Fast/scalable way of creating a REST webservice api in PHP5?

[Marian Steinbach]

Howdy!

I am just switching from PHP4 to PHP5. Since there are many different
ways to create XML in PHP5, I'd like to know from the community which
one would be suited best for a REST web service API.

I guess that beeing CPU friendly and using little RAM both count very
high here as criteria.

Here are some methods to be considered (probably not complete):

1) XMLWriter
haven't tested that yet.

2) Using a template framework like PEAR HTML_Template_S igma
I'm doing this for RSS feeds in PHP 4 already. Unfortunately, I have
no comparison with other methods.

3) Writing XML "manually"
like $xml .= '<tag>'.utf8_en code($value).'</tag>';

4) you name it

Thanks to everybody who helps me to investigate/benchmark into the
right direction! I'd also be happy about articles on that topic.

Marian

[Marian Steinbach]

On 19 Mrz., 15:29, "Marian Steinbach" <marian.steinb. [e-mail]>
wrote:

>
4) you name it

Of course, I forgot

4) DomDocument

5) SimpleXML
Marian

[Toby A Inkster]

Marian Steinbach wrote:

3) Writing XML "manually"
like $xml .= '<tag>'.utf8_en code($value).'</tag>';

I tend to do this. Don't forget liberal use of htmlentities(). Unlike
parsing XML, outputting XML manually is very easy, and I find that most XML
output libraries fall into the "overkill" category.

--
Toby A Inkster BSc (Hons) ARCS
Contact Me ~ http://tobyinkster.co.uk/contact
Geek of ~ HTML/SQL/Perl/PHP/Python*/Apache/Linux

* = I'm getting there!

[Marian Steinbach]

On 19 Mrz., 17:18, Toby A Inkster <usenet200...@t obyinkster.co.u k>
wrote:

Marian Steinbach wrote:

3) Writing XML "manually"
like $xml .= '<tag>'.utf8_en code($value).'</tag>';

I tend to do this. Don't forget liberal use of htmlentities(). Unlike
parsing XML, outputting XML manually is very easy, and I find that most XML
output libraries fall into the "overkill" category.

I just did a very simple comparison of "manual XML writing" and
XMLWriter (which is supposed to be very fast). Surprisingly to me,
XMLWriter is even twice as fast as manual XML writing.

I ran creation of a simple document 10.000 times. Results:

manual.php: ~ 5 seconds
xmlwriter.php: ~ 2 secs

Here is the code I used:

manual.php:

<?php

$start = microtime(true) ;

require './common.inc.php' ;

function makeXmlDocument ($short, $long) {
$ret = '<?xml version="1.0" encoding="UTF-8" ?>
<document>'."\n ";
if (isset($short) && !empty($short)) {
$ret .= '<short>'.htmls pecialchars($sh ort).'</short>'."\n";
}
if (isset($long) && !empty($long)) {
$ret .= '<long>'.htmlsp ecialchars($lon g).'</long>'."\n";
}
$ret .= '</document>';
return $ret;
}

for ($i=0; $i<$num_iterati ons; $i++) {
$xml = makeXmlDocument ($short_string, $long_string);
}

echo 'time used: '.(microtime(tr ue) - $start);
?>

xmlwriter.php:

<?php

$start = microtime(true) ;

require './common.inc.php' ;

function makeXmlDocument ($short, $long) {
$memory = xmlwriter_open_ memory();
xmlwriter_start _document($memo ry,'1.0','UTF-8');
xmlwriter_start _element($memor y, 'document');
if (isset($short) && !empty($short)) {
xmlwriter_write _element($memor y, 'short', $short);
}
if (isset($long) && !empty($long)) {
xmlwriter_write _element($memor y, 'long', $long);
}
xmlwriter_end_e lement($memory) ;
$ret = xmlwriter_outpu t_memory($memor y, true);
return $ret;
}

for ($i=0; $i<$num_iterati ons; $i++) {
$xml = makeXmlDocument ($short_string, $long_string);
}

echo 'time used: '.(microtime(tr ue) - $start);
?>

common.php:

<?php

$num_iterations = 10000;

$short_string = 'Some Short Value';

$long_string = 'Some very long text (truncated here)';

?>

It would be interesting to see which version scales better... That
means: How would the two behave with multiple concurrent requests
(rather typical for a REST API, I guess) and with very large XML
documents (rather untypical for REST services, since lists should be
limited anyway)?

I'll test that.

Marian

[Marian Steinbach]

On 19 Mrz., 22:47, "Marian Steinbach" <marian.steinb. [e-mail]>
wrote:

...
It would be interesting to see which version scales better... That
means: How would the two behave with multiple concurrent requests
(rather typical for a REST API, I guess) and with very large XML
documents (rather untypical for REST services, since lists should be
limited anyway)?

I'll test that.

I just ran a test with JMeter. I altered the scripts a little so that
100 times larger documents would be produced.

Both methods seem to scale equally well, they use the same amount of
RAM (measured with up to 90 concurrent threads).

However, along the comparison result posted earlier, the XMLWriter
version answers almost twice as many requests per time period.

So far,

Marian

[Toby A Inkster]

Marian Steinbach wrote:

I just did a very simple comparison of "manual XML writing" and
XMLWriter (which is supposed to be very fast). Surprisingly to me,
XMLWriter is even twice as fast as manual XML writing.

It is somewhat surprising. Skimming through the code, as far as I can see,
the only think that might be slowing it down is your use of:

."\n";

to append a line break to strings occasionally. This obviously makes the
generated XML a lot more usable, but it also forces PHP to attempt
interpolation on the string, as it's double-quoted. Does removing these
line breaks speed things up?

If these line breaks *are* what's responsible, I'm going to have to
seriously rethink my own (X|HT|XHT)ML generating code!

--
Toby A Inkster BSc (Hons) ARCS
Contact Me ~ http://tobyinkster.co.uk/contact
Geek of ~ HTML/SQL/Perl/PHP/Python*/Apache/Linux

* = I'm getting there!