自动HTML编码NVelocity输出（EventCartridge＆安培; ReferenceInsert）

问题描述

我想尝试让NVelocity自动HTML EN code在我的单轨的应用程序的某些字符串。

我看遍了NVelocity源$ C ​​$ C，发现 EventCartridge ，这似乎是，你可以插件更改各种行为的类。

在特定该类有一个 ReferenceInsert 方法，这似乎做的正是我想要的。它基本上被调用之前的基准（如：$ foobar的）的价值得到输出，并且允许你修改的结果。

我不能工作了我是怎么配置NVelocity /单轨电车NVelocity视图引擎使用我的执行？

的建议velocity.properties可以包含一个条目添加特定的事件处理程序是这样的，但我找不到在NVelocity源$ C ​​$ C，看起来这个配置的任何地方nofollow的>速度文档。

任何帮助非常AP preciated！

---

编辑：一个简单的测试，显示这方面的工作（！概念证明这样不生产code）

 私人VelocityEngine _velocityEngine;
私人VelocityContext _velocityContext;

[建立]
公共无效设置（）
{
    _velocityEngine =新VelocityEngine（）;
    _velocityEngine.Init（）;

    //创建的背景下...
    _velocityContext =新VelocityContext（）;

    //附加一个新的事件盒
    _velocityContext.AttachEventCartridge（新EventCartridge（））;

    //添加我们的自定义处理程序的ReferenceInsertion事件
    _velocityContext.EventCartridge.ReferenceInsertion + = EventCartridge_ReferenceInsertion;
}

[测试]
公共无效恩codeReference（）
{
    _velocityContext.Put（thisShouldBeEn codeD，＆LT; P＆gt;这\\应该是恩codeD'＆LT; / P＆gt;中）;

    VAR作家=新的StringWriter（）;

    VAR的结果= _velocityEngine.Evaluate（_velocityContext，作家，HtmlEncodingEventCartridgeTestFixture.En codeReference，@＆LT; P＆gt;这，不应该，将连接codeD＆LT; / P＆GT; $ thisShouldBeEn codeD）;

    Assert.IsTrue（结果是，评估返回失败）;
    Assert.AreEqual（@＆LT; P＆gt;这，不应该，将连接codeD＆LT; / P＆GT;＆放大器; LT; P＆安培; gt;这与安培; QUOT; QUOT;应与功放是和放大器; ＃39; EN coded和放大器;＃39;＆放大器; LT; / P＆放大器; GT;，writer.ToString（））;
}

私有静态无效EventCartridge_ReferenceInsertion（对象发件人，ReferenceInsertionEventArgs E）
{
    VAR originalString = e.OriginalValue为字符串;

    如果（originalString == NULL）回报;

    e.NewValue = HtmlEn code（originalString）;
}

私人静态字符串HtmlEn code（字符串值）
{
    返回值
        .Replace（与＆amp;，＆放大器;放大器;）
        .Replace（＆所述;，＆安培;其中;）
        .Replace（＆gt;中，与＆amp; gt;中）
        .Replace（\，与＆amp; QUOT;）
        .Replace（'，与＆amp;＃39;）; //＆功放;者;在IE浏览器无法正常工作
}
 

解决方案

尽量将新EventCartridge到VelocityContext。请参阅这些测试作为参考。

现在，你已经证实，这种方法的工作原理，从 Castle.MonoRail.Framework.Views.NVelocity.NVelocityEngine 继承，覆盖 BeforeMerge ，并设置 EventCartridge 和事件出现。然后配置单轨使用此自定义视图引擎。

I wanted to try getting NVelocity to automatically HTML encode certain strings in my MonoRail app.

I looked through the NVelocity source code and found EventCartridge, which seems to be a class which you can plugin to change various behaviours.

In particular this class has a ReferenceInsert method which would seem to do exactly what I want. It basically gets called just before the value of a reference (e.g. $foobar) gets output, and allows you to modify the results.

What I can't work out is how I configure NVelocity/the MonoRail NVelocity view engine to use my implementation?

The Velocity docs suggest that velocity.properties can contain an entries for adding specific event handlers like this, but I can't find anywhere in the NVelocity source code that looks for this configuration.

Any help greatly appreciated!

---

Edit: A simple test that shows this working (proof of concept so not production code!)

private VelocityEngine _velocityEngine;
private VelocityContext _velocityContext;

[SetUp]
public void Setup()
{
    _velocityEngine = new VelocityEngine();
    _velocityEngine.Init();

    // creates the context...
    _velocityContext = new VelocityContext();

    // attach a new event cartridge
    _velocityContext.AttachEventCartridge(new EventCartridge());

    // add our custom handler to the ReferenceInsertion event
    _velocityContext.EventCartridge.ReferenceInsertion += EventCartridge_ReferenceInsertion;
}

[Test]
public void EncodeReference()
{
    _velocityContext.Put("thisShouldBeEncoded", "<p>This \"should\" be 'encoded'</p>");

    var writer = new StringWriter();

    var result = _velocityEngine.Evaluate(_velocityContext, writer, "HtmlEncodingEventCartridgeTestFixture.EncodeReference", @"<p>This ""shouldn't"" be encoded.</p> $thisShouldBeEncoded");

    Assert.IsTrue(result, "Evaluation returned failure");
    Assert.AreEqual(@"<p>This ""shouldn't"" be encoded.</p> &lt;p&gt;This &quot;should&quot; be &#39;encoded&#39;&lt;/p&gt;", writer.ToString());
}

private static void EventCartridge_ReferenceInsertion(object sender, ReferenceInsertionEventArgs e)
{
    var originalString = e.OriginalValue as string;

    if (originalString == null) return;

    e.NewValue = HtmlEncode(originalString);
}

private static string HtmlEncode(string value)
{
    return value
        .Replace("&", "&amp;")
        .Replace("<", "&lt;")
        .Replace(">", "&gt;")
        .Replace("\"", "&quot;")
        .Replace("'", "&#39;"); // &apos; does not work in IE
}

解决方案

Try attaching a new EventCartridge to the VelocityContext. See these tests as reference.

Now that you've confirmed that this approach works, inherit from Castle.MonoRail.Framework.Views.NVelocity.NVelocityEngine, override BeforeMerge and set the EventCartridge and event there. Then configure MonoRail to use this custom view engine.

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