The other day, when I was editing Jeremy’s weekly viral video roundup post, it occurred to me that it would be nice to display a thumbnail image for the post, taken from one of the videos in his review. I thought I’d write a short post to show you how to easily pull thumbnail images for a YouTube video.
How To Download A Thumbnail Image From YouTube
There are a few different ways that you can get thumbnails from a YouTube video, one of which is to use YouTube’s Video API to extract the thumbnail. YouTube API responses may contain multiple thumbnail images for a video, each of which is identified by a tag. Creating a call to YouTube to get the video and thumbnail information can take some time and when you are like me and don’t know a think about writing code, then the API is relatively useless. For me, I needed a simple way to pull down a thumbnail and thankfully, there is a simple way to do this.
Here is the YouTube URL format that you will need in order to view and download a thumbnail from a YouTube video:
http://img.youtube.com/vi/VIDEO_ID/#.jpg
… where for the video example above, VIDEO_ID=bQVoAWSP7k4 and # (1,2, or 3) corresponds to one of the 3 thumbnails that YouTube automatically generates.
#2, is the default thumbnail, or the one that the owner ends up choosing for their video.
Using this convention, below are the URLs and the thumbnails that I was able to pull off of YouTube for the “wedding proposal” video from Jeremy’s post.
What's PHP ? The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.
What Is a Session?
A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests.
There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.
Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.
What is meant by PEAR in php?
Answer1:
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organised OOP library. PEAR also provides a command-line interface that can be used to automatically install "packages"
Answer2:
PEAR is short for "PHP Extension and Application Repository" and is pronounced just like the fruit. The purpose of PEAR is to provide:
A structured library of open-sourced code for PHP users
A system for code distribution and package maintenance
A standard style for code written in PHP
The PHP Foundation Classes (PFC),
The PHP Extension Community Library (PECL),
A web site, mailing lists and download mirrors to support the PHP/PEAR community
PEAR is a community-driven project with the PEAR Group as the governing body. The project has been founded by Stig S. Bakken in 1999 and quite a lot of people have joined the project since then.
How can we know the number of days between two given dates using PHP?
Simple arithmetic:
$date1 = date('Y-m-d');
$date2 = '2006-07-01';
$days = (strtotime() - strtotime()) / (60 * 60 * 24);
echo "Number of days since '2006-07-01': $days";
This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.
What is the difference between $message and $$message?
Anwser 1:
$message is a simple variable whereas $$message is a reference variable. Example:
$user = 'bob'
is equivalent to
$holder = 'user';
$$holder = 'bob';
Anwser 2:
They are both variables. But $message is a variable with a fixed name. $$message is a variable who's name is stored in $message. For example, if $message contains "var", $$message is the same as $var.
What Is a Persistent Cookie?
A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer. By default, cookies are created as temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:
*Temporary cookies can not be used for tracking long-term information.
*Persistent cookies can be used for tracking long-term information.
*Temporary cookies are safer because no programs other than the browser can access them.
*Persistent cookies are less secure because users can open cookie files see the cookie values.
What does a special set of tags do in PHP?
The output is displayed directly to the browser.
How do you define a constant? Via define() directive, like define ("MYCONSTANT", 100);
What are the differences between require and include, include_once?
Anwser 1:
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.
But require() and include() will do it as many times they are asked to do.
Anwser 2:
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.
Anwser 3:
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. It des not call a fatal error if file not exists. require_once() does the same as include_once(), but it calls a fatal error if file not exists.
Anwser 4:
File will not be included more than once. If we want to include a file once only and further calling of the file will be ignored then we have to use the PHP function include_once(). This will prevent problems with function redefinitions, variable value reassignments, etc.
What is meant by urlencode and urldecode?
Anwser 1:
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.
Anwser 2:
string urlencode(str) - Returns the URL encoded version of the input string. String values to be used in URL query string need to be URL encoded. In the URL encoded version:
Alphanumeric characters are maintained as is.
Space characters are converted to "+" characters.
Other non-alphanumeric characters are converted "%" followed by two hex digits representing the converted character.
string urldecode(str) - Returns the original string of the input URL encoded string.
You will get "http://domain.com/submit.php?disc=10%2E00%25".
How To Get the Uploaded File Information in the Receiving Script?
Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:
$_FILES[$fieldName]['name'] - The Original file name on the browser system.
$_FILES[$fieldName]['type'] - The file type determined by the browser.
$_FILES[$fieldName]['size'] - The Number of bytes of the file content.
$_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the uploaded file was stored on the server.
$_FILES[$fieldName]['error'] - The error code associated with this file upload.
The $fieldName is the name used in the .
What is the difference between mysql_fetch_object and mysql_fetch_array?
MySQL fetch object will collect first single matching record where mysql_fetch_array will collect all matching records from the table in an array
How can I execute a PHP script using command line?
Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, "php myScript.php", assuming "php" is the command to invoke the CLI program.
Be aware that if your PHP script was written for the Web CGI interface, it may not execute properly in command line environment.
I am trying to assign a variable the value of 0123, but it keeps coming up with a different number, what’s the problem?
PHP Interpreter treats numbers beginning with 0 as octal. Look at the similar PHP interview questions for more numeric problems.
Monday, August 31, 2009
PHP is a server-side scripting language.
What You Should Already Know
Before you continue you should have a basic understanding of the following:
HTML/XHTML
JavaScript
If you want to study these subjects first, find the tutorials on our .
PHP is a powerful server-side scripting language for creating dynamic and interactive websites.
PHP is the widely-used, free, and efficient alternative to competitors such as Microsoft's ASP. PHP is perfectly suited for Web development and can be embedded directly into the HTML code.
The PHP syntax is very similar to Perl and C. PHP is often used together with Apache (web server) on various operating systems. It also supports ISAPI and can be used with Microsoft's IIS on Windows.
