Category Archives: php - Page 2

new API for WebME

As I said in the last post, an API would be required to make the system more testable and more consistent.

I started straight away and wrote up something quickly. Over the next week, it solidified into something that appears to cover any needs that I have.

So here’s how the API works:

Requests are sent to a URL which is generated like this:

/a
[/p=plugin-name]
/f=function-name
[/other-parameters]

The plugin name is optional. Leaving it out means you want to call a core function.

Parameters can be added by adding /key=value pairs to the URL.

An example URL might be this:

/a/f=login/email=kae@verens.com

Sending that, with a POST parameter for the password, will log me in.

To log out, I can use this URL:

/a/f=logout

Simple!

Function Names

mod_rewrite is used to direct a request through a script which tears the URL apart into parameters.

If a p parameter is given, the function is named after the plugin, rewritten to match the WebME coding standard.

For example, if the URL is /a/p=comments/f=editComment, then the “comments” part is rewritten as Comments, and ‘_’ and “editComment” are appended to form the function name “Comments_editComment”, which is called and the result returned to the browser.

For double-barrel plugin names, such as “image-gallery”, the name is rewritten to “ImageGallery”.

If no p parameter is given, then the request is a core function, and “Core_” is prepended to the function name.

For example, the login URL above, /a/p=login calls the function Core_login.

If a function name begins with “admin”, it is an admin function (see below for more on this).

File names

If no plugin name is supplied, then the core API file, /ww.incs/api-funcs.php is loaded. This contained common API functions that might be used by any core script or plugin.

If a plugin name is supplied, then the API file is expected to be located at /ww.plugins/plugin-name/api.php for common functions, and /ww.plugins/plugin-name/api-admin.php for admin functions.

For core functions, common functions are at /ww.incs/api-funcs.php and admin functions are at /ww.incs/api-admin.php

Security things

Having a central point for RPC means that we can apply security rules in one place and know that they cover all scripts. Before-hand, I would sometimes come across scripts and realise that they were open for abuse if someone knows that magic URL incantation. I would silently curse myself or whoever had written the script and fix it up. Now, though, having one single point of entry means I can secure everything at once.

If a function name starts with “admin”, then the script checks to see if the user is logged in and is a member of the administrators group. If not, the API will return an error. It’s as simple as that!

Of course, this doesn’t stop abuse by people that are logged in as admins or who are victims of XSS, but it helps stop a few problems caused by developers not noticing their scripts were open to use by anyone at all.

Conclusion

So now, when people are creating new plugins for WebME, the following could be used as a bare-bones directory structure:

/ww.plugins/plugin-name/plugin.php    details, server-side functions
/ww.plugins/plugin-name/api.php       common RPC functions
/ww.plugins/plugin-name/api-admin.php admin RPC functions
/ww.plugins/plugin-name/admin.js      admin scripts in JS

testing KV-WebME

I’ve been working on my CMS for about 10 years. It’s monstrously huge (41,000 lines, not including external libraries), and for most of those 10 years, I’ve been too busy building it to concentrate on niceties such as comments, testing, code formatting, etc.

This has caused problems in the past. As most programmers know, when you change any one thing, it has a ripple effect and can break things in places that don’t seem obvious at all.

Recently I’ve been remedying this. I’ve been religiously using PHPCS to make sure my code is neat and consistent, and I’ve started writing a test suite.

The most difficult part of the testing is that the CMS is composed of many separate technologies. If it was just a plain old HTML and PHP application, then PHPUnit would be enough, or maybe Selenium.

The problem is, though, that the system uses a large amount of AJAX – especially in the administration areas. No single testing system would do it all.

Another problem has to do with AJAX itself. In jQuery, you can speak to the server by writing something like this:

$.post('/a/server/script.php', {
  "id": 2
}, function(res) {
  // do stuff
}, 'json');

This makes it incredibly simple to speak to any server-side script at all on the server, and promotes it. It becomes tempting when writing new functionality to build new server-side scripts specifically for the new client-side stuff.

This has the effect that there is no single point for RPC (remote procedure calls) which can be tested, making it very difficult to be sure you have covered all potential problems.

