How to add wordpress Uploader to plugins

WordPress has a nice media uploader dialog that it uses on the editor pages. Now wouldn’t it be nice if you could use it to handle image uploads for part of a plugin or theme you’re writing? Maybe you want to add an easy way to change the logo in a theme? A simple “Upload Image” button would work quite well for that, wouldn’t it?

It’s fairly simple to implement, providing you already have a bit of experience with the WordPress API.
The first step is to prepare your HTML. Put it wherever the code for your admin page is. You want to have a text input for the image URL, and a button that will launch the uploader dialog.

<tr valign="top">

<th scope="row">Upload Image</th>

<td><label for="upload_image">

<input id="upload_image" type="text" size="36" name="upload_image" value="" />

<input id="upload_image_button" type="button" value="Upload Image" />

<br />Enter an URL or upload an image for the banner.

</label></td>

</tr>

Now that the easy part is out of the way, it’s time to start making it do something. You need to enqueue some scripts and styles. Here’s an example function to show how it’s done:

function my_admin_scripts() {

wp_enqueue_script('media-upload');

wp_enqueue_script('thickbox');

wp_register_script('my-upload', WP_PLUGIN_URL.'/my-script.js', array('jquery','media-upload','thickbox'));

wp_enqueue_script('my-upload');

}

function my_admin_styles() {

wp_enqueue_style('thickbox');

}

if (isset($_GET['page']) && $_GET['page'] == 'my_plugin_page') {

add_action('admin_print_scripts', 'my_admin_scripts');

add_action('admin_print_styles', 'my_admin_styles');

}

We need the media-upload and thickbox scripts for starters, as well as jQuery, which is already included. Then we have to register and enqueue our own JavaScript file, my-script.js, which will handle the media uploader functionality. We also need to load the thickbox stylesheet in the next function.
The if (…) block ensures that the scripts and styles will only be included if the user is on a specific admin page. If you look at your plugin’s (or theme’s) admin page, the URL should have a ?page=some_string at the end. Substitute my_plugin_page for that string.
Now for the part the actually invokes the uploader: the JavaScript. This will go in the my-script.js file we included earlier.

jQuery(document).ready(function() {

jQuery('#upload_image_button').click(function() {

formfield = jQuery('#upload_image').attr('name');

tb_show('', 'media-upload.php?type=image&TB_iframe=true');

return false;

});

window.send_to_editor = function(html) {

imgurl = jQuery('img',html).attr('src');

jQuery('#upload_image').val(imgurl);

tb_remove();

}

});

The first click() event listener opens a ThickBox dialog when the “Upload Image” button is clicked, and loads the uploader page inside it. It also stores the name of the URL input field in a variable, for later use.
The second function overrides the send_to_editor() function in the media-upload script. This is probably the most important part. When the “Insert into Post” button is clicked in the uploader dialog, this function fires. It collects the URL of the image that was uploaded, dumps it into the awaiting form field, and closes the ThickBox dialog.
That’s it. Providing everything went according to planned, you should have a form field that will either accept an arbitrary image URL, or allow a user to upload one on the spot.

how to Strip filename from a URL with php

Using PHP, you might need to strip the path from a URL, leaving behind just the filename at the end of the URL. You can achieve this with a regular expression pattern of course, but I have a much simpler solution. See the example code below.

$url = "http://www.domain.com/path/to/file/filename.php";
$filename = basename($url);
echo $filename; //filename.php

And that’s all there is to it. I hope that you found this useful.

How to replace all instances of a character in a string with Javascript

The easiest would be to use a regular expression with g flag to replace all instances: str.replace(/foo/g, "bar") This will replace all occurrences. If you just have a string, you can convert it to a RegExp object like this: var pattern = "foobar",     re = new RegExp(pattern, "g");

how to to add options to a select from an array with jQuery

Using DOM Elements Creator plugin : $.create('option', {'value': 'val'}, 'myText').appendTo('#mySelect'); Using the Option constructor (not sure about browser support): $(new Option('myText', 'val')).appendTo('#mySelect'); Using document.createElement (avoiding extra work parsing HTML with $("<option></option>")): $('#mySelect').append($(document.createElement("option")).attr("value","val").text("myText"));

how to Find base name in URL in Javascript

Simply use this regex : 

url.replace(/^.*\/|\.[^.]*$/g, '')


how to fix PHP Fatal error: Class ‘DOMDocument’ not found

from the tail -f /var/log/httpd/error
[Tue Mar 10 16:01:30 2009] [error] [client 127.0.0.1] PHP Fatal error: Class 'DOMDocument' not found in /home/namran/src/....php on line 15, referer: http://...

the solution turn out to be
yum install php-xml


How do I Find Out Linux CPU Utilization?

