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Why do I get a SAXParseException when I use an HTML entity, such as   in my template?

Tapestry uses a standard SAX parser to read your templates. This means that your templates must be well formed: open and close tags must balance, attribute values must be quoted, and entities must be declared. The easiest way to accomplish this is to add a DOCTYPE to your the top of your template:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

Part of the DOCTYPE is the declaration of entities such as &nbsp;.

Alternately, you can simply use the numeric version: &#160; This is the exact same character and will render identically in the browser.

Why do some images in my page show up as broken links?

You have to be careful when using relative URLs inside page templates; the base URL may not always be what you expect. For example, inside your ViewUser.tml file, you may have:

  <img class="icon" src="icons/admin.png"/>${user.name} has Administrative access

This makes sense; ViewUser.tml is in the web context, as is the icons folder. The default URL for this page will be /viewuser 1

However, most likely, the ViewUser page has a page activation context to identify which user is to be displayed:

public class ViewUser

  @Property
  @PageActivationContext
  private User user;

  . . .

—

With a page activation context, the URL for the page will incorporate the id of the User object, something like /viewuser/37371. This is why the relative URLs to the admin.png image is broken: the base path is relative to the page's URL, not to the page template 2 .

One solution would be to predict what the page URL will be, and adjust the path for that:

  <img class="icon" src="../icons/admin.png"/>${user.name} has Administrative access

But this has its own problems; the page activation context may vary in length at different times, or the template in question may be a component used across many different pages, making it difficult to predict what the correct relative URL would be.

The best solution for this situation, one that will be sure to work in all pages and all components, is to make use of the context: binding prefix:

  <img class="icon" src="${context:icons/admin.png}"/>${user.name} has Administrative access

The src attribute of the <img> tag will now be bound to a dynamically computed value: the location of the image file relative to the
web application context. This is especially important for components that may be used on different pages.

  1. Assuming that class ViewUser is in the root-package.pages package.     
  2. In fact, the page template may not even be in the web context, it may be stored on the classpath, as component templates are.     

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