Olat webview provides downloads.

AndroidManifest.xml

@@ -8,6 +8,7 @@
     <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <!--
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

src/main/java/de/bps/asist/module/olat/HostSetBuilder.java

+package de.bps.asist.module.olat;
+
+import android.content.Context;
+
+import java.net.URL;
+import java.util.HashSet;
+import java.util.Set;
+
+public class HostSetBuilder {
+    private HashSet<String> hosts;
+
+    private void addHost(String addingHost) {
+        if (addingHost != null) {
+            if (!addingHost.isEmpty()) {
+                if (this.hosts == null) {
+                    this.hosts = new HashSet<>();
+                }
+                this.hosts.add(addingHost);
+            }
+        }
+    }
+
+    public HostSetBuilder extractHost(URL url) {
+        throwExceptionIfNull(url, "url");
+        this.addHost(url.getHost());
+        return this;
+    }
+
+    public HostSetBuilder host(String host) {
+        throwExceptionIfNull(host, "host");
+        this.addHost(host);
+        return this;
+    }
+
+    public HostSetBuilder host(int resId, Context context) {
+        this.host(context.getString(resId));
+        return this;
+    }
+
+    public HostSetBuilder hosts(int resId, Context context) {
+        String[] addingUrls = context.getResources().getStringArray(resId);
+        for (String url : addingUrls) {
+            this.host(url);
+        }
+        return this;
+    }
+
+    public Set<String> build() {
+        if (this.hosts == null) {
+            return new HashSet<>();
+        } else {
+            return new HashSet<>(this.hosts);
+        }
+    }
+
+    private static void throwExceptionIfNull(Object object, String paramterName) {
+        if (object == null) {
+            throw new NullPointerException(paramterName + "should not be null.");
+        }
+    }
+}

src/main/java/de/bps/asist/module/olat/OlatFragment.java

@@ -4,6 +4,7 @@
 package de.bps.asist.module.olat;
 
 import android.annotation.SuppressLint;
+import android.app.DownloadManager;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
@@ -21,17 +22,26 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.webkit.CookieManager;
 import android.webkit.CookieSyncManager;
+import android.webkit.DownloadListener;
+import android.webkit.URLUtil;
 import android.webkit.ValueCallback;
 import android.webkit.WebChromeClient;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
+import android.widget.Toast;
 
 import java.io.File;
 import java.io.IOException;
+import java.lang.reflect.Array;
 import java.text.SimpleDateFormat;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
 
 import de.bps.asist.R;
 import de.bps.asist.core.manager.push.PushNotificationManager;
@@ -115,6 +125,14 @@ public class OlatFragment extends AbstractASiSTFragment {
                 return true;
             }
         });
+
+        Set<String> allowedHosts = new HostSetBuilder()
+                .host(R.string.olat_url, getContext())
+                .hosts(R.array.olat_allowed_download_hosts, getContext())
+                .build();
+
+        webView.setDownloadListener(new OpalDownloadListener(this.getContext(), allowedHosts));
+
         return view;
     }
 