To help solve this problem, I’ve recently started converting WebME’s coding style so all RPC is done through a single API (application programming interface) script.

This has a few extra effects which are beneficial:

  • Having a single point of entry into the system makes it easier to secure it.
  • Having an API promotes the construction of a solid method of adding functionality to it – there’s no need to start from scratch anymore, potentially building disparate scripts that are hard to abstract. Instead, it’s now easy to force the code to match a minimum spec.
  • APIs tend to have specific rules for how parameters are passed into it, making it easier to remember what the right parameters are when writing new client-side code. Also, it makes it easier to “guess” what the right parameters are if you’ve forgotten.

The main benefit, though, is that it makes it much easier to test. The URL of the API always stays the same, and the only thing that changes is the parameters sent to the URL. Previously, each separate script would have a different URL and could have any parameter scheme at all.

So, currently, I’m writing tests that use the API directly, speaking to the server directly through URL calls. After I’ve finished writing all of those (hah! if ever), I can get on to testing that JavaScript.

growing up

For a long time, whenever I did something that I thought was interesting, I would write it in an article.

I don’t write as much as I used to. Not because what I’m doing is not interesting, but because it’s taking a lot longer now to complete the interesting jobs, now that they’re basically full projects and not just little snippets here and there.

As an example, we’re doing some interesting work over in the KV WebME project. The most recent is an upgrade to image galleries allowing the gallery layouts to be defined using templates, instead of saying “you want layout 1, or layout 2?”. This work is then also used in the products plugin to let people sell images in their online stores.

There are a number of bits in that project that deserve full posts themselves, but as I basically commissioned the piece and got others to do the work, it’s no longer mine to describe. For me, the cool little tricks are now just a smaller part of a bigger picture.

The bigger picture right now is 20eu.com, where you can create your own online store within literally minutes for only €20 (compare that to the “free” getting business online project, which doesn’t have an e-commerce aspect).

It’s now harder for me to write about, because there are no longer single cool aspects that I can point to that can be re-used by other people.

I was walking to work today with Conor (an employee), discussing stuff along these lines, and these points stood out:

  • In the beginning, I was a programmer, and every task had something new to me but nothing I could write about that would interest experienced programmers.
  • After a few years, I was a good programmer, and I did less tasks, but they were larger, and there were often aspects to them that were brand new, so I ended up being one of the first to build them (it helps that my field is Ajax, which is basically new-born).
  • And now, I’m tired of being just a programmer and have started branching into managing other programmers. I’m more interested now in getting full projects done than in the nitty-gritty.

Unfortunately, this means there is less to talk about that is even vaguely techie. I feel like I’m shifting focus into marketing and project management.

Ick!

On the plus side (for me), it means that eventually, I’ll have enough resources that I can get the projects done that I’ve always wanted to do.

So, I plan on starting to write about the business end of my work.

Don’t worry – I’ll categorise it correctly, so if you’re only interested in my PHP or Linux posts, then just change your reader settings to only read from those RSS feeds.

What I’ve been up to

Being self-employed is hard work!

Naive person that I am, I thought it would be easy enough – I get to work on my own ideas all day long, occasionally selling something to customers who are happy every time.

Of course, that’s not true.

I spend a lot of my time working on jobs for my previous employer, and some other clients that have known me for years. The large pool of new clients that I expected would magically appear, never magically appeared.

Of course, it’s not all doom and gloom.

Being out on my own has taught me quite a lot, and in a very short time.

  • Cash is king – there’s no point having a huge job which may potentially pay you thousands of euro in two months, when you need the money right now to go buy food for the house.
  • Advertising is not easy! I hate to pester, so advertising is not a natural thing for me, but it’s tricky to get new people to come in and buy from me if they don’t know where I am. Especially if they don’t know whether to trust my work! Conveying trust in ads is not a very easy thing to do.
  • Word-of-mouth is a brilliant thing. It is much easier to sell to someone if they’ve already been half-sold by their friends.
  • Low prices don’t always pull people in. Even though I charge about a fifth of other local web designers, I think I must also be getting only a fifth of the customers 😉
  • Salary is a wonderful thing, when it’s someone else’s job to make sure it gets paid.

