iWebDevel » Coding

SQLite, MySQL, PHP: Ternary operator (IF() statement) in MySQL and SQLite

Dragos — Wed, 03 Feb 2010 19:46:36 +0000

While working on a proxy checker tool for one of my projects, I was struggling on how to execute a conditional query on my SQLite database to update a column only if its value is greater than 0 (it would be pointless in my case to let the script update the column with negative values).

In Mysql one would do like this (we use the ternary operator IF(to_check_expression>0,expression1,expression2)):

update table_name set column_name=IF((column_name-1)>0,(column_name-1),0)

However, in SQLite this method will not work. Instead I had to use the case when (condition) then expression1 else expression2 end method.

The above query in MySQL can be rewritten like this in SQLite:

update table_name set column_name=case when (column_name-1)>0 then (column_name-1) else 0 end

That’s it. I hope it helps someone!

Programming: Google programming language is now real! Go GO Google!

Dragos — Thu, 12 Nov 2009 09:05:34 +0000

GOlang Google programming language

First the Google Browser (Chrome), then the Google mobile operating system (Android), Google is getting really close to launching its own (and hopefully open source) operating system for computers. But before that, we needed to expect a “default” programming language from the Goliath of all technological times. And it’s here! GO is the name of Google’s programming language, which from the words of the inventors it is a programming language that is:

simple
fast
safe
concurrent
fun
and of course.. open-source

Though the language looks very similar to C and C++, the developers say that the GO language has many improvements that put this novelty in the same row with languages such as C, C++, Java or Python.

Here are some points, which are the main features of GO:

Go compilers produce fast code fast. Typical builds take a fraction of a second yet the resulting programs run nearly as quickly as comparable C or C++ code.

Go is type safe and memory safe. Go has pointers but no pointer arithmetic. For random access, use slices, which know their limits.

Go promotes writing systems and servers as sets of lightweight communicating processes, called goroutines, with strong support from the language. Run thousands of goroutines if you want—and say good-bye to stack overflows.

Go has fast builds, clean syntax, garbage collection, methods for any type, and run-time reflection. It feels like a dynamic language but has the speed and safety of a static language. It’s a joy to use.

Yet not convinced about the power of GO? Russ Cox from Google, explains the fast compiles of big programs with GO:

Convinced now? Then GO for it!

Note from Google: The Go project was conceived to make it easier to write the kind of servers and other software Google uses internally, but the implementation isn’t quite mature enough yet for large-scale production use.

PHP: How to download a webpage (aka web scrapping) with PHP

Dragos — Sat, 03 Oct 2009 08:08:27 +0000

There are many ways of downloading web pages, or web content. Personally I like to use cURL for my web scrapping needs, but sometimes I also use fsockopen and file_get_contents.

Here are 3 different functions that will allow you to download web content.

cURL:

function getData($url) {
    if($url!='localhost' && $url!='http://localhost') {
        $ch=curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
        curl_setopt($ch,CURLOPT_USERAGENT,"Mozilla/6.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.3");
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION,3);
        $result['data']=curl_exec($ch);
        $result['error']=curl_error($ch);
        curl_close($ch);
        return $result;
    }
    else return $result['error']='err';
}

fsockopen

function getData($url) {
    $arr=parse_url($url);
    $fp = fsockopen($arr['host'], 80, $errno, $errstr, 30);
    if(!$fp) {
        return false;
    }else {
    // send headers
        $out = "GET ".fsockopen($arr['host'], 80, $errno, $errstr, 30)." HTTP/1.1\r\n";
        $out .= "Host: ".str_replace('http://'.$arr['host'],'',$url)."\r\n";
        $out .= "User-Agent: FSOCKOPEN\r\n";
        $out .= "Connection: Close\r\n\r\n";
        fwrite($fp, $out);
        while(!feof($fp)) {
            $contents .= fgets($fp, 4096);
        };
        fclose($fp);
        return $contents;
    }
}

file_get_contents

function getData($url) {
return file_get_contents($url);
}

As you see the easiest way of downloading web content is by using the file_get_contents function, but if you need more options, especially if you are working with the headers, then cURL is the best way to go for you.

JavaScript: Send function as a parameter to another function (callbacks)

WordPress: Best SEO iTranslator for WordPress, get free traffic from fully automated plugin script

Dragos — Fri, 04 Sep 2009 15:30:59 +0000

I’ve just decided to publish my translation plugin for WordPress. It has helped me a lot to get free traffic, so I think other people might find it also useful.

== Description ==

Best SEO iTranslator for WordPress is a translation plugin, fully automated, that will help you get new traffic and at the same time help your readers translate your posts in their native languages (from the available 40 languages). This is a perfect SEO instrument for those who want to get traffic from search engines. Best SEO iTranslator for WordPress generates new translated posts, which are treated by search engines as being new different posts, containing different information.

