Tài liệu Matchmaker Make Me a Match pdf

VOLUME III - ISSUE 3

MARCH 2004

The Magazine For PHP Professionals

Matchmaker
Make Me a Match
Using the Amazon.com API
through PHP and XML-RPC
Explore your HTML code with Tidy

www.phparch.com

PHP And WAP: Past, Present & Future
Testing Automation With PHP

PHP Ahoy!
A Look at: php | Cruise

Bahamas 2004

Plus:

Tips & Tricks, Security Corner, Product Reviews and much more...



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TABLE OF CONTENTS

php|architect
Departments

5

Features

9

Editorial

Connecting to Amazon.com Web
Services with NuSOAP
by Alessandro Sfondrini

I N D E X

6

What’s New!

16
34

Matchmaker, Matchmaker Make Me A
Match: An Introduction to Regular
Expressions

Book Review
Flash MX 2004 for Rich Internet
Applications

by George Schlossnagle

42

Product Review
Mambo Open Source: Content Management
System

28
Automated Testing For PHP
Applications
by Dr. James McCaffrey

59

Security Corner
Shared Hosting
by Chris Shiflett

35
PHP Ahoy! A look at php|cruise
by Marco Tabini

63

Tips & Tricks
By John W. Holmes

47
WAP: Past, Present and Future
by Andrea Trasatti

66

exit(0);
I Am Jack's Total Lack of Linux Support
By Marco Tabini

53
Tidying up your HTML in PHP5
by John Coggeshall

March 2004

●

PHP Architect

●

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3


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EDITORIAL

E D I T O R I A L

R A N T S

I

'm sure you're familiar with the Chinese proverb "may
you live in interesting times." Even though I rarely
think of my professional life as dull and boring, the
last month has been particularly exciting. As promised
in my exit(0) column from last month's issue, if you
look through the middle of the magazine you'll find a
full report (in colour!) on the best conference I have
ever attended—our very own php|cruise (forgive me
for a bit of professional price—eight months of prep

work will do that to you). Things went so well that
we're working on another cruise—this time going to
Alaska in the fall—and plan on making php|c an annual event for many years to come.
All good things come to an end, of course, and, once
back from the cruise, it's back to work. Luckily for us,
work means bringing you yet another great issue of
php|architect—and I personally consider that another
good thing. Like every month, we've got some great
content waiting for you in the following pages.
The one I'm most proud of is George Schlossnagle's
regular expressions article. Regexes are something that
pretty much every programmer has to deal with, but
that very few among us really know how to use. In fact,
I've seen developers write extremely complicated code
with the explicit purpose of getting around having to
use a regular expression—and that is just plain wrong.
After all, using the best solution for each problem is
what being a programmer is all about.
Thus, I approached George about writing an article
on regular expressions—and it became quickly evident
that one article would not even come close to covering
the complexity of regex. Now, everyone knows that I
always try my best to stay away from multi-part articles
for a multitude of reasons, but in this case I felt that the
topic more than deserved our attention over multiple
issues and, therefore, George's article is the first in a
series of three. Over the next three months, he will take
you for a ride from the basics (which are covered in this
issue) to the more complex and exotic aspects of regular expressions, thus hopefully providing the PHP world
with a definitive guide to this topic.

If regular expressions are not your bag, one of the
other topics covered in this month's issue is certain to
tickle your fancy. For example, you may want to read
Alessandro Sfondrini's excellent article on using the
Amazon.com API directly from your PHP website, or
Andrea Trasatti's look at the world of WAP. As you can
probably imagine, both Andrea and Alessandro hail
from my native Italy—and that alone makes their articles more than worth reading. There, my monthly heritage tax is now paid up!
As I'm sure you've noticed, in the past few months
we've been publishing material about testing practices
quite frequently. As larger and larger projects are devel-

php|architect
Volume III - Issue 3
March, 2004

Publisher
Marco Tabini

Editorial Team
Arbi Arzoumani
Peter MacIntyre
Eddie Peloke

Graphics & Layout
Arbi Arzoumani

Managing Editor
Emanuela Corso

Director of Marketing
J. Scott Johnson


Account Executive
Shelley Johnston


Authors
John Coggeshall, John Holmes,
Dr. James McCaffrey, George Schlossnagle, Alessandro
Sfondrini, Chris Shiflett, Andrea Trasatti
php|architect (ISSN 1709-7169) is published twelve times a year by Marco Tabini &
Associates, Inc., P.O. Box 54526, 1771 Avenue Road, Toronto, ON M5M 4N5, Canada.
Although all possible care has been placed in assuring the accuracy of the contents of this
magazine, including all associated source code, listings and figures, the publisher assumes
no responsibilities with regards of use of the information contained herein or in all associated material.

Contact Information:
General mailbox:

Editorial:

Subscriptions:

Sales & advertising:

Technical support:

Copyright © 2003-2004 Marco Tabini & Associates, Inc.

— All Rights Reserved

Continued on page 8...
March 2004

●

PHP Architect

●

www.phparch.com


NEW STUFF

N E W

S T U F F

What’s New!

ing the ability to access low-level socket operations on streams.

PHP 5.0 Beta 4
PHP.net has announced the release of PHP 4.3.5 RC1.
This fourth beta of PHP 5 is also scheduled to be the
last one (barring unexpected surprises, that did occur
with beta 3). This beta incorporates dozens of bug fixes
since Beta 3, rewritten exceptions support, improved

interfaces support, new experimental SOAP support, as
well as lots of other improvements, some of which are
documented in the ChangeLog. Some of the key features of PHP 5 include:
• PHP 5 features the Zend Engine 2.
• XML support has been completely redone in
PHP 5, all extensions are now focused around
the excellent libxml2 library
( />• SQLite has been bundled with PHP. For more
information on SQLite, please visit their website.
• A new SimpleXML extension for easily accessing and manipulating XML as PHP objects. It
can also interface with the DOM extension
and vice-versa.
• Streams have been greatly improved, includ-

March 2004

●

PHP Architect

●

www.phparch.com

PHP.net also announced the release of PHP 4.3.5 RC
3. This will be the last release candidate prior to the
final release, so please test it as much as possible.
For more information visit />
ZEND Optimizer 2.5.1
Zend has announced the release of Zend Optimizer

2.5.1.
Zend.com describes the Optimizer as: "a free application that runs the files encoded by the Zend Encoder
and Zend SafeGuard Suite, while enhancing the running speed of PHP applications.
Benefits:
• Enables users to run files encoded by the Zend
Encoder
• Increases runtime performance up to 40%."
Get more information from Zend.com.

