From: [EMAIL PROTECTED]
Operating system: Windows 2000
PHP version: 4.0.4pl1
PHP Bug Type: IIS related
Bug description: Header redirect and db connection cause "CGI misbehaved"
Under the category of "You Can Never Have Too Much Information On A Bug", here is my
experience with the "CGI App Misbehaved" bug (related bug reports: #8571 and #8744).
Bug report summary:
A PHP script that sends a 'Location' header directive and makes a database connection
causes IIS to intermittently return a 'Gateway Error 502' when the client browser asks
for the page specified in the redirect. The address bar will correctly show the page
that should have loaded when the error is displayed, and pressing F5 (refresh) will
correctly load the page. Note that the error is (seemingly) completely random,
sometimes you get it, other times the script works correctly. The error message text
is:
-- Begin --
CGI Error
The specified CGI application misbehaved by not returning a complete set of HTTP
headers. The headers it did return are:
-- End --
This error depends on:
1) Using PHP in CGI mode (i.e. using php.exe, the ISAPI dll does not seem to produce
this error, although it has it's own problems).
2) A PHP script that connects to a database (tested both mssql_connect and
odbc_connect) *and* sends a 'Location:' header. If the script redirects to something
other than a .php file (i.e. .html or .pdf) or does not connect to the database, the
error will not occur.
3) A successful db connection. If the db connect call fails (due to bad password,
etc.), the redirect always works.
This error does *not* depend on:
1) A fully qualified 'Location' header. The following also fails:
header('Location: http://10.0.0.30/test/done.php');
2) The relative order of the header() and xxx_connect() calls in 'doit.php'. I
wouldn't expect the order to affect the result, but I checked it anyway.
Interesting note: While upgrading the server to SP1 to see if it had any affect on
this bug, I continued to test while it was in the process of performing the upgrade.
It was very difficult (I gave up) trying to get the error. The CPU was at 100% due to
the upgrade which (obviously) caused the web server performance to suffer. Combined
with the fact that it occurs randomly anyway, this suggests that it may have something
to do with the timings between the request for doit.php, execution of doit.php, and
the request for done.php.
Hardware/Software:
Web server:
Win2000 Server (with and without SP1)
IIS 5.0
PHP 4.0.4pl1 (CGI mode)
Database server:
WinNT 4.0 SP6
MS-SQL 7.0
Client:
Win2000 Professional SP1
IE 5.5 SP1
========================================
Test scripts
========================================
start.php
----------------------------------------
<html><head><title>Test</title></head>
<body>
<a href="doit.php">Do test</a>
</body></html>
----------------------------------------
doit.php
----------------------------------------
<?php
// Either connect line will cause the error
$conn = mssql_connect('host', 'uid, 'pwd') or die("couldn't connect");
//$conn = odbc_connect('dsn', 'uid', 'pwd') or die("couldn't connect");
header('Location: done.php');
?>
----------------------------------------
done.php
----------------------------------------
<html><head><title>Test</title></head>
<body>
Test complete
<p><a href="start.php">Reset test</a>
</body></html>
========================================
Here are actual HTTP headers recorded using a packet sniffer:
========================================
Scenario #1 - CGI Error Occurs
========================================
Client request
----------------------------------------
GET /test/doit.php HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel,
application/msword, */*
Referer: http://10.0.0.30/test/start.php
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
Host: 10.0.0.30
Connection: Keep-Alive
----------------------------------------
Server response
----------------------------------------
HTTP/1.1 302 Object Moved
Location: done.php
Server: Microsoft-IIS/5.0
Content-Type: text/html
Connection: close
Content-Length: 131
----------------------------------------
Client request (automatic IE request)
----------------------------------------
GET /test/done.php HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel,
application/msword, */*
Referer: http://10.0.0.30/test/start.php
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
Host: 10.0.0.30
Connection: Keep-Alive
----------------------------------------
Server response (Incorrect response)
----------------------------------------
HTTP/1.1 502 Gateway Error
Server: Microsoft-IIS/5.0
Date: Tue, 20 Mar 2001 00:30:10 GMT
Connection: close
Content-Length: 215
Content-Type: text/html
----------------------------------------
Client request (F5 - refresh)
----------------------------------------
GET /test/done.php HTTP/1.1
Accept: */*
Referer: http://10.0.0.30/test/start.php
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
Host: 10.0.0.30
Connection: Keep-Alive
----------------------------------------
Server response
----------------------------------------
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.0
Date: Tue, 20 Mar 2001 00:30:11 GMT
Connection: close
X-Powered-By: PHP/4.0.4pl1
Content-type: text/html
========================================
========================================
Scenario #2 - Correct operation
========================================
Client request
----------------------------------------
GET /test/doit.php HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel,
application/msword, */*
Referer: http://10.0.0.30/test/start.php
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
Host: 10.0.0.30
Connection: Keep-Alive
----------------------------------------
Server response
----------------------------------------
HTTP/1.1 302 Object Moved
Location: done.php
Server: Microsoft-IIS/5.0
Content-Type: text/html
Connection: close
Content-Length: 131
----------------------------------------
Client request (automatic IE request)
----------------------------------------
GET /test/done.php HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel,
application/msword, */*
Referer: http://10.0.0.30/test/start.php
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
Host: 10.0.0.30
Connection: Keep-Alive
----------------------------------------
Server response (Correct response)
----------------------------------------
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.0
Date: Tue, 20 Mar 2001 00:33:02 GMT
Connection: close
X-Powered-By: PHP/4.0.4pl1
Content-type: text/html
========================================
--
Edit Bug report at: http://bugs.php.net/?id=9852&edit=1
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