== Installation ==

Upload this plugin in your plugins folder on your host. Enable Best SEO iTranslator for WordPress from the plugin management page.

== Configuration ==

From Settings->BSW iTranslator select the language your blog is written in. On the same page, choose what languages you would like to have your blog posts translated in.

== Frequently Asked Questions ==

= The translation time takes a little bit longer than my blog usually loads. Why? =

This is normal. This plugin relies on an external website (Google Translate) and the loading time of your translated posts mainly depends on how fast Google will translate your pages. If it takes more than 10 seconds, there must be something wrong with your server. In this case check your host’s error log to see whether everything is OK with your hosting.

= “Please return to this page in some minutes.” message =

There has been something wrong with the translation process, or Google temporarily banned your website for excessive queries. Don’t worry! A 503 Service Temporarily Unavailable message is displayed to both human readers and search bots, informing them that the page is not available at the moment.

= The cache gets too large in size =

This is normal. Every page is stored in a cached file, so the next time a request is made for that page, it is quickly fetched from the cache, saving a lot of time and server resources. The cache can grow quickly in size, make sure you have the required space on your server, before activating the plugin.

= The translated page has a bad/broken layout =

Usually Google Translate will deliver translated pages in the original format, however it may happen sometimes to get a page with a broken layout. Unfortunately, it is almost impossible to regenerate such broken files automatically.

= Why does a yellow box appear at the top of my translated page? =

That box informs the readers that the page they are currently viewing is a translated version and the original source is to be found in a different place (link provided).

= What is Cache Duration? =

Cache Duration is the time a cached file can stay on your server before it can be removed with a new one (if obsolete). Best Cache Duration time to set in the plugins settings are higher than 86000 seconds (one day). If you notice that translated pages are displayed correctly and they don’t need to be replaced, set the Cache Duration to 1 week or more (use the calculator to get the value in seconds: Xdays*24hours*60minutes*60seconds)

= Best SEO iTranslator for WordPress plugin doesn’t work =

First things to check is that the cache folder inside the plugin’s directory exists and is chmoded to 0755. If that is not the problem you may write a comment message on my blog at , and I’ll see what I can do to help you.

DEMO

To see this plugin in action, just scroll down to the end of this post and you’ll see the option to translate the current post. Choose whatever language you want.

Update: This plugin has been tested with PHP 5.3 . I do not guarantee that it will work with earlier versions of PHP.

DOWNLOAD

Download from here: Best SEO iTranslator for WordPress

WordPress 2.8.4: Not ready to be installed with PHP 5.3 ?

Dragos — Tue, 01 Sep 2009 19:43:24 +0000

I’ve just tried to install WordPress 2.8.4 on my testing machine (PHP 5.3). Right on the installation page a dozen of errors filled my screen, something like:

Strict Standards: Declaration of Walker_Page::start_lvl() should be compatible with that of Walker::start_lvl() in /opt/lampp/htdocs/wordpress/wp-includes/classes.php on line 1214

This is not a big issue and it doesn’t interrupt the installation, it’s just that PHP 5.3 has many new changes compared to previous versions of PHP. However, wordpress should still correct those errors, because it doesn’t look so good to see errors right on the installation page.

PHP: How to get creation time of file with PHP on Linux machines

Dragos — Tue, 01 Sep 2009 17:19:37 +0000

PHP 5.3 5.4 6 logo

Unfortunately it is not possible to get the creation time of a file on Linux machines. None of the functions fileatime,filemtime or filctime will return the file
creation time.

Note: Note also that in some Unix texts the ctime of a file is referred to as being the creation time of the file. This is wrong. There is no creation time for Unix files in most Unix filesystems. (from php.net)

In order to solve this issue, you could try to store in a database/file the time when a file is created for later use.

PHP:ob_start() Display page at once, forget about cookie,headers sent too early errors

Dragos — Fri, 21 Aug 2009 20:04:55 +0000

If you want to display your web pages at once, not subsequently, and reduce the “headers already sent, cannot send cookie information” errors, add ob_start() at the start of your script.

This function will turn output buffering on. While output buffering is active no output is sent from the script (other than headers), instead the output is stored in an internal buffer. (php.net)

You can also manipulate the contents of the output by using the function ob_get_contents()

PHP: Script to extract one’s contacts from email (Gmail, Yahoo,Hotmail,AOL…) and send invites – OpenInviter to go!

Dragos — Tue, 18 Aug 2009 07:17:36 +0000

OpenInviter -email extractor php script-logo

You’ll find many scripts to extract email contacts, but many of these are either commercial or just given as apis. For the last case, it’s good to extract contacts from an email using an external server, because that’ll help reduce the server load, but what if the website providing that service goes down? Not good.