@@ -221,4 +239,134 @@ public class OlatFragment extends AbstractASiSTFragment {
         File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
         return File.createTempFile(imageFileName,".jpg",storageDir);
     }
+
+    /**
+     * Download listener for opal web view. This download listner will block every download which is not in the given hosts.
+     */
+    private class OpalDownloadListener implements DownloadListener {
+
+        private final static String USER_AGENT_HEADER = "User-Agent";
+        private final static String COOKIE_HEADER = "Cookie";
+
+        private Context context;
+        private Set<String> allowedHosts;
+
+        /**
+         * Contructs a new OpalDownloadListener instance.
+         *
+         * @param context - context wich will be used for system calls
+         */
+        OpalDownloadListener(Context context) {
+            this.context = context;
+            this.allowedHosts = null;
+        }
+
+        /**
+         * Contructs a new OpalDownloadListener instance.
+         *
+         * @param context      - context which will be used for system calls
+         * @param allowedHosts - allowed hosts for downloading
+         */
+        OpalDownloadListener(Context context, Collection<String> allowedHosts) {
+            this.context = context;
+            this.allowedHosts = new HashSet<>(allowedHosts);
+        }
+
+        /**
+         * Contructs a new OpalDownloadListener instance.
+         *
+         * @param context      - context which will be used for system calls
+         * @param allowedHost - allowed host for downloading
+         */
+        OpalDownloadListener(Context context, String allowedHost) {
+            this(context, Arrays.asList(allowedHost));
+        }
+
+        /**
+         * Contructs a new OpalDownloadListener instance.
+         *
+         * @param context      - context which will be used for system calls
+         * @param allowedHost - allowed host for downloading
+         */
+        OpalDownloadListener(Context context, Uri allowedHost) {
+            this(context, allowedHost.getHost());
+        }
+
+        @Override
+        public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
+            Uri downloadUri = Uri.parse(url);
+            if (this.isHostAllowed(downloadUri)) {
+                String downloadFileName = guessFileName(url, contentDisposition, mimetype);
+
+                DownloadManager.Request downloadRequest = new DownloadManager.Request(Uri.parse(url));
+                downloadRequest.setMimeType(mimetype);
+                downloadRequest.setTitle(downloadFileName);
+                downloadRequest.setDescription(this.context.getString(R.string.module_olat_download_description) + " " + downloadFileName + ".");
+
+                downloadRequest.addRequestHeader(COOKIE_HEADER, CookieManager.getInstance().getCookie(url));
+                downloadRequest.addRequestHeader(USER_AGENT_HEADER, userAgent);
+
+                downloadRequest.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, downloadFileName);
+
+                downloadRequest.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE | DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
+                downloadRequest.allowScanningByMediaScanner();
+
+                DownloadManager downloadManager = (DownloadManager) this.context.getSystemService(Context.DOWNLOAD_SERVICE);
+                downloadManager.enqueue(downloadRequest);
+            } else {
+                Toast.makeText(this.context, getString( R.string.module_olat_download_blocking, downloadUri.getHost()), Toast.LENGTH_LONG).show();
+            }
+        }
+
+        /**
+         * Check wether the included uri host is permitted in downloading files.
+         *
+         * @param checkingUri  - Uri wich will be checked
+         * @param allowedHosts - List of allowed hosts
+         * @return true if host is allowed or false if not
+         */
+        private boolean isHostAllowed(Uri checkingUri, Set<String> allowedHosts) {
+            boolean isHostAllowed = true;
+            if (allowedHosts != null) {
+                isHostAllowed = allowedHosts.contains(checkingUri.getHost());
+            }
+            return isHostAllowed;
+        }
+
+        /**
+         * Check wether the included uri host is permitted in downloading files.
+         *
+         * @param checkingUri - Uri wich will be checked
+         * @return true if host is allowed or false if not
+         */
+        private boolean isHostAllowed(Uri checkingUri) {
+            return this.isHostAllowed(checkingUri, this.allowedHosts);
+        }
+
+        /**
+         * Guesses a filename that a download would have, using url and contentDisposition. Is no file extension spicified the mime type is used as fallback.
+         *
+         * @param url
+         * @param contentDisposition
+         * @param mimetype
+         * @return
+         */
+        private String guessFileName(String url, String contentDisposition, String mimetype) {
+            String guessingFileName = URLUtil.guessFileName(url, contentDisposition, mimetype);
+
+            String contentDispositionContentParts[] = contentDisposition.split(";");
+            for (String contentDispositionContentPart : contentDispositionContentParts) {
+                contentDispositionContentPart = contentDispositionContentPart.trim();
+                if (contentDispositionContentPart.startsWith("filename=")) {
+                    guessingFileName = contentDispositionContentPart.substring(contentDispositionContentPart.indexOf('=') + 1);
+                    if (guessingFileName.startsWith("\"") && guessingFileName.endsWith("\"")) {
+                        guessingFileName = guessingFileName.substring(1, guessingFileName.length() - 1);
+                    }
+                    break;
+                }
+            }
+
+            return guessingFileName;
+        }
+    }
 }

src/main/res/values-en/strings.xml

@@ -201,6 +201,8 @@
 
     <!-- OLAT Module -->
     <string name="module_olat_name">OPAL</string>
+    <string name="module_olat_download_description">Downloading</string>
+    <string name="module_olat_download_blocking">Downloading from %1$s is not allowed.</string>
 
     <!-- Impressum Module -->
     <string name="module_impressum_name">Legal Notice</string>

src/main/res/values/settings.xml

@@ -47,4 +47,8 @@
     <!-- Module Room -->
     <string name="module_room_url">https://your-openasistserver.net/raum.html?content</string>
 
+    <!-- special settings for olat module -->
+    <string-array name="olat_allowed_download_hosts">
+    </string-array>
+
 </resources>
\ No newline at end of file

src/main/res/values/strings.xml

@@ -203,6 +203,8 @@
 
     <!-- OLAT Module -->
     <string name="module_olat_name">OPAL</string>
+    <string name="module_olat_download_description">Download gestartet.</string>
+    <string name="module_olat_download_blocking">Downloaden von %1$s ist nicht erlaubt.</string>
 
     <!-- Impressum Module -->
     <string name="module_impressum_name">Impressum</string>