Initial Implementation

src/main/java/de/kosit/validationtool/impl/RelativeUriResolver.java

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+/*
+ * Licensed to the Koordinierungsstelle für IT-Standards (KoSIT) under
+ * one or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  KoSIT licenses this file
+ * to you 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.
+ */
+
+package de.kosit.validationtool.impl;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.net.URI;
+
+import javax.xml.transform.Source;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.URIResolver;
+import javax.xml.transform.stream.StreamSource;
+
+import lombok.RequiredArgsConstructor;
+
+import net.sf.saxon.Configuration;
+import net.sf.saxon.lib.UnparsedTextURIResolver;
+import net.sf.saxon.trans.XPathException;
+
+/**
+ * {@link URIResolver} that resolves artifacts relative to a given base uri. The resolved URI must be resolving as child
+ * e.g. the baseUri must be a parent of the resolved artifact.
+ *
+ * @author Andreas Penski
+ */
+@RequiredArgsConstructor
+public class RelativeUriResolver implements URIResolver, UnparsedTextURIResolver {
+
+    /** the base uri */
+    private final URI baseUri;
+
+    @Override
+    public Source resolve(final String href, final String base) throws TransformerException {
+        final URI resolved = URI.create(base).resolve(href);
+        if (isUnderBaseUri(resolved)) {
+            try {
+                return new StreamSource(resolved.toURL().openStream());
+            } catch (final IOException e) {
+
+                throw new IllegalStateException(String.format("Can not resolve required  %s", href), e);
+            }
+        } else {
+            throw new IllegalStateException(
+                    String.format("The resolved transformation artifact %s is not within the configured repository %s", resolved, baseUri));
+        }
+    }
+
+    private boolean isUnderBaseUri(URI resolved) {
+        String base = baseUri.toASCIIString().replaceAll("file:/+", "");
+        String r = resolved.toASCIIString().replaceAll("file:/+", "");
+        return r.startsWith(base);
+    }
+
+    @Override
+    public Reader resolve(URI absoluteURI, String encoding, Configuration config) throws XPathException {
+        if (isUnderBaseUri(absoluteURI)) {
+            try {
+                return new InputStreamReader(absoluteURI.toURL().openStream(), encoding);
+            } catch (IOException e) {
+                throw new IllegalStateException(String.format("Can not resolve required  %s", absoluteURI), e);
+            }
+        } else {
+            throw new IllegalStateException(
+                    String.format("The resolved transformation artifact %s is not within the configured repository %s", absoluteURI, baseUri));
+        }
+    }
+}