At what point in the startup process does PHP set the REQUEST_TIME variables

Question

As noted in the PHP documentation, the $_SERVER superglobal array contains two elements, REQUEST_TIME and REQUEST_TIME_FLOAT, both of which contain the timestamp of the start of the request, in varying precision levels.

I am currently using the following snippet to include the time (in milliseconds) it took the server to generate the page in the footer of the page:

round((microtime(true)-$_SERVER['REQUEST_TIME_FLOAT'])*1000,2);

It returns an accurate value (can't really check, but it seems to match the time it takes the browser to start loading the page), but I am wondering which exact moment do the $_SERVER['REQUEST_TIME'] and $_SERVER['REQUEST_TIME_FLOAT'] variables contain the timestamp of? While I believe that the differences between those timestamps aren't significant, I would like to know which moment is the timestamp taken at. Is it the time when the request was sent, when the request was received, when PHP started parsing the document or something else?

I'm pretty sure that `$_SERVER` is populated by the webserver processing the request. — Ash, Mar 26 '15 at 21:41
IIRC correctly it is at the time the request is received. Let me see if I can find the docs for that. [Have a look here](http://stackoverflow.com/questions/28703822/measuring-the-time-of-php-scripts-using-requestrequest-time). — Jay Blanchard, Mar 26 '15 at 21:41
$_SERVER is mostly data from apache. I'm guessing, but almost certainly the request_times are when apache started processing the request. — Marc B, Mar 26 '15 at 21:41

score 5 · Answer 1 · answered Jan 15 '19 at 06:07

5

By checking PHP source code it seems most of the times it gets the initial request time from the SAPI itself - meaning from Apache, Nginx, CLI server, CGI... etc.

Sources:

$_SERVER['REQUEST_TIME'] definition
sapi_get_request_time() (SG() stands for "SAPI Global [value]")
php_apache_sapi_get_request_time()
sapi_module definitions [1] [2]

answered Jan 15 '19 at 06:07

igorsantos07

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Is `$_SERVER["REQUEST_TIME_FLOAT"]` always defined ? – beppe9000 Feb 14 '19 at 18:45
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Yep. It gets added as soon as PHP starts processing the request, as all $_SERVER contents. – igorsantos07 Feb 14 '19 at 18:49

score 2 · Answer 2 · edited Jun 23 '15 at 06:38

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$_SERVER['REQUEST_TIME'] and $_SERVER['REQUEST_TIME_FLOAT'], is the time when the request was received by your HTTP server.

A little warning regarding your php version: https://bugs.php.net/bug.php?id=64370

edited Jun 23 '15 at 06:38

empiric

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answered Mar 26 '15 at 21:54

bigben3333

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What is your source on this? – akukas Mar 26 '15 at 22:00

At what point in the startup process does PHP set the REQUEST_TIME variables

2 Answers2

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