Lipstick on a Pig
Dynamically re-skinning a
legacy .NET portal with python
Matt Hamilton
matth@netsight.co.uk
30th June 2009 Europython 2009, Birmingham, UK 1

Introduction
 Dynamically re-skinning a .NET portal site
 Can't name the client
 Portal for teachers in the UK
 Aggregating content across legacy portal,
Plone and Moodle
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Who Am I
 Technical Director of Netsight
→ Web development firm in Bristol, UK
 10 years experience with Zope/Plone
 More of an integrator than core developer
→ I get involved in all those sticky projects of merging
Plone in with other systems in an enterprise
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Where Were We?
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Existing Portal (1.0)
 Five years old by November 2009
 User registrations: 46,681
 Course enrolments: 33,664
 Resource Bank views: 247,911
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Existing Portal (1.0)
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Problems with Current Portal
 Look-and-feel
→ Not very compelling
 Usability
→ Challenging in places
 A poor content management system
→ Can't really edit general content, so use a separate FTP
server and Dreamweaver
 Vendor lock-in
→ Even small changes, very expensive
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The Future - Portal 2.0
 Usability, Design and Content Review April
2008
 Strategic Review August 2008
 Feasibility Studies Jan 2009
 Pilot Demonstrator (“Portal V1.5”) March 2009
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Design Review
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Architecture Review
 Portal 1.0 - Monolithic, tightly coupled, poor
separation of skin
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Architecture Review
 Portal 2.0 - Extensible, loosely coupled, good
separation of skin
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How Do We Get There?
Remember: We Can't Touch the Existing System!
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The Cunning Plan
Browser
Portal 1.0
Existing Skin 1.0
Portal Module of
functionality
e.g. portfolio
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Total Skin Graft!
Browser
web server
New skin via
Skin 2.0 xpath and xslt Portal 1.5
transformation proxy transformation.
Web server
needs to handle
SSL.
Skin 1.0 Together they
give us nice
URLs.
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Deliverance
 Several Different Projects
→ xdv
→ Deliverance 0.3
To learn more on specifics of Deliverance go
to http://deliverance.openplans.org
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WSGI
 WSGI allows you to write small modules
chained together in a 'pipeline'
 Many small filters combined together as you
need
 Lots of existing components out there
 Very easy to write new ones
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WSGI Power - The Pipeline
[pipeline:portal] [filter:theme.portal]
pipeline = use = egg:dv.xdvserver#xdv
theme.portal theme_uri = file://%(here)s/theme/theme.html
rules = %(here)s/rules/content.xml
ploneinterceptor
xslt [filter:ploneinterceptor]
linkrewrite use = egg:ns.ploneinterceptor#ploneinterceptor
htmlcleaner
source.portal [filter:xslt]
use = egg:dv.xdvserver#xslt
xslt_file = %(here)s/rules/transform.xsl
[filter:linkrewrite]
use = egg:ns.linkrewrite#linkrewrite
[filter:htmlcleaner]
use = egg:ns.htmlcleaner#htmlcleaner
[app:source.portal]
use = egg:Paste#proxy
address = http://www.theexistingsite.org.uk/
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Link Rewriting
 Old URL:
→ http://www.theclient.org.uk/WebPortal.aspx?
page=1&module=DB920A53-01EA-4886-8878-
F2CDF5FA8CFD&mode=101&IsNonNewsDB920A53_01EA
_4886_8878_F2CDF5FA8CFD=True&newsIdDB920A53_
01EA_4886_8878_F2CDF5FA8CFD=11208#10
→ 205 characters!
 New URL:
→ http://www.theclient.org.uk/news/11208#10
→ 41 characters!
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HTML Cleanup
 LXML rules!
→ from lxml.html.clean import Cleaner
cleaner = Cleaner(...)
# Pretty print the HTML
dom = document_fromstring(body)
body = etree.tostring(dom, pretty_print=True)
# Clean the HTML
body = cleaner.clean_html(body)
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Result
 Old
→ 70kb of HTML
→ 120 Validation errors, 61 warnings
 New
→ 40Kb of HTML
→ 27 Errors, 1 warning (mainly xhtml/html conflicts)
→ No significant performance impact
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Putting all together
Composite:main
pipeline:portal pipeline:plone pipeline:moodle
theme.content theme.content theme.content
xslt navmerger navmerger
linkrewrite plonecontent moodlecontent
htmlcleaner source.plone source.moodle
source.portal
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End Result New Style
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Portal content 22

Complications
 Navigation
→ One page, two content sources, how is the
navigation built?
 Search
→ Search needs to go across multiple systems
→ Will soon be looking at Solr, Xapian, Google Mini
 .NET viewstate postback
→ Massive hidden state variable, form wraps entire
site!
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Questions?
matth@netsight.co.uk
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We are looking for Developers!
Come chat to me
or
drop an email to
careers@netsight.co.uk
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