Of course, there are also the upsides.

I get to work on my own projects without worrying that they my conflict with the company’s plans. Basically, I am the company, so anything I want to work on is the company plan.

To that end, I’ve created 20eurowebsites.com, a site-creator which is built on my kvWebME CMS (open source, PHP – download it yourself if you’re techie!). €20 to buy a website (including the domain name), and €10 per month hosting after that.

I have other plans in the works as well, such as a local odd-jobs finder which has a pretty good twist, and a free face-book-like chat application which people will be able to add to their own websites with just a few keystrokes.

multi-tenanted CMS architecture

Last week, I did a talk at the Dublin Google buildings titled “Multi-tenanted CMS Architecture using PHP”.

Here are the slides that I used:

While talking with Google’s Brian Brazil, he explained that it is actually more efficient to use one database and many separate tables, than to separate each installation into a separate database, so one point I made (that KV-WebME uses separate databases per site) will change in the future.

I think the talk went down well, by the number of questions afterwards.

Last year, I gave a similar talk, and made the mistake of including way too much PHP in it – I had assumed that the audience would be composed of PHP developers. This year, there is just one slide of PHP, and that’s just to illustrate one possible way to build a proxy config.

Lesson’s learned for this time:

  • Talk slower. When I’m explaining something, I tend to try to get as much in as possible, so speak very fast. This makes it hard to hear what I’m saying.
  • More pictures, less words!
  • Stats. Some of the questions were around how efficient certain parts of the method were – particularly on the overhead of piping a file through a script as opposed to simply delivering it via Apache. I need to come up with numbers for that.

Overall, I was happy with this presentation.

script for shrinking videos

For this tip, you’ll need mencoder, ffmpeg and php installed. Only tested on Linux.

I’ve a load of videos, because I don’t like deleting anything in case I want to watch it again later (hoarding!).

I’ve three 1TB drives stuffed full of what I’ve collected over the last 20 years, but still I keep running out of room.

So, choice – buy more drives, or shrink what I have? I chose to shrink what I have, because I’m totally happy with VHS-quality video in stereo – I don’t need to watch fan-subbed Bleach in HD in 5.1 surround sound!

So, I wrote a script which will search the current directory (and its sub-directories) for all videos, will figure out their bit-rates, and will shrink them if they’re too large.

The script also reduces the videos so they match a maximum width and height.

It’s written in such a way that it will start with the most wasteful files (those that are taking up the most room), and work from that to the least wasteful.

It’s also written to only do 100 videos in a run. There’s no point shrinking absolutely every video you have, as most will probably save only a few kilobytes. The script does 100 of the most wasteful ones.

Of course, you could always run it again and again afterwards, and it should choose different videos each time to shrink.

How to use: copy the file into the root directory of your video repository. Go to that directory. Type “php shrink.php” into the console. Now go do something for a few days. Simple as that!

<?php

$maxwidth=624;
$maxheight=352;

function list_files($dir, $list) {
  $files=new DirectoryIterator($dir);
  foreach ($files as $f) {
    if ($f->isDot()) {
      continue;
    }
    $fname=$f->getPathname(); 
    if (is_dir($fname)) {
      $list=list_files($fname, $list); 
      continue;
    } 
    if (in_array(
      strtolower(preg_replace('/.*\./', '', $fname)),
      array('avi', 'mpg', 'mp4')
    )) {
      if (preg_match('/-shrink.avi$/', $fname)) {
        unlink($fname);
        continue;
      }
      $arr2=array();
      // { get duration of video
        exec('ffmpeg -i "'.$fname.'" 2>&1 | grep Duration', $arr2);
        $bits=explode(':', preg_replace('/.*Duration: ([^,]*),.*/', '\1', $arr2[0]));
        if (count($bits)!=3) {
          echo 'failed to get duration of "'.$fname.'"'."\n";
        }
        $duration=(int)preg_replace('/^0/', '', $bits[2])
          +((int)preg_replace('/^0/', '', $bits[1]))*60
          +((int)preg_replace('/^0/', '', $bits[0]))*3600;
      // }
      // { get width/height of video
        exec('ffmpeg -i "'.$fname.'" 2>&1 | grep "Video:"', $arr2);
        $bits=explode('x', preg_replace('/.*\s([0-9]+x[0-9]+)[\s,].*/', '\1', $arr2[1]));
        if (count($bits)!=2) {
          echo 'failed to get dimensions of "'.$fname.'"'."\n";
          continue;
        }
        $width=$bits[0];
        $height=$bits[1];
      // }
      $fsize=filesize($fname);
      $bps=$fsize/$duration;
      echo '.';
      $list[]=array($bps, $fsize, $width, $height, $duration, $fname);
    }
  }
  return $list;
}