6


NEW STUFF
Zend Launches New PHP5 In-Depth
Articles Section
Zend Technologies have launched a new version of
their Developer's
Corner on the zend.com website. PHP5 In-depth
showcases articles from many well-known PHP authors
on the new features of PHP. For more information,
check out />
DEV Web Management System
Dev is small, but powerful and very flexible content
management system for web portals. System is licensed
as freeware under the terms of GNU/GPL license. It is
absolutely free for non-commercial and commercial
use. Based on php4 + MySQL technology.
This project allows the user to publish articles, evaluate article by taking the pool, publish short news and
create back-ends in xml format, manage download
lists, Manage advertisement on your site, Be informed

about events on your site, create system reports and
export them into MS Excel or XML format and much
more.

For more information visit: />
PhpMyAdmin 2.5.6
Phpmyadmin.net has released their latest version of
phpMyAdmin. PHPMyAdmin is a tool written in PHP
intended to handle the administration of MySQL over
the Web.
"Welcome to this new version, aimed at stabilization of
the 2.5 branch. Meanwhile, work is continuing on the new
2.6 branch. PhpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web.
Currently it can create and drop databases,
create/drop/alter tables, delete/edit/add fields, execute
any SQL statement, manage keys on fields."
For more information visit: www.phpmyadmin.net.

PhpSQLiteAdmin 0.2
PhpSQLiteAdmin is a Web interface for the administration of SQLite databases.
Version 0.2 comes with some new features and a lot
of internal cleanups and refactoring. PhpSQLiteAdmin
is still in an early stage of development. It comes free of
charge and without warranty.
For more information visit: www.phpsqliteadmin.net.
phpMyEdit 5.4
phpMyEdit generates PHP code for displaying/editing
MySQL tables in HTML. All you need to do is to write a
simple calling program (a utility to do this is included).

Looking for a new PHP Extension? Check out some of the latest offerings from PECL.
ps 1.1.0
ps is an extension similar to the pdf extension but for creating PostScript files. Its api is modeled after the pdf extension.
Memcache 0.2
Memcached is a caching daemon designed especially for dynamic web applications to decrease
database load by storing objects in memory. This extension allows you to work with memcached through handy OO interface. This extension allows you to call the functions made available by libstatgrab library.
POP3 1.0
The POP3 extension makes it possible for a PHP script to connect to and interact with a POP3
mail server. It is based on the PHP streams interface and requires no external library.
Fileinfo 0.1
This extension allows retrieval of information regarding vast majority of file. This information
may include dimensions, quality, length etc. Additionally it can also be used to retrieve the
mime type for a particular file and for text files proper language encoding.

March 2004

●

PHP Architect

●

www.phparch.com

7


NEW STUFF
It includes a huge set of table manipulation functions
(record adition, change, view, copy, and remove), table

sorting, filtering, table lookups, and more.
Several minor bugs were fixed. A few new options
were added. Major features include tabs support, the
ability to specify SQL expressions for fields when writing to the database, the ability to define new triggers,
and more. All eval() calls were removed due to security
and performance reasons. Some code was optimized.
Several parts of the documentation were updated. A lot
of new language files were added and updated.
For more information visit:
phpMyEdit/ .

ionCube Releases New Encoder
UK-based ionCube has released a new version of their
compiled code PHP encoding tools. New features
include a choice of ASCII or binary encoded file formats
and optional support for OpenSource extensions such
as mmcache.
Prices start at a special price of $159 in their March
20% off sale.
For further information, please visit the homepage of
the Encoder:

Editorial: Contiuned from page 5
oped using PHP, serious testing processes are going to
become an integral part of every good developer's
arsenal of programming tools. What we never quite
considered is that PHP is a great testing platform even
for those projects that are not written using it.
Thankfully, James McCaffrey came to the rescue and
provided us with a wonderful article on the subject.

Our final article this month is about the new Tidy
extension, which author John Coggeshall has recently
introduced in PHP. You may have already heard about
the Tidy project, which provides a series of libraries
capable of parsing and automatically required documents written in markup languages like HTML or XML.
Tidy brings an important set of capabilities to PHP, and
I'm happy to have the author of the extension introduce us to it.
That's it for this month—time for me to go tend to
my sunburn while I start working on the next issue.
Until then, happy readings!

/>
php|a

Check out some of the hottest new releases from PEAR.
Mail_Queue 1.1
Class to handle mail queue managment.Wrapper for PEAR::Mail and PEAR::DB (or
PEAR::MDB).It can load, save and send saved mails in background and also backup some mails.
The Mail_Queue class puts mails in a temporary container waiting to be fed to the MTA (Mail
Transport Agent) and send them later (eg. every few minutes) by crontab or in other way.
XML_Transformer 0.9.1
With the XML/Transformer class one can easily bind PHP functionality to XML tags, thus transforming the input XML tree into an output XML tree without the need for XSLT.
Net_LMTP 0.7.0
Provides an implementation of the RFC2033 LMTP using PEAR's Net_Socket and Auth_SASL
class.
Text_Wiki 0.8.3
Abstracts parsing and rendering rules for Wiki markup in structured plain text.

