CABasicAnimation *dartWiggleAnimation = [CABasicAnimation animationWithKeyPath:@"position"];
dartWiggleAnimation.fromValue =
   [NSValue valueWithCGPoint:CGPointMake(self.center.x-DART_WIGGLE_HALF, self.center.y+DART_CENTER_H_OFFSET)];
dartWiggleAnimation.toValue =
   [NSValue valueWithCGPoint:CGPointMake(self.center.x+DART_WIGGLE_HALF, self.center.y+DART_CENTER_H_OFFSET)];
dartWiggleAnimation.timingFunction =
   [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut]; 
 
dartWiggleAnimation.duration = 0.4;
dartWiggleAnimation.repeatCount = HUGE_VALF;
dartWiggleAnimation.autoreverses = YES;
dartWiggleAnimation.removedOnCompletion = NO;
 
[[nextDart layer] addAnimation:dartWiggleAnimation forKey:@"dartWiggle"];

Does this seem like a bug or a feature?

When you installed the beta, it will upgrade your iTunes library database but if you try to downgrade back to the old version at a later date you’ll be presented with an error message saying that iTunes cannot read your library.

Don’t panic! The beta version has just moved your library database to a backup folder and with a simple drag and drop you can have your old library database up and running again. Your old database should be found in ~/Music/iTunes/Previous iTunes Libraries dated with when you upgraded. Just drag that back into ~/Music/iTunes renaming it to iTunes Library.itl (you’ll probably need to delete the existing iTunes Library.itl file too as that belonged to the beta version and you just uninstalled that).

That’s all you need to do to get your old iTunes library working again. Just before you begin make sure you back up everything!

The keynote was fantastic and had many interesting details about the upcoming OS X Lion and iOS 5 software which I recommend you read about as well as familiarise yourself with iCloud – Apple’s hot solution to working with multiple devices. iCloud is actually much more than just a document syncing solution. It effectively challenges that old-fashioned idea that your document is a physical file where you move this file from computer-to-computer as you need to work on it. Instead your document is ready when you need it. It doesn’t matter if you’re mid-edit on your iMac at home… if you pop out for a bit and carry on editing the document on your iPhone it’s just there for you, just as you left it on your iMac. The idea is that it’s ready whenever you are and this is a huge but subtle shift in today’s thinking.

So if you ask yourself what needs to change in modern day computing for your document to always be ready, what needs to happen? The answer is it needs to save itself whenever anything significant happens and that is where Lion’s Auto Save comes in! By saving whenever possible you’re also committing changes to the cloud and this enables your document to be easily editable by another device… lets say an iPhone.

Most apps on the iPhone have auto saved in some form or another because originally apps could get closed at any moment by the iPhone itself from an incoming call, a request to free memory, or a user pressing the home button. Starting with iOS5 there are now API methods for letting this all happen automatically. This is great because by using Apple’s classes and methods you also get iCloud support almost for free! There is a great overview of iCloud at the Apple Developer Center but as it’s still under NDA so you’ll need to log in.

I could write a small book talking about just some of the new technology but I’m going to reduce it down to just 5 key points I’ve set myself as a personal aim to focus on in my apps.

Key points to take note of:

1. iCloud is big. Start integrating now. Every app should support it, even if it’s just remembering a page number, a post code, etc. iMessage is a great example of iCloud support as messages sync between devices.
2. Twitter integration is smart, and saves all that OAuth panic and confusion. Integrate into apps whenever the user achieves something they might want to share. You might not use it but if your users do you’ve just advertised your app to all their followers.
3. Notifications have received a revamp with the Notification Center which make them incredibly useful. More apps need to take advantage of these, even if it’s just to badge number in-app news.  Many developers find the need for server setup an extra hassle but it’s worth it and the new Newsstand notifications mean magazine apps can now automatically download new issues in the background – complete with the latest covers ready for reading on your morning commute.
4. Now the iPhone and iPad is PC-free, apps should focus on supporting all functions not just consuming data but generating it as well like the new calendar app.
5. GameCenter – photos and turn-based multiplayer mean GameCenter takes one step closer to bringing gaming alive and adds another reason to bring users back into your app. The turn-based multiplayer looks like it has potential to be really addictive and should cater for busy lives by breaking game sessions out of an app… games can now last days if you want them to as you bounce moves back and forth between your friends.

So they are the 5 key points I’m going to be focusing on in my apps. Feel free to suggest others in the comments.

