Jun 29 2009

WordPress Shortcode To Generate A TinyURL For Any Post

TinyURLs can be very useful when you have a long url to type into something like an iphone or some other mobile device where the keyboard is rather tedious. On a few of my sites I was looking for a way to automatically generate a tinyURL with the least amount of effort. Since I use wordpress for most of them I decided to go with a shortcode.

Shortcodes seem to be gaining a fair amount of attention in the wordpress community and with good reason. The Shortcode API, which was new in wordpress 2.5, is a simple set of functions for creating macro codes for use in your posts. Shortcodes are written by providing a handler function and they accept parameters too. Here is a wordpress shortcode to generate a tinyURL for a post.

//Generate Tiny URLS For A Post 
function get_tiny_url($arguments)
    $url = get_permalink($post->ID);
    $url = urlencode($arguments['url']);
      $tiny_url = 'http://tinyurl.com/api-create.php?url='.$url;
      $new_url = file_get_contents($tiny_url);
      $new_url = "Error";
    return $new_url;

add_shortcode('small_url', 'get_tiny_url');

If the url parameter is not defined then the function will attempt to use the wordpress function get_permalink($post->ID) which will return the current posts url. Also you can pass in a parameter if you want to show a tinyURL to another location. Using curl instead of file_get_contents would probably be faster but I didn’t want to make the example to long. The add_shortcode function is what tells the API to use the get_tiny_url function when it encounters the small_url shortcode. Note that this will call on the tinyurl api every page view so it would probably be prudent to set the tiny urls in the database so you only have to check once on a production site although I’m not sure if they expire or not.
This shortcode can be called in the post by typing :

[small_url]  // or
[small_url url='http://codytaylor.org']


Jun 26 2009

Make Your PHP Faster

I was reading about some php performance tips at work today and decided to throw together some of the ways to make your php site faster.

Here’s a couple of short tips to avoid making your site lag for the user:

  1. Unset your variables. This frees up a surprising amount of memory
  2. Use memcache
  3. Turn on apache’s mod_deflate
  4. If your database is local then close your connections when you’re done with them
  5. If your database is remote then use persistant connections
  6. Don’t use functions inside of a for loop control expression unless absolutely necessary. Example :

    The some_big_calculation function will be called every iteration.
  7. Use string concatenation instead of embedding variables in strings.
    $some_string = "asdf $asdf2 asdf"; //bad
    $some_string = 'asdf '.$asdf2.' asdf'; //good
  8. When including files, use at least a relative path so PHP doesn’t have to look in the entire path.
    include("./some_file.php"); // looks in the current directory
    include("wrong.php"); // searches every directory in the path
  9. Try not to use include_once or require_once. They are more expensive and it really isn’t that hard to only include files once
  10. Not everything needs to be an object. There is a fair amount of overhead when doing everything OOP.
  11. Use output buffering to make everything seem faster.

Hopefully I didn’t miss any of the big ones.


Jun 17 2009

Generate A Tiny URL On The Fly With PHP

Uniform resource locators (URL) are starting to get very long and I’m getting sick of typing ridiculously long strings into safari on my iphone. I don’t really care about the extra bandwidth, It’s just annoying when you’re on the phone telling someone to go check out a 67 character long url and they mistype it three times.

I’ve just started using the tiny url service and so far it’s been useful. On one of my sites I wanted to generate a tiny url for each of my pages to make them quicker to type in and also so people don’t know what get variables I’ve set until they get there. Here is the PHP function that I used to generate a tiny url for every page on the site.

There doesn’t seem to be any documentation at all on the Tiny URL website about this so I’m not sure if it’ll change in the future.
This function passes your desired url to the api-create.php script on the tinyurl domain which returns a nice short url that isn’t a pain to put into your iphone.

function get_tiny_url($url)
  $new_url = file_get_contents('http://tinyurl.com/api-create.php?url='.$url);
  return $new_url;

$tiny_url = get_tiny_url("http://codytaylor.org");

Not much to it but it made my life easier.