March 2004

●

PHP Architect

●

www.phparch.com

8


Connecting to Amazon.com
Web Services with NuSOAP

F E A T U R E

by Alessandro Sfondrini
Have you ever wanted to add an online shop to your
website but gave up on the idea because you lack the
expertise and resources to run it? Using SOAP, you can
connect to Amazon Web Services and create a PHP application to remotely browse and search products, add
them to Amazon shopping carts or wish lists and, yes,
you can even earn money on every purchase performed
from your site.

I

n the article "Exploring the Google API with SOAP,"
which appeared in the January issue of php|a, I
showed you what SOAP is and how it can be used

together with PHP. We used a SOAP-encoded document to perform a search using the Google Engine,
then we parsed the response to display the results on
our website. To perform these operations, we wrote an
application from scratch; this approach can be great to
understand how SOAP works, but when a customer
asks you to implement a SOAP-based feature in an
application, you can't waste your time in that way.
In this case, there are some libraries that will make
your coding quicker and easier: one of these is
NuSOAP, which allows you to send Remote Procedure
Calls (RPCs) over HTTP.
This article will show you how we can use the
Amazon.com API with NuSOAP to perform searches
and display product details, without having to sort
through a lot of SOAP syntax: if you have had an
opportunity to read my previous article, you will notice
how much shorter an application written this way is,
and how much time can actually be saved by using this
method.

What are Amazon Web Services?
Amazon.com is one of the most widely known on-line
shops. You can find and buy almost everything, from
books to toys to power tools. Several years ago,
Amazon launched a very successful affiliate program,
which they later expanded in their Web Services program.
Why would you want to use Amazon Web Services
March 2004

●

PHP Architect

●

www.phparch.com

(AWS)? For instance, if your website is about Literature,
you may want to allow your users to look for books in
the (huge) Amazon database directly from your pages,
without redirecting them to Amazon.com. You can provide them with a detailed description of each book and,
when they decide to buy one, you can add it directly to
their Amazon shopping cart. When the time comes to
complete the purchase, you can redirect the user
directly to the Amazon website, where the checkout
process actually takes place and you receive credit for
your affiliate referral.
It is important to understand that AWS are designed
only to retrieve information about products and create,
as well as populate, shopping carts, not to perform payments: this must be done directly on the Amazon website-the reason being, of course, one of security for the
customer's personal information. In any case, a significant portion of the transaction is performed from your
website. This results in a benefit both for you and for
your users, since you can offer your customers a nearly
seamless user experience and collect your referral fees.
Access to AWS, as well as to the affiliate program,
requires you to register with the Amazon Associates
Program and obtain an Associates ID, which will identi-

REQUIREMENTS
PHP: 4.1 and higher

OS: Any
Other software:: NuSOAP 0.6.4
Code Directory: webs-nusoap

9


FEATURE

Connecting to Amazon.com Web Services with NuSOAP

fy each purchase sent through our website.

Getting started
Before we start coding, I recommend you download
the
AWS
Software
Developer's
Kit
from
It contains
the License Agreement, a guide (you should have a
look at it to familiarize yourself with the concepts associated with the program) and some code samplesincluding a few written in PHP!
As I mentioned earlier, you will also have to apply for
your Developer's token-an alphanumerical string needed for performing searches and purchases: to do so,
you have to visit :
/>oin/developer/application.html

and accept the AWS terms and conditions.

To write our application, we will take advantage of a
PHP library called NuSOAP-which is really just a group
of "userland" classes written in PHP and designed to
allow developers to manage SOAP web services, which
will speed up our coding by allowing us to focus on
functionality
rather
than
on
the
communication protocols. NuSOAP is distributed
under the LGPL license, and can be downloaded here:
.
To add NuSOAP support to our project, we simply
have to include nusoap.php to our PHP scripts using
require(). Performing a Remote Procedure Call (RPC) is
simple—look at this example:
require("nusoap.php");
$params = array('name' => 'value');

Figure 1
Parameter Name
keyword

mode

tag

type

devtag

$proxy = $s -> getProxy();
$result = $proxy -> method($params);

Figure 2
Result Datum

Type

The keyword on which the search
should be performed.

Description

Url

String

The URL of the product page for
this item on Amazon

Asin

String

The Amazon.com Standard Item Number
for this product

ProductName

String

The name of the product (in our
case, the title of the book)

Catalog

String

The category of the product (e.g.:
books)

Authors

String

The name(s) of the author(s)

ReleaseDate

String

The release date, in human-readable
format (e.g.: "23 February, 1976").

String

The page number. AWS returns ten
results per page, so page 1 will

contain results 1 through 10, page
2 results 11 through 20, and so on.

Manufacturer

String

The name of the product's manufacturer (the publisher in our case)

String

Specifies the ID of the store to
browse. Each Amazon store has its
unique ID, which indicates what
kind of products it sells (e.g.:
books, music, dvd, vhs, etc.). You
can find a complete list of all the
IDs available in the AWS documentation.

ImageUrlSmall

String

A pointer to the products "small"
image on the Amazon website

ImageUrlMedium

String

Same as above, for a slightly larger image

String

Your Associate ID. If you don't
have one, you can use the generic
ID webservices-20.

ImageUrlLarge

String

Same as above, but for an even
larger image

ListPrice

String

The product's list price, including
the currency symbol (e.g.: "$
20.55")

String

Determines the type of search
results. Lite indicates a simpler
result set, while heavy provides a
richer set of information about
each item returned. We'll use lite

for our example.

OurPrice

String

The product's selling price on
Amazon, including the currency symbol

UsedPrice

String

The product's price for used
copies.

