Updated chapter 8

chapter-eight/src/main/scala/sample/lib/Wiki.scala

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+package sample {
+package lib {
+
+import scala.xml.{Text, NodeSeq}
+import net.liftweb.common.{Box,Full,Empty,Failure}
+import net.liftweb.util.NamedPF
+import net.liftweb.util.Helpers._
+import net.liftweb.http.{SHtml,RewriteRequest,RewriteResponse,ParsePath}
+import net.liftweb.sitemap.Loc
+import net.liftweb.mapper.{OrderBy,Ascending,By}
+import net.liftweb.textile.TextileParser
+import net.liftweb.textile.TextileParser.WikiURLInfo
+import sample.model.WikiEntry
+
+/**
+ * A wiki location
+ *
+ * @param page - the name of the page
+ * @param edit - are we viewing or editing the page?
+ */
+case class WikiLoc(page: String, edit: Boolean) {
+
+  /**
+   * Get the underly database record for this page. 
+   * When requested, the page will go to the database and look
+   * for an entry who's name matches that passed as the
+   * paramerter to the WikiLoc instance.
+   */
+  lazy val record: WikiEntry =
+    WikiEntry.find(By(WikiEntry.name, page)) openOr WikiEntry.create.name(page)
+}
+
+/**
+ * The WikiStuff object that provides menu, URL rewriting,
+ * and snippet support for the page that displays wiki contents
+ */
+object Wiki extends Loc[WikiLoc] {
+  object AllLoc extends WikiLoc("all", false)
+
+  // the name of the page
+  def name = "wiki"
+
+  // the default parameters (used for generating the menu listing)
+  def defaultValue = Full(WikiLoc("HomePage", false))
+
+  def params = Nil
+
+  /**
+   * Is the current page an "edit" or "view"? 
+   * This confusses most newbies, as its not always clear 
+   * where these values come from.
+   * As this Loc defines its own RewritePF, it added extra S.params 
+   * to the incoming request, which is what this requestValue is accessing. 
+   */ 
+  def currentEdit = requestValue.is.map(_.edit) openOr false
+
+  /**
+   * Check for page-specific snippets and do appropriate dispatching
+   */
+  override val snippets: SnippetTest = {
+    case ("wiki", Full(AllLoc)) => showAll _
+    case ("wiki", Full(wp @ WikiLoc(_ , true))) => editRecord(wp.record) _
+    case ("wiki", Full(wp @ WikiLoc(_ , false))) if !wp.record.saved_? => editRecord(wp.record) _
+    case ("wiki", Full(wp: WikiLoc)) => displayRecord(wp.record) _
+  }
+
+  /**
+   * Generate a link based on the current page
+   */
+  val link = new Loc.Link[WikiLoc](List("wiki"), false){
+    override def createLink(in: WikiLoc) = 
+      if(in.edit) Full(Text("/wiki/edit/"+urlEncode(in.page)))
+      else Full(Text("/wiki/"+urlEncode(in.page)))
+  }
+
+  /**
+   * What's the text of the link?
+   */
+  val text = new Loc.LinkText(calcLinkText _)
+  def calcLinkText(in: WikiLoc): NodeSeq = 
+    if(in.edit) Text("Wiki edit "+in.page) else Text("Wiki "+in.page)
+
+  /**
+   * Rewrite the request so that we a) get friendly URLs and
+   * b) get the appropriate page and context (edit or view) params
+   * in order to pass them to the WikiLoc 
+   */
+  override val rewrite: LocRewrite = Full(NamedPF("Wiki Rewrite"){
+    case RewriteRequest(ParsePath("wiki" :: "edit" :: page :: Nil, _, _,_),_, _) =>
+      (RewriteResponse("wiki" :: Nil), WikiLoc(page, true))
+    case RewriteRequest(ParsePath("wiki" :: page :: Nil, _, _,_),_,_) =>
+      (RewriteResponse("wiki" :: Nil), WikiLoc(page, false))
+  })
+
+  /**
+   * Show all the pages that are part of the wiki
+   */
+  def showAll(in: NodeSeq): NodeSeq = WikiEntry.findAll(OrderBy(WikiEntry.name, Ascending)).flatMap(entry =>
+    <div><a href={url(entry.name)}>{entry.name}</a></div>)
+
+
+  /**
+   * Make the URL to be accessed based up the page in the WikiLoc. 
+   * The createLink method already ensures that spaces etc are encoded
+   */
+  def url(page: String) = createLink(WikiLoc(page, false))
+
+  /**
+   * The render bind for actually displaying the wiki contents. This will 
+   * look just like what you are familiar with for creating snippets
+   */
+  def editRecord(r: WikiEntry)(xhtml: NodeSeq): NodeSeq = {
+    val isNew = !r.saved_?
+    val pageName = r.name.is
+    <form action={url(pageName)} method="post">{
+      bind("e", chooseTemplate("display","edit", xhtml),
+      "message" -> (if(isNew) Text("Create Entry named '"+pageName+"'") 
+          else Text("Edit entry named '"+pageName+"'")),
+      "cancel" -> <a href={url(pageName)}>Cancel</a>,
+      "textarea" -> r.entry.toForm,
+      "submit" -> SHtml.submit(isNew ? "Add" | "Save", () => r.save)
+    )}</form>
+  }
+
+  /** 
+   * Pretty much the same as the editRecord method, but obviously
+   * minus the err, editing.
+   */
+  def displayRecord(entry: WikiEntry)(xhtml: NodeSeq): NodeSeq = 
+    bind("v",chooseTemplate("display","view", xhtml),
+      "content" -> TextileParser.toHtml(entry.entry, textileWriter),
+      "edit" -> <a href={createLink(WikiLoc(entry.name, true))}>Edit</a>
+    )
+
+  private val textileWriter = Some((info: WikiURLInfo) =>
+    info match {
+      case WikiURLInfo(page, _) => (stringUrl(page), Text(page), None)
+    })
+
+  def stringUrl(page: String) = url(page).map(_.text) getOrElse ""
+
+}
+
+
+}}