Added a convenience URIResolver that uses the ServletContext in a servlet to access resources packed into a web application.

The URIResolver listens to the "servlet-context:" protocol.
Integrated the new URIResolver into out two servlets at all levels (TransformerFactory, Transformer and FOP).

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@379810 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 119 insertions, 4 deletions

diff --git a/src/java/org/apache/fop/servlet/FopPrintServlet.java b/src/java/org/apache/fop/servlet/FopPrintServlet.java
index 3b4f92f60..8ac980ccd 100644
--- a/src/java/org/apache/fop/servlet/FopPrintServlet.java
+++ b/src/java/org/apache/fop/servlet/FopPrintServlet.java
@@ -31,11 +31,13 @@ import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.Result;
 import javax.xml.transform.Source;
+import javax.xml.transform.URIResolver;
 import javax.xml.transform.sax.SAXResult;
 import javax.xml.transform.stream.StreamSource;
 
 // XML
 import org.apache.commons.logging.impl.SimpleLog;
+import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.Fop;
 import org.apache.fop.apps.MimeConstants;
 
@@ -77,6 +79,8 @@ public class FopPrintServlet extends HttpServlet {
     
     /** The TransformerFactory to use to create Transformer instances */
     protected TransformerFactory transFactory = null;
+    /** URIResolver for use by this servlet */
+    protected URIResolver uriResolver; 
 
     /**
      * @see javax.servlet.GenericServlet#init()
@@ -84,7 +88,9 @@ public class FopPrintServlet extends HttpServlet {
     public void init() throws ServletException {
         this.log = new SimpleLog("FOP/Print Servlet");
         log.setLevel(SimpleLog.LOG_LEVEL_WARN);
+        this.uriResolver = new ServletContextURIResolver(getServletContext());
         this.transFactory = TransformerFactory.newInstance();
+        this.transFactory.setURIResolver(this.uriResolver);
     }
 
     /**
@@ -132,11 +138,12 @@ public class FopPrintServlet extends HttpServlet {
     public void renderFO(InputStream foFile,
                          HttpServletResponse response) throws ServletException {
         try {
-            Fop fop = new Fop(MimeConstants.MIME_FOP_PRINT);
+            Fop fop = new Fop(MimeConstants.MIME_FOP_PRINT, getFOUserAgent());
 
             // Setup JAXP
             TransformerFactory factory = TransformerFactory.newInstance();
             Transformer transformer = factory.newTransformer(); //identity transformer
+            transformer.setURIResolver(this.uriResolver);
             
             // Setup input for XSLT transformation
             Source src = new StreamSource(foFile);
@@ -163,11 +170,12 @@ public class FopPrintServlet extends HttpServlet {
     public void renderXML(File xmlfile, File xsltfile,
                           HttpServletResponse response) throws ServletException {
         try {
-            Fop fop = new Fop(MimeConstants.MIME_FOP_PRINT);
+            Fop fop = new Fop(MimeConstants.MIME_FOP_PRINT, getFOUserAgent());
 
             // Setup XSLT
             TransformerFactory factory = TransformerFactory.newInstance();
             Transformer transformer = factory.newTransformer(new StreamSource(xsltfile));
+            transformer.setURIResolver(this.uriResolver);
             
             // Setup input for XSLT transformation
             Source src = new StreamSource(xmlfile);
@@ -202,5 +210,13 @@ public class FopPrintServlet extends HttpServlet {
             throw new ServletException(ex);
         }
     }
+
+    /** @return a new FOUserAgent for FOP */
+    protected FOUserAgent getFOUserAgent() {
+        FOUserAgent userAgent = new FOUserAgent();
+        userAgent.setURIResolver(this.uriResolver);
+        return userAgent;
+    }
+
 }
 
diff --git a/src/java/org/apache/fop/servlet/FopServlet.java b/src/java/org/apache/fop/servlet/FopServlet.java
index a5d8612d7..cd1d23014 100644
--- a/src/java/org/apache/fop/servlet/FopServlet.java
+++ b/src/java/org/apache/fop/servlet/FopServlet.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 1999-2005 The Apache Software Foundation.
+ * Copyright 1999-2006 The Apache Software Foundation.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import javax.xml.transform.Source;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.URIResolver;
 import javax.xml.transform.sax.SAXResult;
 import javax.xml.transform.stream.StreamSource;
 
@@ -37,6 +38,7 @@ import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.commons.logging.impl.SimpleLog;
 
