XML - ISGMLUG

Different Types of XML Parser

XML parser is a software module to read documents and a way to give access for their content. XML parser generates a structured tree to return the results to the browser. An XML parser resembles a processor that determines the construction and properties of the data. An XML document can be read by an XML parser to create an output to build a screen sort. There are numerous parsers available and some of these are listed below:

The Xerces Java Parser
The primary function of the Xerces Java Parser is the building up of XML-aware web servers
Also to ensure the integrity of e-business data expressed in XML, James Clark contributed this parser to the community.

XP and XT

XP is a Java XML and XT is an XSL processor. Both are written in Java.XP detects all non well formed files. It plans to function as most rapid conformant XML parser in Java and gives high performance. On the other hand XT is a set of tools for building program transformation systems. The tools include pretty printing; bundling

SAX

Simple API for XML (SAX) originated by the members of a public mailing list (XML-DEV).It gives an occasion based approach to XML parsing. It indicates that instead of going from node to node, it goes from event to event. SAX is event. Events contain XML tag, detecting errors etc, such as this reference.

It’s optimal for a small XML parser and applications that need fast. It must be used when all of the procedure must be performed economically and quickly to input components.

XML parser

It runs on any platform where there’s Java virtual machine. It’s sometimes called XML4J.It has an interface which allows you to have a chain of XML formatted text, decide the XML tags and rely on them to extract the tagged information.

Harold Evensen
http://www.uktv-online.com/

Identity Systems - Distributing Authentication and Authorization

Any identity system which is automated needs some way of both creating and distributing authorization and authentication assertions. One of the most famous is of course Kerberos, which has it’s own methods for dealing with this requirement. However many digital systems are now starting to use SAML - the Security Assertion Markup Language - it’s becoming the de facto security credential standard.

SAML of course uses XML as a standard to represent security credentials, but it also defines a protocol for requesting and receivfing the credential data from an authority services (SAML based). One of the key benefits to SAML is that using it is pretty straight forward, this fact alone has increased it’s usage considerably. A client will make a request about a subject through to the SAML authority. The authority in turn makes assertions about the identity of the subject in regards to a particular security domain. To take an example - the subject could be identified by an email address linked to it’s originating DNS domain, this is just one simple example though.

So what exactly is a SAML authority? Well it is quite simply a service (usually online) that responds to SAML requests. These SAML requests are called assertions. There are three different types of SAML authorities which can be queried - authentication authorities, attribute authorities and policy decision points (PDPs). These types of authorities all return distinct types of assertions -

SAML authentication assertions
SAML attribute assertions
SAML authorization assertions

Although there are three different definitions here, in practice most authorities are set up to produce each type of assertions. Sometimes in very specific applications, you’ll find an authority that is designed to only produce a specific subset but this is quite rare especially in online applications - although they’re sometimes used as proxy authorisation - see this. All of them contain certain elements however like IDs for issuers, time stamps, assertion IDs, subjects including security domains and names.

Each SAML attribute request will begin using a standard syntax - <samlp:Request…..> - the content then would refer to the specific parts of the request. This could be virtually anything but in practice it’s often something straight forward like asking which department or domain an email is associated with.

Source : Sam Wilkin - IT Consultant

Confidentiality Using XML Encryption

Just like every other type of communication method that exists online, you can use encryption for securing XML documents. In fact it is recommended if possible that all important XML documents should be encrypted completely before being transmitted across the wire. The document would then be decrypted using the appropriate key when it reaches it’s correct destination.

There is a problem with this however, in that when you encrypt something you also obfuscate the entire message. This means that unfortunately some parts of an XML message will need to be sent using clear text only. Take for example SOAP messages, these are a format that computers use to exchange rpc (remote procedure calls) over the internet. Although you can encrypt certain parts of the SOAP message, at a minimum the headers must be in clear text otherwise intermediary devices would not be able to see routing and other important information.

The other alternative is to encrypt the channel itself, typically using something like SSL or SSH. This ensures that the message is protected in transit by encrypting the entire channel. However there is another issues here that channel encryption only protects the two endpoints, the message will otherwise be displayed in clear text. These problems were real issues for XML developers and to combat them - the XML encryption standard was developed.