echo "\ngetting file details\n";
$list=list_files('.', array());

echo "\nsorting by bits per second\n";
for ($i=0; $i<count($list)-1; ++$i) {
  echo '.';
  for ($j=$i+1; $j<count($list); ++$j) {
    if ($list[$j][0]>$list[$i][0]) {
      $tmp=$list[$j];
      $list[$j]=$list[$i];
      $list[$i]=$tmp;
    }
  }
}

echo "\nshrinking\n";
for ($i=0; $i<100&&$i<count($list); ++$i) {
  $fname=$list[$i][5];
  echo $fname."\nold size: ".$list[$i][1]."\n";
  @unlink('divx2pass.log');
  $resize='';
  if ($list[$i][2]>$maxwidth || $list[$i][3]>$maxheight) {
    $rx=$maxwidth/$list[$i][2];
    $ry=$maxheight/$list[$i][3];
    $ratio=$rx<$ry?$rx:$ry;
    $width=(int)($list[$i][2]*$ratio);
    $height=(int)($list[$i][3]*$ratio);
    $resize='-vf scale='.$width.':'.$height;
  }
  exec('mencoder "'.$fname.'" -ovc xvid -xvidencopts bvhq=1:chroma_opt:quan'
    .'t_type=mpeg:bitrate=400:pass=1 '.$resize.' -alang en -oac copy -o "'
    .$fname.'-shrink.avi" 2>&1');
  exec('mencoder "'.$fname.'" -ovc xvid -xvidencopts bvhq=1:chroma_opt:quan'
    .'t_type=mpeg:bitrate=400:pass=2 '.$resize.' -alang en -oac mp3lame '
    .' -o "'.$fname.'-shrink.avi" 2>&1');
  echo 'new size: '.filesize($fname.'-shrink.avi')."\n\n";
  if (filesize($fname.'-shrink.avi')<$list[$i][1]) {
    unlink($fname);
    rename($fname.'-shrink.avi', preg_replace('/\.[^\.]*$/', '.avi', $fname));
  }
  else {
    unlink($fname.'-shrink.avi');
  }
}

2010

I’ve the most awful memory.

While trying to remember what the hell I’d done in the last year, I came up with nothing.

Luckily, I have a spare brain in the form of my facebook friends, who came up with this list for me:

  • I started a new company, KV Sites, which will be up and running properly within a month or so, and will be selling affordable CMS websites and programming.
  • I got grade 2 in piano. I’m still waiting for an examiner for grade 3 (which I wanted to do in September). I’ll be doing grade 4 in March.
  • I got my first grading in Genbukan Ninjutsu.
  • I finished another book, CMS Design using PHP and jQuery. I hope it is as well-received as the previous book, jQuery 1.3 with PHP. btw, Packt would like me to remind people that the book “Mastering phpMyAdmin […] for effective mysql management” (reviewed here and here) has been updated to version 3.3.x.
  • I am building up to a new release of my CMS, WebME, which, despite the last downloadable version being from early 2009, has actually been very actively updated. It should be ready for release tomorrow, right on time for 2011!
  • I wrote and released two jQuery plugins: k3dCarousel, and SaorFM (which I hope to vastly improve in 2011).
  • I also built a first attempt at a clavichord made from plywood. I’ve got some new tuning pegs and redesigned the keyboard, so will hopefully be able to record on it soon.

