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Posted to commits@tapestry.apache.org by bu...@apache.org on 2018/02/12 12:21:02 UTC
svn commit: r1025260 - in /websites/production/tapestry/content: assets.html
cache/main.pageCache
Author: buildbot
Date: Mon Feb 12 12:21:02 2018
New Revision: 1025260
Log:
Production update by buildbot for tapestry
Modified:
websites/production/tapestry/content/assets.html
websites/production/tapestry/content/cache/main.pageCache
Modified: websites/production/tapestry/content/assets.html
==============================================================================
--- websites/production/tapestry/content/assets.html (original)
+++ websites/production/tapestry/content/assets.html Mon Feb 12 12:21:02 2018
@@ -163,7 +163,7 @@ private Asset icon;
@Path("${skin.root}/style.css")
private Asset style;
</pre>
-</div></div><div class="confluence-information-macro confluence-information-macro-note"><span class="aui-icon aui-icon-small aui-iconfont-warning confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>The use of the <code>${...</code>} syntax here is a <em>symbol expansion</em> (because it occurs in an annotation in Java code), rather than a <em>template expansion</em> (which occurs only in Tapestry template files).</p></div></div><p>An override of the skin.root symbol would affect all references to the named asset.</p><h3 id="Assets-LocalizationofAssets">Localization of Assets</h3><p>Main Article: <a href="assets.html">Assets</a></p><p>Assets are localized; Tapestry will search for a variation of the file appropriate to the effective locale for the request. In the previous example, a German user of the application may see a file named <code>edit_de.png</code> (if such a file exists).</p><h3 id="Assets-NewAssetDomains">New Asset Domains</h3><p>I
f you wish to create new domains for assets, for example to allow assets to be stored on the file system or in a database, you may define a new <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/AssetFactory.html">AssetFactory</a> and contribute it to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/AssetSource.html">AssetSource</a> service configuration.</p><h3 id="Assets-AssetFingerprinting(Tapestry5.3andearlier)">Asset Fingerprinting (Tapestry 5.3 and earlier)</h3><p>Tapestry creates a new URL for assets (whether context or classpath). The URL is of the form /assets/<strong>version</strong>/<strong>folder</strong>/<strong>path</strong>.</p><ul><li><strong>version</strong>: Application version number, defined by the <code>tapestry.application-version</code> symbol in your application module (normally AppModule.java). The default is a random hex number.</li><li><strong>
folder</strong>: Identifies the library containing the asset, or "ctx" for a context asset, or "stack" (used when combining multiple JavaScript files into a single virtual asset).</li><li><strong>path</strong>: The path below the root package of the library to the specific asset file.</li></ul><h3 id="Assets-AssetFingerprinting(Tapestry5.4andlater)">Asset Fingerprinting<span> (Tapestry 5.4 and later)</span></h3><p>Tapestry 5.4 changes how Asset URLs are constructed. The version number is now a <em>content fingerprint</em>, a hash of the actual content of the asset.</p><p>Assets get a far-future expires header. It is no longer necessary or desirable to change the application version number.</p><p>During development or production, if an asset is changed in any way, it will have a new content fingerprint and will appear, to the browser, to be an entirely new immutable resource.</p><h3 id="Assets-CSSLinkRewriting">CSS Link Rewriting</h3><p>It is frequently the case that CSS fi
les will include links to other files, such as background images, using the <code>url</code>() value syntax. Under 5.4, the URL for the CSS file and the targeted file would be broken, due to the inclusions of the CSS file's content hash fingerprint. To fix this, Tapestry parses CSS files, locates the <code>url()</code> directives, and rewrites the URLs to be absolute (including the targeted file's content hash fingerprint).</p><h3 id="Assets-PerformanceNotes">Performance Notes</h3><p>Assets are expected to be entirely static (not changing while the application is deployed). This allows Tapestry to perform some important performance optimizations.</p><p>Tapestry GZIP compresses the content of all assets – if the asset is compressible, the client supports it, and you don't <a href="assets.html">explicitly disable it</a>.</p><p><span>Further, the asset will get a </span><em>far future expires header</em><span>, which will encourage the client browser to cache the asset
