PHP

The PHP script should be placed on your web server. If you have a dedicated host (or virtual host) for this task, you can name it index.php and make it the directory index. Also, if you're paranoid, you can move the more sensitive definitions to an include file located outside the web directory. And, if you're doubly paranoid, you can chose to not display the SQL error messages when something fails by modifying the error handling parts of the code.

<?php

error_reporting(0); # 0 for production

$host = 'localhost';
$user = 'islandjohn';
$password = 'changethis';
$db = 'islandjohn';
$header = 'X-IslandJohn-Status';

$ip = $_SERVER['REMOTE_ADDR'];
$udid = stripslashes($_GET['udid']);
$bid = stripslashes($_GET['bid']);
$version = stripslashes($_GET['version']);

if (!$ip || !$udid || !$bid || !$version) {
    header($header.' Missing parameters');
    exit();
}

$d = mysql_connect($host, $user, $password);
if (!$d) {
    header($header.': Could not connect: '.mysql_error());
    exit();
}

if (!mysql_select_db($db)) {
    header($header.': Could not select database: '.mysql_error());
    mysql_close($d);
    exit();
}

$q = sprintf('INSERT INTO `analytics` (`ip`,`udid`,`bid`,`version`) VALUES("%s","%s","%s","%s") ON DUPLICATE KEY UPDATE `timestamp`=CURRENT_TIMESTAMP(),`updates`=`updates`+1,`ip`=VALUES(`ip`)', mysql_real_escape_string($ip), mysql_real_escape_string($udid), mysql_real_escape_string($bid), mysql_real_escape_string($version));

if (!mysql_query($q)) {
    header($header.': Could not update table: '.mysql_error());
    mysql_close($d);
    exit();
}

mysql_close($d);

header($header.': OK');

?>

SQL

The SQL statements below will create database and table to store the submitted data. It's setup to collect simple information only, but can be easily extended. User access setup is left as an exercise for the reader.

CREATE DATABASE `islandjohn`;
CREATE TABLE `analytics` (
  `timestamp` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
  `updates` int(11) NOT NULL default '0',
  `ip` varchar(64) NOT NULL,
  `udid` varchar(64) NOT NULL,
  `bid` varchar(64) NOT NULL,
  `version` varchar(64) NOT NULL,
  UNIQUE KEY `idx_ubv` (`udid`,`bid`,`version`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

Objective-C

The code below is used to start the HTTP connection to submit the data, and record success. My goal was to collect information only one time any given version of my application is launched, so I record a successful submission and won't submit again unless there's a version mismatch. If you want to keep track of all launches, you can modify the code accordingly.

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    if (![response isKindOfClass:[NSHTTPURLResponse class]]) {
        return;
    }

    NSHTTPURLResponse *http = (NSHTTPURLResponse *)response;
    NSMutableDictionary *headers = [NSMutableDictionary dictionaryWithDictionary:[http allHeaderFields]];
    for (NSString *key in [headers allKeys]) {
        [headers setObject:[headers objectForKey:key] forKey:[key lowercaseString]];
    }
    NSString *status = [headers objectForKey:@"x-islandjohn-status"];

    if ([status isEqualToString:@"OK"]) {
        [[NSUserDefaults standardUserDefaults] setObject:[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]
                                                  forKey:@"IJAnalyticsSubmittedVersion"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
}

- (void) submitAnalytics {
    if ([[[NSUserDefaults standardUserDefaults] objectForKey:@"IJAnalyticsSubmittedVersion"]
         isEqualToString:[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]]) {
        return;
    }

    NSString * udid = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                          (CFStringRef)[[UIDevice currentDevice] uniqueIdentifier],
                                                                          NULL,
                                                                          (CFStringRef)@" !*'();:@&=+$,/?%#[]",
                                                                          kCFStringEncodingUTF8);
    NSString * bid = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                         (CFStringRef)[[NSBundle mainBundle] bundleIdentifier],
                                                                         NULL,
                                                                         (CFStringRef)@" !*'();:@&=+$,/?%#[]",
                                                                         kCFStringEncodingUTF8);
    NSString * version = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                             (CFStringRef)[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"],
                                                                             NULL,
                                                                             (CFStringRef)@" !*'();:@&=+$,/?%#[]",
                                                                             kCFStringEncodingUTF8);        

    NSString *url = [NSString stringWithFormat:
                     @"http://analytics.domain.com/?udid=%@&bid=%@&version=%@",
                     udid,
                     bid,
                     version];
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
    NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
}

- (void) applicationDidFinishLaunching:(UIApplication*)application {
    @try {
        [self submitAnalytics];
    }
    @catch (NSException *e) {
    }
    @finally {
    }

    // Your code continues here...
}

The code, music and sound effects were arranged/created/written by me. Most of the art however, with the exception of some graphic design and sprites, was subcontracted out. The project overall is smaller than Word Quest, about half the amount of source code, but took substantially longer to complete, with about the same number of total hours, because of the many tedious tasks involved. It should be available soon for both iPad and iPhone.

