On Mon, Dec 7, 2009 at 12:50 PM, Alex Black <a...@alexblack.ca> wrote:
> Hi David,
>
> I just tried something similar out.
> 1. I created a blank 1.0 lift project
>
How about starting with a Lift 1.1 project?
> 2. I updated the pom file to reference lift-1.1M6
>
Did you update the version of Scala?
> 3. I added a line to the hello world snippet in its body:
> println("Constructor")
> 4. I modified index.html to call the snippet twice.
> 5. I then launched the web server (mvn jetty:run) and accessed the
> main page once via a browser
>
> The line println("Constructor") gets called twice, I expected it just
> to get called once.
>
>
And Lift may choose to instantiate a snippet instance more than once for a
given request. But, there is just one instance used across all the requests
to the named snippet for the balance of the call.
> Am I doing something wrong? Your test is not exactly the same as the
> problem I described, I described the constructor getting called 18
> times, I haven't yet verified whether or not the data is shared.
>
What is the issue with the constructor being called repeatedly?
>
> and here is the output:
>
> [INFO] Started Jetty Server
> [INFO] Starting scanner at interval of 5 seconds.
> Constructor
> Constructor
> INFO - Service request (GET) / took 393 Milliseconds
> INFO - Service request (GET) /classpath/jquery.js took 39 Milliseconds
> INFO - Service request (GET) /ajax_request/
> liftAjax.js;jsessionid=11x3vru6uimmg took 11 Milliseconds
> INFO - Service request (GET) /favicon.ico took 6 Milliseconds
> INFO - Service request (POST) /ajax_request/F318697140471TRN/ took 11
> Milliseconds
> INFO - Service request (POST) /ajax_request/F318697140471TRN/ took 1
> Milliseconds
>
> Snippet code:
>
> package com.liftcode.hello.snippet
>
> class HelloWorld {
> println("Constructor")
>
> def howdy = <span>Welcome to hello-lift at {new
> _root_.java.util.Date}</span>
> }
>
> index.html:
>
> <lift:surround with="default" at="content">
> <h2>Welcome to your project!</h2>
> <p><lift:helloWorld.howdy /></p>
> <p><lift:helloWorld.howdy /></p>
> </lift:surround>
>
> Here is the pom.xml:
>
> <project xmlns="http://maven.apache.org/POM/4.0.0"; xmlns:xsi="http://
> www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://
> maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd";>
> <modelVersion>4.0.0</modelVersion>
> <groupId>com.liftcode.hello</groupId>
> <artifactId>hello-lift</artifactId>
> <version>1.0-SNAPSHOT</version>
> <packaging>war</packaging>
> <name>hello-lift</name>
> <inceptionYear>2007</inceptionYear>
> <properties>
> <scala.version>2.7.3</scala.version>
> </properties>
>
> <repositories>
> <repository>
> <id>scala-tools.org</id>
> <name>Scala-Tools Maven2 Repository</name>
> <url>http://scala-tools.org/repo-releases</url>
> </repository>
> </repositories>
>
> <pluginRepositories>
> <pluginRepository>
> <id>scala-tools.org</id>
> <name>Scala-Tools Maven2 Repository</name>
> <url>http://scala-tools.org/repo-releases</url>
> </pluginRepository>
> </pluginRepositories>
>
> <dependencies>
> <dependency>
> <groupId>org.scala-lang</groupId>
> <artifactId>scala-library</artifactId>
> <version>${scala.version}</version>
> </dependency>
> <dependency>
> <groupId>net.liftweb</groupId>
> <artifactId>lift-util</artifactId>
> <version>1.1-M6</version>
> </dependency>
> <dependency>
> <groupId>net.liftweb</groupId>
> <artifactId>lift-webkit</artifactId>
> <version>1.1-M6</version>
> </dependency>
> <dependency>
> <groupId>javax.servlet</groupId>
> <artifactId>servlet-api</artifactId>
> <version>2.5</version>
> <scope>provided</scope>
> </dependency>
> <dependency>
> <groupId>junit</groupId>
> <artifactId>junit</artifactId>
> <version>4.5</version>
> <scope>test</scope>
> </dependency>
