Archive for December, 2009

Sample list items with lift

Add/Edit/Remove items in lift sample

  • 1- Create the menu in boot

    in src/main/scala/bootstrap/liftweb/Boot.scala

    
    // List items menu
    val itemsMenu = Menu(Loc("Items", "items" :: "index" :: Nil, "List items"))
    
    // Build SiteMap
    val entries = Menu(Loc("Home", List("index"), "Home")) :: itemsMenu :: Nil
    
  • 2- Define the default database
    The properties in src/main/resources/props/default.props with the connection url

    
    db.driver   = org.h2.Driver
    db.url      = jdbc:h2:~/hello_db
    db.user     =
    db.password =
    

    in src/main/scala/bootstrap/liftweb/Boot.scala

    
    
    DB.defineConnectionManager(DefaultConnectionIdentifier, DefaultDBVendor)
    Schemifier.schemify(true, Log.infoF _, Item)
    
    ...
    
    object DefaultDBVendor extends ConnectionManager {
        def newConnection(name: ConnectionIdentifier): Box[Connection] = {
            try {
                val connectionUrl = Props.get("db.url").openOr("") + "?user=" +
                                    Props.get("db.username").openOr("") + "&password=" +
                                    Props.get("db.password").openOr("")
    
                Class.forName(Props.get("db.driver").open_!)
                val dm = DriverManager.getConnection(connectionUrl)
                return Full(dm)
            }
            catch {
                case e: Exception => {
                    Log.error(e.getMessage);
                    return Empty
                }
            }
        }
    
        def releaseConnection(conn: Connection) = conn.close
    }
      
    
  • 3- Create items/index.html
    in src/main/webapp/items/index.html

    
    <lift:surround with="default" at="content">
        <ul>
            <lift:adminItems.list>
                <li>
                    <item:name />
                </li>
            </lift:adminItems.list>
        </ul>
    </lift:surround>
    
    

    and snippet in src/main/scala/com/sample/snippet/AdminItems.scala

    
    package com.sample.snippet
    
    import scala.xml.{NodeSeq, Text}
    
    import net.liftweb.util.{Helpers, Log}
    import Helpers._
    
    import com.sample.model.Item
    
    class AdminItems {
    
        def list(node: NodeSeq): NodeSeq = {
            Item.findAll match {
                case Nil   => Text("There is no items in db")
                case items => items.flatMap(i => bind("item", node, "name" -> {i.name}))
            }
        }
    ...
    }
    
  • 4- Add item form

    create a template for add/edit items in src/main/webapp/templates-hidden/item_form.html,
    we are going to use the same template for edit and add items,
    using TemplateFinder in AdminItems snippet

    
    <fieldset>
        <legend><itemForm:title /></legend>
        <label for="name">Name</label>
    
        <itemForm:name />
        <itemForm:id />
    
        <itemForm:submit />
    </fieldset>
    
    

    we are going to use two requestvars to decide when to display the edit form or the add form

    
        private object ShowAddItem  extends RequestVar[Int](0)
        private object SelectedItem extends RequestVar[Long](0)
    

    declare a showAddItem and showEditItem function in adminItems snippet

    
        def clear = {
            ShowAddItem(0)
            SelectedItem(0)
        }                  
    
        def showAddItem(node: NodeSeq): NodeSeq = {
            ShowAddItem.get match {                
                case 1 => {                        
                    var name = ""                  
                    val template: NodeSeq = TemplateFinder.findAnyTemplate(ITEM_TEMPLATE :: Nil).openOr(<p></p>)                                                                     
                    val content = bind("itemForm", template, "title"  -> Text("New item"),    
                                                              "name"   -> SHtml.text(name, name = _),                                                                                   
                                                              "id"     -> Text(""),           
                                                              "submit" -> SHtml.submit("save", () => addItem(name)),                                                                    
                                                              "close"  -> SHtml.link("index", () => clear, Text("close")))                                                              
    
