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authorGravatar Adam Chlipala <adamc@hcoop.net>2009-05-03 12:24:39 -0400
committerGravatar Adam Chlipala <adamc@hcoop.net>2009-05-03 12:24:39 -0400
commitd8de44ce7c70fc8ce462e764223e413a9a6ea6b6 (patch)
treebbd4fa663e5c412c295510f3cc6c75afa5191e48 /demo/prose
parentebbae2ae752fe3b0774207920c7510853ffcbdcf (diff)
url demo
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diff --git a/demo/prose b/demo/prose
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@@ -64,6 +64,12 @@ cookie.urp
<p>After setting the cookie, try browsing back to this demo from the main index. The data you entered should still be there.</p>
+url.urp
+
+<p>Up to this point, we haven't included a single URL in our source code. This may be very surprising to programmers used to working with traditional web frameworks! In Ur/Web, we avoid writing URLs explicitly wherever possible. To link to an external web page, we rely on an abstract type <tt>url</tt>. Strings can't be treated implicitly as URLs; rather, they must be "blessed" explicitly. This helps avoid some classes of code injection attacks.</p>
+
+<p>Further, each Ur/Web application enforces a global condition on which strings are allowed as URLs. The <tt>.urp</tt> file for this demo shows an example that specifies particular rules about which URLs are allowed. You can try entering a variety of URLs on the form on the front page. Only those satisfying the <tt>allow url</tt>/<tt>deny url</tt> conditions should be permitted.</p>
+
listShop.urp
<p>This example shows off algebraic datatypes, parametric polymorphism, and functors.</p>