I’m hoping 2011 turns out to be awesomer and that my head will be able to remember it all!

SaorFM progress – the Hidden Files plugin

In the last post, I mentioned that a jQuery plugin had been created.

At the time, it could only be used as a file or directory selector.

It can now also be used to upload, download, and delete files.

I’ve also enhanced the core engine so that it now has plugin support.

The first plugin is a Hidden Files plugin, which lets you hide files or directories depending on their names. The default pattern is to hide nodes with names that begin with a ‘.’ – this is the default for most systems out there.

I’ll explain how plugins work, in the hope that someone out there may be interested in creating one 😉

For this example, I’ll use the Hidden Files plugin, as it’s already created, and uses everything in the engine so far.

First off, you create a directory in the /plugins/ directory of the plugin. In this case, I created the directory /plugins/hidden-files/.

In that, the only essential file is config.php, which holds a configuration for the plugin:

<?php
$config=array(
  'triggers'=>array(
    'checkfilename'=>'HiddenFiles_checkFilename'
  )
);

When you tell SaorFM to install the plugin (using $SaorFM->installPlugin('hidden-files');), it will read through that array and add the details to its own configuration file, so it doesn’t have to open up multiple files every time it boots up.

As an example, here’s my test config before the plugin is installed:

<?php
$SaorFM_config='{"user_files_directory":"\/home\/kae\/websites\/saorfm\/trunk\/tests\/\/userfiles"}';

And here’s how it appears after the installation of the plugin:

<?php
$SaorFM_config='{"user_files_directory":"\/home\/kae\/websites\/saorfm\/trunk\/tests\/\/userfiles","plugins":["hidden-files"],"hiddenfiles":"#^\/?\\.#","triggers":{"checkfilename":["HiddenFiles_checkFilename"]}}';

There are three additions:

  • "plugins":["hidden-files"] – this is an array of installed plugins.
  • "triggers":{"checkfilename":["HiddenFiles_checkFilename"]} – the $config array above had a trigger mentioned – that’s converted into an object and added to the SaorFM config.
  • "hiddenfiles":"#^\/?\\.#" – this is to tell the hidden files plugin what pattern to apply to file names to decide whether they should be hidden or not.

The first two are obvious – the first is the name of the plugin, and the second is the name of a trigger named in the config array.

For the third, we need to run an installation script when Hidden Files is installed, so SaorFM checks the /plugins/hidden-files/ directory to see if a file exists named install.php:

<?php
if (!isset($this->_config->hiddenfiles)) {
  // the default pattern hides files that begin with .
  $this->_config->hiddenfiles='#^/?\.#';
}

That’s run by SaorFM when the plugin is installed. It adds a default hiddenfiles value to the config. This can be changed at any time afterwards.

Ok – so we have the config installed – now how does it work?

Let’s say we ask SaorFM to list the files in ‘/’: $SaorFM->listFiles('/');

Inside the listFiles method, there is a loop which adds filenames to an array. For each one of the filenames, we check it before adding to the array:

    foreach ($files as $f) {
      if ($f->isDot()) {
        continue;
      }
      if ($this->trigger('checkfilename', $f->getFilename())) {
        continue;
      }
      $arr[$f->getFilename()]=array(
        $f->getFilename(),
        $f->getSize(),
        $f->isDir()?1:0 // record as 1 or 0 to save http traffic
      );
    }

Notice the $this->trigger('checkfilename', $f->getFilename()) – if that returns anything other than false, then the file is not added to the list.

The trigger method cycles through any functions which have been named for that trigger, and calls each one in turn. If any return a result other than false, the method returns that result immediately:

  public function trigger($trigger, $vals) {
    if (!isset($this->_config->triggers->{$trigger})) {
      return false;
    }
    foreach ($this->_config->triggers->{$trigger} as $function) {
      $ret=$function($this, $vals);
      // if the trigger gives any response other than false, then return it
      if ($ret) {
        return $ret;
      }
    }
    return false;
  }

Note that we haven’t yet defined the function HiddenFiles_checkFilename.

