在 Play 2.5 中创建自定义模板格式

Question

我正在尝试制作自定义模板格式（在 Play 2.5_ & _Scala 2.11.11 中）遵循 Play documentation 但我在这里所以这意味着它不适合我。

我希望新模板的文件扩展名为“stream”（this video 已经有几年了）所以我创建了这个文件如文档所示：

   package ui

   import akka.NotUsed
   import akka.stream.scaladsl.{Source}
   import play.twirl.api._

   import scala.collection.immutable

   case class HtmlStream(source: Source[Html, NotUsed]) extends Appendable[HtmlStream] {

     def +=(other: HtmlStream): HtmlStream = andThen(other)
     def andThen(other: HtmlStream): HtmlStream = HtmlStream(source.merge(other.source))

   }

   object HtmlStream {

     def apply(text: String): HtmlStream = apply(Html(text))
     def apply(html: Html): HtmlStream = HtmlStream(Source.single(html))

   }

   object HtmlStreamFormat extends Format[HtmlStream] {

     def raw(text: String): HtmlStream = HtmlStream(text)
     def escape(text: String): HtmlStream = raw(HtmlFormat.escape(text).body)

     override def empty: HtmlStream = ???
     override def fill(elements: immutable.Seq[HtmlStream]): HtmlStream = ???

   }

并将其添加到 build.sbt 文件中：

   TwirlKeys.templateFormats += ("stream" -> "ui.HtmlStreamFormat.instance")

我看不到在哪里或如何包含以下隐式（在前面提到的 Play documentation - 在底部）；这可能是问题所在：

Play can write an HTTP response body for any value of type A for which it exists an implicit play.api.http.Writeable[A] value. So all you need is to define such a value for your template result type. For instance, here is how to define such a value for HTTP:

   implicit def writableHttp(implicit codec: Codec): Writeable[Http] =
  Writeable[Http](result => codec.encode(result.body), Some(ContentTypes.HTTP))

当我尝试创建一个新的 view 文件时，例如称为 test.scala.stream 它无法识别它应该是什么类型所以看起来肯定是错误的。这方面需要帮助！

Answer 1

所以我已经破解了这个，本着社区的精神，它就在这里。

1) 创建一个文件（我将我的文件命名为“HtmlStream”，因为我正在寻找流 HTML）：

   package ui

   import akka.NotUsed
   import akka.stream.scaladsl.{Source}
   import play.twirl.api._

   import scala.collection.immutable
   import scala.concurrent.ExecutionContext

   case class HtmlStream(source: Source[Html, NotUsed]) extends Appendable[HtmlStream] {

     def +=(other: HtmlStream): HtmlStream = andThen(other)
     def andThen(other: HtmlStream): HtmlStream = HtmlStream(source.merge(other.source))

   }

   object HtmlStream {

     def apply(text: String): HtmlStream = apply(Html(text))
     def apply(html: Html): HtmlStream = HtmlStream(Source.single(html))

   }

   object HtmlStreamFormat extends Format[HtmlStream] {

     def raw(text: String): HtmlStream = HtmlStream(text)
     def escape(text: String): HtmlStream = raw(HtmlFormat.escape(text).body)

     override def empty: HtmlStream = raw("")
     override def fill(elements: immutable.Seq[HtmlStream]): HtmlStream = elements.reduce((agg, curr) => agg.andThen(curr))

   }

   object HtmlStreamImplicits {

      implicit def toSource(stream: HtmlStream)(implicit ec: ExecutionContext): Source[Html, NotUsed] = {
      stream.source.filter(_.body.nonEmpty)

   }

2) 我将这些行添加到 build.sbt 文件中：

   TwirlKeys.templateFormats += ("stream" -> "ui.HtmlStreamFormat")
   TwirlKeys.templateImports ++= Vector("ui.HtmlStream", "ui.HtmlStream._", "ui.HtmlStreamFormat._", "ui.HtmlStreamImplicits._")

3) 我添加了一个名为 test1.scala.stream 的模板（出现提示时使用 HTML 的 文件关联 ）：

   @(body: HtmlStream)

   <!DOCTYPE html>
   <html lang="en">
      <head>
          <title>title</title>
          <link rel="stylesheet" media="screen" href="assets/stylesheets/main.css">
          <link rel="shortcut icon" type="image/png" href="assets/images/favicon.png">
          <script src="assets/javascripts/hello.js" type="text/javascript"></script>
      </head>
      <body>
      <h1>Streaming the body</h1>

      <div>
          <div>
              @body
          </div>
      </div>
      </body>
   </html>

4) 最后，我可以像使用任何其他模板一样使用此模板，方法是将其转换为新的 HtmlStream 类型。

  def streamHtml = Action { request =>

    val async1: Future[Result] = rr.getAsync(embed = true)(request) // get future
    val async1Html: Future[Html] = async1.flatMap(x => Pagelet.readBody(x)) // separate function to convert Future[Result] to Future[Html]
    val htmlStream: HtmlStream = HtmlStream(fromFuture(async1Html)) // c onvert to HtmlStream type

    Ok.chunked(views.stream.test1(htmlStream)) // chunk the new data type by sending through new template

  }

希望这对其他人有帮助！

Answer 2

这是我根据播放规范为 cvs 和作品编写的自定义格式，包括您关于 ContentTypes.HTTP 的问题：

一些建议：

1-如果您希望播放框架可以编写 HTTP 响应主体，您需要定义主体内容。查看下面的代码 implicit def contentTypeCsv 这是您必须在特定正文内容中执行的操作。

2-其他重要建议，自定义格式的 twirl 模板应在自定义模板所在的 built.sbt 中定义，不管项目是单个项目还是多个项目。

class Csv(buffer: immutable.Seq[Csv],text:String,escape:Boolean) extends BufferedContent[Csv](buffer, text) {

  val contentType = Csv.contentType

  def this(text: String) = this(Nil, Formats.safe(text),false)
  def this(buffer: immutable.Seq[Csv]) = this(buffer, "",false)


  override protected def buildString(builder: StringBuilder) {
    if (elements.nonEmpty) {
      elements.foreach { e =>
        e.buildString(builder)
      }
    } else if (escape) {
      // Using our own algorithm here because commons lang escaping wasn't designed for protecting against XSS, and there
      // don't seem to be any other good generic escaping tools out there.
      text.foreach {
        case '"' => builder.append("\"\"")
        case c => builder += c
      }
    } else {
      builder.append(text)
    }
  }
}


object Csv {
  val contentType = "text/csv"
  implicit def contentTypeCsv(implicit codec: Codec): ContentTypeOf[Csv] = ContentTypeOf[Csv](Some(Csv.contentType))

  def apply(text: String): Csv = new Csv(text)

  def empty: Csv = new Csv("")
}
object CsvFormat extends Format[Csv] {
  def raw(text: String): Csv = Csv(text)
  def escape(text: String): Csv = {
    new Csv(Nil, text, true)
  }

  def empty: Csv = new Csv("")

  def fill(elements: Seq[Csv]): Csv = new Csv(elements)
}

在 Play 2.5 中创建自定义模板格式

Creating a custom template format in Play 2.5

model-view-controller

customization

types

scala

playframework