The primary goal of this standard is to allow the partial and secure encryption of any XML document. The encryption standard, very much like other XML standards like the signature protocol has quite a lot of different parts. This is to enable the standard to deal with all sorts of different contingencies, however the core functions are quite simple and easy to follow.

Any encrypted element in an XML document is identified using the following element - , this element consists of two distinct parts -

An optional element that gives information. The element is actually the same one that is defined in the XML signature specification.
A element that can either include the actual data which is being encrypted inside the element. Alternatively it can contain a reference to the encrypted data enclosed in a element.

For instance XML encryption may be used in something like an online payment system which sends orders through an XML document. The order document may contain all the information about the order including sensitive information like the payment details, credit card numbers all contained in a element. In this example most of the order should be left in clear text so that it can be processed quickly, but the payment information should be encrypted and decrypted only when the payment is actually being processed. XML encryption allows this facility by ensuring the specific encryption of certain parts of the document - i.e the payment information.

James Hassenberg: Technical Blogger.

XML Sitemaps - A Brief Introduction

Google was the very first search engine to introduce sitemaps with the Google XML sitemap format in 2005. As the internet evolved, so the standard evolved with all the search engines and it soon became the standard for all these search giants on how to complete a crawl of a website and of course the subsequent indexing of the site. Essentially an XML sitemap is merely an XML file containing a listing of a site that includes URLs and some info about those URLs. A site can have multiple sitemaps all stored in multiple directories, so it’s useful if you can test from a variety of sources perhaps through VPNs and proxies like this if you have the facility available.To assist search engines detect the various sitemaps an organization may have, the locations of the XML file are detailed at the end of a site’s robots.txt file. Make sure that the search engine can access all these pages using a standard TCP/IP connection.

An XML sitemap is ideal for sites where some pages are updated more often or where some pages are more significant than many others. For instance, a local company might update its opening hours or product lists quite often, while infrequently updating the page describing the history of its company. In that case, the webmaster would need to notify search engines when it does its ordinary site crawling to put a higher priority in the hours page. Likewise, the webmaster can put an increased importance on the hours pages or perhaps on other pages with particular content, so the search engine’s site indexing ranks those pages greater.

Sitemaps should comprise the date a page was last altered, how often that page changes and that page’s priority. The last modified date is merely the calendar date the page last changed. The precedence is a value from zero to 1 with a default of 0.5. Writing out this advice for each page isn’t challenging, but it could be boring. Using an XML sitemap generator can help decrease the quantity of work a webmaster has to do when creating the sitemap. While other web sites provide offline generators several web sites provide an on-line sitemap generator.

In case your site features many thousands of web pages, you must utilize a professional sitemap creator instead. It can save you a huge amount of time and in some cases your sanity! They’re not expensive in fact I used one in Paris for many years which was completely free although it was restricted to French IP addresses only, so I had to use a proxy in France like this.

Although a sitemap is frequently overlooked, it is an essential resource which helps search engines understand sites. Sitemaps can be basic or complicated, conditioned upon the site’s size and demands.

Use the InterestBot to Project Interest Growth

Another new application that recently launched is the InterestBot Interest Calculator. It’s a PHP/JavaScript application initialized via AJAX.

Some people think that the key to saving would be having the largest amount of money to start with. However, this is simply not the case. Very often, people with a lot of money have many expenses to manage. They spend more money than the person that does not have very much, this can leave them with little or nothing to save. The best way to make sure that you are saving for the future would be to simply take advantage of an interest calculator that would allow you to decide the value of putting your money in different places. It is likely that you are getting a lower interest rate than you would like by putting your money into your current savings account.

However, you would never be able to determine this if you are not making use of an interest calculator that would give you this understanding. After you learn how much of a return you are getting on your investment, you may become interested in putting your money somewhere else. Before you decide how you would like to do this, you want to use a calculator in order to ensure that you are making a great financial decision. Saving is not all about making money. Instead, it is about learning to take the time to make sure that you are saving correctly when it comes to your future. If you take this approach, you will be very happy with the nest egg that you build in the future.

