AD111Harnessing the Power of Server-Side JavaScript and Other Advanced XPage TechniquesTim Tripcony | GROUP Experts - XMageStephan H. Wissel | IBM - Lotus Technology & Productivity Advisor

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Agenda● What exactly is Server Side Java Script (SSJS)

● Common practices: pattern & anti-pattern

● Code samples

The REAL Agenda: code, code, code

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Server-side JavaScript is JavaScript● all ECMAScript 3 keywords, operators and syntax still apply

▬ var myNumber = 0;▬ var myArray = [ ]; // preferred over new Array();▬ var myObject = { }; // preferred over new Object();▬ function foo(){return "bar";}▬ var depends = someBoolean ? "default" : "other";

● ECMAScript scope rules apply, including closure▬ More in the Demo section

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Server-side JavaScript is not JavaScript (1) ● browser-specific globals not available

▬ window▬ document▬ location

● Platform-specific globals and JSF-specifics▬ session: current NotesSession▬ database: current NotesDatabase, equal to

session.getCurrentDatabase()▬ param: URL parameters and post data▬ context & facesContext: current state data and direct access to

servlet engine

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Server-side JavaScript is not JavaScript (2) ● @functions (e.g. @UserName() )● scope variables

▬ requestScope▬ viewScope▬ sessionScope▬ applicationScope

● Optional type declarations● Seamless Java™ integration

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Agenda● What exactly is Server Side Java Script (SSJS)

● Common practices: pattern & anti-pattern

● Code samples

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The use of context● getUser(): access to name, roles, groups, and more● getUrl(): no more String parsing to get query string parameters and other

URL info● getUserAgent(): server-side browser detection● redirectToPage() / redirectToHome(): easy programmatic navigation

The use of facesContext● getResponseWriter() / getResponseStream(): send your own output to

the browser (like Print in LotusScript)● getExternalContext(): direct access to the servlet

▬ getRequest()▬ GetResponse()

● You need to understand the difference between the ResponseWriter and ResponseStream

▬ Writer doesn't take binary data▬ Stream excludes Writer▬ Can only use one per request

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JavaScript Closures● An object returned from a function has access to variables defined within

that function▬ Includes arguments passed to the function

● This allows for OOP constructs in JavaScript objects▬ Private properties▬ Private functions▬ Inheritance without .prototype

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Take advantage of XPages' JSF heritage● Java Objects at your disposal

▬ java.util: powerful storage and iteration▬ java.net: easy access to remote data▬ Core JSF packages and IBM's implementation

● Get to the servlet● Write your own servlet (you are on your own here)

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Write agent Style code in XPages● Control the rendering● Get the output writer● Get the output stream (one of the two)● Use cases:

▬ Replace web agent (?OpenAgent)▬ Output other formats (PDF, ODF)

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The use of scope● requestScope: storage for anything needed multiple times in the same

HTTP request● viewScope: survives for the life of a page - including partial and full

refresh events● sessionScope: "shopping cart" storage - survives for the duration of a

user's session, BUT can expire even if the user is still logged in (set in application properties to balance server performance with application performance)

● applicationScope: storage shared among all users of the NSF - any data that numerous users are likely to need but shouldn't be queried on every request

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Anti-Pattern: What always goes wrong● The network is fast and reliable● Configuration parameters are retrieved through @DBLookup● Connect to JDBC without a session pool● Use data binding when you access data, not anything else

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Everybody's favorite objects● UI Elements

▬ Create a control programmatically▬ Update control properties via event handlers

● DOMUtil▬ Parse DXL and other XML

● cookie▬ Set and read cookies using .put() and .get()

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Error Handling● try/catch: provide individual operations that might fail a specific response

to failure● Enable “Display default error page” during development and testing● Create custom error pages to display uncaught exceptions

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Debugging● print(): send a single String statement to server log and console● _dump(): send detailed info about any object to log and console

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Unit Tests● Courtesy of Lorcan McDonald (IBM Lab Dublin)● Available on OpenNTF● Enables Test Driven

Development (get used to it)

http://openntf.org/internal/ontfcatalog.nsf/topicThread.xsp?action=openDocument&documentId=9C66A4F3854E61BE852575A1003C6CAD

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Reaching out to Java● Put source into webcontent/source● Add directory to Java build path● Package name required● Define like a JavaScript variable:

var xy = new com.acme.RoadRunner();xy.foolCoyote(“Meep Meep”);

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Managed Beans● Concept inherited from JSF underpinnings● Bean is described in XML declaration● Can be used in JavaScript expressions● Automatically loaded when needed● Bound to a specific scope● Take advantage of Java capabilities (e.g. Connection pooling, threading

etc)

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Agenda● What exactly is Server Side Java Script (SSJS)

● Common practices: pattern & anti-pattern

● Code samples

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Application Chat● Application Context● Synchronized Access● Closure● Periodic partial refresh

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Shopping Cart● Session Context● Closure● Java integration

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Cached Search● Application Context● Managed Bean● Network handling

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Q&A

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