]]> http://www.islandjohn.com/2010/10/23/bee-patrol-an-action-puzzle-and-strategy-game-combination/feed/ 0 http://www.islandjohn.com/2010/02/09/word-quest-iphone-application-my-introduction-to-apple-development/ http://www.islandjohn.com/2010/02/09/word-quest-iphone-application-my-introduction-to-apple-development/#comments Tue, 09 Feb 2010 04:00:46 +0000 janos http://www.islandjohn.com/wp/?p=22 Exactly one month ago I decided to dive into Apple's Xcode, Objective-C and their, what I now think are, lovely APIs. I thought about this adventure before, but I just never pushed myself. It was apparently a very bored evening, so what else was I going to do. I must say Objective-C seemed strange at first, but once I went through it all, wrote a few lines of code, it seemed almost elegant. It's an extension of C, and if you think about it, you could almost implement a parser for Objective-C that would generate plain C code to do all the magic. It's a pretty abstraction layer with a mandatory runtime environment. I like it. After a few hours of playing with Xcode, it became apparent that I should just dive right in.

I decided on a somewhat simple word search game, but with some added twists. I thought the algorithm to place the words so that you generate well-rounded puzzles was interesting, so it gave me a chance to come up with some quirky logic, and I'd have a chance to dive into their Core Graphics and Core Animation graphics APIs. It was fun. It was actually the most fun I had developing since back in high-school when I was writing demos in assembler and C. Apple's documentation and guides were excellent on most everything (I used nothing but those), and I've had no issues with the iPhone Developer Program so far. Along the way I explored Garage Band for some of the sound, used iWeb for the site, and played with Gimp for the grahpics. So, exactly one month later, with a dozen or so really late nights invested, the game is done, submitted to the App Store, and "In Review".

I thought it was time to reboot a device that, for all intents and purposes, should not have anything to do with this problem. A few minutes passed as the unit went through its cycle, and without as much as laying a finger on the MacBook, queued test jobs began streaming from the printer.

cd /Library/Desktop\ Pictures/Solid\ Colors; for r in 00 33 66 99 cc ff; do for g in 00 33 66 99 cc ff; do for b in 00 33 66 99 cc ff; do echo Creating image for color $r$g$b; convert -background "#$r$g$b" -page 256x256 text:- "Background $r$g$b.jpg" < /dev/null; done; done; done

Alternatively, since the preference pane displays the images in a five column layout, you can use the script below to create images that will be more aesthetically pleasing during selection, as they'll line up nicely according to shades:

cd /Library/Desktop\ Pictures/Solid\ Colors; for r in 00 40 80 c0 ff; do for g in 00 40 80 c0 ff; do for b in 00 40 80 c0 ff; do echo Creating image for color $r$g$b; convert -background "#$r$g$b" -page 256x256 text:- "Background $r$g$b.jpg" < /dev/null; done; done; done

#!/bin/bash

# args: [lockfile=$0.lock] [lockwait=0]
# ret: 0 on success, 1 on failure, -1 on unknown
function lockcreate() {
    lockfile="$1"
    lockwait="$2"

    if [ -z "$lockfile" ]; then
        lockfile="$0.lock"
    fi

    if [ -z "$lockwait" ]; then
        lockwait=0
    fi

    lockerr=-1
    lockcount=0

    echo "$$" > "$lockfile.$$"

    while [ "$lockwait" -lt 0 -o "$lockcount" -le "$lockwait" ]; do
        ln -hs "$lockfile.$$" "$lockfile"

        # the lock exists
        if [ "$?" -gt 0 ]; then
            lockpid="`cat \"$lockfile\"`"

            # the lock PID is empty (race condition?), cleanup and retry
            if [ -z "$lockpid" ]; then
                rm "$lockfile"
                continue
            else
                # the lock PID is this PID (previous same PID died), success
                if [ "$$" -eq "$lockpid" ]; then
                    $lockerr=0
                    break
                fi

                ps -p "$lockpid"

                # the lock PID is not running, cleanup and retry
                if [ "$?" -gt 0 ]; then
                    rm "$lockfile"
                    continue
                # the lock PID is running, fail or wait
                else
                    if [ "$lockwait" -eq 0 ]; then
                        rm "$lockfile.$$"
                        lockerr=1
                        break
                    fi
                fi
            fi
        # the lock was created, success
        else
            lockerr=0
            break
        fi

        # wait and retry
        sleep 1
        lockcount="`expr \"$lockcount\" + 1`"
    done

    return $lockerr
}

# args: [lockfile]
function lockremove() {
    lockfile="$1"

    if [ -z "$lockfile" ]; then
        lockfile="$0.lock"
    fi

    lockpid="`cat \"$lockfile\"`"

    if [ -z "$lockpid" ]; then
        true
    else
        if [ "$$" -eq "$lockpid" ]; then
            rm "$lockfile"
        fi
    fi

    # clean up any temporary would-be lock
    if [ -e "$lockfile.$$" ]; then
        rm "$lockfile.$$"
    fi
}

The following example creates a synchronized block that will execute exclusively. All other copies of the script will wait indefinitely for the currently executing copy to finish before executing their own block. The order in which waiting processes execute is not predictable, that is, there is no wait queue.

lockcreate /tmp/example.lock -1
echo Running...
sleep 60
echo Done.
lockremove /tmp/example.lock

The example below attempts to execute a block. If another copy of the script is already executing the synchronized block, the current script will exit.

lockcreate /tmp/example.lock
if [ $? -eq 0 ]; then
    echo Running...
    sleep 60
    echo Done.
else
    echo Another copy of this script is already running, or an error occured.
fi
lockremove /tmp/example.lock

Neither of the locking functions are quiet. If the underlying operating system commands display any output, they will show up in the script calling the functions. In order to provide a clean and quiet run, the functions' output must be redirected (something like lockcreate >/dev/null 2>&1 works nicely).