More About XML

Extensible Markup Language or XML has become of tremendous importance for the net. It is mark up language. It has the advantage of being both human-readable and machine-readable. It’s simplicity and useability has seen XML become the default language for many computing applications.

For example programs such as Microsoft Office, Open Office and Apple’s iWork all use XML-based formats. Many important API or application programming interfaces have been developed to process XML data. Since 2009 there has been a proliferation of XML-based languages including RSS, Atom, and XHTML.

XML based languages are not difficult to pick up. In a way XML is like BASIC in that both clearly differentiate content from code that manipulates content. In XML code is indicated by the tags <> and </>. Thus in the following code:

<p>Obama for President.</p>

The first <p> tag tells a computer to start a new paragraph and the closing </p> tells the computer to close the paragraph. The end user will only see:

Obama for President.

When coding it is important to remember that each page starts with an XML declaration such as:

<html xmlns="http://www.w3.org/1999/xhtml">

Many WYSIWYG editors will automatically generate this code for every page of HTML generated.

People ask about the value of knowing how to use XML and HTML now that the internet has seen a flurry of websites that offer free blogs and increasingly intuitive website templates. Obviously for serious website developers a knowledge of XML is essential. Otherwise the websites designed are going to be restricted by the limitation placed on all templates or ‘themes’. To be truly creative and innovative you must get back to basic principles and design from the bottom up - not fit in from the top down.

Moreover, you can drive a car without understanding how an engine works. However, when you have a breakdown such information can prove indispensable. Accumulating knowledge is never a waste of time. Ignorance is nothing to boast about.

Website Owners Don’t Need To Know XML

Things have gotten much easier for anyone who wants to start a website or blog. In 2012, I’d say that most website owners know little to nothing about XML or even HTML. This is because they don’t need to anymore with all the automation and WordPress themes that are available today.

I first got started with my website (DayJobNuker.com) in 2007 and I was extremely worried that I would have to learn all sorts of computer languages in order to get my website live on the Internet. I didn’t know much about Dreamweaver but I was sure I didn’t want to have to learn something that complicated. It turned out that while I did have to learn some basic HTML and how to go into the back end of my website, it was all a lot easier than I thought it would be.

Now it seems, each year things get easier and easier for blog owners and it has come to the point where absolutely anyone can start a blog. There is hardly any reason or need to learn XML or HTML at all. The great majority of coding issues and behind the scenes work that was once important to start a website is no longer needed and people with very little computer and Internet experience can easily create great looking websites.

There are dozens of free blogging platforms that are now available and nothing more than point and click skills are needed to get started. People can choose from thousands of themes and change their headers and styles within their chosen theme with nothing more than a push of a button. Easy!

So, if you are one of the people who is scared to jump into the world of blogging or having your own website, it is a lot easier technically than you might think. Gone are the days where you had to sit down with a thick computer XML or HTML manual and toil late into the night trying to understand the basics. Now, if you know how to navigate your way around the Internet, chances are good that you also have the skills to put up your own website.

Create an Image From XML Data

I had some time to kill and a silly problem to solve, which means here’s some more SimpleXML fun for you:

The Problem: It’s not really a “problem,” but FeedBurner’s FeedCount^TM image is a rigid 88 pixels wide, and I wanted to include it on my homepage under the “syndicate” heading, an area that I’ve defined in my template as having only 80 pixels in width. The 88 pixels were throwing things off, so I used the width attribute of the HTML img tag to solve the problem. Unfortunately, it just squeezes the image, making the text in it appear fuzzy.

The Solution: FeedBurner conveniently provides what they call their “Awareness API,” which is a RESTful interface to retrieve (as XML data) the same exact information displayed in the FeedCount^TM image. Since I wanted to maintain the same kind of image (because it’s a recognized look-and-feel for FeedBurner feeds), I simply fired up an image editing program, shuffled things around a bit until the image was a nice, clean 80 pixels wide, and saved it as the base image (shown to the right) I would use for generating an image similar to the one FeedBurner provides.