So here’s a better solution: OpenInviter^TM.

OpenInviter is a precious tool for those who want to get viral traffic to their websites. This technique has been widely used by most social networks, such as FaceBook, Twitter, Hi5… The best part about OpenInviter is that it supports a lot of email providers and social networks. Yup! You’ve heard it well, you can even send invites to friends from social networks as private/direct messages; it works on your own server, meaning that you’ll have a functional invite system even when all other websites are down.

Go get it quickly while it’s warm and free: http://openinviter.com/

JavaScript: Send function as a parameter to another function (callbacks)

Dragos — Wed, 29 Jul 2009 13:16:20 +0000

I’m sure you’ve seen a lot of code where functions are send as parameters, usually working as function callbacks e.g:

setTimeout(function () { alert('test'); },1000);

But how does the function setTimeout execute the passed function as a parameter? The answer is simple, but I need to provide you an example to understand it

Let’s create a simple function, accepting two parameters: first a boolean value, the second – a function. Our function will analyze the boolean parameter and in case the value is true, the function passed as a parameter will be executed.

function simpleFunc(bool,func) {
    if(bool) func();
}

As you notice, we add parentheses after the name of the second parameter, because we’ll treat it as a function. And that’s te whole secret.

Now that is how we will use the simpleFunc function:

simpleFunc(false,function() { alert('Yupee!'); }; // this won't alert anything, because the boolean parameter is false
//example two
simpleFunc(true,function() { alert('Yupee!'); }); // this will alert Yupee!

Wish you luck!

JavaScript: GIFless animation. Animate images,logos with jQuery

Dragos — Thu, 23 Jul 2009 18:29:29 +0000

After playing some time with position relative and absolute, I’ve noticed one a great aspect of the png image format (probably gif images are also good, but since we are trying to create a GIFless animation, I won’t use any gif images in this tutorial).

So here’s a a PNG (transparent text), with the name of this website:

Transparent Logo

The trick of animating images, without the need of using the GIF image format features, are as follow:

We have an image with transparent text written on it. To animate the transparent text, we need to place a background image below the actual image and move this background image, in order to create a so called “animation”. To be more precise, the image we want to be animated should have a higher z-index than the background image below it (it’s like working with layers in Photoshop). In order to animate the background image we need some javascript work to be done. Of course, as a big fan of jQuery, I’ve used jQuery to do all the animation stuff.

Here’s the script I’ve come up with:

(function($){
            $.fn.enliven = function(options) {
                var defaults = {
                    bgImage: '',
                    duration:3000
                };
                var options = $.extend(defaults, options);
                var imH=this.attr("height"),
                imW=this.attr("width");
                this.wrap('

');
                this.css("position","absolute");
                $('#'+this.attr("className")+'Cont').append('

');
                var
                maxLeft=($('.lbg'+this.attr("className")).attr('clientWidth')-this.attr('width'))/2,
                maxTop=($('.lbg'+this.attr("className")).attr('clientHeight')-this.attr('height'))/2;
                function getrand() {
                    var nr=Math.floor(Math.random()*2);
                    return nr==0?-1:1;
                }
                function randimate(obj) {
                    var ph=Math.floor(imH*20/100),pw=Math.floor(imW*20/100);
                    newLeft=$(".lbg"+obj.attr("className")).attr("offsetLeft")+Math.floor(Math.random()*pw)*getrand();
                    newTop=$(".lbg"+obj.attr("className")).attr("offsetTop")+Math.floor(Math.random()*ph)*getrand();
                    if(newLeft>0) newLeft=0;
                    else if(newLeft<-maxLeft)                         newLeft=-maxLeft+1;                     if(newTop>0) newTop=0;
                    else if(newTop<-maxTop)
                        newTop=-maxTop+1;
                    $('.lbg'+obj.attr("className")).animate({left:newLeft+"px",top:newTop+"px"},defaults.duration,"linear",function(){ randimate(obj); });
                }
                return this.each(function(){
                    randimate($(this));
                });
            };
        })(jQuery);

The code above works as a plugin of jQuery, so it should be included in the page, after the inclusion of jQuery. In order to animate an image, you should use this code:

$('image_selector').enliven({bgImage:"./path_to_background_image.png",duration:1000}); //duration is the time of one time background animation

Here’s a crazy example 1: http://iwebdevel.com/wp-content/uploads/2009/07/logo.php
Here’s another non-crazy example 2: http://iwebdevel.com/wp-content/uploads/2009/07/logo2.php

If you like the idea and want more features, drop me a line in a comment and I’ll try to improve the code and add more features