Whenever a Linux system CPU is occupied by a process, it is unavailable for processing other requests. Rest of pending requests must wait till CPU is free. This becomes a bottleneck in the system. Following command will help you to identify CPU utilization, so that you can troubleshoot CPU related performance problems.
Finding CPU utilization is one of the important tasks. Linux comes with various utilities to report CPU utilization. With these commands, you will be able to find out:
* CPU utilization
* Display the utilization of each CPU individually (SMP cpu)
* Find out your system's average CPU utilization since the last reboot etc
* Determine which process is eating the CPU(s)

Old good top command to find out Linux cpu load

The top program provides a dynamic real-time view of a running system. It can display system summary information as well as a list of tasks currently being managed by the Linux kernel.
The top command monitors CPU utilization, process statistics, and memory utilization. The top section contains information related to overall system status - uptime, load average, process counts, CPU status, and utilization statistics for both memory and swap space.

Top command to find out Linux cpu usage

Type the top command:
$ top
Output:


You can see Linux CPU utilization under CPU stats. The task’s share of the elapsed CPU time since the last screen update, expressed as a percentage of total CPU time. In a true SMP environment (multiple CPUS), top will operate in number of CPUs. Please note that you need to type q key to exit the top command display.
The top command produces a frequently-updated list of processes. By default, the processes are ordered by percentage of CPU usage, with only the "top" CPU consumers shown. The top command shows how much processing power and memory are being used, as well as other information about the running processes.

Find Linux CPU utilization using mpstat and other tools

Please note that you need to install special package called sysstat to take advantage of following commands. This package includes system performance tools for Linux (Red Hat Linux / RHEL includes these tools by default).
# apt-get install sysstat
Use up2date command if you are using RHEL:
# up2date sysstat

Display the utilization of each CPU individually using mpstat

If you are using SMP (Multiple CPU) system, use mpstat command to display the utilization of each CPU individually. It report processors related statistics. For example, type command:
# mpstat Output:

Linux 2.6.15.4 (debian)         Thursday 06 April 2006
05:13:05  IST  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
05:13:05  IST  all   16.52    0.00    2.87    1.09    0.07    0.02    0.00   79.42    830.06

The mpstat command display activities for each available processor, processor 0 being the first one. Global average activities among all processors are also reported. The mpstat command can be used both on SMP and UP machines, but in the latter, only global average activities will be printed.:
# mpstat -P ALL
Output:

Linux 2.6.15.4 (wwwportal1.xxxx.co.in)         Thursday 06 April 2006
05:14:58  IST  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
05:14:58  IST  all   16.46    0.00    2.88    1.08    0.07    0.02    0.00   79.48    835.96
05:14:58  IST    0   16.46    0.00    2.88    1.08    0.07    0.02    0.00   79.48    835.96
05:14:58  IST    1   15.77    2.70    3.17    2.01    0.05    0.03    0.00   81.44    822.54

Another output from my HP Dual Opteron 64 bit server:# mpstat -P ALLOutput:

Linux 2.6.5-7.252-smp (ora9.xxx.in)   04/07/06
07:44:18     CPU   %user   %nice %system %iowait    %irq   %soft   %idle    intr/s
07:44:18     all    3.01   57.31    0.36    0.13    0.01    0.00   39.19   1063.46
07:44:18       0    5.87   69.47    0.44    0.05    0.01    0.01   24.16    262.11
07:44:18       1    1.79   48.59    0.36    0.23    0.00    0.00   49.02    268.92
07:44:18       2    2.19   42.63    0.28    0.16    0.01    0.00   54.73    260.96
07:44:18       3    2.17   68.56    0.34    0.06    0.03    0.00   28.83    271.47

Report CPU utilization using sar command

You can display today’s CPU activity, with sar command:
# sar
Output:

Linux 2.6.9-42.0.3.ELsmp (dellbox.xyz.co.in)         01/13/2007
12:00:02 AM       CPU     %user     %nice   %system   %iowait     %idle
12:10:01 AM       all      1.05      0.00      0.28      0.04     98.64
12:20:01 AM       all      0.74      0.00      0.34      0.38     98.54
12:30:02 AM       all      1.09      0.00      0.28      0.10     98.53
12:40:01 AM       all      0.76      0.00      0.21      0.03     99.00
12:50:01 AM       all      1.25      0.00      0.32      0.03     98.40
01:00:01 AM       all      0.80      0.00      0.24      0.03     98.92
...
.....
..
04:40:01 AM       all      8.39      0.00     33.17      0.06     58.38
04:50:01 AM       all      8.68      0.00     37.51      0.04     53.78
05:00:01 AM       all      7.10      0.00     30.48      0.04     62.39
05:10:01 AM       all      8.78      0.00     37.74      0.03     53.44
05:20:02 AM       all      8.30      0.00     35.45      0.06     56.18
Average:          all      3.09      0.00      9.14      0.09     87.68

