Friday 2 March 2012

Removing cache manifest in Chrome

In an earlier post, I explained how to use cache-manifest for localstorage. Once you've achieved this, you'll find that in order to continue editing the site that the cache manifest will need to be removed. Otherwise, you won't see your changes. To do this in Chrome, you need to put this command in the address bar:
chrome://appcache-internals/
This will list all the sites in your application cache with a 'remove' link.
A full list of such commands, enter chrome://chrome-urls/

Tuesday 13 December 2011

Invalid field count in csv input on line 1

I came across this annoying phpmyadmin 'feature' when trying to import some data to a newly created MySQL table. I had a CSV file full of data. The columns matched the number of fields but I kept getting the error 'Invalid field count in csv input on line 1'.

The problem was, that the 'Fields terminated by' field in the import screen was set to ';' instead of a ','. By resetting this field, everything worked.

Monday 5 December 2011

Reset the Index of a MySQL table

Sometimes, I will be playing about with a MySQL database, often at the start of an application. I'll fire a load of dummy data in and test. When I've finally done with this phase I'm ready to start from the beginning. I might have an ID field which I'd like to auto increment but this time starting from 0. To reset this field, first empty all the records in the table, then you can apply a line like this:
ALTER TABLE `mytable` AUTO_INCREMENT=0

Monday 7 November 2011

Getting single row results MySQL using PHP

I'm always using this code. Sometimes I know there should be/is only one record returned from my MySQL query. Especially if I have specified 1 result as in the query below. As long as I know the resulting column names, this is a very useful technique.

<?php

$query = mysql_query("SELECT * FROM `users` WHERE `username` = '{$username}' LIMIT 1;");
$row = mysql_fetch_assoc($query);
echo 'Hello '.$row['firstname'];
?>

Tuesday 1 November 2011

How to use PHP __autoload over multiple directories

Funny this. One of those things where you do a bit of surfing to find the easy answer. The resulting pages of your search contain the name of the solution you are looking for in the title, but the containing code solves a different problem.
So, here is the problem.
I am creating a PHP application which has multiple directories containing classes will need throughout it's build.
I want to use the PHP __autoload function.

I will need 2 PHP files to support this activity, but below this I will show how they are called.
First file, config.php. This will contain a class containing all the support data needed throughout my application.

<?php
class supportdata
{
public $supportArray = array('lib', 'helper');
}
?>
There. Not too difficult was it.
Next, my autoload.php.

<?php
require_once 'config.php';
function __autoload($class_name) 
{
$sd = new supportdata;
$classString = '';
foreach($sd->supportArray as $value)
{
$classString = $DOCUMENT_ROOT.$value.'/'.$class_name.'.php';
if(file_exists($classString))
{
require_once $classString;
}
}
}
?>
As you can see it calls config.php and makes use of the supportArray to iterate through the directories, checking to see if the class exists. If it does we do a require_once on it.

Now, here is how my autoloading is called.

<?php
include_once 'autoload.php';
class index
{
function __construct()
{


}
}
new index;
?>

In my index class I can now call any of the classes contained in the directories named in config.php. In fact, I can call any of the those classes, anywhere in my application.

Thursday 20 October 2011

How to use cache-manifest for localstorage

So, you want your website to continue working on someone's laptop, when they're on a train and going through a tunnel.

Here is a technique for doing just that.

First create a .htaccess file for your site and add to it the following line:
AddType text/cache-manifest    .manifest

Next, create a file called cache.manifest. In this file, add the lines:
CACHE MANIFEST
index.html

Continue to add entries for any file you wish to be cached such as additional pages, images, scripts, stylesheets etc.

Now let's create the index.html file which will be cached:
<!DOCTYPE html>
<html manifest=”cache.manifest”>
<head>
<title>Cached Page</title>
</head>
<body>
My cached page.
</body>
</html>

There. Wasn't too difficult was it.

Wednesday 19 October 2011

I was forced to find an IE Tester

First post in a long time. I've been very busy.

Normally, by keeping to W3C standards, I can develop a site and then do some tweaks for IE at the end. Recently developed an application in which I tested for IE along the way. Or so I thought. I was in fact, testing in IE8. Not good enough. The application came out a total mess in IE7. This was one particular customers IT Department browser of choice. This seems like a ramble but I'm getting to the point.

I then discovered IE Tester at http://www.my-debugbar.com/wiki/IETester/HomePage. This is an excellent tool if you need to view your work in various versions of IE without messing up your existing install. It works stand-alone and also happily access pages delivered by your localhost.

Well done DebugBar!