[PrivacyBrowserAndroid.git] / app / src / main / java / com / stoutner / privacybrowser / asynctasks / SaveUrl.java

/*
 * Copyright © 2020 Soren Stoutner <soren@stoutner.com>.
 *
 * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
 *
 * Privacy Browser is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Privacy Browser is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.stoutner.privacybrowser.asynctasks;

import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.view.View;
import android.webkit.CookieManager;
import android.webkit.MimeTypeMap;

import androidx.core.content.FileProvider;

import com.google.android.material.snackbar.Snackbar;
import com.stoutner.privacybrowser.R;
import com.stoutner.privacybrowser.helpers.ProxyHelper;
import com.stoutner.privacybrowser.views.NoSwipeViewPager;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.Proxy;
import java.net.URL;
import java.text.NumberFormat;

public class SaveUrl extends AsyncTask<String, Long, String> {
    // Define a weak references for the calling context and activity.
    private WeakReference<Context> contextWeakReference;
    private WeakReference<Activity> activityWeakReference;

    // Define a success string constant.
    private final String SUCCESS = "Success";

    // Define the class variables.
    private String filePathString;
    private String userAgent;
    private boolean cookiesEnabled;
    private Snackbar savingFileSnackbar;

    // The public constructor.
    public SaveUrl(Context context, Activity activity, String filePathString, String userAgent, boolean cookiesEnabled) {
        // Populate weak references to the calling context and activity.
        contextWeakReference = new WeakReference<>(context);
        activityWeakReference = new WeakReference<>(activity);

        // Store the class variables.
        this.filePathString = filePathString;
        this.userAgent = userAgent;
        this.cookiesEnabled = cookiesEnabled;
    }

    // `onPreExecute()` operates on the UI thread.
    @Override
    protected void onPreExecute() {
        // Get a handle for the activity.
        Activity activity = activityWeakReference.get();

        // Abort if the activity is gone.
        if ((activity==null) || activity.isFinishing()) {
            return;
        }

        // Get a handle for the no swipe view pager.
        NoSwipeViewPager noSwipeViewPager = activity.findViewById(R.id.webviewpager);

        // Create a saving file snackbar.
        savingFileSnackbar = Snackbar.make(noSwipeViewPager, activity.getString(R.string.saving_file) + "  0% - " + filePathString, Snackbar.LENGTH_INDEFINITE);

        // Display the saving file snackbar.
        savingFileSnackbar.show();
    }

    @Override
    protected String doInBackground(String... urlToSave) {
        // Get handles for the context and activity.
        Context context = contextWeakReference.get();
        Activity activity = activityWeakReference.get();

        // Abort if the activity is gone.
        if ((activity == null) || activity.isFinishing()) {
            return null;
        }

        // Define a save disposition string.
        String saveDisposition = SUCCESS;

        // Because everything relating to requesting data from a webserver can throw errors, the entire section must catch `IOExceptions`.
        try {
            // Get the URL from the calling activity.
            URL url = new URL(urlToSave[0]);

            // Instantiate the proxy helper.
            ProxyHelper proxyHelper = new ProxyHelper();

            // Get the current proxy.
            Proxy proxy = proxyHelper.getCurrentProxy(context);

            // Open a connection to the URL.  No data is actually sent at this point.
            HttpURLConnection httpUrlConnection = (HttpURLConnection) url.openConnection(proxy);

            // Add the user agent to the header property.
            httpUrlConnection.setRequestProperty("User-Agent", userAgent);

            // Add the cookies if they are enabled.
            if (cookiesEnabled) {
                // Get the cookies for the current domain.
                String cookiesString = CookieManager.getInstance().getCookie(url.toString());

                // Only add the cookies if they are not null.
                if (cookiesString != null) {
                    // Add the cookies to the header property.
                    httpUrlConnection.setRequestProperty("Cookie", cookiesString);
                }
            }

            // The actual network request is in a `try` bracket so that `disconnect()` is run in the `finally` section even if an error is encountered in the main block.
            try {
                // Get the content length header, which causes the connection to the server to be made.
                String contentLengthString = httpUrlConnection.getHeaderField("Content-Length");

                // Define the file size long.
                long fileSize;

                // Make sure the content length isn't null.
                if (contentLengthString != null) {  // The content length isn't null.
                    // Convert the content length to an long.
                    fileSize = Long.parseLong(contentLengthString);
                } else {  // The content length is null.
                    // Set the file size to be `-1`.
                    fileSize = -1;
                }

                // Get the response body stream.
                InputStream inputStream = new BufferedInputStream(httpUrlConnection.getInputStream());

                // Get the file.
                File file = new File(filePathString);

                // Delete the file if it exists.
                if (file.exists()) {
                    //noinspection ResultOfMethodCallIgnored
                    file.delete();
                }

                // Create a new file.
                //noinspection ResultOfMethodCallIgnored
                file.createNewFile();

                // Create an output file stream.
                OutputStream outputStream = new FileOutputStream(file);

                // Initialize the conversion buffer byte array.
                byte[] conversionBufferByteArray = new byte[1024];

                // Initialize the downloaded kilobytes counter.
                long downloadedKilobytesCounter = 0;

                // Define the buffer length variable.
                int bufferLength;

                // Attempt to read data from the input stream and store it in the output stream.  Also store the amount of data read in the buffer length variable.
                while ((bufferLength = inputStream.read(conversionBufferByteArray)) > 0) {  // Proceed while the amount of data stored in the buffer in > 0.
                    // Write the contents of the conversion buffer to the output stream.
                    outputStream.write(conversionBufferByteArray, 0, bufferLength);