                    <div>{content}</div>
                }                       
                case _ => SHtml.link("index", () => ShowAddItem(1), <p>Add</p>)
            }                                                                  
        }                                                                      
    
        def showEditItem(node: NodeSeq): NodeSeq = {
            if (SelectedItem.get > 0) {             
                var id = SelectedItem.get           
                val item = Item.find(id).open_!     
    
                var name = item.name.is
    
                val template = TemplateFinder.findAnyTemplate(ITEM_TEMPLATE :: Nil).openOr(<p></p>) 
                val content  = bind("itemForm", template, "title"  -> Text("Edit item"),      
                                                          "name"   -> SHtml.text(name, name = _),                                                                                       
                                                          "id"     -> Html.hidden(() => {id = id}),                                                                                    
                                                          "submit" -> SHtml.submit("save", () => saveItem(id, name)),                                                                   
                                                          "close"  -> SHtml.link("index", () => clear, Text("close")))                                                                  
    
                <div>{content}</div>
            }                       
            else {                  
                <div></div>
            }                       
        }           
    

    Now we can call the showEditItem and showAddItem snippets functions in items/index view

    
    <lift:surround with="default" at="content">
        <ul>
            <lift:adminItems.list>
                <li>
                    <item:name />
    
                    <item:edit />
                    <item:remove />
                </li>
            </lift:adminItems.list>
        </ul>
    
        <lift:adminItems.showAddItem  form="POST" />
        <lift:adminItems.showEditItem form="POST" />
    </lift:surround>
    
    

    The attribute form=”POST” on the snippet will create a form with method=”POST” automatically arround the snippet content.

    And that’s it, a simple list with liftweb.
    The code can be found on http://github.com/jgoday/sample_lift_testing

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Lift testing with dbunit and specs

Here’s a post about Lift and testing,
using scala specs and dbunit.

We can use dbunit to populate a sample database for testing purposes,
in this example we are going to use the embedded h2 database.

  • 1. Create a sample liftweb (1.1-M8) application using maven 2.2

    
    mvn org.apache.maven.plugins:maven-archetype-plugin:2.0-alpha-4:generate        \
        -DarchetypeGroupId=net.liftweb        \
        -DarchetypeArtifactId=lift-archetype-blank        \
        -DarchetypeVersion=1.1-M8        \
        -DremoteRepositories=http://scala-tools.org/repo-releases        \
        -DgroupId=com.sample -DartifactId=hello
    
    

    And add the testing dependencies to pom.xml (specs, h2database and dbunit)

    
    
    <dependency>
        <groupId>org.scala-tools.testing</groupId>
        <artifactId>specs</artifactId>
        <version>1.4.4</version>                  
        <scope>test</scope>
    </dependency>                                 
    
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.2.125</version>   
        <scope>test</scope>     
    </dependency>                     
    
    <dependency>
        <groupId>org.dbunit</groupId>
        <artifactId>dbunit</artifactId>
        <version>2.4.7</version>
        <scope>test</scope>
    </dependency>
    
    
  • 2. Create a sample model vo (Item with name and id)

    in src/main/scala/com/sample/model/Item.scala,
    a sample object with a string attribute name that cannot be empty.

    
    package com.sample.model
    
    import net.liftweb.mapper.{By, IdPK,
                               LongKeyedMapper, LongKeyedMetaMapper,
                               MappedString}
    
    class Item extends LongKeyedMapper[Item] with IdPK {
        def getSingleton = Item
    
        object name extends MappedString(this, 100) {
            override def validations = valMinLen(1, "Must be not empty") _ ::
                                       super.validations
        }
    }
    
    object Item extends Item with LongKeyedMetaMapper[Item] {
        def findByName(name: String): List[Item] = {
            Item.findAll(By(Item.name, name))
        }
    }
    
    

    We can test the compilation to let maven download the dependencies
    without testing : mvn package -Dmaven.test.skip=true