String

●

First of all, we include NuSOAP and we store the
parameters we will use for the RPC in the $params associative array. We then create a new soapclient object,
passing two arguments to the constructor: the SOAP
server address and a boolean value that indicates
whether the server uses a WSDL document. WSDL
(Web Services Description Language) documents contain information about a web service, as well as its
methods and properties. They are often used by web
service providers—including Amazon.
Once we have created the object, all we have to do
is to actually execute the RPC by invoking the call()

method and specifying the remote method name and
the parameters to be passed (contained in $params in
our case). NuSOAP automatically fetches the results of
the call and stores them in the $result array.
Since we are working with a WSDL-based server,
NuSOAP can actually create a "proxy" PHP class capable of providing a better interface to our scripts. Once
we have instantiated $s, we can also invoke a remote
method in this way:

Description

String

page

March 2004

Type

$s = new soapclient("http://server/file.wsdl", true);
$result = $s -> call('method', $params);

PHP Architect

●

The Developer Token you have
received from Amazon.

www.phparch.com

10


FEATURE

Connecting to Amazon.com Web Services with NuSOAP

This can be useful to simplify our code: first, we create a proxy client, $proxy; any subsequent RPCs to
methods specified in the WSDL can be performed using
the proxy, without having to use the NuSOAP call()
method again. In our application, we will use proxies to
work with AWS.

Designing the application
Now that we've laid down some ground rules, it's time
to decide in detail what the goals of our application are
going to be. Since we're all PHP fans, our example website will be about PHP and, therefore, we'll want to
allow our users to buy books on this topic from
Amazon.
The first thing that we need is a search page: users
will be able to search for a particular keyword (or for a
set of keywords) and the page will display some basic
information about each book that matches the criteria,
such as its title, an image, the publishing company,
author or authors and price. We also have to provide a
way to browse the results, since AWS calls only return
ten results per call.
The search page should also contain a link for each
product to another page on our website that will contain a detailed description of the book, including any

user reviews and comments. From here, the users will
be able to continue their purchase on Amazon.com or

add the product to their wish lists.

The search page
If you have had an opportunity to read through the
AWS documentation, you have probably discovered
that searches by keyword can be performed using the
KeywordSearchRequest() method, which requires the
parameters shown in Figure 1.
Assuming that the call will be successful, the server
will return an array containing several items:
• The TotalResults element, which indicates
the number of total results returned by the
query.
• The TotalPages element, which provides the
number of pages available in the search
result.
• The Details sub-array, which contains a set
of data about each search result matching
our search criteria that is included in the
page we have requested. Given that a search
only returns a maximum of ten items per
page, you can expect that this array will
contain no more than ten elements. The
lite search mode returns the data shown in
Figure 2.

Listing 1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

31
32
33
34
35
36
37
38
39
40
41
42
43
44

<input type=”text” name=”keyword” value=”” />
<input type=”hidden” name=”page” value=1 />
<input type=”submit” name=”button” value=”Search!” />
</form>
if (empty($_GET[“keyword”])) // If the form has’n been submitted
exit;
// Stops the execution
require(“nusoap.php”);
$client = new soapclient(“ true);
$proxy = $client -> getProxy(); // Creates a WSDL client and a proxy
$param = array(
‘keyword’
‘page’

‘mode’
‘tag’
‘type’
‘devtag’
);

=>
=>
=>
=>
=>
=>

$_GET[“keyword”],
$_GET[“page”],
‘books’,
‘webservices-20’,
‘lite’,
‘YOUR-DEV-TOKEN’

$results = $proxy -> KeywordSearchRequest($param); // Calls the method
if(empty($results[“Details”])) // Checks whether there are results
die(“

No results found for "”.$_GET[“keyword”].”".

”);
echo “

Searched Amazon.com for "”.$_GET[“keyword”].”" - page “
.$_GET[“page”].” of “.$results[“TotalPages”].”

”;
foreach($results[“Details”] as $res) // Prints each product details
echo “<img src=’”.$res[“ImageUrlMedium”].”’ align=’left’ />
\n”
.”<a href=’details.php?asin=”.$res[“Asin”].”’><b>”.$res[“ProductName”].”</b></a>

\n”

.”<b>Authors</b>: “.@implode(‘, ‘, $res[“Authors”]).”
\n”
.”<b>Publishing Company</b>: “.$res[“Manufacturer”].”
”
.”<b>List Price</b>: “.$res[“ListPrice”].” - <b>Our Price</b>: “
.$res[“OurPrice”].” - <b>Used Price</b>: “.$res[“UsedPrice”].”


\n\n”;
if($_GET[“page”] > 1) // Prints a link to prev. page if any
echo “<a href=’$PHP_SELF?keyword=”.$_GET[“keyword”].”&page=”.($_GET[“page”]-1).”’>Previous Page</a> \n”;
if($_GET[“page”] < $results[“TotalPages”]) // Prints a link to next page if any
echo “  <a href=’$PHP_SELF?keyword=”.$_GET[“keyword”].”&page=”.($_GET[“page”]+1).”’>Next Page</a>”;
?>

March 2004

●

PHP Architect

●

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11


FEATURE
Parameter

Connecting to Amazon.com Web Services with NuSOAP

Type

Basic Character ClassesDescription

asin

String

The product's ASIN (which, in our
case, can be retrieved from
$_GET['asin']

tag

String

The Associate ID, or [webservices20] if you want to use a generic
one

type

String

The type of search. In this case,
we'll choose heavy, since we want
all the information available on a
particular book

devtag

String

Your Developer Token

Result Datum

SalesRank

Type

Description

Integer
Array of
Strings

Lists

The product's sales ranking
The names of the ListMania lists
that contain the product

Indicates the product categories in
which the product can be found. Its
contents look like this:

BrowseList

Array of
Arrays

BrowseList =>
Array
(
[0] => Array
(
BrowseName => PHP
)
)

Media

String

The type of medium on which the
product is distributed (e.g.:
paperback or hardcover for books)

Isbn

String

The ISBN code of the product (books
only)

Availability

String

Indicates how long the product
takes to be shipped

Reviews

SimilarProducts

Element

Array

This array contains information
about the customer reviews associated with the product. It includes
three elements: AvgCustomerRating,
which indicates the average customer rating for the product,
TotalCustomerReviews, which contains the number of customer
reviews available and
CustomerReviews, which is an array
that contains the three most recent
reviews (you can find the contents
of this array in Figure 6).