> <dependency>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>jetty</artifactId>
> <version>[6.1.6,)</version>
> <scope>test</scope>
> </dependency>
> <!-- for LiftConsole -->
> <dependency>
> <groupId>org.scala-lang</groupId>
> <artifactId>scala-compiler</artifactId>
> <version>${scala.version}</version>
> <scope>test</scope>
> </dependency>
> </dependencies>
>
> <build>
> <sourceDirectory>src/main/scala</sourceDirectory>
> <testSourceDirectory>src/test/scala</testSourceDirectory>
> <plugins>
> <plugin>
> <groupId>org.scala-tools</groupId>
> <artifactId>maven-scala-plugin</artifactId>
> <executions>
> <execution>
> <goals>
> <goal>compile</goal>
> <goal>testCompile</goal>
> </goals>
> </execution>
> </executions>
> <configuration>
> <scalaVersion>${scala.version}</scalaVersion>
> </configuration>
> </plugin>
> <plugin>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>maven-jetty-plugin</artifactId>
> <configuration>
> <contextPath>/</contextPath>
> <scanIntervalSeconds>5</scanIntervalSeconds>
> </configuration>
> </plugin>
> <plugin>
> <groupId>net.sf.alchim</groupId>
> <artifactId>yuicompressor-maven-plugin</artifactId>
> <executions>
> <execution>
> <goals>
> <goal>compress</goal>
> </goals>
> </execution>
> </executions>
> <configuration>
> <nosuffix>true</nosuffix>
> </configuration>
> </plugin>
> <plugin>
> <groupId>org.apache.maven.plugins</groupId>
> <artifactId>maven-eclipse-plugin</artifactId>
> <configuration>
> <downloadSources>true</downloadSources>
> <excludes>
> <exclude>org.scala-lang:scala-library</exclude>
> </excludes>
> <classpathContainers>
>
> <classpathContainer>ch.epfl.lamp.sdt.launching.SCALA_CONTAINER</
> classpathContainer>
> </classpathContainers>
> <projectnatures>
> <java.lang.String>ch.epfl.lamp.sdt.core.scalanature</
> java.lang.String>
> <java.lang.String>org.eclipse.jdt.core.javanature</
> java.lang.String>
> </projectnatures>
> <buildcommands>
> <java.lang.String>ch.epfl.lamp.sdt.core.scalabuilder</
> java.lang.String>
> </buildcommands>
> </configuration>
> </plugin>
> </plugins>
> </build>
> <reporting>
> <plugins>
> <plugin>
> <groupId>org.scala-tools</groupId>
> <artifactId>maven-scala-plugin</artifactId>
> <configuration>
> <scalaVersion>${scala.version}</scalaVersion>
> </configuration>
> </plugin>
> </plugins>
> </reporting>
> </project>
>
>
>
> On Dec 7, 3:28 pm, David Pollak <feeder.of.the.be...@gmail.com> wrote:
> > On Sun, Dec 6, 2009 at 5:44 AM, Alex Black <a...@alexblack.ca> wrote:
> > > > We made this change for Lift 1.1. So, if you're using 1.1, the same
> > > > instance of a snippet should be used for a given HTTP request.
> >
> > > Hi David, I've just switch from Lift 1.0 to Lift 1.1-M6, do you think
> > > this change is in M6?
> >
> > Yes.
> >
> > Snippet:
> >
> > class HelloWorld {
> > lazy val date: Box[Date] = DependencyFactory.inject[Date] // inject the
> > date
> >
> > val random = randomString(20)
> >
> > def howdy(in: NodeSeq): NodeSeq =
> > Helpers.bind("b", in, "time" -> date.map(d => Text(d.toString)))
> >
> > def dog: NodeSeq = <b>String is {random}</b>
> >
> > def cat: NodeSeq = <b>From cat String is {random}</b>
> >
> > }
> >
> > View:
> >
> > <lift:surround with="default" at="content">
> > <h2>Welcome to your project!</h2>
> > <lift:helloWorld.howdy>
> > <span>Welcome to iscached at <b:time/></span>
> > </lift:helloWorld.howdy>
> > </p>
> >
> > <p> Dog sez <lift:HelloWorld.dog/></p>
> >
> > <p> Cat sez <lift:HelloWorld.cat/></p>
> >
> > </lift:surround>
> >
> > Browser:
> >
> > Welcome to your project!
> >
> > Welcome to iscached at Mon Dec 07 12:26:41 PST 2009
> >
> > Dog sez String is 4G2NRM4TBGCJBYNGFCUF
> >
> > Cat sez From cat String is 4G2NRM4TBGCJBYNGFCUF
> >
> > Works as advertised and has been in the code since at least M6.
