Custom logic for browser caching

app/build.gradle

@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 29
+    compileSdkVersion 30
     buildToolsVersion "21.1.0"
 
     defaultConfig {
         applicationId "org.eu.octt.browserocto"
         minSdkVersion 1
-        targetSdkVersion 29
+        targetSdkVersion 30
         versionCode 1
         versionName "1.0.1"
     }

app/src/main/java/org/eu/octt/browserocto/MainActivity.java

@@ -20,7 +20,7 @@ public class MainActivity extends Activity {
 		final EditText EditUrl = findViewById(R.id.EditUrl);
 		final Button BtnOpen = findViewById(R.id.BtnOpen);
 		final Button BtnShortcut = findViewById(R.id.BtnShortcut);
-		final Switch SwitchCache = findViewById(R.id.SwitchCache);
+		final CheckBox SwitchCache = findViewById(R.id.SwitchCache);
 		
 		BtnOpen.setOnClickListener(new OnClickListener() {
 			@Override
@@ -141,4 +141,4 @@ public class MainActivity extends Activity {
 
 		Dial.show();
 	};
-};
+};

app/src/main/java/org/eu/octt/browserocto/WebWindowActivity.java

@@ -10,64 +10,60 @@ import java.io.*;
 import java.net.*;
 
 public class WebWindowActivity extends Activity {
+	WebView Web0;
+	
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		setContentView(R.layout.webwindow);
-		Bundle Extra = getIntent().getExtras();
+		final Bundle Extra = getIntent().getExtras();
 		LinearLayout LayMain = findViewById(R.id.LayMain);
 
-		WebView Web0 = findViewById(R.id.Web0);
-		//Web0.setWebViewClient(new WebViewClient());
-
+		/*final WebView */Web0 = findViewById(R.id.Web0);
+		final String WebCacheDir = "/data/data/" + getPackageName() + "/cache/WebCache/";
+		
 		Web0.setWebViewClient(new WebViewClient() {
 			// https://gist.github.com/kmerrell42/b4ff31733c562a3262ee9a42f5704a89
 			@Override
 			public WebResourceResponse shouldInterceptRequest(WebView v, String Url) {
 				return HandleRequest(Url);
-			}
+			};
 			@Override
 			public WebResourceResponse shouldInterceptRequest(WebView v, WebResourceRequest Req) {
 				return HandleRequest(Req.getUrl().toString());
-			}
+			};
+			// TODO: Save all HTTP headers too and return them somehow
 			private WebResourceResponse HandleRequest(String Url) {
-				//Thread thread = new Thread(new Runnable() {
-				//	@Override
-				//	public void run() {
 				try {
-					//URL url;
-					//HttpURLConnection Connection = null;
-					URL Url_ = new URL(Url);
-					HttpURLConnection Connection = (HttpURLConnection)Url_.openConnection();
-					String ContentType = Connection.getContentType();
-					String ContentEncoding = null;
+					final String UrlDir = WebCacheDir + Url + "_";
+					final File UrlFile = new File(UrlDir, "Content");
+					if (!UrlFile.exists() || !Extra.getBoolean("Cache")) {
+						final URL Url_ = new URL(Url);
+						final HttpURLConnection Connection = (HttpURLConnection)Url_.openConnection();
+						_Util.WriteStreamToFile(new BufferedInputStream(Connection.getInputStream()), UrlDir, "Content");
+						_Util.WriteStreamToFile(new ByteArrayInputStream(Connection.getContentType().getBytes()), UrlDir, "Content-Type");
+					};
+					String ContentType = _Util.StreamToString(new FileInputStream(new File(UrlDir, "Content-Type")));
+					final String ContentEncoding = null;
 					if (ContentType != null) {
-						ContentType = ContentType.split("\\;")[0];
-						ContentEncoding = ContentType.split("\\=")[1];
-					}
-					InputStream In = new BufferedInputStream(Connection.getInputStream());
-					return new WebResourceResponse(ContentType, ContentEncoding, In);
+						//ContentEncoding = ContentType.split("=")[1];
+						ContentType = ContentType.split(";")[0];
+					};
+					return new WebResourceResponse(ContentType, ContentEncoding, new FileInputStream(UrlFile));
 				} catch (Exception Ex) {
 					Log.e("browserocto/Log", "", Ex);
 				};
-				//	};//});
 				return null;
 			};
 		});
 