Array of
Strings

Contains the ASINs of products that
are similar to this one.

Type

Description

The rating of the product in this
review

Rating

Integer

Summary

String

A summary of the review

Comment

String

The full review itself

March 2004

●

PHP Architect

●

www.phparch.com

As you can see, the KeywordSearchRequest() method
returns quite a few pieces of information for every
result item, although, of course, we don't have to output all of them on our site. If you look at Listing 1—the
source for our search page—you'll see that the very first
part of the file is nothing more than a simple HTML
form, which contains an input text box for the keyword
and a hidden field that forces the page number to 1—
this way, a new search will automatically start from the
first page of results.
The form uses the GET method because we need to
use links for the "Next Page" and "Previous Page" operations (something like page.php?keyword=blah&page=2).
Naturally, you could also use POST, but in that case it
would be much more difficult for someone to create a
direct link to your search results, which could, in theory, prevent you from completing some sales.
The second part of the script contains the actual PHP
code. First of all, an if-then-else control block stops the
execution of the script if $_GET["keyword"] is empty.
Otherwise, we include NuSOAP and create a SOAP
client by passing the URI of the *.wsdl file for Amazon
(which is provided in AWS documentation) and the
boolean true to indicate to the constructor of the soapclient() class that the SOAP client features WSDL support. We also create a proxy to call AWS methods
directly as we have seen in the first part of the article.
The
parameters
needed
to
invoke

KeywordSearchRequest() are stored in the $param array;
the first two (the keyword and the page number) are to
be found in the $_GET superglobal, since they change
each time we perform or browse a search, while the
others are constant and, therefore, we hardcode them
in our script. Remember to insert your developer token
in $param["devtag"].
Once we have invoked the method and stored the
search results in $results, we have to display the latter
in a format that is comprehensible to the user. First, we
check whether there are any results to begin with. If
the search returned no data, the program displays a
warning and exits. Otherwise, we print a short summary of the search: the keyword, the current page number and total page count, followed by details about
each product in the current result page. These are actually produced by a simple foreach loop, which browses the $results["Details"] array, echoing the title of
each book, a medium-size image, its authors, publishing company and prices. We will also provide a link to
another page, details.php, which contains further
information on each book. The link contains a reference to the product's ASIN (the Amazon identifier for
each product) in order to make the application able to
retrieve the correct product from Amazon's catalogue
with another RPC.
The last part of this page allows the user to browse
the results: if the current page isn't the first one (Page

12


FEATURE

Connecting to Amazon.com Web Services with NuSOAP

1), the script prints a link to the previous one and, if it
isn't the last page (based on the information returned
by our AWS call), it prints a link to the next one.
Figure 3 shows our search page at work.

The Product Detail Page
Now that we are done with the first part of the application, it's time to move on to the product detail page,
which will show advanced information about a particular book. The AWS method we need in this case is
AsinSearchRequest(), which needs the parameters
shown in Figure 4. Just like before, the response that we
get back from Amazon is an array of arrays—except
that, in this case, we will simply concern ourselves with
the first result set, since the ASIN uniquely identifies
one product. Our data, therefore, will be stored in
$results['Details'][0], which, in turn, will contain
the information shown in Figure 5. As you can see,
some of the values returned are the same as the results
of the KeywordSearchRequest() call that we used in
Listing 1, while some others, like the customer reviews,
are more appropriate for a detailed product page.
Speaking of the product page, Listing 2 contains the
code for details.php. First, we check $_GET["asin"]; if
it is empty, the program displays a warning and exits.

In a more complete application, you may want a slightly more verbose explanation of what went wrong, or
perhaps an automatic redirection to the search page.
If we have an ASIN, we include the NuSOAP library,
then create a SOAP client and proxy as we did in the
previous page. Please note that we have to use
sprintf() to transform the ASIN in a ten-character

strings, since AWS requires it to be submitted in that
format (as an alternative, you could use str_pad() to
ensure that the string is ten character long).
This time, we only need to pass the ASIN and specify
heavy as the search type. Once the RPC has been executed, we retrieve the results and print them out, using
a foreach loop to cycle through the user reviews.
The final touch in our application consists of providing a link back to the Amazon website in order to make
it possible for our users to purchase a product—you
can't do much selling by just showing which products
are available!
The AWS documentation specifies that an HTTP form
must be set up for the purpose of submitting the purchase information over to Amazon.com. This form (you
can look at the one in Listing 2 for an example) uses the
POST method, and its action attribute is really nothing
more than a page on Amazon.com that contains the

Listing 2
1
2
3
4
5
6
7
8
9
10
11
12
13

14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

44
45
46
47

if(empty($_GET[“asin”]))
die(“

No ASIN specified

”);
require(“nusoap.php”);
$_GET[“asin”] = sprintf(“%010d”, $_GET[“asin”]);
$client = new soapclient(“ true);
$proxy = $client -> getProxy(); // Creates a WSDL client and a proxy
$param = array(
‘asin’
‘tag’
‘type’
‘devtag’
);

=>
=>
=>
=>

$_GET[“asin”],
‘webservices-20’,
‘heavy’,
‘YOUR-DEV-TOKEN’

$results = $proxy -> AsinSearchRequest($param); // Calls the method

?>

<?=$results[“Details”][0][“ProductName”] ?>

<b>Authors:</b> <?=@implode(‘, ‘, $results[“Details”][0][“Authors”])?>


<b>Published by</b> <?=$results[“Details”][0][“Manufacturer”]?>
<b> on</b> <?=$results[“Details”][0][“ReleaseDate”]?>


<b>List Price</b>: <?=$results[“Details”][0][“ListPrice”] ?> <b>Our Price</b>: <?=$results[“Details”][0][“OurPrice”] ?> <b>Used Price</b>: <?=$results[“Details”][0][“UsedPrice”] ?>



