AD1279 best practices track session from IBM Connect 2016

1. "Marty, You're Just Not Thinking Fourth
Dimensionally": Troubleshooting XPages
Paul Withers / 2nd Feb 2016

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3. About Me
“My name is Darth Vader. I
am an extraterrestrial from
the planet Vulcan”

4. Why This Session?
• XPages often doesn’t work “as expected”
 Custom Control -> XPage -> Browser
 Browser -> Server -> Browser
 SSJS / CSJS
 State management
 Partial Refresh
• Lots of StackOverflow questions
 Which wouldn’t be referenced here unless many developers hit
the same issues!

5. Agenda
• Buzz-Quote Bingo!
• Twin Pines Mall / Lone Pine Mall
• Marty’s Family Photo
• Marty McFly and the Tannens
• Power of Love
• Alternate 1985
• Indians!
• It’s Erased!

6. BuzzQuote Bingo
• http://hermes.intec.co.uk/bttf
• Enter Name and Email
• Click when you hear
• Shout if you win!

7. Twin Pines Mall / Lone
Pine Mall

8. Some Questions
• http://stackoverflow.com/questions/32256155/why-does-this-
code-write-out-two-documents/32259533#32259533
• http://stackoverflow.com/questions/24400934/xpages-save-
cancel-actions-scenario
• http://stackoverflow.com/questions/24407003/xpages-unid-of-
documents-why-it-is-changing
• http://stackoverflow.com/questions/21015953/xpages-conflict-
is-created-everytime-a-document-is-saved

9. 1. Retrieve/Create Code in documentId
• ALWAYS use ${…} when calculating properties like
documentId
• Otherwise calculated FOUR times on page load
 If attached to a Panel, TWICE AFTER beforePageLoad
 If attached to XPage, TWICE BEFORE beforePageLoad
• Can’t use scoped variables set in beforePageLoad!
 Always TWICE DURING render response

10. 1a. Timing of Initialisations
• viewScoped variables can’t be set before PAGE LOAD
 Controller frameworks put variable in requestScope and move to
viewScope
• data, dataContexts etc
 attached to XPage / Custom Control - initialised alongside
component
 Attached to Panel – initialised during PAGE LOAD

11. 2. ignoreRequestParams
• ALWAYS use ignoreRequestParams where appropriate
 If no params, computed settings respected
 If params passed, computed settings overwritten

12. 3. Submit Button Type
• DON’T use save=“true” (“Submit” button type)
 Use script, not simple actions
• Greater control, less risk
• You save only what should be saved
• Preparing you for Java / beans / beyond
• Form with single rich text field can cause problems even with
script

13. Marty’s Family Photo

14. Some Questions
• http://stackoverflow.com/questions/33259105/xpages-button-
unresponsive-after-4-ajax-calls/33260337#33260337
• http://stackoverflow.com/questions/32628012/xpages-losing-a-
viewscoped-bean-again/32633453#32633453
• http://stackoverflow.com/questions/32482575/xpages-falling-
out-of-server-side-cache/32483154#32483154
• http://stackoverflow.com/questions/33686362/xpages-page-
loosing-context-weird-behaviour
• http://stackoverflow.com/questions/32628012/xpages-losing-a-
viewscoped-bean-again/32633453#32633453

15. 4. Keep Pages In Memory
• XPages is stateful
• Number of component trees restricted for performance
• Dumped xsp.session.timeout minutes after browser closed
 Browser doesn’t tell server session is no longer used!

16. 5. viewState=“nostate”
• viewState=“nostate”
 Don’t store a component tree for this page
 Best practice for XAgents / REST services

17. 6. Explanation of “nostate”
• DataView and nostate
 Toggle expand/collapse is fine
 Navigating to specific pages is fine
 Next / Previous is relative to defaults
 Toggle detail is relative to defaults
• Unless detailsOnClient=“true”
• Details pushed to browser along with rest of content
• “Toggle” is client-side show/hide

18. Marty and the Tannens

19. Some Questions
• http://stackoverflow.com/questions/31561306/how-do-i-access-
a-repeat-control-from-the-outside-e-g-via-
csjs/31575723#31575723
• http://stackoverflow.com/questions/27982313/xprepeat-inside-
xedataview/27982614#27982614
• http://stackoverflow.com/questions/34158779/inherit-index-
from-repeatcontrol-in-nested-custom-
controls/34158954#34158954
• http://stackoverflow.com/questions/34652364/slider-in-repeat-
control-and-manipulation-of-text-via-
jouery/34653561#34653561

20. 7. Repeat Controls and Component Tree
• Only one set of components in component tree
• repeatControls=“true” changes behaviour
 x many sets of components
 Hard-wired to specific entries at page load
 Pagers have no effect because of hard-wiring
 Allows “loaded” computations within the repeat, e.g. id’s
• Cannot compute repeatControls=“true” within compositeData

21. 8. Dynamic Content Control
• Only components from current facet exist in component tree
• Component tree dynamically updated
• Better than showing / hiding via rendered property

22. 9. Custom Controls and Scope
• Custom control is inserted into component tree
• Variable names outside custom control available
• As long as same variable used, no need to pass
• Same rules as for any component
 Is variable available by navigating upwards in tree?
 Cannot retrieve variables from another branch
• E.g. different repeat entry, repeat entry from outside repeat

23. Power of Love

24. ControllingViewHandler
• Creates component tree for specific XPage
• Runs before beforePageLoad event
• super.createView() loads component tree
• Also creates viewScope
 Not available before call to super.createView()
 Load variables to requestScope before super.createView()
 Move to viewScope after super.createView()