 		Web0.getSettings().setJavaScriptEnabled(true);
 		Web0.getSettings().setDomStorageEnabled(true);
-		Web0.getSettings().setCacheMode(WhichCacheMode(Extra.getBoolean("Cache")));
-
-		// This is apparently not working like I want (force caching of all site resources in spite of bad Cache-Control HTTP headers)
-		//webView.getSettings().setAppCacheMaxSize(1024*1024*8);
-		//webView.getSettings().setAppCachePath("/data/data/" + getPackageName() + "/cache");
-		//webView.getSettings().setAllowFileAccess(true);
-		//webView.getSettings().setAppCacheEnabled(true);
+		Web0.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);//WhichCacheMode(Extra.getBoolean("Cache")));
 
 		Web0.loadUrl(Extra.getString("Url"));
 		_Util.ToastMsg(Extra.getString("Url"), this);
-
+		
 //		Thread thread = new Thread(new Runnable() {
 //			@Override
 //			public void run() {
@@ -97,10 +93,12 @@ public class WebWindowActivity extends Activity {
 //		thread.start();
 	};
 
-	public int WhichCacheMode(boolean Opt) {
-		if (Opt) {
-			return WebSettings.LOAD_CACHE_ELSE_NETWORK;
+	@Override
+	public void onBackPressed() {
+		if (Web0.canGoBack()) {
+			Web0.goBack();
+		} else {
+			super.onBackPressed();
 		};
-		return WebSettings.LOAD_NO_CACHE;
 	};
-};
+};

app/src/main/java/org/eu/octt/browserocto/_Util.java

@@ -38,21 +38,43 @@ public class _Util extends Activity {
 	};
 
 	// https://stackoverflow.com/a/5713929
-	public static String StreamToString(InputStream is) throws IOException {
-		if (is != null) {
+	public static String StreamToString(InputStream In) throws IOException {
+		if (In != null) {
 			Writer writer = new StringWriter();
 			char[] buffer = new char[1024];
 			try {
-				Reader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
+				Reader reader = new BufferedReader(new InputStreamReader(In, "UTF-8"));
 				int n;
 				while ((n = reader.read(buffer)) != -1) {
 					writer.write(buffer, 0, n);
 				};
 			} finally {
-				is.close();
+				In.close();
 			};
 			return writer.toString();
 		};
 		return "";
 	};
-};
+	
+	// https://stackoverflow.com/a/10857407
+	public static void WriteStreamToFile(InputStream In, String Path, String Name) throws IOException {
+		try {
+			File dir = new File(Path);
+			dir.mkdirs();
+			File file = new File(Path, Name);
+			file.createNewFile();
+			try (OutputStream output = new FileOutputStream(file)) {
+				byte[] buffer = new byte[4 * 1024];
+				int read;
+
+				while ((read = In.read(buffer)) != -1) {
+					output.write(buffer, 0, read);
+				}
+
+				output.flush();
+				}
+		} finally {
+			In.close();
+		}
+	};
+};

app/src/main/res/layout/main.xml

@@ -9,7 +9,8 @@
 
 	<EditText
 		android:layout_width="match_parent"
-		android:ems="10"
+		android:inputType="text"
+		android:maxLines="1"
 		android:layout_height="wrap_content"
 		android:hint="URL..."
 		android:text="https://"
@@ -38,8 +39,7 @@
 
 	</LinearLayout>
 
-	<!-- TODO: Make this be CheckBox on Android < ICS because Switch doesn't exist -->
-	<Switch
+	<CheckBox
 		android:layout_width="wrap_content"
 		android:layout_height="wrap_content"
 		android:text="[Open Now] Force load from local cache"
@@ -47,4 +47,4 @@
 		android:checked="true"
 		android:id="@+id/SwitchCache"/>
 
-</LinearLayout>
+</LinearLayout>