<!— Form to purchase on Amazon.com —>
<form method=”POST” action=” ?>”>
<input type=”hidden” name=”tag-value” value=”webservices-20”>
<input type=”hidden” name=”tag_value” value=”webservices-20”>
<input type=”hidden” name=”dev-tag-value” value=”YOUR-DEV-TOKEN”>
<input type=”submit” name=”submit.add-to-cart” value=”Buy From Amazon.com”>  
<input type=”submit” name=”submit.add-to-registry.wishlist” value=”Add to Wish List”>
</form>
<!— End Form —>
<b>ISBN:</b> <?=$results[“Details”][0][“Isbn”]?>


<b>Availability:</b> <?=$results[“Details”][0][“Availability”]?>

<b>Sales Ranking:</b> <?=$results[“Details”][0][“SalesRank”]?>


<b>Average customer rating:</b> <?=$results[“Details”][0][“Reviews”][“AvgCustomerRating”]?>

Read user reviews:

foreach($results[“Details”][0][“Reviews”][“CustomerReviews”] as $res)
echo “

”.$res[“Summary”].”

”
.”<b>Rating: </b>”.$res[“Rating”].”

”.$res[“Comment”].”
<hr />”;
?>

March 2004

●

PHP Architect

●

www.phparch.com

13

FEATURE

Connecting to Amazon.com Web Services with NuSOAP

ASIN of product that must be added to the user's shopping basket. A few additional hidden fields provide the
ASIN, the Associates Id and the Developer's token. The
form supports two different buttons: one adds the
product to the user's basket, while the other adds it to
his wishlist.

Further Improvements
As you have probably noticed, writing a SOAP-based
application using a library like NuSOAP is much faster
than developing your own SOAP classes—if you have
read my article about the Google API that appeared on
the January issue of php|a, you probably know what I
am talking about. This means that you can develop
rather complex applications without having to waste
time dealing with the nitty-gritty details of the underlying protocol; in fact, we didn't even write any SOAP
code for our Amazon application—NuSOAP did it all for
us.
Naturally, the code that I have introduced here is very
basic and could stand to gain from some improvements. For instance, Amazon Web Services allow you to
to manage a a remote shopping cart or wish list by
adding and removing items to them. The very last part
of the purchase—the one where money changes
hands—must still take place on Amazon.com, but you
can let the user perform most of the normal operations
associated with an e-commerce website without leaving your website. However, do keep in mind that if you
choose to manage the user's shopping cart remotely,

you can't change it once you've submitted to
Amazon—this is done to protect the end user from
fraudulent transactions. You can check out the AWS
documentation for more details on this topic—you'll

find that it's not complicated at all.
Depending on your needs, you may choose to perform a different kind of search operation on your website: by similar products, by author, by ISBN, by manufacturer, and so on. You may also want to browse a
"node", or product category (e. g. "programming",
"web", etc.) directly, without performing a search. It
goes without saying that all this depends on what your
goals are.
If your Amazon-based shop becomes very popular,
you may decide to join the Amazon Associates
Program, an affiliate system that pays you commissions
on every sale. Be careful, however, that your application
must not send more than one request per second to
Amazon—even if you provide an error handling system,
you must not immediately retry a request if the previous one has failed.
You should also provide a caching system, in order to
store the data needed by your site without going back
and forth to AWS for every request—you can check out
Bruno Pedro's excellent article in the February 2004
issue of php|a for more idea on caching data from your
PHP scripts. If you choose to do so, don't forget that
you can't keep your data cached for more than twentyfour hours.
Finally, please keep in mind that in the examples
shown in this article we always referred to
Amazon.com, the American website. AWS are also
available for Amazon.co.uk, Amazon.de and
Amazon.co.jp, but you have to modify the URIs in the

script, changing the specifications in the WSDL document
from
[soap.amazon.com/]
to
soapeu.amazon.com/, and so on. You will also have to add
the locale parameter to your RPC invocations—its value
can be set to uk, de or jp, depending on which Amazon

Figure 3

March 2004

●

PHP Architect

●

www.phparch.com

14


FEATURE

Connecting to Amazon.com Web Services with NuSOAP

website you are referring to.

I'm Outta Here

Amazon.com Web Services is a powerful tool that you
can use to add e-commerce functionality to your site
without going to the expense of developing an online
store of your own and stocking all the merchandise.
Even if you can't create a complete on-line shop using
ASW (because the purchase must be completed on the
Amazon website), you can still give your users a customized shopping experience that relies on the practically limitless resources of one of the world's most popular e-commerce websites.
The sample application that I showed you in this article is quite simple: if you plan to use it in a production
environment—especially if your site has a lot of traffic—
you should probably consider implementing features
like error handling and caching in order to prevent
problems with the Amazon servers. Adding these elements to your application may require some extra
work, but it could all pay off if you enjoy decent traffic
and join the Amazon Associates Program.
Perhaps most importantly, I hope to have given you
a good idea of how much a SOAP library (in this article
we have chosen NuSOAP, but there are some others

packages, like PEAR::SOAP) can simplify the creation of
a complex application—write in few lines of code to
perform a Remote Procedure Call and you're practically done.
If you want to extend our sample application and create a "complete" on-line shop using AWS, have a look
to the documentation: there you will find a detailed
description of every method that's available for use. If
you want to learn more about SOAP, you can check out
the World Wide Web Consortium's notes about the protocol at or—if you missed it—
read the article "Exploring the Google API with SOAP"
published in the January 2004 issue of php|a.

About the Author

?>

Alessandro Sfondrini is a young Italian PHP programmer from Como. He
has already written some on-line PHP tutorials and published scripts on
most important Italian web portals. You can contact him at
.