.</span></p><p>You should have an explicit application version number for any production application. Client browsers will aggressively cache downloaded assets; they will usually not even send a request to see if the asset has changed once the asset is downloaded the first time. Because of this it is <em>very important</em> that each new deployment of your application has a new <a href="assets.html">version number</a>, to force existing clients to re-download all assets.</p><h3 id="Assets-AssetSecurity">Asset Security</h3><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>This applies to how Tapestry 5.3 and earlier manage classpath assets; Tapestry 5.4 introduces another system which doesn't have this issue.</p></div></div><p>Because Tapestry directly exposes files on the classpath to the clients, some thoug
ht has gone into ensuring that malicious clients are not able to download assets that should not be visible to them.</p><p>First off all, there's a package limitation: classpath assets are only visible if there's a <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/LibraryMapping.html">LibraryMapping</a> for them, and the library mapping substitutes for the initial folders on the classpath. Since the most secure assets, things like <code>hibernate.cfg.xml</code> are located in the unnamed package, they are always off limits.</p><p>But what about other files on the classpath? Imagine this scenario:</p><ul><li>Your Login page exposes a classpath asset, <code>icon.png</code>.</li><li><p>A malicious client copies the URL, <code>/assets/1.0.0/app/pages/icon.png (</code><span>which would indicate that the Login page is actually inside a library, which is unlikely. More likely, icon.png is a context asset and the malicious user guessed
the path for Login.class by looking at the Tapestry source code.) </span><span>and changes the file name to </span><code>Login.class</code><span>.</span></p></li><li><p>The client decompiles the class file and spots your secret emergency password: goodbye security! (<span>Never create such back doors, of course!)</span></p></li></ul><p>Fortunately, this can't happen. Files with extension ".class" are secured; they must be accompanied in the URL with a query parameter that is the MD5 hash of the file's contents. If the query parameter is absent, or doesn't match the actual file's content, the request is rejected.</p><p>When your code exposes an Asset that is secured, Tapestry generates a URL that automatically includes MD5 hash query parameter. The malicious user is locked out of access to the files. (The only way they could generate the MD5 hash is if<span> they somehow already have the files, in which case they don't need to download them again anyway.)</span></p><p>By default
, Tapestry secures file extensions ".class', ".tml" and ".properties". The list can be extended by contributing to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ResourceDigestGenerator.html">ResourceDigestGenerator</a> service:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent pdl">
+</div></div><div class="confluence-information-macro confluence-information-macro-note"><span class="aui-icon aui-icon-small aui-iconfont-warning confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>The use of the <code>${...</code>} syntax here is a <em>symbol expansion</em> (because it occurs in an annotation in Java code), rather than a <em>template expansion</em> (which occurs only in Tapestry template files).</p></div></div><p>An override of the skin.root symbol would affect all references to the named asset.</p><h3 id="Assets-LocalizationofAssets">Localization of Assets</h3><p>Main Article: <a href="assets.html">Assets</a></p><p>Assets are localized; Tapestry will search for a variation of the file appropriate to the effective locale for the request. In the previous example, a German user of the application may see a file named <code>edit_de.png</code> (if such a file exists).</p><h3 id="Assets-NewAssetDomains">New Asset Domains</h3><p>I
f you wish to create new domains for assets, for example to allow assets to be stored on the file system or in a database, you may define a new <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/AssetFactory.html">AssetFactory</a> and contribute it to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/AssetSource.html">AssetSource</a> service configuration.</p><h3 id="Assets-AssetFingerprinting(Tapestry5.3andearlier)">Asset Fingerprinting (Tapestry 5.3 and earlier)</h3><p>Tapestry creates a new URL for assets (whether context or classpath). The URL is of the form /assets/<strong>version</strong>/<strong>folder</strong>/<strong>path</strong>.</p><ul><li><strong>version</strong>: Application version number, defined by the <code>tapestry.application-version</code> symbol in your application module (normally AppModule.java). The default is a random hex number.</li><li><strong>