Jun 14 2009

Detect Bots By Parsing The User Agent With PHP

Because I’ve been starting to keep a closer eye on my traffic I’ve been logging everything to my databases. When writing reports for this information I noticed that there was huge amounts of traffic from bots. Yahoo, Google, MSN and many others have been hammering my sites quite a lot lately. Since I’m writing my reports in PHP I needed a quick little function to identify whether the visitor was real traffic or some machine scraping my site. I couldn’t find one after a few quick Google queries but the solution was trivial so I wrote my own. Hopefully this will save someone a few minutes. The function is as simple as possible and it seems to be working so far. I’ve been watching it for awhile and it hasn’t missed any yet. I’m assuming that it’s not going to catch everything but it would be nice to get most. Any bot user agent string suggestions would be helpful.

//returns 1 if the user agent is a bot
function is_bot($user_agent)
  //if no user agent is supplied then assume it's a bot
  if($user_agent == "")
    return 1;

  //array of bot strings to check for
  $bot_strings = Array(  "google",     "bot",
            "yahoo",     "spider",
            "archiver",   "curl",
            "python",     "nambu",
            "twitt",     "perl",
            "sphere",     "PEAR",
            "java",     "wordpress",
            "radian",     "crawl",
            "yandex",     "eventbox",
            "monitor",   "mechanize",
  foreach($bot_strings as $bot)
    if(strpos($user_agent,$bot) !== false)
    { return 1; }
  return 0;


Jun 9 2009

Adding Sack Ajax To Your WordPress Plugin’s Admin Page

Using my previous wordpress example plugin I’m going to demonstrate how to use ajax within the admin panel. WordPress uses the Simple AJAX Code-Kit (SACK) which is relatively easy to use and understand.

For this example I’m going to expand on my previous example and add a simple javascript function that queries some data from the server. WordPress forces us to do this in a roundabout way. First we have to add two new function hooks. One prints my javascript function in the scripts section of the admin panel and the other is the code that gets called by the ajax sack request.

//add my custom ajax function to the scripts section in the admin panel
add_action('admin_print_scripts', 'ajax_request');

//add data returning ajax refresh table function
add_action('wp_ajax_do_something', 'get_random_number');

The ajax_request function is a shell function for the javascript ajax call get_random_number_from_server which is our sack ajax request. Note that we are calling the admin-ajax.php script. This script will handle the calling of the get_random_number function for us because of the action defined above.

//This function will print out in the header section. 
//Put all your javascript in this function.
function ajax_request()
        //print out the sack ajax library
        wp_print_scripts( array( 'sack' ));  
  <script type="text/javascript">
  function get_random_number_from_server()
    //creates the sack object and 
                //gives it the url that it should request to.
    var mysack = new sack( '<?php 
                bloginfo( "wpurl" ); ?>/wp-admin/admin-ajax.php' );    
    mysack.execute = 1;   //execute whatever is returned
    mysack.method = 'POST';
    //Set POST fields
    mysack.setVar( "action", "do_something" );
    mysack.encVar( "cookie", document.cookie, false );
    mysack.onError = function() { alert('Ajax Error')};
    mysack.runAJAX();  //run the result

    return true;

  } // end of JavaScript function myplugin_ajax_elevation

This is the php function that is called by the javascript function above. It spits out a alert javascript function and then dies. Not sure why but it is recommended to die in this function.

//This is the server side code for the ajax sack request
function get_random_number()
  $minimum_number = 0;
  $maximum_number = 100;

This code can now be run like the following in your plugins admin page.

<input type='button' value='Get Random Number' 

When the button is hit a popup with a random number in it will pop up. Here’s a link to the entire example plugin code.


Jun 6 2009

Get Site Visitor Information With PHP

I wanted to do a few custom things with one of my site’s stats. PHP made this nice and simple with the $_SERVER array. When someone visits one of your scripts the $_SERVER array is automatically filled so as long as you know the keys then you can get all the information needed. These are the most useful items for identifying a visitor that I found in this using this array.