To Discuss this article:
/>
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15


Matchmaker, Matchmaker Make Me A Match
An Introduction to Regular Expressions

F E A T U R E

by George Schlossnagle
A quick search for the words "hate" and "regular expressions" on your favourite search engine is likely to bring up
thousands upon thousands of hits. While most developers
recognize the usefulness of regular expressions (and many
can't do without them once they have figured out how
regexes work), their use remains something of a blackmagic art—right up there with hypnosis and session management. Despite looking complicated, however, regular
expressions are much easier to work with than most people are willing to admit.

A Few Myths about Regexes
Before we get started, we should dispel a
few popular myths about regexs:
Myth: Regular Expressions are Slow.
Truth: Regular expressions can be slow,
but they don't need to be. The main regular expression library used by PHP (called
PCRE and consisting of the preg_ family of
functions) is quite fast and also quite
powerful. This power means that it is

easy to write a short regular expression
that performs a lot of work, and performing a lot of work with any tool can be
slow.
Myth: You should use basic string functions instead of regular expressions.
Truth: Regular string functions (for
example strstr or strtok) are (marginally)
faster than the regular expression to
accomplish the same task. That having
been noted, this myth often leads to people implementing complicated string
parsers using string matching functions
where a single regular expression would
do the trick. The PCRE library will always
match complex patterns faster than
implementing a parser on your own.

March 2004

●

PHP Architect

●

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R

egular expressions (commonly known as regexes)
are a powerful tool for pattern matching and text
manipulation. A typical problem that pulls people

into learning regular expressions is text munging: you
have a string of text and you need to replace portions
of it based on certain rules. For instance, you
might want to obfuscate all the email addresses
in a block of text so that email addresses like
get translated to the form
george [at] example [dot] com. Regular
expressions are the tool for the job, and provide a powerful and deep syntax for handling tasks like these.
Alternatives to the PCRE
Functions
PHP supplies some alternatives to the PCRE functions.
The most direct competitor is the POSIX regular expression library that consists of ereg, ereg_replace and others. We won't be looking at the POSIX regular expression functions because the PCRE library provides a
broader pattern-matching facility than its POSIX counterpart and the PCRE library is about 30% faster on
average. The other option is to perform string matching with the standard string functions. As noted above,

REQUIREMENTS
PHP: ANY
OS: Any
Applications: N/A
Code Directory: match-regex

16


FEATURE

Matchmaker, Matchmaker Make Me A Match

the string functions are faster on the tasks they were
designed for (finding specific characters or substrings),

but are not an appropriate fit for anything but the simplest patterns.
Your First Regex
The simplest regex is a match against a static string. To
determine if the string '' is present in a piece of text, we can use the following code
fragment:
if(preg_match("/george@example\.com/", $text)) {
print "Matches";
} else {
print "Does not match";
}

this function in more detail later in the article.
• preg_replace_callback—This function
makes it possible to perform very complex
operations on a per-match basis through
the use of callback functions. We will cover
it in a future article, but some of its functionality overlaps with evaluated replacements, which are discussed in this article.
• preg_quote(string text)—When using input
text in a pattern, you may want to sanitize it
to ensure it does not contain any regex
metacharacters. preg_quote escapes all regex
metachacters in a string.

Despite its simplicity, this example illustrates the
basic syntax of a regex match. The regex itself is the
first parameter, and is contained within slashes ([/]).
• preg_split(string pattern, string subject
The second parameter is the text you want to test
[, int limit [, int flags]])—ppreg_split
the pattern against. The preg_match function returns

performs similarly to explode, allowing us to
true if the match succeeds, and false if it fails. Using
break up the string subject into limit parts.
slashes to delimit regular expressions is a convention
Instead of splitting on a specific delimiter,
(taken from the UNIX utility awk), but is not necespreg_split allows the string to be broken
sary—you can actually use any non-alphanumeric
based on a regex.
character. Alternative delimiters are convenient if
your pattern itself contains slashes.
Regex Basics
For instance, when dealing with file
Of course, we can (and should) perpaths or URLs (both of which conform the previous simple match using
tain numerous slashes), it is common
“The power of regustrstr(), which is faster than any regex
to use a different delimiter.
lar expressions is
function. What if, however, we want to
We can also perform substitutions
match all email addresses in a string,
in matching comwith PCREs. To substitute 'george at
rather than a specific one? What if you
plex patterns that
nospam.example.com' for my address
wanted to change text only if it
(a common anti-spam technique), you
cannot be identiappeared in a particular position within
can use
your string?
preg_replace("/george@example\.com/",

"george [at]
nospam.example.com",
$text);

The other PCRE functions are:

fied using straightforward textsearch functions
like strstr().”

• pcre_grep(string pattern,
array subjects [, int flag])—ppcre_grep
applies the specified pattern to every element of subjects, returning an array consisting of those that matched. If the optional
flag is set to PREG_GREP_INVER, only those
elements that did not match will be
returned.
• pcre_match_all( s t r i n g p a t t e r n , s t r i n g
subject [,array matches, int flags]])—
pcre_match returns only the first match
found in its subject text. pcre_match_all
matches as many times as possible, returning an array of all the matches. I will discuss

March 2004

●

PHP Architect

●

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The power of regular expressions is in
matching complex patterns that cannot be identified using straightforward
text-search functions like strstr(). The
basic components of a regular expression pattern are:

• Character Classes—Patterns rarely consist of
specified letters, but classes of letters. For
example 'any number' instead of a particular
number, or 'any letter' instead of a particular
letter.
• Grouping—Grouping allows for changing
the precedence of operations as well as
providing a means to extract the text you
matched with a pattern.
• Enumerations—Enumerators allow you to
specify how many times a character class or
sub-pattern appears. This allows for conven-

17


FEATURE

Matchmaker, Matchmaker Make Me A Match

Second, if you test this pattern you will find the following results.

ient expression of fixed length patterns like
'a US zipcode is 5 digits' as well as variable

length patterns such as 'a domain is a number of alphanumeric characters separated by
dots'.