So today I picked up my WWDC attendee badge and hitched a ride on the small army of buses that Jeff LaMarche had arranged to go to Apple’s HQ in 1 Infinite Loop, Cupertino, CA. It’s such a historic place in tech history and I was there! Not only has it been the main home of Apple since Steve Jobs returned to Apple but also features on the front of the Google Map icon on every single iPhone, iPad and iPod Touch.

Me outside Apple HQ

I got my photo taken and chilled in the oddly named BJ’s bar opposite. I also visited the company store there and bought some Apple gear, I just need to work out how to fit the coffee mugs into my suitcase now! Just about to grab some food and chill in a bar with a number of other iPhone developers before getting an early night. Some people recommended getting up at 3am to get a good seat. Mmm, if only I hadn’t just tested out my new coffee mugs…

I was also learning some crazy assembly code at the time too so I was also making sense of putting bitwise operations to task. Rather than let this code languish on my hard drive, I thought I’d share…

The main nib file contains a matrix with the the button cells set to a check box style. The whole matrix has an action attached that calls the AppController’s calculatePermission: method. This method is quite simple and I’ve carefully commented it for you so please feel free to check it out. It loops around the matrix and bitwise OR up the checkbox values and then converts this into a C string. I decided to use a C string because the text version of the permissions can only be ASCII values and we might as well be as efficient as possible.

int i,octal = 0;
char *permission[8] = {"___", "__x", "_w_", "_wx", "r__", "r_x", "rw_", "rwx"};
char text[11] = "-";
 
// Loop through each row (user) - User, Group, All
for(i=0; i<3; i++) {
 
  // Loop through each column (permission bit) and OR up the results - r=4, w=2, x=1
  int c, row = 0;
  for(c = 0; c < 3; c++) {        
    /*
       We get our checkbox toggle bit and left shift to move it along a column.
       Next we do a bitwise OR which allows us to mask it. The result is 1 if the first bit
       is 1 OR the second bit is 1 OR both bits are set to 1. Else, the result is 0
 
       e.g. 0 << 0 = 00000000 = 0
            1 << 1 = 00000010 = 2
            1 << 2 = 00000100 = 4
     */
    bool isTicked = [[sender cellAtRow:i column: c] state];
    row |= (isTicked << c); 
  }
 
  // Concat this string row to the last. We want a big permissions char array :)
  strcat(text, permission[row]);
 
  row *= (int) pow(10, 2-i); // Shift row along into decimal 10's
  octal += row;
}

I’ve uploaded Permissions to GitHub in the hope that someone might find it useful when they’re learning Cocoa. If you do find it helpful please post a quick comment. Feedback is always appreciated.

WebGL was originally an experiment started by Vladimir Vukićević at Mozilla and has grown to the point where it’s now ready to take flight and is being added to browsers such as Firefox, Chrome and Safari. It’s a very rich JavaScript API with DOM support that’s based on OpenGL ES 2.0, the same API used by modern iPad and iPhones which is great because iPhone developers should feel right at home with shaders and framebuffer objects.

Currently WebGL has been added to Safari nightly builds but it hasn’t quite hit the main release yet so if you’d like to explore these demos you’ll need to fire up Google Chrome, alternatively check out the video on the tech side of the ROME site. I feel the most impressive demos of this technology show off lighting of a finely textured surface by way of normal mapping, in this case using a 3D bust and an implementation of the Marching Cubes algorithm to create metaballs.

Already, there are some interesting developments with this technology such as a web version of id Software’s Rage so it will be interesting to see what developers imagine in the coming months. That’s quite impressive for a scripting language that has it’s origins in DHTML!

It currently only works in Google Chrome 11 or Firefox 4 as it uses part of the WebGL HTML5 spec that Safari hasn’t implemented yet but is definitely worth playing around with. You can even compile C files!

Sure, the pages themselves can be version-controlled but much of the metadata about the pages such as which datasources are attached are stored in the database and previously this data was only really accessible by clicking on each page within Symphony individually. Now this is fine if you have just a couple of pages but on some of the sites I’ve worked on this involved 50 pages or more with almost as many sections…

My solution was to create a Symphony extension called Blueprint Metadata that pulled this metadata out of the database and export it as an XML file conveniently time-stamped containing the server hostname. This allows you to quickly ‘diff’ the changes between two servers and quickly see the differences so you can apply them manually. I wrote this extension quite a few years ago but still find myself using this even today and have decided to make it open source under a very flexible BSD license.

