Update tutorial on loading local content

tutorials/serve-from-directory/src/main/java/com/teamdev/jxbrowser/examples/interceptor/Application.java

@@ -29,38 +29,37 @@
 import com.teamdev.jxbrowser.net.Scheme;
 import com.teamdev.jxbrowser.view.swing.BrowserView;
 import java.awt.BorderLayout;
-import java.nio.file.Path;
 import java.nio.file.Paths;
 import javax.swing.JFrame;
 import javax.swing.WindowConstants;
 
 /**
- * This example demonstrates how to serve files from the folder for a certain domain.
+ * This example demonstrates how to serve files from the folder for
+ * a certain domain.
  */
 public final class Application {
 
     public static void main(String[] args) {
-        Path contentRoot = Paths.get("content-root").toAbsolutePath();
-        DomainToFolderInterceptor interceptor =
-                DomainToFolderInterceptor.create("mydomain.com", contentRoot);
-        EngineOptions options =
+        var interceptor = new DomainToFolderInterceptor("mydomain.com",
+                Paths.get("content-root"));
+        var options =
                 EngineOptions.newBuilder(HARDWARE_ACCELERATED)
-                        .addScheme(Scheme.HTTP, interceptor)
+                        .addScheme(Scheme.HTTPS, interceptor)
                         .build();
-        Engine engine = Engine.newInstance(options);
-        Browser browser = engine.newBrowser();
+        var engine = Engine.newInstance(options);
+        var browser = engine.newBrowser();
 
         invokeLater(() -> {
-            BrowserView view = BrowserView.newInstance(browser);
+            var view = BrowserView.newInstance(browser);
 
-            JFrame frame = new JFrame("Serve Files from Folder");
+            var frame = new JFrame("Serve Files from Folder");
             frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
             frame.add(view, BorderLayout.CENTER);
             frame.setSize(1280, 720);
             frame.setLocationRelativeTo(null);
             frame.setVisible(true);
         });
 
-        browser.navigation().loadUrl("http://mydomain.com/index.html");
+        browser.navigation().loadUrl("https://mydomain.com/index.html");
     }
 }

tutorials/serve-from-directory/src/main/java/com/teamdev/jxbrowser/examples/interceptor/DomainContentInterceptor.java

@@ -0,0 +1,115 @@
+/*
+ *  Copyright 2025, TeamDev. All rights reserved.
+ *
+ *  Redistribution and use in source and/or binary forms, with or without
+ *  modification, must retain the above copyright notice and the following
+ *  disclaimer.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.teamdev.jxbrowser.examples.interceptor;
+
+import static com.teamdev.jxbrowser.net.HttpStatus.INTERNAL_SERVER_ERROR;
+import static com.teamdev.jxbrowser.net.HttpStatus.NOT_FOUND;
+import static com.teamdev.jxbrowser.net.HttpStatus.OK;
+
+import com.teamdev.jxbrowser.net.HttpHeader;
+import com.teamdev.jxbrowser.net.HttpStatus;
+import com.teamdev.jxbrowser.net.UrlRequestJob;
+import com.teamdev.jxbrowser.net.callback.InterceptUrlRequestCallback;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+
+/**
+ * A base URL interceptor that serves content for a specific domain by
+ * delegating the actual content lookup to subclasses.
+ *
+ * <p>This interceptor:
+ * <ul>
+ *     <li>Intercepts only requests whose host matches the configured domain.</li>
+ *     <li>Delegates the content lookup to {@link #openContent(String)}.</li>
+ *     <li>Streams the returned content into the {@link UrlRequestJob}.</li>
+ * </ul>
+ *
+ * <p>Subclasses need to provide the logic that locates the content (for example,
+ * on disk or on the classpath) and returns it as an {@link InputStream}.
+ * The MIME type is derived from the requested path by this base class.
+ */
+abstract class DomainContentInterceptor implements InterceptUrlRequestCallback {
+
+    private static final String CONTENT_TYPE = "Content-Type";
+    private final String domain;
+
+    DomainContentInterceptor(String domain) {
+        this.domain = domain;
+    }
+
+    @Override
+    public Response on(Params params) {
+        var uri = URI.create(params.urlRequest().url());
+        if (!uri.getHost().equals(domain)) {
+            // Let Chromium process requests to other domains as usual.
+            return Response.proceed();
+        }
+        var path = uri.getPath().substring(1);
+        try (var content = openContent(path)) {
+            if (content == null) {
+                var job = createJob(params, NOT_FOUND);
+                job.complete();
+                return Response.intercept(job);
+            }
+            var mimeType = MimeTypes.mimeType(path);
+            var contentType = HttpHeader.of(CONTENT_TYPE, mimeType);
+            var job = createJob(params, OK, contentType);
+            writeToJob(content, job);
+            job.complete();
+            return Response.intercept(job);
+        } catch (IOException e) {
+            // Return 500 response when the file read failed.
+            var job = createJob(params, INTERNAL_SERVER_ERROR);
+            job.complete();
+            return Response.intercept(job);
+        } catch (Exception e) {
+            return Response.proceed();
+        }
+    }
+
+    /**
+     * Locates the content for the given {@code uri}.
+     *
+     * <p>If the content cannot be found, this method should return
+     * {@code null}. If the content cannot be read, it should throw an
+     * {@link IOException}.
+     */
+    protected abstract InputStream openContent(String path) throws IOException;
+
+    private UrlRequestJob createJob(Params params, HttpStatus status,
+            HttpHeader... headers) {
+        var options = UrlRequestJob.Options.newBuilder(status);
+        for (var header : headers) {
+            options.addHttpHeader(header);
+        }
+        return params.newUrlRequestJob(options.build());
+    }
+
+    /**
+     * Writes content of the input stream into the HTTP response.
+     */
+    private void writeToJob(InputStream stream, UrlRequestJob job)
+            throws IOException {
+        var content = stream.readAllBytes();
+        job.write(content);
+    }
+}