!/bin/sh

SERVER="ns.example.net"
ZONE="example.net"
HOST="home.example.net"
KEYNAME="key-name"
KEYSECRET="key-secret"

ROUTER="airport_extreme"
COMMUNITY="string"

OLDIP=`dig @"$SERVER" "$HOST" A +short`
NEWIP=`snmpwalk -c "$COMMUNITY" "$ROUTER" ipAdEntAddr | awk '{print $NF}' | egrep -v "^127\\.0\\.0\\." | egrep -v "^169\\.254\\." | egrep -v "^10\\." | egrep -v "^172\\.1[6-9]\\.|^172\\.2[0-9]\\.|^172\\.3[0-1]\\." | egrep -v "^192\\.168\\."`

if [ -z "$NEWIP" ]; then
        echo The commands did not return an IP address.
        exit 1
fi

if [ "$OLDIP" != "$NEWIP" ]; then
        echo Old IP address: "$OLDIP"
        echo New IP address: "$NEWIP"
        (
                echo server "$SERVER"
                echo zone "$ZONE"
                echo update delete "$HOST" A
                echo update add "$HOST" 3600 A "$NEWIP"
                echo key "$KEYNAME" "$KEYSECRET"
                echo send
        ) |\
        nsupdate -d
fi

Using regular expressions, the SNMP query commands simply egrep out all the interface addresses that could not possibly be externally facing, then the script uses nsupdate to send the information to the DNS server. I run this from a cron job every hour, and whenever there's a change of IP address, output is e-mailed to me. Although I haven't tested it, I believe the Airport Express also has SNMP capabilities and this script/setup should work just as well with that device as with the Airport Extreme.

export CCFLAGS='-arch ppc -arch ppc64 -arch i386 -arch x86_64 -g -Os -pipe'
export CFLAGS='-arch ppc -arch ppc64 -arch i386 -arch x86_64 -g -Os -pipe -no-cppprecomp'
export CXXFLAGS='-arch ppc -arch ppc64 -arch i386 -arch x86_64 -g -Os -pipe'
export LDFLAGS='-arch ppc -arch ppc64 -arch i386 -arch x86_64 -bind_at_load'
export MACOSX_DEPLOYMENT_TARGET=10.5

If the configuration and compilation all went well, the libraries should now be in /usr/local/lib, and we can configure the ODBC driver. Launch ODBC Administrator (located in /Applications/Utilities) then select the Drivers tab and click Add. You can enter whatever you like for the description, something like SQLite ODBC Driver, then choose or enter /usr/local/lib/libsqlite3odbc.dylib for both the Driver file and Setup file. Click Ok to complete the driver configuration.

We now need to configure a database source, and for this I'll assume you already have an SQLite database file named /tmp/test.db. Select the User DSN tab, click Add and select the SQLite ODBC Driver that we just created. Then, enter whatever you like for the Data Source Name (DSN), maybe Test, and anything you want for the Description. To provide the name of the database file we need to add a field with the keyword Database and the value of /tmp/test.db. Clicking Add will provide you with a dummy Key and Value entry that you can then modify by clicking on the each cell individually. Modify Key to Database and Value to the path of the database file, in this example /tmp/test.db. Save the changes by clicking Ok and then Apply.

These steps created the driver and the source for the current user. To create this setup as a system-wide configuration, unlock the ODBC Administrator before you start the configuration. Then, when creating the driver, select System for the Define as option, and create the source under the System DSN tab. The configuration will be created in /Library/ODBC instead of your user directory.

To test the results, open an SQL client that supports ODBC, and you should see Test as an available data source. OpenOffice Database will let you view the data, but not modify it, but for testing purposes this should be convincing enough.

After some head scratching, I was able to reproduce the problem by restarting Finder. Every time Finder started, I would get a warning within a few seconds; at least this was a consistent behavior. So what now? How do I see what is happening? While Activity Monitor is a good application to use for quick process snapshots, it doesn't provide enough debugging capability to see what a process may have done in the past, but dtrace does.

Running "dtrace" on Finder, displaying every system call entry, showed that prior to launching smbclient another process is invoked: nmblookup. This is a good clue. If you read the man page and look at the command's options, this behavior should start to make sense. I ran "nmblookup -M -- -" and it returned none other than the questionable IP address; mystery solved: Finder appears to launch nmblookup to search for master browsers as part of normal discovery, and if it finds one, it tries to connect to it.