$_SERVER[‘REMOTE_ADDR’] gives you their ip address.
$_SERVER[‘HTTP_USER_AGENT’] is their user-agent (What browser they are using).
$_SERVER[‘HTTP_REFERER’] is where they came from.
$_SERVER[‘REQUEST_URI’] is the page they want to view.

This data is kinda useless unless you put it in a database so here’s a create table mySQL statement.

$sql = "CREATE TABLE visitors (
      `visitor_id` mediumint(11) NOT NULL AUTO_INCREMENT,
      `ip_address` VARCHAR(16)  NOT NULL,
      `user_agent` varchar(100) NOT NULL default '',
      `referrer` varchar(256) NOT NULL default '',
      `target_url` VARCHAR(256) NOT NULL,
      PRIMARY KEY  (`visitor_id`)      

If you’d like to explore the $_SERVER array more there is very detailed info at the php web site.


Jun 4 2009

Make Web Sites Think that PHP CURL is a Browser.

I’ve been doing a bit of site scraping using curl and PHP lately. I’ve found that most sites will ban your ip if they think you’re a bot (good thing I’m on DSL) so you need to make them think that your script is a browser. The easiest way to do this is to add a user agent header to your script. Here is an example of getting a results page from google for a specific search query.

function get_google_result($search_term)
  $ch = curl_init();
  $url = 'http://www.google.ca/search?hl=en&safe=off&q='
  $useragent="Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:".
                            " Gecko/20061204 Firefox/";
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_HEADER, 1);
  curl_setopt($ch, CURLOPT_USERAGENT, $useragent);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $google_string = curl_exec($ch);
  $google_string = utf8_encode($google_string);
  return $google_string;

So this function will take the search term that was provided and request the results from google for it. Our user agent header makes the script look like firefox.
I put the returned string (The entire google results page) into the google_string variable and return it for parsing out what is needed. My newest scrape experiment is a site called Quick Content and basically scrapes some results from google based on some parameters from google hot trends and posts it all as a feed. It was fun to code up but it is desperate need of a makeover.


Jun 3 2009

10 Things To Know About JSON (JSON Javascript Examples)

I used JSON for the first time today and it’s really nothing special. I’ve heard about it a few times but never really given it much thought and theres no reason I should have. Here is the list of all you really need to know about this syntax for passing around name value pairs and arrays to javascript.

  1. JSON is an acronym for ‘Javascript Object Notation’.
  2. JSON is fast. Mostly because it is recognized natively by Javascript so there’s no processing overhead.
  3. JSON is an ordered list of name value pairs.
  4. JSON is so much easier to read and write than XML due to it’s simplicity.
  5. Apperently (Untested by me) data is formatted as JSON then Ajax can travel across domains.
  6. Almost every language used in web development either already has a JSON library or set of functions. If one doesn’t, then creating functions is a trivial task.
  7. ‘var jsonObject = { ‘cody : ‘taylor’ };’ is referenced by ‘jsonObject.cody’ which gives us ‘taylor’.
  8. ‘var jsonObect = {‘javascript’ : {‘json’ : ‘not xml’ };’ is referenced by ‘jsonObject.javascript.json’ which gives us ‘not xml’.
  9. You can also reference the JSON object as if it was an associative array like ‘jsonObject[‘cody’]’ or ‘jsonObject.javascript[‘json’]’ which gives the same values as previously.
  10. If you don’t want to use key/value pairs you can define a normal data array. ‘jsonObject = {‘arrayOfData’: {‘numbers’ : [‘1’, ‘2’, ‘3’]}};’ We use indexes for this dataset. Don’t use indexes for the collections defined in the ‘{ }’. ‘jsonObject.arrayOfData.numbers[1]’ will give us ‘2’.
  11. You can put functions in the dataset to pass around executable code.

So now you know basically all there is to know about JSON.