tutorials/serve-from-directory/src/main/java/com/teamdev/jxbrowser/examples/interceptor/DomainToFolderInterceptor.java

@@ -20,139 +20,62 @@
 
 package com.teamdev.jxbrowser.examples.interceptor;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-import static com.teamdev.jxbrowser.examples.interceptor.MimeTypes.mimeType;
-import static com.teamdev.jxbrowser.internal.string.StringPreconditions.checkNotNullEmptyOrBlank;
-import static com.teamdev.jxbrowser.logging.Logger.error;
-import static com.teamdev.jxbrowser.net.HttpStatus.INTERNAL_SERVER_ERROR;
-import static com.teamdev.jxbrowser.net.HttpStatus.NOT_FOUND;
-import static com.teamdev.jxbrowser.net.HttpStatus.OK;
-import static java.util.Collections.emptyList;
-import static java.util.Collections.singletonList;
+import static java.nio.file.Files.exists;
+import static java.nio.file.Files.isDirectory;
 
-import com.teamdev.jxbrowser.net.HttpHeader;
-import com.teamdev.jxbrowser.net.HttpStatus;
-import com.teamdev.jxbrowser.net.UrlRequestJob;
-import com.teamdev.jxbrowser.net.callback.InterceptUrlRequestCallback;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.net.URI;
-import java.nio.file.Files;
+import java.io.InputStream;
 import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.Arrays;
-import java.util.List;
 
 /**
- * An interceptor that treats every URL under the given domain as a path to the file on disk and
- * loads it.
+ * An interceptor that treats every URL under the given domain as a path to a
+ * file on disk and loads it.
  *
- * <p>The interceptor is configured with the domain name and the content directory. For every
- * request, it takes the path component of the URL and looks for it in the content directory. That
- * means a request to {@code example.com/docs/index.html} will load {@code docs/index.html} file
- * from the content directory. The mime type of the file is derived automatically.
+ * <p>The interceptor is configured with the domain name and the content
+ * directory. For every request, it takes the path component of the URL and
+ * looks for it in the content directory. That means a request to
+ * {@code example.com/docs/index.html} will load {@code docs/index.html} file
+ * from the content directory. The MIME type of the file is derived
+ * automatically.
  *
  * <p>This interceptor responds with the following status codes:
  *
  * <ul>
  *     <li><b>200 OK</b> - the file was found and read properly.
  *         In this case, the {@code Content-Type} header is sent.</li>
- *     <li><b>404 Not Found</b> - the file could not be found due to an invalid path.</li>
+ *     <li><b>404 Not Found</b> - the file could not be found.</li>
  *     <li><b>500 Internal Server Error</b> - couldn't read the file.</li>
  * </ul>
  *
- * <p>This interceptor considers only the path component of the URL request. It ignores request
- * parameters and headers.
- *
- * <p>Note: using this interceptor can reduce performance since it processes all incoming
- * traffic under the scheme.
+ * <p>This interceptor considers only the path component of the URL request.
+ * It ignores request parameters and headers.
  */
-public final class DomainToFolderInterceptor implements InterceptUrlRequestCallback {
-
-    private static final String CONTENT_TYPE = "Content-Type";
+public final class DomainToFolderInterceptor extends DomainContentInterceptor {
 
