Web Technology Solutions
Class: Application Syndication: Parse and Publish RSS & XML Data
Date : 3/3/2010
Tonight
✤
Introduction to XML
✤
Creating XML, RSS, and JSON with PHP
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using simpleXML for XML\RSSLab
Lab Preview
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Application Development
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Registration Feature
✤
Login\Logout
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Maintain State
✤
Admin CRUD for Survey
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Publish XML and RSS
Lab Preview
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Application Development:
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Adding XML and RSS
✤
✤
Publish an RSS feed of your survey
responses
✤
Publish an XML dump of your survey
responses
You will implement an ECO to provide XML
publication of a table in your database. Provide
a URL of feed.
Final Project Review
✤
Final Project - Web App (link)
✤
registration feature (week 6)
✤
login logout (week 7)
✤
admin ability to
create\read\update\delete
(CRUD) (week 4-5)
✤
Maintain State throughout app
(cookies\sessions) (week 7)
✤
XML and RSS feeds (week 8)
✤
Valid XHTML and CSS design
Web Apps
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Problem with apps:
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Data stored in other systems
can’t be shared easily.
✤
Data is in different formats
✤
Data has no meaning to
other systems, just its own
native system.
Web Apps
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Goals:
✤
Share information across
multiple environments
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Open, flexible language to
share data
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Provide schematic meaning to
data elements
Solution: XML
Intro to XML
✤
Markup language for
documents containing
structured information.
✤
Extensible Markup Language
(akin to HTML)
✤
Supported by W3C as a
standard
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Provides known structure and
relevant meaning to that data
structure.
✤
Widely used (iTunes, e.g.)
✤
Perfect for PHP developers to
Terms
of
XML
Meta: literally “provides
✤
meaning”.
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Schema: A logical organized
structure of data.
✤
Tags: Elements in XML that are
data containers
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Attributes: Extend meaning of
a tag
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Serialize: saving or storing
data
✤
Nodes: a DOM structure of a
data object (tree)
XML Sample
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Consider this example:
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<?xml version=”1.0”?>
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<product barcode=”2323423”>
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<maker>Smithson</maker>
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<name>Apex DVD Player 1.2</name>
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<quantity>3</quantity>
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<size>33cm</size>
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<color>black</color>
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</product>
XML Syntax Structure
✤
Consider this example:
✤
<?xml version=”1.0”?> // XML Definition (version)
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<product barcode=”2323423”>
✤
<maker>Smithson</maker>
✤
<name>Apex DVD Player 1.2</name>
✤
<quantity>3</quantity>
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<size>33cm</size>
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<color>black</color>
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</product>
XML Syntax Structure
✤
Consider this example:
✤
<?xml version=”1.0”?> // XML Definition (version)
✤
<product barcode=”2323423”> // Extending Tagging System (user defined markup adds meaning)
✤
<maker>Smithson</maker>
✤
<name>Apex DVD Player 1.2</name>
✤
<quantity>3</quantity>
✤
<size>33cm</size>
✤
<color>black</color>
✤
</product>
XML Syntax Structure
✤
Consider this example:
✤
<?xml version=”1.0”?> // XML Definition (version)
✤
<product barcode=”2323423”> // Extending Tagging System (user defined markup adds meaning)
✤
<maker>Smithson</maker> //Tags are created and defined by the developer (XSD) XML Schema
✤
<name>Apex DVD Player 1.2</name>
✤
<quantity>3</quantity>
✤
<size>33cm</size>
✤
<color>black</color>
✤
</product>
XML Syntax Structure
✤
Consider this example:
✤
<?xml version=”1.0”?> // XML Definition (version)
✤
<product barcode=”2323423”> // Extending Tagging System (user defined markup adds meaning)
✤
<maker>Smithson</maker> //Tags are created and defined by the developer (XSD) XML Schema
✤
<name>Apex DVD Player 1.2</name> //Tags contain strictly strings
✤
<quantity>3</quantity> //requires: start tag <quantity> and end tag </quantity>
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<size>33cm</size> // string value is found between the tags.
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<color hexvalue=”0x000000”>black</color> //tags can have attributes
✤
</product>
Nodes in XML
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The Node:
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Contains all relevant data
about an element.
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For example: <product>,
which contains all the data
for that individual product.
✤
✤
This node has “childnodes”,
such as <color>
Data can be a string (but
more...)
CDATA in XML
✤
CDATA
✤
Data can hold more complex
data, like HTML, using CDATA.
✤
Tells the node to contain “raw
character data”, not markup.
✤
<![CDATA[
✤
]]>
✤
Good for containing html, JS,
etc, as it will not be treated as
plain string data.
Create XML with PHP
✤
fopen() - allows you to open a document on the filesystem. // resource
✤
you can $file= fopen("presidents.xml", "w"); // note safe_mode ,
open_basedir
✤
✤
read only (r)
✤
read and write(r+)
✤
write only(w)
✤
write and create(w+)
✤
write to end of file (a)
✤
write to end and create (a+)
permissions are an issue! Try chmod to 777 to start and throttle back.
Create XML with PHP
✤
fwrite()
✤
Write to the resource you were using.
✤
Allows you to complete the write to the file system
✤
will return the bytes written if successful.
✤
Be aware of permissions! chmod 777 to start and go lower as
needed.
Create XML with PHP
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fclose()
✤
closes the current resource.
✤
returns boolean. worth checking!
XML Example
Create RSS
with PHP
✤
✤
✤
Stands for “Real Simple
Syndication”
great for sharing or syndicating
your content to outside
systems
commonly only holds “some
recent data”
✤
natively uses XML as a
transport
✤
Has several standardized
formats.
✤
We’ll use RSS 2.0, common
Create RSS
with PHP
✤
RSS has a defined format:
✤
A Channel which allows to add
meta about what your
syndicating
✤
Should Contain a title, link, and
description, (optional date,
language,etc)
✤
RSS should have a defined
tabbed structure
✤
Related Links: often found on
blogs to send a person to the
correct page to get more
details.
Create RSS
with PHP
✤
✤
✤
Browsers “sniff” for RSS feeds
on a site
You let the browser know
you’re publishing RSS by
embedding a meta data tag:
<link rel="alternate" type="application/rss+xml"
title="RSS" href="/pathto/rss.xml" />
RSS Example
SimpleXML
✤
Simple XML is PHP5’s longawaited class that allows PHP
developers to easily and
effectively parse XML data!
✤
Simple to Use (its in the name)
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Lets see it in action.
xPath
✤
What is xPath and why do I
care?
✤
XSLT Standard by the W3C
✤
xPath is a syntax for finding
information in XML documents
✤
Can find values in nodes or
attributes
✤
xPath is part of SimpleXML
✤
Learn more about it!
Lab & Next Week
✤
✤
Lab
✤
implement xml\rss in app
✤
working session for final
Reading: Chapter 13
See you Sunday!