header("Content-Type:text/plain");

3. Location header MUST be absolute uri with scheme, domain, port, path, etc.

good: header("Location: http://www.example.com/something.php?a=1");

4. Relative URIs are NOT allowed

wrong:  Location: /something.php?a=1
wrong:  Location: ?a=1

It will make proxy server and http clients happier.
up
-1
scott at lucentminds dot com
7 years ago
If you want to remove a header and keep it from being sent as part of the header response, just provide nothing as the header value after the header name. For example...

PHP, by default, always returns the following header:

"Content-Type: text/html"

Which your entire header response will look like

HTTP/1.1 200 OK
Server: Apache/2.2.11 (Unix)
X-Powered-By: PHP/5.2.8
Date: Fri, 16 Oct 2009 23:05:07 GMT
Content-Type: text/html; charset=UTF-8
Connection: close

If you call the header name with no value like so...

<?php

    header
( 'Content-Type:' );

?>

Your headers now look like this:

HTTP/1.1 200 OK
Server: Apache/2.2.11 (Unix)
X-Powered-By: PHP/5.2.8
Date: Fri, 16 Oct 2009 23:05:07 GMT
Connection: close
up
-1
nospam at nospam dot com
1 year ago
<?php

// Response codes behaviors when using
header('Location: /target.php', true, $code) to forward user to another page:

$code = 301;
// Use when the old page has been "permanently moved and any future requests should be sent to the target page instead. PageRank may be transferred."

$code = 302; (default)
// "Temporary redirect so page is only cached if indicated by a Cache-Control or Expires header field."

$code = 303;
// "This method exists primarily to allow the output of a POST-activated script to redirect the user agent to a selected resource. The new URI is not a substitute reference for the originally requested resource and is not cached."

$code = 307;
// Beware that when used after a form is submitted using POST, it would carry over the posted values to the next page, such if target.php contains a form processing script, it will process the submitted info again!

// In other words, use 301 if permanent, 302 if temporary, and 303 if a results page from a submitted form.
// Maybe use 307 if a form processing script has moved.

?>
up
-1
jp at webgraphe dot com
13 years ago
A call to session_write_close() before the statement

<?php
    header
("Location: URL");
    exit();
?>

is recommended if you want to be sure the session is updated before proceeding to the redirection.

We encountered a situation where the script accessed by the redirection wasn't loading the session correctly because the precedent script hadn't the time to update it (we used a database handler).

JP.
up
-3
Jamesb
8 years ago
Here is a php script I wrote to stream a file and crypt it with a xor operation on the bytes and with a key :

The encryption works very good but the speed is decrease by 2, it is now 520KiB/s. The user is now asked for a md5 password (instead of keeping it in the code directly). There is some part in French because it's my native language so modify it as you want.

<?php
// Stream files and encrypt the data on-the-fly

// Settings
// -- File to stream
$file = "FILE_out";
// -- Reading buffer
$bufferlength = 3840;
// -- Key in hex
//$keychar = "9cdfb439c7876e703e307864c9167a15";

// Function: Convertion hex key in a string into binary
function hex2bin($h) {
    if (!
is_string($h)) return null;
   
$r = array();
    for (
$a=0; ($a*2)<strlen($h); $a++) {
       
$ta = hexdec($h[2*$a]);
       
$tb = hexdec($h[(2*$a+1)]);
       
$r[$a] = (int) (($ta << 4) + $tb);
    }
    return
$r;
}

// Function to send the auth headers
function askPassword($text="Enter the password") {
   
header('WWW-Authenticate: Basic realm="'. utf8_decode($text) .'"');
   
header('HTTP/1.0 401 Unauthorized');
    return
1;
}

// Key is asked at the first start
if (!isset($_SERVER['PHP_AUTH_PW'])) {
   
askPassword();
    echo
"Une clé est nécessaire !<br />";
    exit;
}
// Get the key in hex
$keychar = $_SERVER['PHP_AUTH_PW'];

// Convert key and set the size of the key
$key = hex2bin($keychar);
$keylength = count($key);
// Teste si la clé est valide en hex
if ($key == "" || $keylength <= 4) {
   
askPassword("Clé incorrecte !");
   
//echo "Clé incorrecte !<br />";
   
exit();
}
// Teste si la clé est de longueur d'une puissance de 2
if ( ($keylength%2) != 0) {
   
askPassword("Clé de longueur incorrecte (multiple de 2 uniquement)");
   
//echo "Clé de longueur incorrecte (puissance de 2 uniquement)<br />";
   
exit();
}

// Headers
header("Content-Type: application/octet-stream; ");
header("Content-Transfer-Encoding: binary");
header("Content-Length: " . filesize($file) ."; ");
header("filename=\"".$file."\"; ");
flush(); // this doesn't really matter.

