sally kleinfeldt - plone application development patterns
DESCRIPTION
In 2004 The Nature Conservancy adopted Plone as the platform for ConserveOnline.org, a community site for sharing conservation information. Since then, we have gained experience implementing several successful Plone intranet applications, made plenty of mistakes, and learned how to - and how not to - approach new Plone projects. This talk will compare our experiences developing two very different intranet Plone applications that manage conservation information. The first application has a complex data model with a relational database backend and makes minimal use of Archetypes. Its requirements - including data model and user interface - were rigidly specified based on a spreadsheet tool. The second application is Archetypes-based and was developed using UML modeling and ArchGenXML. It has a simple data model, uses the ZODB for storage, and its requirements were more loosely specified. From the lessons we learned on these projects, we have developed a set of application pattern definitions to guide us when choosing technologies and estimating costs. We think these pattern definitions can help managers, integrators, and people new to Plone understand when to use Plone, when not to use Plone, and how to structure their interactions with clients to ensure a successful Plone project.TRANSCRIPT
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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Plone Application Development PatternsSally Kleinfeldt, The Nature Conservancy
October 2007 -- Naples
Overview
BackgroundFirst application: ConProSecond application: EASTPattern LibraryQuestions
The Nature Conservancy
Environmental nonprofit protecting ecologically important lands and watersScience-based approach117 million acres protected1 million membersWork in 50 states and 30 countries3,000 employees
Background - Technology
Traditional IT shopSupporting HR, Finance, database applicationsPlus creating conservation applications
Adopted Zope in 2000Nature.org, intranet, internal applicationsZMI development, RDB storage
Background - Technology
Adopted Plone in 2004ConserveOnline.org, internal applicationsFilesystem development, RDB or ZODB storage
Background - Applications
Spatial and non-spatialMix of data and contentUsers, roles, permissions important
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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Workflow sometimesIncreasing need for custom applications for conservationIncreasing need for cross-application integration
ConPro - What Is It
System to manage structured and unstructured information about our conservation projectsInformation previously managed in complex Excel spreadsheets, and associated documents, oftenin the fieldNeed for import, export, versioning, locking, security, search
ConPro - Requirements
50+ page functional requirementsAssumption of relational storage for ad hoc SQL queriesSpreadsheet dictated the data modelUsers defined edit screen mockups based on the spreadsheetVersioning, security, workflow requirements less clear
ConPro - Data Model
Customer-specified data model for RDB was very complex.
ConPro - Development
Plone chosen for compatibility with ConserveOnlineUnable to hire expert consultant to guide development
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Initial focus on spreadsheet import/export, SQL methods, edit formsDesign of classes, security, overall application left until the end
ConPro - Development
Archetypes stub objects for object security, the rest hand crafted SQL methods and page templates;workflow not usedCustomers changed their minds midstream about data model and edit formsRescued by Plone experts and much effort
ConPro - Results
Late and overbudget - 30 person months~400 hand written SQL methods50 hand written edit, display, report formsAd hoc SQL queries never implementedDifficult to maintain and extendBig success with users!
ConPro - Home Page
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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ConPro - Project Info Page
ConPro - Project Info Page
Turn it on its side - here's all the information...
ConPro - Project Viability
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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ConPro - Project Viability
Turn it on its side - here's all the information...
ConPro - Lessons
Avoid excessive requirements phase for new/unclear applicationsUsers should not dictate technology decisionsRelational storage increases cost, avoid if possibleHave guidance from experts on your first project, learn to do things The Plone WayStart with classes, security, overall application functioning; page templates later
EAST - What Is It
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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Ecoregional Assessment Status ToolERA: science-based analysis of an ecoregion to determine highest value areas for conservationNew system for management to track status of this work<200 assessments, each with <20 attributes
EAST - Requirements
Well understood applicationInitial version done in pure Zope prior to ConPro
Informal project driven by developer to re-implement The Plone WayCustomer flexible, no technology assumptionsSimple application
EAST - Class Diagram
Developer and customer created the UML diagram together.
EAST - Development
Archetypes content types with ZODB storageUML modeling with ArchGenXML generating starter productSecurity and UI refinements added (listing, search, reports, view)
EAST - Results
1 week to develop2 content types, 23 page templates, workflow to track status
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Easy to maintain and extendBig success with users!
Customer: "This has been my most pleasant development experience ever"
EAST - ERA Page
Learning Lessons
Our technology choices had been haphazardNeed to base decisions on what works in our environmentConsistencyRepeatable development results
Application Patterns
Solution: define "application patterns"A set of components, technologies, and toolsUsed to create a certain type applicationGood at solving certain types of problems
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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In the context of our organization and level of development expertise
Pattern Definition - Problem
Internet or intranetType of information (spatial, structured, unstructured)Sensitivity of informationAmount of informationNumber of users, sessionsOrganizational level (global, regional, local)Community (conservation, marketing, finance, legal, etc.)
Pattern Definition - Technology
Components
GIS, web, database, ORM, search, authentication, user management, security, workflow, errorhandling, logging, help system, etc.
Platform and toolkit
Development platform, language, testing frameworks, OS, etc.
Pattern Definition - Technology
Integration mechanisms
Web services platforms, enterprise search, etc.
Risks (security, business)
Cost
Plone Pattern - Problem
Intranet
Mix of structured and unstructured information, non-spatial or minimally
Non-spatial or minimally spatial requirements
(We use .Net framework with ESRI tools for spatial apps)
Suitable when information is restricted to authorized users/groups
Plone Pattern - Problem
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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Small to mid size (up to thousands of objects, not millions)Any number of TNC staffAny organizational level or community
Plone Pattern - Technology
Non-spatial or embedded maps onlyLDAP authenticationArchetypes, ArchGenXML
Plone Pattern - Technology
ZODB storage unless special circumstancesExtra cost for RDB must be justifiedMySQL supported - but not Oracle???
When Is RDB Storage Justified?
Good reasons:
Legacy data that can't be movedSimultaneous access from other (legacy) tools
When Is RDB Storage Justified?
Bad reasons:
Faster, more stable than ZODB
Making reports with Crystal Reports etc.
Ad hoc SQL queries by power users
=> Provide capability to periodically load data into the RDB
How Fast Can We Make One?
Plone Application Development Patterns file:///Users/sek/tnc/naples/sallyk-slides/plone-patterns.html
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90 seconds at 900 degrees F (485 C)
http://www.fornobravo.com/vera_pizza_napoletana/pizza_napoletana.html
Pretty Fast...
15 days to produce application with ZODB storage given UML diagram produced jointly by customer and developer with up to
5 content types, 1 custom view per type5 reports and/or custom search pagesStandard editing pages6 custom permissions, 2 custom roles, 1 custom workflow
Plone Pattern - Cost Caveats
Predictable cost requires:
Use of shared product providing common elementsLDAP setupProvide application mixin class with common behaviorCustomize portal look and feel
Better for users as well as developers
Acknowledgements
Eric Coffman, lead developer on these projects
Questions