Feel free to grab the Blueprint Metadata extension on Github now.

The biggest feature this new version supports is Facebook integration. Yes thats right… you can now log in and pull a “friend’s” profile picture straight onto the dartboard ready to let off some steam. Mmm, now if only you could download and try it out for free… wait you can because I made it free for a short while!
Here’s the link for Pub Darts.

So what else is in this free update?
Well I’ll tell you. This is what some people have been begging me for…

• Ability to refresh dartboard
  (You can now remove the tiny dart holes)
• Dart sound effects
  (Satisfying thuds as a dart hits the board – woop!)
• Bug fixes related to using camera and albums
  (Needed fixing particularly for large images)

Just in case you can’t find it, to access Facebook navigate to…
Settings > Boss Image > Camera > Grab From Facebook

Let me know what you’d like to see in the next update. Either in the comments or an email. Of course, you could always leave a really positive review if you enjoy it

In a sample app I’ve created a food table that lists food in categories.

FetchedResultsController method grouping sections using a key-path:

- (NSFetchedResultsController *)fetchedResultsController {
	if (fetchedResultsController != nil) {
		return fetchedResultsController;
	}
 
	// Create and configure a fetch request with the food entity.
	NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
	NSEntityDescription *entity = [NSEntityDescription entityForName:@"RWFood" inManagedObjectContext:managedObjectContext];
	[fetchRequest setEntity:entity];
 
	// Create the sort descriptors array.
	NSSortDescriptor *nameDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
	NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:nameDescriptor, nil];
	[fetchRequest setSortDescriptors:sortDescriptors];
 
	// Create and initialize the fetch results controller.
	NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"category" cacheName:@"Food"];
	self.fetchedResultsController = aFetchedResultsController;
	fetchedResultsController.delegate = self;
 
	// Memory management.
	[aFetchedResultsController release];
	[fetchRequest release];
	[nameDescriptor release];
	[sortDescriptors release];
 
	return fetchedResultsController;
}

Save and quit the app a few times and you’ll see the objects seem to be in the wrong sections. If you look closer you’ll see that the objects are actually sorted in ascending name order. On looking at the code, it seems this is exactly what we asked the program to do! After some testing it also seems to show up more often if the table is a grouped one.

As per the docs, after you specify a key-path to group each section with you also need to make sure the first sort descriptor is sorting this key-path. Add a sort descriptor and everything will work as expected.

Revised fetchedResultsController method with missing sort descriptor:

- (NSFetchedResultsController *)fetchedResultsController {
 
	if (fetchedResultsController != nil) {
		return fetchedResultsController;
	}
 
	// Create and configure a fetch request with the plant entity.
	NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
	NSEntityDescription *entity = [NSEntityDescription entityForName:@"RWPlant" inManagedObjectContext:managedObjectContext];
	[fetchRequest setEntity:entity];
 
	// Create the sort descriptors array.
        NSSortDescriptor *typeDescriptor = [[NSSortDescriptor alloc] initWithKey:@"type" ascending:YES];
	NSSortDescriptor *nameDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
	NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:typeDescriptor, nameDescriptor, nil];
	[fetchRequest setSortDescriptors:sortDescriptors];
 
	// Create and initialize the fetch results controller.
	NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"type" cacheName:@"Plants"];
	self.fetchedResultsController = aFetchedResultsController;
	fetchedResultsController.delegate = self;
 
	// Memory management.
	[aFetchedResultsController release];
	[fetchRequest release];
        [categoryDescriptor release];
	[nameDescriptor release];
	[sortDescriptors release];
 
	return fetchedResultsController;
}

First, export your spreadsheet as a .csv file. Use Unicode UTF8 encoding if possible. Lets say I saved this file as StudentNames.csv in my Documents folder.

Next, create a new .php file and paste in the following code. I called mine student-exporter.php and placed it in my Documents folder also.

<?php
echo "(\n";
if (($handle = fopen("StudentNames.csv", "r")) !== FALSE) {
    while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
        echo "\t\"" . $data[0] . "\",\n";
    }
    fclose($handle);
}
echo ")\n";

Now open the Terminal app on your Mac and type the following into the console:

cd ~/Documents
php -f student-exporter.php > Students.plist

This should create a Students.plist file that will open in Xcode. However this is using the old NextSTEP text plist format which was deprecated when Mac OS X 10.0 came out. To convert into the more compact binary format, type the following into the console:

plutil -convert binary1 Students.plist

Lets say your file is called NinjaApp-1.0.ipa and you use SSH/SFTP on your server to copy everything…
1. Drop your file onto a spare Mac or server.
2. Type the following into a terminal window:

scp NinjaApp-1.0.ipa user@webserver.com:/var/www/downloads/.
&& echo "Upload done" | mail -s "Upload Complete" me@example.com

That’s it! You’ll get an email when it’s done.