Comparison of CPU utilization

The sar command writes to standard output the contents of selected cumulative activity counters in the operating system. The accounting system, based on the values in the count and interval parameters. For example display comparison of CPU utilization; 2 seconds apart; 5 times, use:
# sar -u 2 5
Output (for each 2 seconds. 5 lines are displayed):

Linux 2.6.9-42.0.3.ELsmp (www1lab2.xyz.ac.in)         01/13/2007
05:33:24 AM       CPU     %user     %nice   %system   %iowait     %idle
05:33:26 AM       all      9.50      0.00     49.00      0.00     41.50
05:33:28 AM       all     16.79      0.00     74.69      0.00      8.52
05:33:30 AM       all     17.21      0.00     80.30      0.00      2.49
05:33:32 AM       all     16.75      0.00     81.00      0.00      2.25
05:33:34 AM       all     14.29      0.00     72.43      0.00     13.28
Average:          all     14.91      0.00     71.49      0.00     13.61

Where,

• -u 12 5 : Report CPU utilization. The following values are displayed:
• %user: Percentage of CPU utilization that occurred while executing at the user level (application).
• %nice: Percentage of CPU utilization that occurred while executing at the user level with nice priority.
• %system: Percentage of CPU utilization that occurred while executing at the system level (kernel).
• %iowait: Percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.
• %idle: Percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.

To get multiple samples and multiple reports set an output file for the sar command. Run the sar command as a background process using.
# sar -o output.file 12 8 >/dev/null 2>&1 &
Better use nohup command so that you can logout and check back report later on:
# nohup sar -o output.file 12 8 >/dev/null 2>&1 &
All data is captured in binary form and saved to a file (data.file). The data can then be selectively displayed ith the sar command using the -f option.
# sar -f data.file

Task: Find out who is monopolizing or eating the CPUs

Finally, you need to determine which process is monopolizing or eating the CPUs. Following command will displays the top 10 CPU users on the Linux system.
# ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
OR
# ps -eo pcpu,pid,user,args | sort -r -k1 | less
Output:

%CPU   PID USER     COMMAND
  96  2148 vivek    /usr/lib/vmware/bin/vmware-vmx -C /var/lib/vmware/Virtual Machines/Ubuntu 64-bit/Ubuntu 64-bit.vmx -@ ""
 0.7  3358 mysql    /usr/libexec/mysqld --defaults-file=/etc/my.cnf --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-locking --socket=/var/lib/mysql/mysql.sock
 0.4 29129 lighttpd /usr/bin/php
 0.4 29128 lighttpd /usr/bin/php
 0.4 29127 lighttpd /usr/bin/php
 0.4 29126 lighttpd /usr/bin/php
 0.2  2177 vivek    [vmware-rtc]
 0.0     9 root     [kacpid]
 0.0     8 root     [khelper]

Now you know vmware-vmx process is eating up lots of CPU power. ps command displays every process (-e) with a user-defined format (-o pcpu). First field is pcpu (cpu utilization). It is sorted in reverse order to display top 10 CPU eating process.

iostat command

You can also use iostat command which report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions. It can be use to find out your system's average CPU utilization since the last reboot.
# iostatOutput:

Linux 2.6.15.4 (debian)         Thursday 06 April 2006
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
     16.36    0.00    2.99    1.06    0.00   79.59
Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda               0.00         0.00         0.00         16          0
hdb               6.43        85.57       166.74     875340    1705664
hdc               0.03         0.16         0.00       1644          0
sda               0.00         0.00         0.00         24          0 

You may want to use following command, which gives you three outputs every 5 seconds (as previous command gives information since the last reboot):$ iostat -xtc 5 3

GUI tools for your laptops/desktops

Above tools/commands are quite useful on remote server. For local system with X GUI installed you can try out gnome-system-monitor. It allows you to view and control the processes running on your system. You can access detailed memory maps, send signals, and terminate the processes.
$ gnome-system-monitor

(Click to enlarge image)
In addition, the gnome-system-monitor provides an overall view of the resource usage on your system, including memory and CPU allocation.

(Click to enlarge image)