> >
> > Thanks,
> >
> > David
> >
> >
> >
> > > It doesn't seem to be... I have many calls to my
> > > snippet for a particular page, and I put a println statement in the
> > > body of the snippet, and it gets called 18 times each request!
> >
> > > - Alex
> >
> > > > > I'd imagine lift could even generate a requestVar representing each
> > > > > snippet for the developers, allowing snippets in a given HTTP
> request
> > > > > to access each other easily.
> >
> > > > I don't think this is technically possible within the bounds of the
> type
> > > > system.
> >
> > > > > On Nov 20, 11:09 am, Ross Mellgren <dri...@gmail.com> wrote:
> > > > > > RequestVar is the standard way of doing this. For example
> >
> > > > > > object MySharedInformation {
> > > > > > object myData extends RequestVar[List[Thing]](loadThings)
> > > > > > // ^^^^^^^^^^^ ^^^^^^^^^^
> > > > > > // Type of thing to store How to
> initialize
> > > > > > variable first time it's accessed
> >
> > > > > > private def loadThings: List[Thing] = ...
> >
> > > > > > }
> >
> > > > > > class Snippet1 {
> > > > > > import MySharedInformation.myData
> > > > > > def render(ns: NodeSeq): NodeSeq = {
> > > > > > myData.is.map(thing => { ... })
> > > > > > }
> >
> > > > > > }
> >
> > > > > > class Snippet2 {
> > > > > > import MySharedInformation.myData
> > > > > > ...
> >
> > > > > > }
> >
> > > > > > The lifetime of the value is during the current request
> processing
> > > and
> > > > > > any AJAX calls related to it.
> >
> > > > > > If you really want to initialize it in a snippet, then use a Box
> with
> > > > > > a RequestVar, like this:
> >
> > > > > > object MySharedInformation {
> > > > > > object myData extends RequestVar[Box[List[Thing]]](Empty)
> >
> > > > > > }
> >
> > > > > > class LoaderSnippet {
> > > > > > import MySharedInformation.myData
> > > > > > def render(ns: NodeSeq): NodeSeq = {
> > > > > > myData.set(Full(...))
> > > > > > }
> >
> > > > > > }
> >
> > > > > > class ReaderSnippet {
> > > > > > import MySharedInformation.myData
> > > > > > def render(ns: NodeSeq): NodeSeq = {
> > > > > > // If the data has not been loaded, default to an empty
> list
> > > > > > val data = myData.is.openOr(Nil)
> > > > > > ...
> > > > > > }
> >
> > > > > > }
> >
> > > > > > class OtherReaderSnippet {
> > > > > > import MySharedInformation.myData
> > > > > > def render(ns: NodeSeq): NodeSeq = {
> > > > > > // Do two entirely different things if the data has
> versus
> > > > > > has not been loaded
> > > > > > myData.is match {
> > > > > > case Full(data) => // do something when the data has
> > > been
> > > > > > loaded
> > > > > > case _ => // do something when the data has not been
> > > loaded
> > > > > > }
> > > > > > }
> >
> > > > > > }
> >
> > > > > > HTH,
> > > > > > -Ross
> >
> > > > > > On Nov 20, 2009, at 10:59 AM, Alex Black wrote:
> >
> > > > > > > I've got a template page, say foobar.html, that makes a number
> of
> > > > > > > calls to functions in a snippet, e.g. mysnippet.foo1,
> > > mysnippet.foo2,
> > > > > > > mysnippet.foo3.
> >
> > > > > > > I'd like to do some initial work in foo1, e.g. retrieve some
> data
> > > and
> > > > > > > do some work on it, then in foo2 and foo3 display parts of that
> > > data.
> >
> > > > > > > Whats the easiest way to do this? I think I misunderstood the
> lift
> > > > > > > book:
> >
> > > > > > > "That means that for each request, Lift creates a new instance
> of
> > > the
> > > > > > > snippet class to execute. Any changes you make to instance
> > > variables
> > > > > > > will be discarded after the request is processed."
> >
> > > > > > > I thought this meant that for a given HTTP request, there would
> be
> > > one
> > > > > > > (and only one) instance of my snippet, so I could call several
> of
> > > its
> > > > > > > methods and they could all access the snippet's member
> variables,
> > > > > > > which would then be discarded at the end of the request.
> >
> > > > > > > Am I going about this wrong? should I only have one snippet
> > > function
> > > > > > > per template?
> >
> > > > > > > Thx
> >
> > > > > > > - Alex
> >
> > > > > > > --
> >
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