• OpenType Format (OTF)
• TrueType Format (TTF)

Once you’ve dragged your chosen font file into an Xcode project, the next step is to add a line into the application’s Info.plist file. Add a new key UIAppFonts and make it an array. Expand the array and add a new string for each font, making the string the file’s full name including an extension.

You’re all set up now to use the font. That would be great if you knew which font it was! Here is a great little snippet for looping through all the fonts loaded into the system. Scan through the list and find your font.

// Get all the fonts on the system
NSArray *familyNames = [UIFont familyNames];
for( NSString *familyName in familyNames ){
	printf( "Family: %s \n", [familyName UTF8String] );
	NSArray *fontNames = [UIFont fontNamesForFamilyName:familyName];
	for( NSString *fontName in fontNames ){
		printf( "\tFont: %s \n", [fontName UTF8String] );
	}
}

To use your font now, just use the standard UIFont constructor…

self.titleLabel.font = [UIFont fontWithName:@"Inkpen Medium" size:31.0];

Some points to note: -

• You can also use the font inside UIWebViews.
• Interface Builder for XCode 3.2 has a bug that won’t let you choose the font. You have to do it in code.
• Loading in too many fonts will slow your loading time down and will hurt your users’ eyes.

The NSFetchedResultsController is the main power house when dealing with such a scenario and is great for the master part of a master/detail data relationship. It’s main purpose is to manage the results returned from a fetch request similar to the above and provide data for a UITableView via delegate methods. It reacts on the model level so if you delete an Event object, the NSFetchedResultsController informs it’s delegate and so updates the UITableView automatically. It’s very clever indeed!

As I found out earlier yesterday, the problem comes when you want to re-order the objects in a user-defined way. Instead of sorting on a timestamp, I wanted the user to be able to specify that one object should occur before the other… I’m working on an app that lets you place waypoints down on a map. Timestamps in waypoints aren’t much use. It’s much more critical that they have a specific order.

After some Googling I came across a useful article on CocoaIsMyGirlfriend. This helped me 90% of the way but I had problems when re-ordering. When you re-order the objects, the UITableView would move cells about seemingly at random. This is because NSFetchedResultsController is model-driven. When you re-order something using the tableview methods the view is already correct (because you’ve dragged and dropped the cell there - it’s a user-driven change) and so when the delegate detects your index changes, it walks all over your view believing the cells to be in their original position. The trick is to ‘disable’ the UI updates with a boolean in your delegate methods. Set the boolean just before your re-indexing and unset it afterwards.

For an example, see this stack overflow link on re-ordering.

Also have a look at what the Apple docs say on user-driven updates on the NSFetchedResultsController.

However due to work commitments it has had to sit on the back-burner but with the recent release of the iPhone 4, I couldn’t help but update Pub Darts with gorgeous high resolution artwork. I also managed to add in some instructions, make a new icon, fix a few bugs, allow games to save themselves when you quit and completely redo the shadows to be more ‘iPhone-like’. This free update can be grabbed immediately from your iPhone by updating in the App Store application.

More updates are coming soon. Feel free to suggest some features you’d like to see. If you’ve yet to experience Pub Darts on your iPhone, grab it for free now.

As a team, we spent considerable time making sure the rotating mechanism worked just right and making sure the app loads in less than half a second. I’m looking forward to starting on the next issue soon!

Buy it now for only £1.19 ($1.99). For a short time only it’s now completely free! Grab it now.