                    // Update the file download progress snackbar.
                    if (fileSize == -1) {  // The file size is unknown.
                        // Negatively update the downloaded kilobytes counter.
                        downloadedKilobytesCounter = downloadedKilobytesCounter - bufferLength;

                        publishProgress(downloadedKilobytesCounter);
                    } else {  // The file size is known.
                        // Update the downloaded kilobytes counter.
                        downloadedKilobytesCounter = downloadedKilobytesCounter + bufferLength;

                        // Calculate the download percentage.
                        long downloadPercentage = (downloadedKilobytesCounter * 100) / fileSize;

                        // Update the download percentage.
                        publishProgress(downloadPercentage);
                    }
                }

                // Close the input stream.
                inputStream.close();

                // Close the output stream.
                outputStream.close();

                // Create a media scanner intent, which adds items like pictures to Android's recent file list.
                Intent mediaScannerIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);

                // Add the URI to the media scanner intent.
                mediaScannerIntent.setData(Uri.fromFile(file));

                // Make it so.
                activity.sendBroadcast(mediaScannerIntent);
            } finally {
                // Disconnect the HTTP URL connection.
                httpUrlConnection.disconnect();
            }
        } catch (Exception exception) {
            // Store the error in the save disposition string.
            saveDisposition = exception.toString();
        }

        // Return the save disposition string.
        return saveDisposition;
    }

    // `onProgressUpdate()` operates on the UI thread.
    @Override
    protected void onProgressUpdate(Long... downloadPercentage) {
        // Get a handle for the activity.
        Activity activity = activityWeakReference.get();

        // Abort if the activity is gone.
        if ((activity == null) || activity.isFinishing()) {
            return;
        }

        // Check to see if a download percentage has been calculated.
        if (downloadPercentage[0] < 0) {  // There is no download percentage.  The negative number represents the raw downloaded kilobytes.
            // Calculate the number of bytes downloaded.  When the `downloadPercentage` is negative, it is actually the raw number of kilobytes downloaded.
            long numberOfBytesDownloaded = 0 - downloadPercentage[0];

            // Format the number of bytes downloaded.
            String formattedNumberOfBytesDownloaded = NumberFormat.getInstance().format(numberOfBytesDownloaded);

            // Update the snackbar.
            savingFileSnackbar.setText(activity.getString(R.string.saving_file) + "  " + formattedNumberOfBytesDownloaded + " " + activity.getString(R.string.bytes) + " - " + filePathString);
        } else {  // There is a download percentage.
            // Update the snackbar.
            savingFileSnackbar.setText(activity.getString(R.string.saving_file) + "  " + downloadPercentage[0] + "% - " + filePathString);
        }
    }

    // `onPostExecute()` operates on the UI thread.
    @Override
    protected void onPostExecute(String saveDisposition) {
        // Get handles for the context and activity.
        Context context = contextWeakReference.get();
        Activity activity = activityWeakReference.get();

        // Abort if the activity is gone.
        if ((activity == null) || activity.isFinishing()) {
            return;
        }

        // Get a handle for the no swipe view pager.
        NoSwipeViewPager noSwipeViewPager = activity.findViewById(R.id.webviewpager);

        // Dismiss the saving file snackbar.
        savingFileSnackbar.dismiss();

        // Display a save disposition snackbar.
        if (saveDisposition.equals(SUCCESS)) {
            // Create a file saved snackbar.
            Snackbar fileSavedSnackbar = Snackbar.make(noSwipeViewPager, activity.getString(R.string.file_saved) + "  " + filePathString, Snackbar.LENGTH_LONG);

            // Add an open action if the file is not an APK on API >= 26 (that scenario requires the REQUEST_INSTALL_PACKAGES permission).
            if (!(Build.VERSION.SDK_INT >= 26 && filePathString.endsWith(".apk"))) {
                fileSavedSnackbar.setAction(R.string.open, (View v) -> {
                    // Get a file for the file path string.
                    File file = new File(filePathString);

                    // Define a file URI variable
                    Uri fileUri;

                    // Get the URI for the file according to the Android version.
                    if (Build.VERSION.SDK_INT >= 24) {  // Use a file provider.
                        fileUri = FileProvider.getUriForFile(context, activity.getString(R.string.file_provider), file);
                    } else {  // Get the raw file path URI.
                        fileUri = Uri.fromFile(file);
                    }

                    // Get a handle for the content resolver.
                    ContentResolver contentResolver = context.getContentResolver();

                    // Create an open intent with `ACTION_VIEW`.
                    Intent openIntent = new Intent(Intent.ACTION_VIEW);

                    // Set the URI and the MIME type.
                    if (filePathString.endsWith("apk") || filePathString.endsWith("APK")) {  // Force detection of APKs.
                        openIntent.setDataAndType(fileUri, MimeTypeMap.getSingleton().getMimeTypeFromExtension("apk"));
                    } else {  // Autodetect the MIME type.
                        openIntent.setDataAndType(fileUri, contentResolver.getType(fileUri));
                    }

                    // Allow the app to read the file URI.
                    openIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

                    // Try the intent.
                    try {
                        // Show the chooser.
                        activity.startActivity(openIntent);
                    } catch (ActivityNotFoundException exception) {  // There are no apps available to open the URL.
                        // Show a snackbar with the error.
                        Snackbar.make(noSwipeViewPager, activity.getString(R.string.error) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
                    }
                });
            }

            // Show the file saved snackbar.
            fileSavedSnackbar.show();
        } else {
            // Display the file saving error.
            Snackbar.make(noSwipeViewPager, activity.getString(R.string.error_saving_file) + "  " + saveDisposition, Snackbar.LENGTH_INDEFINITE).show();
        }
    }
}