chxo internets

iPad Filesharing (iWork export)

The iWork suite allows you to export your documents to something called “filesharing” but where do the files actually end up?

It took a while (for me) to figure it out, helped by http://support.apple.com/kb/HT4094:

When you sync up via iTunes, scroll to the bottom of the Apps tab to see the list of files in File Sharing, where you can save them off to other places.

Farmville on Web Scaling

This was a pretty good read, How FarmVille Scales to Harvest 75 Million Players a Month. The lessons learned are worth generalizing:

1. Interactive apps are write-heavy.
2. Design every component as a degradable service, and provide a mechanism to degrade services server-side during peak demand.
3. Cache incoming data - they cache everything coming in from Facebook
4. Usage spikes during new releases of an app
5. Use sampling to make sense of large traffic flows

De-columnize Regex

\s+\|\s*\n\|

This regular expression matches the pipes and spaces in mysql output like:

| $dq$$form                  | 
| $dq$$module                | 
| $dq$$place                 | 
| $dq$$site                  | 
| $dq$$thing                 | 

Sometimes it’s handy to extract just the values from a pasted query result.

Zend Studio 5.5 hangs “loading source control data”

Thanks to a post buried in the Google cache of Zend’s support boards, I give you the means to solve this annoying bug: set the svn and cvs paths to /dev/null.

I tried setting just the svn path to /dev/null, but ZDE.app was still loading source control data when opening the problem project. Then I set the cvs path to /dev/null, restarted, and no more loading.

According to the thread, this also works, changing ZDE/config_5.5/cvs_options.xml so that the value is false. Not sure if it works, I like the /dev/null solution too much.

<customized_property ID="cvs.enableCvsIntegration">
		<boolean value="false"/>

Revert svn deleted symlink

Let’s say you have a symlink or two in your svn repository, and one day you decide to delete one of them. You use the svn rm command to do so.

$ ls -l tinymce-3.2.6
lrwxrwxrwx ... tinymce-3.2.6 -> ../../jslibs/tinymce-3.2.6
$ svn rm tinymce-3.2.6
D         tinymce-3.2.6 
$

But a minute later you realize that you actually need that symlink. You haven’t committed anything. Normally you would just svn revert and go about your business.

Alas, your working directory is in limbo now; svn revert won’t restore, and svn up ignores the missing symlink. The trick, apparently, is that you must commit the deletion before you can roll it back.

$ svn commit -m "Uh, accidentally deleted wrong version of tinymce"
Deleting       tinymce-3.2.6

Committed revision 12679.

Then you copy (I kid you not) the link back in from a previous revision, and commit that.

$ svn copy -r 12678 http://svn.example.org/path/to/tinymce-3.2.6 \ 
 ./tinymce-3.2.6
A         tinymce-3.2.6
$ svn commit -m "Respawned tinymce-3.2.6 from previous revision"
svn commit -m "'Resurrected' link from previous revision"
Adding         tinymce-3.2.6

Committed revision 12680.

Now the symlink is back and you can carry on.

The SVN Book calls this “resurrection”, I call it “respawning.” Thanks to this post for the tip.

Rock Solid HTML Emails

Great (no, really great!) summary of the many quirks to keep in mind when building an HTML email template:

http://24ways.org/2009/rock-solid-html-emails

I had to learn most of these the hard way recently, but I haven’t tested against Y! mail so I’m sure some of my work is broken.

The biggest disappointment, by the way, is Gmail. I mean, inline CSS only? Really? What kind of kludge is that? It bulks up message size considerably. I guess the alternative is to use… an iframe. Oh well.