Tech Chorus

On 30 October 2010, the Bangalore PHP User Group met at Microsoft. I gave a talk, XML For PHP Developers, in the event.

I'm sharing the slides in this entry.

It was an introductory talk on XML for PHP developers. There are hundreds of technologies built on top of XML. We have all heard about RSS, Atom, XML-RPC, SOAP, etc. The goal of the talk was to get PHP developers to start using XML. In the talk, I presented three recipes:

• Parsing RSS feeds using simplexml. This was based on my blog post about retrieving weather information in your location using Yahoo! Weather.
• Generating Atom feed document using DOM.
• Scraping web pages using DOM and XPath. This was based on Web Scraping With lxml. This time I did in PHP.

More and more websites are offering APIs nowadays. Previously, we've talked about XML-RPC and REST. Even though web services are growing exponentially there are a lot of websites out there that offer information in unstructured format. Especially, the government websites. If you want to consume information from those websites, web scraping is your only choice.

What is web scraping?

Web scraping is a technique used in programs that mimic a human browsing the website. In order to scrape a website in your programs you need tools to

• Make HTTP requests to websites
• Parse the HTTP response and extract content

Title: Pro PHP XML and web services
Author: Robert Richards
Publisher: Apress
ISBN13: 978-1-59059-633-3

If you are a PHP programmer and looking to expand your knowledge in XML and web services areas, the book is a good resource. The book assumes no prior knowledge about XML and web services. It assumes you are capable of writing PHP programs independently.

Download the table of contents PDF document from the publisher.

In a previpus blog post we discussed how to consume the Technorati ping web service using XML-RPC. The PEAR package XML_RPC2 provides convenient client and server objects. You can call the remote methods as if they were the methods of the client object.

In this post, let us accomplish the same using a PEAR package XML_RPC2. We will write a client script to update Technorati when there is new post in your blog site.

If you are familiar with blogosphere you know what is Technorati.

Technorati is an Internet search engine for searching blogs. You can submit your blog to Technorati and ping their servers when your blog site is updated. when you ping Technorati their web crawlers read the updated information on your site.

Technorati offers an XML-RPC ping web service to allow blogs to notify content changes.

In this article we discuss how to write a PHP script to programatically ping Technorati when there is new content in your site.

Let us get familiar with some terminology.

RPC From the Wikipedia:
"Remote procedure call (RPC) is an Inter-process communication technology that allows a computer program to cause a subroutine or procedure to execute in another address space (commonly on another computer on a shared network) without the programmer explicitly coding the details for this remote interaction."

Good definition. But what exactly does it mean?

In this article I will explain how to write an XML-RPC server and client in PHP.

To be able to understand the article, you have to have some idea about XML-RPC in general.

If you feel like gleaning more information about XML-RPC visit the following websites:

http://www.xmlrpc.com/
http://en.wikipedia.org/wiki/XML-RPC

For an introduction to XML-RPC in PHP visit Introduction to XML-RPC In PHP

We all know about the URL shortening service offered by many websites. Most notable among them is tinyurl.com. There are also other free URL shortening services available on the Internet.

In this post, I will show you how to generate a short URL link to any URL from a PHP script using the short.ie URL shortening service. The actual code is only about ten lines. We will make use of the Zend_Http_Client component of the Zend Framework.