Then, I wrote a script to grab the FeedBurner data (using SimpleXML) and used PHP’s image functions to open the base image, write the FeedBurner circulation data to it, and save it to use on my site. I simply have a cron job that runs this script once a day to keep my image updated.

Here’s the code. Enjoy!

[code lang=“php”]
<?php
// Get the XML data from Feedburner
$sxe = new SimpleXMLElement(‘http://api.feedburner.com/awareness/1.0/GetFeedData?uri=ramsey’, NULL, TRUE);
$readers = (string) $sxe→feed→entry[‘circulation’];

// make sure it’s a number
$readers = is_numeric($readers) ? $readers : ‘0’;

// 39 is the base position; 6 the width of each char
$xpos = 39 – (strlen($readers) * 6);

// Create the image from the base image
$img = imagecreatefromgif(‘feedburner-base.gif’);
$color = imagecolorallocate($img, 0×00, 0×66, 0xCC);
imagestring($img, 2, $xpos, 2, $readers, $color);

// Save the image
imagegif($img, ‘feedburner-readers.gif’);
?>
[/code]

This is more or less same way in which QR Codes are generated.

Note that I determined the numbers used in lining up the text in the image by trial-and-error. I played around with it a bit to get things right. The $xpos variable is my attempt to right-align the text because you can only specify the left edge of the text with the x coordinate.

XML Web Services and Security

Because a large amount of web services are largely built on XML, this has led to many new standards being developed in order to supply the basic security infrastructure to support it’s use. Here is a quick list (which is by no means complete) of some developing technologies which may be of use to the reader. It will hopefully flag up some further reading for any one new to XML development.

XML Signature - an XML specification for digital signatures. These are essential to provide authentication, integrity of the message and of course non-repudiation.

XML Encryption - a companion to XML Signature - this addresses the need to encrypt and decrypt XML documents and sections of documents.

XML Key Management Specification (XKMS) - definition of messages and protocols for exchanging and distributing public keys. It also has the facility to distribute these keys between unknown transaction clients.

Security Assertion Markup Language (SAML) - protocol for exchanging authentication and authorization information.

In addition to these important XML concepts, there are other technologies which should be considered. For information and articles on security and anonymity particularly in large scale infrastructures - there is a lot of good advice particularly concerning proxies on this technology website - http://www.anonymous-proxies.org/ .

Other useful reading areas would be on more web technologies such as SOAP, WSDL and UDDI. Although these technologies all perform very useful services to any XML developer, they are particularly vulnerable to interception and eavesdropping attacks ‘on the wire’. Because XML is often transmitted in clear text - SSL should be used for any private information.

Good Courses to Learn XML

I’m not a web designer but it is becoming apparently clear that I need to understand XML and HTML when I work on my company’s merchant account website. Even though I only have to make changes to the copy and head tags on the website, it would just make sense for me to know exactly what I’m doing. Usually when something more “difficult” pops up, I send it on to our in-house designer who knows how to hand code and understands the basics way better than I do.

Since I want to show that I am a valuable employee, I would like to be able to do the majority of the things the designer does (except designing logos and headers). I decided to start looking into taking some classes and “getting my knowledge on.” Of course, I started searching online hoping that I would get some good free information. Here’s what I found:

1. XML Tutorial at W3Schools.com: This is a free online tutorial and it looks pretty substantial. The website indicated to me that I need to have an understanding of HTML and JavaScript first. Yikes! I have a lot to learn.

2. XML Basics - An Introduction to XML at XMLFiles.com: It tells me that after studying the chapter presented on their site, I will know what the difference is between HTML and XML and that I will begin to know how to use XML. This sounds promising!

3. XML Tutorial at quackit.com: This site assures me that XML is easy to learn even if I don’t have much experience with HTML or databases (uh-oh, databases?) but the information will be easier to understand if I know both of these, as well as CSS. Ouch - I’ve just added another technology to my “need to learn” list!

I’ve determined that I need to delve into HTML, CSS, JavaScript, and XML and I am going to get as much as I can out of the free information online. Database technology might be something for the future, but we’ll see. I wish I had known at the age of 18 that I was going to love the internet this much. If I had, I would have received my degree in computer programming, not communication. Wish me luck!