 //FOP
+import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.Fop;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.MimeConstants;
@@ -78,6 +80,8 @@ public class FopServlet extends HttpServlet {
     protected SimpleLog log = null;
     /** The TransformerFactory to use to create Transformer instances */
     protected TransformerFactory transFactory = null;
+    /** URIResolver for use by this servlet */
+    protected URIResolver uriResolver; 
 
     /**
      * @see javax.servlet.GenericServlet#init()
@@ -85,7 +89,9 @@ public class FopServlet extends HttpServlet {
     public void init() throws ServletException {
         this.log = new SimpleLog("FOP/Servlet");
         log.setLevel(SimpleLog.LOG_LEVEL_WARN);
+        this.uriResolver = new ServletContextURIResolver(getServletContext());
         this.transFactory = TransformerFactory.newInstance();
+        this.transFactory.setURIResolver(this.uriResolver);
     }
 
     /**
@@ -152,6 +158,7 @@ public class FopServlet extends HttpServlet {
 
         //Setup the identity transformation
         Transformer transformer = this.transFactory.newTransformer();
+        transformer.setURIResolver(this.uriResolver);
 
         //Start transformation and rendering process
         return render(foSrc, transformer);
@@ -178,6 +185,7 @@ public class FopServlet extends HttpServlet {
 
         //Setup the XSL transformation
         Transformer transformer = this.transFactory.newTransformer(xsltSrc);
+        transformer.setURIResolver(this.uriResolver);
 
         //Start transformation and rendering process
         return render(xmlSrc, transformer);
@@ -201,7 +209,7 @@ public class FopServlet extends HttpServlet {
                 throws FOPException, TransformerException {
 
         //Setup FOP
-        Fop fop = new Fop(MimeConstants.MIME_PDF);
+        Fop fop = new Fop(MimeConstants.MIME_PDF, getFOUserAgent());
 
         //Setup output
         ByteArrayOutputStream out = new ByteArrayOutputStream();
@@ -216,5 +224,12 @@ public class FopServlet extends HttpServlet {
         //Return the result
         return out.toByteArray();
     }
+    
+    /** @return a new FOUserAgent for FOP */
+    protected FOUserAgent getFOUserAgent() {
+        FOUserAgent userAgent = new FOUserAgent();
+        userAgent.setURIResolver(this.uriResolver);
+        return userAgent;
+    }
 
 }
diff --git a/src/java/org/apache/fop/servlet/ServletContextURIResolver.java b/src/java/org/apache/fop/servlet/ServletContextURIResolver.java
new file mode 100644
index 000000000..ae8b4eba4
--- /dev/null
+++ b/src/java/org/apache/fop/servlet/ServletContextURIResolver.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2006 The Apache Software Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.servlet;
+
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import javax.servlet.ServletContext;
+import javax.xml.transform.Source;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.URIResolver;
+import javax.xml.transform.stream.StreamSource;
+
+/**
+ * This class is a URIResolver implementation that provides access to resources in the WEB-INF
+ * directory of a web application using "servlet-content:" URIs.
+ */
+public class ServletContextURIResolver implements URIResolver {
+
+    /** The protocol name for the servlet context URIs. */
+    public static final String SERVLET_CONTEXT_PROTOCOL = "servlet-context:";
+    
+    private ServletContext servletContext;
+    
+    /**
+     * Main constructor
+     * @param servletContext the servlet context to access the resources through
+     */
+    public ServletContextURIResolver(ServletContext servletContext) {
+        this.servletContext = servletContext;
+    }
+    
+    /** @see javax.xml.transform.URIResolver#resolve(java.lang.String, java.lang.String) */
+    public Source resolve(String href, String base) throws TransformerException {
+        if (href.startsWith(SERVLET_CONTEXT_PROTOCOL)) {
+            return resolveServletContextURI(href.substring(SERVLET_CONTEXT_PROTOCOL.length()));
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Resolves the "servlet-context:" URI.
+     * @param path the path part after the protocol (should start with a "/")
+     * @return the resolved Source or null if the resource was not found
+     * @throws TransformerException if no URL can be constructed from the path
+     */
+    protected Source resolveServletContextURI(String path) throws TransformerException {
+        try {
+            URL url = this.servletContext.getResource(path);
+            InputStream in = this.servletContext.getResourceAsStream(path);
+            if (in != null) {
+                if (url != null) {
+                    return new StreamSource(in, url.toExternalForm());
+                } else {
+                    return new StreamSource(in);
+                }
+            } else {
+                throw new TransformerException("Resource does not exist. \"" + path
+                        + "\" is not accessible through the servlet context.");
+            }
+        } catch (MalformedURLException mfue) {
+            throw new TransformerException(
+                    "Error accessing resource using servlet context: " + path, mfue);
+        }
+    }
+}