Xdebug also provides the following: -

• Stack traces and function traces in error messages with:
  • Full parameter display for user defined functions
  • Function name, file name and line indications
• Support for member functions
• Memory allocation
• Protection for infinite recursions
• Profiling information for PHP scripts
• Code coverage analysis
• Capabilities to debug your scripts interactively with a debug client

From the above you can see it’s a very powerful tool that every web developer should have installed on his or her machine and is in-fact included with quite a few commercial IDE programs. Surprisingly, Xdebug is actually open-source, so without further ado… I’ll show you how you can easily install it on your Apple Mac using pre-built binaries…

Equipment

This tutorial assumes you have the following already set up: -

• Apple Mac OS 10.4
• Apache (Using Apple’s version that came with OS X)
• PHP 5 Module (I use PHP 5 from www.entropy.ch)
• Some PHP files you can test and debug with

Instructions

Xdebug doesn’t provide any pre-built binaries for Mac OS X, which means we would have to download the source code and compile Xdebug ourselves. Luckily a commercial IDE called Komodo IDE (made by ActiveState who you might remember as the company that makes Perl for Windows), distributes Xdebug with their program and have kindly made their Xdebug binaries available for download. Navigate to the remote debugging page on their website and click on the PHP Remote Debugging option. Make sure you choose Mac OS X / x86 if you have an Intel Mac.
Once downloaded, extract the contents and click on the folder corresponding to your PHP version (I chose 5.2). You should see a single file called xdebug.so. This is our PHP extension… drag it into your user folder.

Now we need to copy the extension into our PHP extensions folder. Drop into the Terminal application and if you used the Entropy PHP 5 extension, you’ll find the PHP folder at /usr/local/php5. The extensions folder is in lib/php/extensions.

At the terminal type:

cd /usr/local/php5/lib/php/extensions

List the contents and you should see a folder called no-debug-non-zts-20060613 or similar, change directory into here. We’ll now move the xdebug.so file into this folder and rename it xdebug. Note: You’ll get prompted for your password since we’re editing system files.

ls
cd no-debug-non-zts-20060613
sudo mv ~/xdebug.so xdebug

Nearly there, we now need to create an .ini file to tell PHP to load in the extension. Change directory to /usr/local/php5/php.d and using vi or your favourite editor create a file called 80-extension-xdebug.ini. Note: You’ll get prompted for your password since we’re editing system files.

cd /usr/local/php5/php.d
sudo vi 80-extension-xdebug.ini

Copy and paste the following into the text file you’ve just created, adjusting the path to where your extensions directory is located.

[xdebug]
zend_extension="/usr/local/php5/lib/php/extensions/no-debug-non-zts-20060613/xdebug"

If you have TextMate, you can add the following line to the config file. This makes clickable error messages that load up the offending PHP file in TextMate and jump to the line containing the error. This is very handy indeed!

xdebug.file_link_format = "txmt://open?url=file://%f&line=%l"

Once your ready to save the config file, close vi by typing ‘:x’ followed by the return key. Restart Apache using your favourite method or simply reboot the whole machine.
Test your new Xdebug configuration by creating a PHP file, which obviously has an error in it such as calling a function that doesn’t exist. Test the PHP file and you should see a lovely coloured error message with a stack trace! You’re all ready to go!

Extras

If you’re interested in getting the most out of Xdebug, I recommend checking out some of the documentation on the Xdebug site. Of particular interest is using the profiler and the basics, which are always good to master.

It’s great but the PHP manual says this about additional headers: –

additional_headers (optional)

String to be inserted at the end of the email header.

This is typically used to add extra headers (From, Cc, and Bcc). Multiple extra headers should be separated with a CRLF (\r\n).

Yes, so according to the manual multiple headers should be separated with CRLF (\r\n). However, if you try this on a Linux web server (sample code provided below) you will probably get some of your headers stuck in the body of the email! There is a quick and easy solution though…

// Recipient
$to = 'dave@test.com';
 
// Subject of email
$subject = 'Message from Eddie';
 
// Message body
$message = 'Hi there, this is Eddie, and I\'m feeling just
great, guys, and I know I\'m just going to get a bundle of kicks out of any
programme you care to run through me';
 
// Additional headers
$headers = 'To: dave@test.com' . "\r\n";
$headers .= 'From: eddie@theheartofgold.com' . "\r\n";
 
// Mail it
if(mail($to, $subject, $message, $headers)) {
echo 'Email sent';
} else {
	echo 'Email not sent';
}

Apparently on Linux web servers, it’s best to use LF (\n) line endings for separating headers instead. This can be done two ways. The first way is to alter the server’s sendmail path in PHP.ini file to first push the email through dos2unix (which converts the line endings automatically) and then pipe it to send mail.

sendmail_path = "/usr/bin/dos2unix | /usr/sbin/sendmail -t -i"

The other option is to alter your PHP code so that instead of appending the line endings on as strings use the PHP_EOL constant which was introduced in PHP 5.0.2. Echoing PHP_EOL on a Windows server will result in “\r\n” whilst echoing the constant on a Linux server will result in “\n”… which in my opinion is a more elegant solution.

