Adding extensions to a Windows PHP

My development environment is set up thanks to EasyPHP. I've used this app since the first days that I started to write PHP and it followed me since.

I guess I have a better understanding of what it does under the scenes now and could probably work with a clean and custom Apache/MySQL/PHP install. But I like simplicity.

Anyway, I just wanted to run my imap script from the CLI but ran into "Fatal error : imapopen not defined_".

The same script was perfectly working when accessing it from my browser but failed when launched from the CLI.

That when I remember that I needed to enabled the php_imap.dll extensions in both EasyPHP PHP options (for web access) and C:\windows\php.ini (for cli access)

Migrating mails from GMail to other IMAP server

I have previously blogged on how I migrate mails from one IMAP server to another. Today I had to migrate some mails again.

My client's staff wasn't happy about the GMail webmail we gave them. The lack of a true "Draft" feature (one tha could be used and reused) had them drop a lot of productivity, so we decided to get back to Squirel Mail.

I started by manually recreating all the email adresses on the back-end on the Dreamhost server. Once at least one address is created, Dreamhost automatically creates the matching A and MX records.

I had to update my zone file on my registrar to update the previously MX and A records that were set to point to Google and updated to point to Dreamhost. I have to use an intermediate zone file on my registrar because I'm dealing with a limitation of the .fr TLD here.

Once the zone were updated and changes repercuted accross the network, I connected to the new Squirel mail. My inbox was empty.

So I ran imapsync to copy all mails from the google hosted service to my new server.

The syntax to be used is a little different than the one I mentioned on my previous post, so here it is :

imapsync --host1 imap.gmail.com --ssl1 --authmech1 LOGIN --user1 foo@domain.fr --passfile1 /path/to/pass1 --host2 208.97.*.* --user2 foo@domain.fr --passfile2 /path/to/pass2 --useheader="X-GMail-Received" --useheader 'Message-Id' --noauthmd5

After that, I reloaded my Squirel Mail inbox, and it was populated. I just had to do that for every account.

Performance improvement : moving assets to subdomains

Disclaimer : What I'm talking about in this blog post can be optimised. Yes, having multiple hosts is a great feature for performance improvement, but I kind of did it wrong. My recent try at the webperf contest gave me more insight on how to do it right.

I'll post more on the subject or update this post to reflect that.

I've just added to this site a performance improvement I read a long time ago but never implemented.

I'm talking about the multiple domains to serve static content. There are two important things to note here : parallel requests and cookies. Let me explain in a little more details what it's all about.

Parallell requests

Your browser is only able to perform a certain number of parallel request at the same time. It means that it can only download a certain number of files concurrently (usually 4).

In other words, it will start the download of, say, a CSS file, a Javascript file, and two images. Then, whenever one of this files is received, it will start downloading a new file, and so on.

This means that there is a certain amount of time that is "lost" in the process. You have to wait for one of the files to be downloaded before starting downloading the next.

The important thing to note is that the limit on the number of parallel downloads is set on a per-domain basis. It means that you can download only 4 files of foo.com while downloading at the same time 4 files from bar.com. This is the basic of what we will be using to our advantage.

Splitting your files accross several domains (or subdomains) allows you to get the best of parallel download. You do not really need to have your content hosted on different servers, you just need them to be accessible through different domain names, and subdomains are just perfect for that.

I have created four subdomains : css.pixelastic.com, js.pixelastic.com, img.pixelastic.com and dl.pixelastic.com.

Each one maps to the exact same site as www.pixelastic.com but using different names improve the number of possible downloads and thus improve page load.

Cookies

All this stuff about subdomains brings me to my second point : cookies.

If you host all your files on the same domain, it means that all requests (be it a php page or a static css file) will send cookie information without you knowing.

Cookie data is usually small, like 100Ko or so, but is added to every single request made. And most of the time this information is not even useful.

Apart from the fact that you are slowly killing your website bandwith with useless information, your are also decreasing your page speed load for your potential user.

The same trick of using a subdomain applies here too, and cookies won't be sent.

There is one caveat that you should be aware of, though. If your site is accessible through domain.com and you host your files on files.domain.com, cookies will still be sent because domain.com is considered the master domain of files.domain.com and thus all cookies set on the main domain will also propagate to the subdomains.

On the other hand, if your main domain is www.domain.com, it is not considered a parent domain of files.domain.com (but rather a sibling domain).

Configuring Apache

If you need to edit your httpd.conf file, here is what I put to add my different subdomains on my local machine :

<VirtualHost *:80>
  ServerName pixelastic
  ServerAlias www.pixelastic
  ServerAlias css.pixelastic
  ServerAlias js.pixelastic
  ServerAlias img.pixelastic
  ServerAlias dl.pixelastic
  DocumentRoot "www/pixelastic.com"
  <Directory "www/pixelastic.com">
    Options Indexes FollowSymLinks Includes ExecCGI
    AllowOverride All
    Order allow,deny
    Allow from all
  </Directory>
</VirtualHost>

The multi-tab admin problem

Today I had to update an important zone file at my registrar. Because it was quite important, and because I already did an almost identical job a few months ago, I decided to copy-paste the old work.

So I started by opening the domain A zone edit page. Then  I opened a new tab, and loaded the domain B zone edit page.

I selected the domain B content and copied it in the domain A page. I had to update some values, mostly IP addresses, and then validate the page.

Instead of updating the domain A zones as I expected, it updated the domain B zones and left the domain A unchanged. Can you guess why ?

Session handling

My guess is that everytime I opened a new page, a Session was tracking my "current" domain, the one I was editing. So opening a new tab to a new domain changed my current domain from domain A to domain B.

Therefore, when I updated the domain A zone, the next page was assuming I was editing the domain B page. If I had opened the tabs in reverse order, it would have worked seamlessly.

Why doing that ?

I have encountered a similar behavior in my own apps. By using the cakePHP Security behavior, a special security token is generated for each form. Its integrity is checked whenever a form is posted, and verify that no field has been tampered (no mandatory field has been deleted, no new field has been added).

This is a great security component, but because a special key is stored on the Session side, it also means that whenever you open several tabs, only the latest can be correctly checked and all other one will get rejected.

It bugs me at first, because I used to open several tabs whenever I need to "batch add" a lot of items. In real life, I found that I was almost the only person to do that... So I finally accepted the multi-tab restriction.

Getting back to my registrar : I guess they did it that way because of security reasons too, but I found it particularly counter-intuitive in that case and that could have led to serious damages.

Using fonts hosted on a subdomain with @font-face and Firefox

As a security reason, Firefox do not allow an @font-face rule to load fonts hosted on a different domain (even a subdomain).

I don't exactly understand why, I guess it has something to do with preventing crosslinking and copyright violation. I think we should keep the website author handle all this stuff and not required the browser to make assumptions like that.

Anyway, I recently tried to move my CSS file to a subdomain, to reduce pages loading times. Doing so I saw that my fonts did not correctly load on Firefox.

After some digging, I found that I had to manually allow them to be linked from an other domain, server-side. Here is the little snippet I added to my .htaccess

<FilesMatch "\.(ttf|otf|woff)$">
  <IfModule mod_headers.c>
    Header set Access-Control-Allow-Origin "*"
  </IfModule>
</FilesMatch>