-    private final String domain;
     private final Path contentRoot;
 
-    private DomainToFolderInterceptor(String domain, Path contentRoot) {
-        this.domain = domain;
-        this.contentRoot = contentRoot;
-    }
-
     /**
-     * Creates a URL interceptor for the given domain to load files from the given directory.
+     * Creates a URL interceptor for the given domain to load files from the
+     * given directory.
      *
      * @param domain      a domain name to intercept
      * @param contentRoot a path to the directory with files to load
      */
-    public static DomainToFolderInterceptor create(String domain, Path contentRoot) {
-        checkNotNull(contentRoot);
-        checkNotNullEmptyOrBlank(domain);
-        return new DomainToFolderInterceptor(domain, contentRoot.toAbsolutePath());
+    public DomainToFolderInterceptor(String domain, Path contentRoot) {
+        super(domain);
+        this.contentRoot = contentRoot.toAbsolutePath();
     }
 
+    /**
+     * Resolves the requested path to a file and opens it.
+     */
     @Override
-    public Response on(Params params) {
-        URI uri = URI.create(params.urlRequest().url());
-        if (shouldNotBeIntercepted(uri)) {
-            return Response.proceed();
-        }
-        Path filePath = getPathOnDisk(uri);
-        UrlRequestJob job;
-        if (fileExists(filePath)) {
-            HttpHeader contentType = getContentType(filePath);
-            job = createJob(params, OK, singletonList(contentType));
-            try {
-                readFile(filePath, job);
-            } catch (IOException e) {
-                error("Failed to read file {0}", e, filePath);
-                job = createJob(params, INTERNAL_SERVER_ERROR);
-            }
-        } else {
-            job = createJob(params, NOT_FOUND);
-        }
-        job.complete();
-        return Response.intercept(job);
-    }
-
-    private boolean shouldNotBeIntercepted(URI uri) {
-        return !uri.getHost().equals(domain);
-    }
-
-    private Path getPathOnDisk(URI uri) {
-        return Paths.get(contentRoot.toString(), uri.getPath());
-    }
-
-    private boolean fileExists(Path filePath) {
-        return Files.exists(filePath) && !Files.isDirectory(filePath);
-    }
-
-    private HttpHeader getContentType(Path file) {
-        return HttpHeader.of(CONTENT_TYPE, mimeType(file).value());
-    }
-
-    private UrlRequestJob createJob(Params params,
-            HttpStatus httpStatus,
-            List<HttpHeader> httpHeaders) {
-        UrlRequestJob.Options.Builder builder = UrlRequestJob.Options.newBuilder(httpStatus);
-        httpHeaders.forEach(builder::addHttpHeader);
-        return params.newUrlRequestJob(builder.build());
-    }
-
-    private UrlRequestJob createJob(Params params, HttpStatus httpStatus) {
-        return createJob(params, httpStatus, emptyList());
-    }
-
-    private void readFile(Path filePath, UrlRequestJob job) throws IOException {
-        try (FileInputStream stream = new FileInputStream(filePath.toFile())) {
-            byte[] buffer = new byte[4096];
-            int bytesRead;
-            while ((bytesRead = stream.read(buffer)) > 0) {
-                if (bytesRead != buffer.length) {
-                    buffer = Arrays.copyOf(buffer, bytesRead);
-                }
-                job.write(buffer);
-            }
+    protected InputStream openContent(String path) throws IOException {
+        var filePath = contentRoot.resolve(path);
+        if (exists(filePath) && !isDirectory(filePath)) {
+            return new FileInputStream(filePath.toFile());
         }
+        return null;
     }
 }