folder</strong>: Identifies the library containing the asset, or "ctx" for a context asset, or "stack" (used when combining multiple JavaScript files into a single virtual asset).</li><li><strong>path</strong>: The path below the root package of the library to the specific asset file.</li></ul><h3 id="Assets-AssetFingerprinting(Tapestry5.4andlater)">Asset Fingerprinting<span> (Tapestry 5.4 and later)</span></h3><p>Tapestry 5.4 changes how Asset URLs are constructed. The version number is now a <em>content fingerprint</em>, a hash of the actual content of the asset.</p><p>Assets get a far-future expires header. It is no longer necessary or desirable to change the application version number.</p><p>During development or production, if an asset is changed in any way, it will have a new content fingerprint and will appear, to the browser, to be an entirely new immutable resource.</p><h3 id="Assets-CSSLinkRewriting">CSS Link Rewriting</h3><p>It is frequently the case that CSS fi
les will include links to other files, such as background images, using the <code>url</code>() value syntax. Under 5.4, the URL for the CSS file and the targeted file would be broken, due to the inclusions of the CSS file's content hash fingerprint. To fix this, Tapestry parses CSS files, locates the <code>url()</code> directives, and rewrites the URLs to be absolute (including the targeted file's content hash fingerprint).</p><h3 id="Assets-PerformanceNotes">Performance Notes</h3><p>Assets are expected to be entirely static (not changing while the application is deployed). This allows Tapestry to perform some important performance optimizations.</p><p>Tapestry GZIP compresses the content of all assets – if the asset is compressible, the client supports it, and you don't <a href="assets.html">explicitly disable it</a>.</p><p><span>Further, the asset will get a </span><em>far future expires header</em><span>, which will encourage the client browser to cache the asset
.</span></p><p>For Talestry 5.3 and earlier, you should have an explicit application version number for any production application. Client browsers will aggressively cache downloaded assets; they will usually not even send a request to see if the asset has changed once the asset is downloaded the first time. Because of this it is <em>very important</em> that each new deployment of your application has a new <a href="assets.html">version number</a>, to force existing clients to re-download all assets.</p><h3 id="Assets-AssetSecurity">Asset Security</h3><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>This applies to how Tapestry 5.3 and earlier manage classpath assets; Tapestry 5.4 introduces another system which doesn't have this issue.</p></div></div><p>Because Tapestry directly exposes files on the classp
ath to the clients, some thought has gone into ensuring that malicious clients are not able to download assets that should not be visible to them.</p><p>First off all, there's a package limitation: classpath assets are only visible if there's a <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/LibraryMapping.html">LibraryMapping</a> for them, and the library mapping substitutes for the initial folders on the classpath. Since the most secure assets, things like <code>hibernate.cfg.xml</code> are located in the unnamed package, they are always off limits.</p><p>But what about other files on the classpath? Imagine this scenario:</p><ul><li>Your Login page exposes a classpath asset, <code>icon.png</code>.</li><li><p>A malicious client copies the URL, <code>/assets/1.0.0/app/pages/icon.png (</code><span>which would indicate that the Login page is actually inside a library, which is unlikely. More likely, icon.png is a context asset a
nd the malicious user guessed the path for Login.class by looking at the Tapestry source code.) </span><span>and changes the file name to </span><code>Login.class</code><span>.</span></p></li><li><p>The client decompiles the class file and spots your secret emergency password: goodbye security! (<span>Never create such back doors, of course!)</span></p></li></ul><p>Fortunately, this can't happen. Files with extension ".class" are secured; they must be accompanied in the URL with a query parameter that is the MD5 hash of the file's contents. If the query parameter is absent, or doesn't match the actual file's content, the request is rejected.</p><p>When your code exposes an Asset that is secured, Tapestry generates a URL that automatically includes MD5 hash query parameter. The malicious user is locked out of access to the files. (The only way they could generate the MD5 hash is if<span> they somehow already have the files, in which case they don't need to download them again an
yway.)</span></p><p>By default, Tapestry secures file extensions ".class', ".tml" and ".properties". The list can be extended by contributing to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ResourceDigestGenerator.html">ResourceDigestGenerator</a> service:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent pdl">
<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">public static void contributeResourceDigestGenerator(Configuration<String> configuration)
{
configuration.add("xyz");
Modified: websites/production/tapestry/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.