Upon installation, we also load up the file /plugins/hidden-files/functions.php if it exists, and this file is loaded every time that SaorFM is instantiated after installation as well:

function HiddenFiles_checkFilename(&$saorfm, &$filename) {
  return preg_match($saorfm->get('hiddenfiles'), $filename);
}

This is a very very simple function – it could get a lot more complex in other plugins. For example, an Authentication plugin would be much more verbose.

I hope this is all very clear. It’s very very simple to add arbitrary triggers to SaorFM, so if you want to write a plugin and the trigger doesn’t exist, just tell me and I’ll put it in place.

After all this, let’s say you want to uninstall the plugin.

Within SaorFM, you just call $SaorFM->uninstallPlugin('hidden-files');.

This automatically removes the ‘hidden-files’ value from the plugins array (and removes that array if it’s empty), then removes any added filters as well.

Finally, it also checks to see if /plugins/hidden-files/uninstall.php exists and runs that if so:

<?php
unset($this->_config->hiddenfiles);

After this, the SaorFM config file is back to the exact state it was in before we installed the plugin. Clean.

If you’re interested in hacking on SaorFM, please download a copy from SVN here.

There are a number of things we need to create before it’s usable by the general public. An installer, for example, and some widgets for popular RTEs like CKeditor or TinyMCE. If you feel you’d like to create those, please contact me.

saorfm: first visible results

The first visible project using SaorFM is a jQuery file-selection widget:


demo

Here is the source of that page:

<html>
	<head>
	</head>
	<body>
		<p>Select a file</p>
		<input id="file-select" />

		<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" type="text/css" />
		<link rel="stylesheet" href="/saorfm/jquery-widgets/jquery.saorfm/jquery.saorfm.css" type="text/css" />

		<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
		<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.js"></script>
		<script src="/saorfm/jquery-widgets/jquery.saorfm/jquery.saorfm.js"></script>
		<script>
			$(function(){
				$('#file-select').saorfm({
					"rpc":"/saorfm/core/rpc.php"
				});
			});
		</script>
	</body>
</html>

In the above demo, we link in the jQuery and jQuery-UI scripts, and load up the widget’s script.

The only content elements are a <p> telling the user to choose a file, and a normal text <input> box which the user can use as a combobox.

The magic happens with this little bit of JavaScript:

$(function(){
	$('#file-select').saorfm({
		"rpc":"/saorfm/core/rpc.php"
	});
});

That tells jQuery to convert the #file-select input box into a saorfm widget. The only parameter in this demo is rpc, which tells the widget where the SaorFM server is to be found online.

To install this on your own server, all you need to do is download the SaorFM engine from Google Code, and add a config.php file to the core directory. Here’s mine:

<?php
$SaorFM_config='{"user_files_directory":"\/home\/verens\/domains\/demo.verens.com\/saorfm","language":"en","json_errors":false}';

In that, a JSON-encoded hash object contains the configuration. Change the user_files_directory parameter to your own files directory, and you are done with the configuration!

I’ll be adding this to my WebME project next week, after I’ve finished writing the tests (Selenium and PHPUnit).

keeping an admin session active

I had a call from a client who asked why, after logging into a CMS admin area and spending an hour or so writing a document, she was unable to submit it because it claimed she was not logged in.

The answer was that the session had expired.

On busy servers, one method of optimisation is to reduce the session-time. This makes it easier for the server to cope with a large number of visitors, but also has the undesired effect of logging people out if they take their time over anything.

One solution to this is to keep the admin session in a database table, tied to a cookie in the browser. Unfortunately, that means that every time the browser sends the cookie, it must be verified, whereas a session is usually trusted.

The workaround is to use some JavaScript to refresh the session every now and then.

I wrote a simple cyclical script which polled the server every minute to refresh the session.

Here it is, using jQuery to handle the AJAX:

function keep_session_alive(){
  setTimeout(keep_session_alive,60000);
  $.get('/ww.admin/keepalive.php');
}
setTimeout(keep_session_alive,60000);

And the server-side code is this:

<?php
session_start();

Very very simple trick. The polling could be enhanced, if you want, to alert the admin of anything interesting that’s happened on the server.