25. ControllingViewHandler

26. PhaseListener
• Handles XPages lifecycle
• On page load, only RENDER RESPONSE triggered
• Runs for every partial refresh
 Ensure optimised
 Ensure error handling
• Crucial for identifying why partial refresh is not behaving “as
expected”

27. PhaseListener

28. Some Questions
• http://stackoverflow.com/questions/20477153/xpages-server-
validation-errors-havent-been-displayed-to-the-user
• http://stackoverflow.com/questions/28339422/ssjs-onclick-
action-will-not-fire-on-xpage/28340759#28340759
• http://stackoverflow.com/questions/33024777/xpages-how-to-
do-partial-refresh-correctly
• http://www.intec.co.uk/view-isrenderingphase-and-buttons/
• http://www.intec.co.uk/fully-understanding-rendered-property-
and-components-with-events/

29. 10. Understanding Partial Refresh
• Partial Refresh is SIX Phases

30. 10. Understanding Partial Refresh
• 1. RESTORE VIEW
 Get component tree again
• 2. APPLY REQUEST VALUES
 Pass String values from browser to executed component tree
• 3. PROCESS VALIDATIONS
 Run validators AND converters for executed component tree

31. 10. Understanding Partial Refresh
• 4. UPDATE MODEL VALUES
 Convert string values and update executed component tree
• 5. INVOKE APPLICATION
 Run application logic (SSJS / Java)
• 6. RENDER RESPONSE
 Update HTML for executed component tree and post refresh area

32. 11. Conditionally Hidden Save Button
• Set rendered property on button
 For best practice, use view.isRenderingPhase()
 Ensure set to true for other phases or code will not run
• Add partial refresh where appropriate
 Ensure refresh area correct or button will not show
 Ensure disableValidators=“true” or button will not hide again if
invalid

33. 12. Reasons Code May Not Work!
• CSJS returning false – check Firebug for POST event
• Conversion error – 1,2,3,6
• Validation error – 1,2,3,6
• Exec id not including components being used by application
logic
• Exec id not including component triggering application logic
• Event handler not rendered in phase 4
• Refresh area not including errors control

34. 13. Troubleshooting
• Use PhaseListener
• java.util.logging.ConsoleHandler.level manages console
logging of server validation errors, since 8.5.3
 In workspace.configrcpinstall.properties
• ALWAYS including errors control in refresh area
• Be conscious of rendered property

35. BONUS 1: Data View
• dataCache=“id” setting available on View datasource
• Better for performance, only caches id, not full ViewEntry
(wrapped)
• “var” not available during Apply Request Values
 Compute value only in Render Response

36. BONUS 2 - Dialog
• To refresh area,
getComponent(“dialog1”).hide(“myRefreshArea”)
 POST
• Run SSJS
• view.postScript - XSP.closeDialog
 GET
• Refresh myRefreshArea

37. Alternate 1985

38. 14. What Requires Restart Task HTTP?
• Picked up immediately
 Classic design elements
 XPages*
 Custom Controls*
 Java classes*
* Provided not in SCXD - http://www.intec.co.uk/single-copy-xpage-design-
some-learning-and-why-its-not-for-me/

39. 14. What Requires Restart Task HTTP?
• Require “res task http”
 JAR files
• http://stackoverflow.com/questions/30939347/jar-file-changes-in-
lotus-notes-database-not-being-picked-up-by-domino-server
 SCXD
 OSGi plugin*
• http://stackoverflow.com/questions/33233724/while-in-development-
in-xpages-libraries-changes-are-not-picked-up/33234041#33234041
 Servlet / OSGi application*
* Without JRebel https://www.youtube.com/watch?v=EHbVgA2oqD0

40. Indians!

41. Question
• http://stackoverflow.com/questions/33190731/value-picker-get-
error-typeerror-resp-is-null-in-xpages/33210520#33210520

42. 15. “Resp is null”
• Understand page load and dynamically
 “resp is null” – options for picker are not available
 Picker is client-side, but values are passed to renderer server-
side

43. 16. SSJS in CSJS
• SSJS in CSJS
 Computed server-side as part of script renderer
 Only re-computed by partial refresh
• To access component values
 Use dojo.byId or variants to access client-side element
 Trigger partial refresh to update SSJS embedded into CSJS

44. It’s Erased!

45. Some Questions
• http://stackoverflow.com/questions/24735862/best-practice-for-
storing-datetime-values-in-xpages
• http://stackoverflow.com/questions/34417067/xpages-
notserializableexception-on-
datetime/34417335?noredirect=1#comment56612210_344173
35
• http://stackoverflow.com/questions/33168499/cannot-serialize-
javascript-function/33168732#33168732

46. 17. Domino Objects in Scopes
• Domino objects can’t be stored in scopes.
 DateTimes are the most common culprit
 Use .toJavaDate() to store Java Date
• Similar issues with SSJS functions stored in variables

47. 18. Impact of Persistence Setting
• For Domino objects in scopes, depending on persistence
setting
 Keep pages in memory – value just lost
 Keep pages on disk – error thrown to server, redirect to error
page (fails to display)
 Keep current page in memory – value just lost, error 500 on
navigating

48. Summary
• Understand ignoreRequestParams
• Avoid simple actions
• Keep Pages in Memory – understand impacts
• Use viewState=“nostate”
• Understand detailsOnClient=“true”
• Understand repeatControls=“true”

49. Summary
• Understand scope and custom controls
• Understand partial refresh is more than just “partial
refresh”
• Understand SSJS is computed and injected into CSJS
• Use Firebug or comparable tool
• Don’t store Domino objects in scopes
• Understand impact of serialization

50. Thank You!
Paul Withers
Intec Systems Ltd
IBM Champion
OpenNTF Board Member
@paulswithers
pwithers@intec.co.uk
http://www.intec.co.uk/blog

51. Thank you