Do I need to modify my Bluehost php.ini file? Header function not working on remote server

问题

This block of code shown below using a php header redirect works locally, but not on my Bluehost server:

if ($_POST['submit']=='No')
{
    $url ='Location: index.php?id='.$id.'&page='.$page;
    header($url);
    exit;
}

When the server gets to this block of code, absolutely nothing happens. No error, no warning, just a blank page. The page that my form submit redirects to isn't supposed to do anything except reroute the user to the relevant page.

I'm pretty dang positive it has nothing to do with the common problem of including HTML before the redirect (since it works locally). Therefore I suspect it has something to do with differences between my php.ini files. I've pulled up PHPinfo() for both servers, and my local server has a module named mod_headers while my Bluehost server has none. I think this potentially could be the problem, although normally my Bluehost has no problems using header redirects, except in this one instance.

So I suspect the problem has something to do with my ini file, but I don't know exactly what.

What makes this problem even stranger is that there are other blocks of code which work just fine, for instance

if(!empty($_POST['id']))
{
    $id = htmlentities(strip_tags($_POST['id']));
    $sql = "UPDATE entries SET title=?, entry=? WHERE id=? LIMIT 1";
    $stmt = $db->prepare($sql);
    $stmt->execute(array($title,$entry,$id));
    $stmt->closeCursor();
    $url= 'Location: ../index.php?id='.$id.'&page='.$page;
    header($url);
    exit;
}

works just great.

回答1:

I had the same problem that it works fine on XAMPP but not on bluehost or 1&1.

PHP documentation says there should be no output before calling the header function. http://php.net/manual/en/function.header.php

In my case there was a space before the opening <?PHP which made the header function not work.

This should help to solve the problem.

The quesiton remains though: why does it work on XAMPP and not on the servers of bluehost, 1&1, etc? (since I use firefox for both tests - it is definitely not a browser issue)

回答2:

I just had this problem. I realized that I was using an editor that was inserting a BOM at the beginning of the file. This BOM character is virtually invisible to most editors but will stop PHP's header from firing because it does count as ouput. Here is more information on the BOM character:

http://en.wikipedia.org/wiki/Byte_order_mark

I was using notepad++ and was able to disable this BOM by using these directions:

Go to Settings > Preferences > New Document/Default Directory
Changed Encoding to UTF-8 without BOM

回答3:

The HTTP standard requires that the URL in the Location: directive is an absolute URL. You can't just use index.php for that redirect. You'll need to use:

header("Location: http://example.com/index.php");

Some browsers ignore the standard and allow relative URLs.

回答4:

I faced the same problem when running moving my Wordpress blog to Bluehost.
The solution was to change output_buffering option in php.ini
Look what at my config along with the explanation of this option:

; Output buffering allows you to send header lines (including cookies) even
; after you send body content, at the price of slowing PHP's output layer a
; bit. You can enable output buffering during runtime by calling the output
; buffering functions. You can also enable output buffering for all files by
; setting this directive to On. If you wish to limit the size of the buffer
; to a certain size - you can use a maximum number of bytes instead of 'On', as
; a value for this directive (e.g., output_buffering=4096). output_buffering = 4096

来源：https://stackoverflow.com/questions/8215576/do-i-need-to-modify-my-bluehost-php-ini-file-header-function-not-working-on-rem

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