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POServer allowing only one request per session
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  1. POServer allowing only one request per session
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    copied!<p><b>Scenario:</b></p> <p>All pages of xyz.com use sessions to check if I am logged in and display customized content. I am logged into xyz.com using Firefox on my iMac. Now, when I try to visit, xyz.com/page1.php and xyz.com/page2.php at the same time, until page1 loads page2 is not processed.</p> <p><b>Code Samples</b></p> <p>xyz.com/contains (links): <br/></p> <pre><code>/* session check code here */ <a href="http://xyz.com/page1.php" rel="nofollow noreferrer">Page1</a> <a href="http://xyz.com/page2.php" rel="nofollow noreferrer">Page2</a> </code></pre> <p>xyz.com/page1.php contains: <br/></p> <pre><code>/* session check code here */ echo "Hello"; flush(); sleep(5); echo "done";</code></pre> <p>xyz.com/page2.php contains: <br/></p> <pre><code>/* session check code here */ echo "Second Page"; /* {insert code} to log time() to log.txt */ </code></pre> <p><b>Testing</b></p> <p>Here's what I do. I login to shell and keep this command running:</p> <pre><code>user@xyz.com [~/public_html]# tail -f log.txt</code></pre> <p>From my browser (Firefox), (on xyz.com), I open multiple instances of page1 and page2 in tabs. If you can see, page1 will at least take 5 seconds to load. Now, until page 1 loads, request to page2 is pending. It's not at all processed. How do I know that? The code at the end of page2 logs access time to a file which I am monitoring. Let's consider the following case:</p> <p>Requests fired to (in order) 1. page1.php 2. page2.php 3. page2.php 4. page1.php 5. page1.php 6. page2.php</p> <p><b>Result (approx)</b></p> <p>1237961919 &lt;-- #2<BR> 1237961920 &lt;-- #3<BR> 1237961931 &lt;-- #6<BR></p> <p><b>What was expected (approx)</b></p> <p>1237961915 &lt;-- #2<BR> 1237961915 &lt;-- #3<BR> 1237961915 &lt;-- #6<BR></p> <p>^Assuming that all calls were fired at the same time</p> <p><b>Observation</b></p> <p>While the calls are being processed, I am obviously not able to visit xyz.com as well (being another request). However, if I open it in another browser (Safari), it works well. That's because it's another session?</p> <p><b>Possible Causes</b></p> <ol> <li><p>The server has some security in place?</p> <blockquote> <p>I am more of a coder but if someone can give pointers, I can check the server (VPS) to see if apache/php is misconfigured.</p> </blockquote></li> <li><p>I am not handling sessions correctly?</p> <blockquote> <p>Does it matter? Shouldn't the second request be processed as a different thread?</p> </blockquote></li> <li><p>Aliens are controlling my VPS. </p> <blockquote> <p>Ok, kidding. I am just tired of tracing this issue. Would really appreciate if anyone has any clue what could be going wrong here.</p> </blockquote></li> </ol>
 

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