• 555-123-4567 matches. This is correct.
• 5555-123-45678 matches. This is not correct.

• Alternations—Alternations allow for multiple
patterns to be combined. Unlike character
classes, which allow for a position to match
multiple characters, alternations allow for
entire patterns to be alternatively matched.
For example, a valid workday can be
Monday, Tuesday, Wednesday, Thursday or
Friday.

The second example does not represent a valid
phone number (the area code and line number are too
long), but it matches because the pattern fits as shown
in Figure 1.
There are a couple of ways to combat this problem.
If you know that your search text should be exactly a
phone number (with no leading or trailing text), you
can use positional anchors to force the pattern to start
at the beginning of the text and end at the end, as we'll
see later on.
If the phone number might be contained in text, on
the other hand, you might try and fix the pattern by
having the numbers have at least one character of leading and trailing whitespace, using a pattern like:

• Positional Anchors—Anchors allow you to

require your pattern to start matching at a
specific location in the search text, for example at the beginning or end of a line.
• Global Pattern Modifiers—Global pattern
modifiers allow you to change the basic
behavior of a regular expression, for example rendering it case-insensitive.

/\s\d\d\d-\d\d\d-\d\d\d\d\s/

Character Classes
While it's usually easy to find a particular substring
within a larger string—for example, my e-mail address
in a message—it's not always easy to find a particular
type of substring-like any e-mail address. To do this,
you need to be able to match against a more generic
pattern and not just against a static string. PCRE supplies character classes to allow you to do this; a character class allows a specific character in a search text
to be matched against a range of possible characters.
For example, a US phone number is composed of a
three digit area code, a three digit exchange, and a four
digit line number, commonly delimited by a '-'. To
match this pattern, you could use the following regular
expression:
/\d\d\d-\d\d\d-\d\d\d\d/

The \d specifier is a built-in PCRE character class
that consists of all the digits. There are a couple
things you should note about the pattern above. The
first is that we have many \d's. In regular expressions, any character or character class matches only
a single character unless you use an enumerator
(which we'll cover later) to attach a quantity to it.
Figure 1

Regex doesn't always work the way you expect
8

8

7

7

-

x

x

x

-

y

y

y

y

\d

\d

\d

-

\d

\d

\d

-

\d

\d

\d

\d

March 2004

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PHP Architect

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y

The \s specifier is another character class for all
whitespace (spaces, tabs, newlines, etc.). This pattern does not work in all situations, though, since if
the text begins with the phone number you will be
unable to match the leading \s. To handle this case,
boundary condition that
PCRE supports \b—a
matches at the border (or boundary) between a
'word' and a 'non-word' (these are words in the C
programming language sense—letters, numbers and
underscores only). \b is actually not a character class,
but what is known as a 'zero-width assertion'; this
means that the \b specifier does not actually match
the character on the other side of the boundary, but
only ensures that such a boundary exists. Putting
that into our pattern we can refine it to:
/\b\d\d\d-\d\d\d-\d\d\d\d\b/

Continuing the testing, we find that "077-xxx-yyyy"
matches. US and Canadian area codes and exchanges
cannot begin with 0 or 1 (these are reserved for long
distance and operator-assisted or international services). To be able to restrict the leading numbers to the
allowed set, we need to be able to create our own
character classes. In PCRE, these are constructed by
filling a set of brackets ([[ ]) with the characters we
want to match. To match 2-9, we can use the character class [23456789], which is commonly shortened via
a range operator to [2-9]. To use a custom character
class in a pattern, you use it exactly as you would a

regular character or character class. Here is the phone
number pattern reworked to employ this:
/\b[2-9]\d\d-[2-9]\d\d-\d\d\d\d\b/

18


FEATURE

Matchmaker, Matchmaker Make Me A Match

PCRE provides six commonly used built-in character classes, described in Figure 2. Additionally, PCRE
provides POSIX-style character classes for compatibility with POSIX-style regular expressions. These classes are described in Figure 3. POSIX character sets
aren't commonly used much in real-life code, which
is a shame because they are often a perfect fit for
problems that programmers encounter in their dayto-day work.
You can negate a POSIX character class by adding a
^ after the first colon. For instance, to match all non-letter characters, you could use the class :^alpha:.
Negations are also available in custom character
classes—for example, to match anything that is not the
greater-than character (>), you can use the custom
character class [^>]. Negations are very useful when
you are creating regular expressions that extract quoted text or if you want to manually parse XML or HTML.
Since '--', '^^' and '[[ ]' have special meanings in custom character classes, if you want those actual characters to be elements of the class, you should escape
Figure 2
Basic Character Classes

them with a backslash (\\). The two exceptions are
the range operator -, which can appear un-escaped
as the last character in a class, since that is unambiguous, and the negation character ^, which can

appear un-escaped in any position but the first.
Grouping and Sub-Patterns
Usually, you will not only want to match a pattern, but
extract data from it as well. To extract a specific part of
a pattern, you surround it within parentheses. For
example, to capture each part of the phone number
pattern, you would add parentheses as follows:
/\b([2-9]\d\d)-([2-9]\d\d)-(\d\d\d\d)\b/

Figure 3
POSIX Style Classes
:alpha:

Any letter

:alnum:

Any alphanumeric character

:ascii:

Any ASCII character

:cntrl:

Any control chatacter.

.

Matches any character

:digit:

Any digit (same as \d)

\w

An alphanumeric character or the underscore character.

:graph:

Any alphanumeric or punctuation character.

\W

Anything not a \w.

:lower:

Any lowercase letter.

\d

A digit.

:print:

Any printable character.

\D

A non-digit.

:space:

Any whitespace character (same as \s).

\s

Any whitespace. This includes spaces, tabs, newlines,
control characters.

:upper:

Any upperspace character.

\S

A non-whitespace character.

:xdigit:]

Any hexadecimal 'digit'.

Figure 4

March 2004

●

PHP Architect

●

www.phparch.com

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