// Opening the file in read-only
$fp = fopen($file, "r");
while (!
feof($fp))
{
   
// Read a buffer size of the file
   
$buffer = fread($fp, $bufferlength);
   
$j=0;
    for (
$i=0; $i < $bufferlength; $i++) {
       
// The key is read in loop to crypt the whole file
       
if ($i%$keylength == 0) {
           
$j=0;
        }
       
// Apply a xor operation between the key and the file to crypt
        // This operation eats a lots of CPU time (Stream at 1MiB/s on my server; Intel E2180)
       
$tmp = pack("C", $key[$j]);
       
$bufferE = ( $buffer[$i]^$tmp); // <==== Le fameux XOR
       
        /*
        echo "<br />key[".$j."]: ";
        var_dump($tmp);
        echo "<br />buffer[".$i."]: ";
        var_dump($buffer[$i]);
        echo "<br />bufferE: ";
        var_dump($bufferE);
        echo "<br />";
        //*/
       
        // Send the encrypted data
       
echo $bufferE;
       
// Clean the memory
       
$bufferE = "";
       
$j++;
    }
   
$buffer = "";
   
flush(); // this is essential for large downloads
    /*
    fclose($fp);
    exit();
    //*/
}
// Close the file and it's finished
fclose($fp);

?>
up
-2
yjf_victor
1 year ago
According to the RFC 6226 (https://tools.ietf.org/html/rfc6266), the only way to send Content-Disposition Header with encoding is:

Content-Disposition: attachment;
                          filename*= UTF-8''%e2%82%ac%20rates

for backward compatibility, what should be sent is:

Content-Disposition: attachment;
                          filename="EURO rates";
                          filename*=utf-8''%e2%82%ac%20rates

As a result, we should use

<?php
$filename
= '中文文件名.exe';   // a filename in Chinese characters

$contentDispositionField = 'Content-Disposition: attachment; '
   
. sprintf('filename="%s"; ', rawurlencode($filename))
    .
sprintf("filename*=utf-8''%s", rawurlencode($filename));

header('Content-Type: application/octet-stream');

header($contentDispositionField);

readfile('file_to_download.exe');
?>

I have tested the code in IE6-10, firefox and Chrome.
up
-3
Kal
9 years ago
I spent a long time trying to determine why Internet Explorer 7 wasn't prompting the user to save a download based on the filename specified on a "'Content-Disposition: attachment; filename=..." header line.

I eventually determined that my Apache installation was adding an additional header: "Vary: Host", which was throwing IE - as per http://support.microsoft.com/kb/824847

I found manually setting the Vary header from within PHP as follows header('Vary: User-Agent'); allowed IE to behave as intended.

Hope this saves someone else some time,

- Kal
up
-5
dheeraj dot br2 at gmail dot com
2 years ago
The piece of code in the manual which is as follows

<html>
<?php
/* This will give an error. Note the output
* above, which is before the header() call */
header('Location: http://www.example.com/');
exit;
?>

this will not throw a warning as the .ini settings for output buffering is by default on.
to get the error you may have to change the server setting or simply add a line explicitly to close output buffering by using "ob_end_clean()" or similar
up
-6
nobileelpirata at hotmail dot com
10 years ago
This is the Headers to force a browser to use fresh content (no caching) in HTTP/1.0 and HTTP/1.1:

<?PHP
header
( 'Expires: Sat, 26 Jul 1997 05:00:00 GMT' );
header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s' ) . ' GMT' );
header( 'Cache-Control: no-store, no-cache, must-revalidate' );
header( 'Cache-Control: post-check=0, pre-check=0', false );
header( 'Pragma: no-cache' );

?>
up
-4
er dot ellison dot nyc at gmail dot com
1 year ago
DO NOT PUT space between location and the colon that comes after that ,
// DO NOT USE THIS :
header("Location : #whatever"); // -> will not work !

// INSTEAD USE THIS ->
header("Location: #wahtever"); // -> will work forever !
up
-6
this dot person at joaocunha dot eti dot br
7 years ago
AVOID ZERO BYTE ORDER MARK!

Header MUST be sent before EVERYTHING in the page. Even a single space will break your script. In my case, there was BOM setted in the encoding, so I opened the file with notepad++ and set the encoding to UTF-8 (no BOM) and voila, everything is working great now.
up
-10
jamie
8 years ago
The encoding of a file is discovered by the Content-Type, either in the HTML meta tag or as part of the HTTP header. Thus, the server and browser does not need - nor expect - a Unicode file to begin with a BOM mark. BOMs can confuse *nix systems too. More info at http://unicode.org/faq/utf_bom.html#bom1

On another note: Safari can display CMYK images (at least the OS X version, because it uses the services of QuickTime)
up
-26
cedric at gn dot apc dot org
6 years ago
Setting a Location header "returns a REDIRECT (302) status code to the browser unless the 201 or a 3xx status code has already been set".  If you are sending a response to a POST request, you might want to look at RFC 2616 sections 10.3.3 and 10.3.4.   It is suggested that if you want the browser to immediately GET the resource in the Location header in this circumstance, you should use a 303 status code not the 302 (with the same link as hypertext in the body for very old browsers).  This may have (rare) consequences as mentioned in bug 42969.
To Top