Undolog Research & Development Blog
/ October 3, 2011 / Leave a comment

How to redirect the WordPress log to a file

Edit your wp-config.php file, located in WordPress root folder, and add or replace define('WP_DEBUG', true);

In this way, WordPress will print the logs on the screen. This may be very annoying, so you would like to redirect all logs in a file.

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true );
define('WP_DEBUG_DISPLAY', false );
ini_set('display_errors', 0 );

// By default, WordPress write the logs in /wp-content/log/debug.log
// comment out the line below to change path and log filename
//ini_set( 'error_log', '/path/site.com/wp-content/logs/debug.log' );

As usual, please don’t hesitate to leave any questions or comments in the feed below, and I’ll aim to respond to each of them.

Very Short Snippet, WordPress
/ September 30, 2011 / Leave a comment

MySQL: random select in a pagination context

MySQL provides a very simple method to select rows in random order. It uses the ORDER BY RAND()statement. If you will be used theORDER BY RAND() statement, MySQL will create a temporary table with all results, then will be assigned a random index to each row and finally will return the random rows! This makes the ORDER BY RAND() quite slow. In fact, some developer prefers alternative techniques, such as PHP random functions or special SQL select.

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MySQL/SQL, PHP
/ September 29, 2011 / Leave a comment

Very short trick: maintenance mode via IP

When you would like to show a page only for a specified user or you wish to create a maintenance page, you may use this simple script:

// List of allowed IP addresses
$allowIP = array("87.6.45.33", "234.34.34.2"); // etc...

// Access denied
if( !in_array($_SERVER['REMOTE_ADDR'], $allowIP ) {
  // include maintenance mode
  die();
}

// Access grant and display the rest of view
PHP, Very Short Trick
/ June 2, 2011 / Leave a comment

Xcode4: backward compatibility code

With Xcode 4 you can develop applications for iPad and iPhone. Also, you can choose a different iOS target. Currently, the last release of iOS is 4.3 and when you will create a new project you will see:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  // Override point for customization after application launch.
  self.window.rootViewController = self.viewController;
  [self.window makeKeyAndVisible];
  return YES;
}

Now, the rootViewController property has been added with iOS 4. This means that when we going to test the application in iOS 3.2 environment we will get a CRASH! Instead of check the iOS version, we can use a feature of Obejctve-C in order to check if a property exists:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  // Override point for customization after application launch.
  if ([self.window respondsToSelector:@selector(setRootViewController:)]) {
    self.window.rootViewController = self.viewController;
  } else {
    [self.window addSubview:self.viewController.view];
  }

  [self.window makeKeyAndVisible];
  return YES;
}

As usual, please don’t hesitate to leave any questions or comments in the feed below, and I’ll aim to respond to each of them.

Objective-C
/ March 29, 2011 / Leave a comment

How to remove the admin bar in WordPress

The last version of WordPress provides a new toolbar in frontend view when you are logged in. To disable this feature you can add the following code in the functions.php file in your active theme:

// Before check if the filter show_admin_bar exists
if( has_filter('show_admin_bar') ) {
  add_filter( 'show_admin_bar', '__return_false' );
}
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WordPress
/ March 1, 2011 / Leave a comment

Best practices for NSFileManager

Apple suggests using an instance of NSFileManager class and avoid the static class method defaultManagerbecause it will return a singleton instance: no thread-safe:

In Mac OS X v.10.5 and later you should consider using [[NSFileManager alloc] init] rather than the singleton method defaultManager. Using [[NSFileManager alloc] init] instead, the resulting NSFileManager instance is thread safe.

For example:

// bad
BOOL result = [[NSFileManager defaultManager] fileExistsAtPath:pathLocalRepository isDirectory:nil];

// good
NSFileManager *fm = [[NSFileManager alloc] init];
BOOL result = [fm fileExistsAtPath:pathLocalRepository isDirectory:nil];
[fm release];
fm = nil;
Objective-C, Very Short Trick
/ January 21, 2011 / Leave a comment

How to use the UIView to show an image

If you  would like to avoid to set the background image of the main view controller through Interface Builder, you can use a different way and delete the UIImageview object from Interface Builder:

- (void)viewWillAppear:(BOOL)animated 
{
  [super viewWillAppear:animated];
  self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"backgroundImage.jpg"]];
}

You may use viewDidLoad as well but viewWillAppear avoid some flickering. With Xcode 3.2.5 is not possible to use the pattern yet.

Objective-C
/ November 25, 2010 / Leave a comment

jQuery snippets

How to check if an element DOM exists

Be careful when you wish if an element DOM exists. If you use:

if ( $("#my-id") ){
  // exists?
}

This method doesn’t work because jQuery will return an [Object object] even if the element doesn’t exist. We may use a couple of methods to be sure that an element exists:

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jQuery, Very Short Snippet
/ November 11, 2010 / Leave a comment

How to get a private post/page content

You remember the post How to get a page/post content, don’t you? Then, we may get the page/post content by:

function getPageBySlug( $slug ) 
{
  $objectPost = get_page_by_path($slug);
  return apply_filters("the_content",$objectPost->post_content);
}
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PHP, WordPress
,
/ September 17, 2010 / Leave a comment

How to customize the WordPress featured image Meta Box

We have to use a little trick! In other words, we will remove the meta box and then we will add a new one again:

function customposttype_image_box() 
{
  // remove
  remove_meta_box( 'postimagediv', 'post', 'side' );

  // add
  add_meta_box('postimagediv', 'Here we here', 'post_thumbnail_meta_box', 'post', 'side', 'low');
  }
add_action('do_meta_boxes', 'customposttype_image_box');
PHP, Very Short Trick, WordPress
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