  • 3. Create a sample Specs test file for item

    in src/test/scala/com/sample/model/ItemSpecs.scala,

    
    package com.sample.model
    
    import org.specs.Specification
    import org.specs.runner.JUnit4
    
    class ItemSpecsAsTest extends JUnit4(ItemSpecs)
    
    object ItemSpecs extends Specification {
        "Item" should {                     
            "do nothing wrong" in {
                true must beTrue
            }
        }
    }
    
    
  • 4. Create a database util class to initialize database and populate data

    in src/test/scala/com/sample/utils/DBUtil.scala,

    it will initialize the default database connection identifier using the properties file in
    src/test/resources (by default src/test/resources/props/test.default.props)

    and will let us choose a dbunit dataset file to populate the test data using
    DBUtil.setupDB(“dbunit_database_file.xml”)

    
    package com.sample.utils                                                     
    
    import net.liftweb.mapper.{DB,
                              ConnectionIdentifier, DefaultConnectionIdentifier,
                              StandardDBVendor}                                 
    import net.liftweb.util.{Log, Props}                                        
    
    import org.dbunit.dataset.{IDataSet}
    import org.dbunit.dataset.xml.{XmlDataSet}
    import org.dbunit.database.{DatabaseConfig, DatabaseConnection}
    import org.dbunit.operation.{DatabaseOperation}                
    
    object DBUtil {
        private var dataset: IDataSet      = null
        private var dbunitConnection: DatabaseConnection = null
    
        lazy val connectionIdentifier: () => ConnectionIdentifier = {
            () => DefaultConnectionIdentifier                        
        }                                                            
    
        def initialize = {
            DB.defineConnectionManager(connectionIdentifier(),
                                      new StandardDBVendor(Props.get("db.driver").openOr(""),
                                                           Props.get("db.url").openOr(""),   
                                                           Props.get("db.user"),             
                                                           Props.get("db.password")))        
        }                                                                                    
    
        def setupDB(filename: String) = {
            this.dataset = new XmlDataSet(this.getClass().getClassLoader().getResourceAsStream(filename))
    
            DB.use(connectionIdentifier()) {
                conn => {
                    this.dbunitConnection = new DatabaseConnection(conn)
                    DatabaseOperation.CLEAN_INSERT.execute(this.dbunitConnection, this.dataset)
                }
            }
        }
    
        def shutdownDB = {
            DB.use(connectionIdentifier()) {
                conn => {
                    try {
                        DatabaseOperation.DELETE.execute(this.dbunitConnection, this.dataset)
                    }
                    catch {
                        case e: Exception => Log.error(e.getMessage)
                    }
                }
            }
    
        }
    }
    
    
  • 5. Now we can do some more interesting test

    using a sample dataset in src/test/resources/dbunit/item_test.xml,
    the lift Shemifier class will create the database table on the beggining of the test
    and destroy it at the end.

    
    package com.sample.model                                                        
    
    import net.liftweb.mapper.{Schemifier}
    import net.liftweb.util.{Log}         
    
    import com.sample.utils.DBUtil
    
    import org.specs.Specification
    import org.specs.runner.JUnit4
    
    class ItemSpecsAsTest extends JUnit4(ItemSpecs)
    
    object ItemSpecs extends Specification {
        "Item" should {                     
            doFirst {                       
                DBUtil.initialize           
                Schemifier.schemify(true, Log.infoF _ , Item)
                DBUtil.setupDB("dbunit/item_test.xml")       
            }                                                
    
            "save without problem" in {
                val item = new Item
                item.name("item name")
    
                item.save must beTrue
                (Item.findAll.length == 3) must beTrue
            }
    
            "find by name" in {
                val items = Item.findByName("Item 1")
                items.length must_== 1
            }
    
            "delete without problem" in {
                val items = Item.findByName("item name")
    
                items.length must_== 1
                items(0).delete_! must beTrue
                Item.findAll.length must_== 2
            }
    
            doLast {
                DBUtil.shutdownDB
                Schemifier.destroyTables_!!(Log.infoF _, Item)
            }
        }
    }
    
    
    

Simple and funny 🙂

The sample code can be found in
http://github.com/jgoday/sample_lift_testing