The particular secret I would like to share involves establishing connections to secure sites (SSL-enabled ones in particular). When you browse to an SSL–enabled site in your web browser, a few things happen… One of the things that happen is that your browser checks to see if the site’s security certificate is trusted. It does this by checking the entity that signed the certificate against it’s built in book of trusted signatures and if it finds a match, onto the next step. However, if your browser can’t find a match the certificate will be invalid and it will complain that the site could potentially be a fake or insecure.

The ‘book of trusted signatures’ is known as a Certificate Authority bundle and usually comes built in with most web browsers. If you install cURL (the standalone version that can be run from the command–line), chances are it will come with the cURL Certificate Authority bundle and you won’t need to do a thing as the cURL functions within PHP will use this as it’s book of trusted signatures. However, on Windows the cURL functions within PHP are pre–built and included in the standard PHP setup, thus do not include this bundle. Chances are if you don’t know this you’ll probably spend a good amount of your time screaming at your webpage as it mocks you with error number 60! I know I spent quite a good few hours wondering why it worked on my Linux PC but not on the Windows server!

CURL Error 60: SSL certificate problem, verify that the CA cert is OK.
Details: error:14090086:SSL routines
SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

Luckily the fix is quite easy…

1. Download standalone cURL for Windows (make sure it is the SSL version).
   Download the .pem file from the cURL site and rename the extension to .crt
2. Extract curl-ca-bundle.crt from the download and copy to your web server folder.
3. Add the following line to your code: -

   curl_setopt($ch, CURLOPT_CAINFO, "c:/path/to/ca-bundle.crt");

4. Remember to change $ch to the variable you’ve assigned your curl connection to and “c:/path/to/ca-bundle.crt” to the location of where you have copied the ca-bundle.crt.
5. Check the server has permission to read this file.

If you are getting started with cURL, here is some sample code I’ve written that should get you started. It outputs the contents of the secure server to a string, which is echoed out to your page.

// Set up cURL connection
$url = 'https://www.verisign.com/';
$ca = 'c:/path/to/ca-bundle.crt';
$ch = curl_init();
 
// Apply various settings
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, 0); // Don’t return the header, just the html
curl_setopt($ch, CURLOPT_CAINFO, $ca); // Set the location of the CA-bundle
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // Return contents as a string
 
$result = curl_exec ($ch);
curl_close($ch);
echo $result;

That’s it! You should now be able to connect successfully to SSL-enabled websites using the cURL functions of PHP on your Windows server.

UPDATE 2010/08/20: Apparently the certificates aren’t shipped with the archived versions any more. To get the latest certificate bundle that’s been extracted from the Mozilla browser you can download the .pem file from the cURL site and rename the extension to .crt.

The algorithm is particularly useful for checking to see if the card number ‘looks’ right before sending it off to the payment provider for processing. This reduces the amount of rejected card payments, which is always a good thing.

More details of how the algorithm works can be found on Wikipedia and my annotated PHP implementation can be found below.

/* PHP function for validating card numbers */
function checkLuhn($cardNumber) {
    // Copyright (c) Richard Warrender. Licenced under the LGPL.
    // http://richardwarrender.com/
 
    // Get total amount of digits to process
    $digitCount = strlen((String) $cardNumber);
    // Checksum must be zero to begin with
    $checksum = 0;
 
    // Loop round card number extracting digits
    for($i = 1; $i<=$digitCount; $i++) {
            // Extract digit number
            $digits[$i] = (int) substr($cardNumber, -$i, 1);
 
            // Check to see if this the luhn number, we need to double it
            if(($i%2) == 0) {
                    // Double luhn digit
                    $digit = $digits[$i] * 2;
 
                    // If greater or equal to 10, then use sum of digits
                    if($digit >= 10) {
                            // Get first digit
                            $firstDigit = substr($digit, 0, 1);
                            // Get second digit
                            $secondDigit = substr($digit, 1, 1);
                            /// Add together and replace original luhn digit
                            $digit = $firstDigit + $secondDigit;
                    }
 
                    // Reload back into array
                    $digits[$i] = $digit;
            }
            // Keep a running total for use in checksum
            $checksum += $digits[$i];
    }
 
    if(($checksum % 10) == 0) {
            return true;
    } else {
            return false;
    }
}