src/com/android/browser/DownloadHandler.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed 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 com.android.browser;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.DownloadManager;
import android.content.ActivityNotFoundException;
import android.content.ComponentName;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.net.Uri;
import android.net.WebAddress;
import android.os.Environment;
import android.util.Log;
import android.webkit.CookieManager;
import android.webkit.URLUtil;
import android.widget.Toast;

/**
 * Handle download requests
 */
public class DownloadHandler {

    private static final boolean LOGD_ENABLED =
            com.android.browser.Browser.LOGD_ENABLED;

    private static final String LOGTAG = "DLHandler";

    Activity mActivity;

    public DownloadHandler(Activity activity) {
        mActivity = activity;
    }

    /**
     * Notify the host application a download should be done, or that
     * the data should be streamed if a streaming viewer is available.
     * @param url The full url to the content that should be downloaded
     * @param contentDisposition Content-disposition http header, if
     *                           present.
     * @param mimetype The mimetype of the content reported by the server
     * @param contentLength The file size reported by the server
     */
    public void onDownloadStart(String url, String userAgent,
            String contentDisposition, String mimetype, long contentLength) {
        // if we're dealing wih A/V content that's not explicitly marked
        //     for download, check if it's streamable.
        if (contentDisposition == null
                || !contentDisposition.regionMatches(
                        true, 0, "attachment", 0, 10)) {
            // query the package manager to see if there's a registered handler
            //     that matches.
            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setDataAndType(Uri.parse(url), mimetype);
            ResolveInfo info = mActivity.getPackageManager().resolveActivity(intent,
                    PackageManager.MATCH_DEFAULT_ONLY);
            if (info != null) {
                ComponentName myName = mActivity.getComponentName();
                // If we resolved to ourselves, we don't want to attempt to
                // load the url only to try and download it again.
                if (!myName.getPackageName().equals(
                        info.activityInfo.packageName)
                        || !myName.getClassName().equals(
                                info.activityInfo.name)) {
                    // someone (other than us) knows how to handle this mime
                    // type with this scheme, don't download.
                    try {
                        mActivity.startActivity(intent);
                        return;
                    } catch (ActivityNotFoundException ex) {
                        if (LOGD_ENABLED) {
                            Log.d(LOGTAG, "activity not found for " + mimetype
                                    + " over " + Uri.parse(url).getScheme(),
                                    ex);
                        }
                        // Best behavior is to fall back to a download in this
                        // case
                    }
                }
            }
        }
        onDownloadStartNoStream(url, userAgent, contentDisposition, mimetype, contentLength);
    }

    // This is to work around the fact that java.net.URI throws Exceptions
    // instead of just encoding URL's properly
    // Helper method for onDownloadStartNoStream
    private static String encodePath(String path) {
        char[] chars = path.toCharArray();

        boolean needed = false;
        for (char c : chars) {
            if (c == '[' || c == ']') {
                needed = true;
                break;
            }
        }
        if (needed == false) {
            return path;
        }

        StringBuilder sb = new StringBuilder("");
        for (char c : chars) {
            if (c == '[' || c == ']') {
                sb.append('%');
                sb.append(Integer.toHexString(c));
            } else {
                sb.append(c);
            }
        }

        return sb.toString();
    }

    /**
     * Notify the host application a download should be done, even if there
     * is a streaming viewer available for thise type.
     * @param url The full url to the content that should be downloaded
     * @param contentDisposition Content-disposition http header, if
     *                           present.
     * @param mimetype The mimetype of the content reported by the server
     * @param contentLength The file size reported by the server
     */
    /*package */ void onDownloadStartNoStream(String url, String userAgent,
            String contentDisposition, String mimetype, long contentLength) {

        String filename = URLUtil.guessFileName(url,
                contentDisposition, mimetype);

        // Check to see if we have an SDCard
        String status = Environment.getExternalStorageState();
        if (!status.equals(Environment.MEDIA_MOUNTED)) {
            int title;
            String msg;

            // Check to see if the SDCard is busy, same as the music app
            if (status.equals(Environment.MEDIA_SHARED)) {
                msg = mActivity.getString(R.string.download_sdcard_busy_dlg_msg);
                title = R.string.download_sdcard_busy_dlg_title;
            } else {
                msg = mActivity.getString(R.string.download_no_sdcard_dlg_msg, filename);
                title = R.string.download_no_sdcard_dlg_title;
            }

            new AlertDialog.Builder(mActivity)
                .setTitle(title)
                .setIcon(android.R.drawable.ic_dialog_alert)
                .setMessage(msg)
                .setPositiveButton(R.string.ok, null)
                .show();
            return;
        }

        // java.net.URI is a lot stricter than KURL so we have to encode some
        // extra characters. Fix for b 2538060 and b 1634719
        WebAddress webAddress;
        try {
            webAddress = new WebAddress(url);
            webAddress.setPath(encodePath(webAddress.getPath()));
        } catch (Exception e) {
            // This only happens for very bad urls, we want to chatch the
            // exception here
            Log.e(LOGTAG, "Exception trying to parse url:" + url);
            return;
        }

        String addressString = webAddress.toString();
        Uri uri = Uri.parse(addressString);
        DownloadManager.Request request = new DownloadManager.Request(uri);
        request.setMimeType(mimetype);
        request.setDestinationInExternalFilesDir(mActivity, null, filename);
        // let this downloaded file be scanned by MediaScanner - so that it can 
        // show up in Gallery app, for example.
        request.allowScanningByMediaScanner();
        request.setDescription(webAddress.getHost());
        String cookies = CookieManager.getInstance().getCookie(url);
        request.addRequestHeader("cookie", cookies);
        request.setNotificationVisibility(
                DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        if (mimetype == null) {
            ContentValues values = new ContentValues();
            values.put(FetchUrlMimeType.URI, addressString);
            // XXX: Have to use the old url since the cookies were stored using the
            // old percent-encoded url.
            values.put(FetchUrlMimeType.COOKIE_DATA, cookies);
            values.put(FetchUrlMimeType.USER_AGENT, userAgent);

            // We must have long pressed on a link or image to download it. We
            // are not sure of the mimetype in this case, so do a head request
            new FetchUrlMimeType(mActivity, request).execute(values);
        } else {
            DownloadManager manager
                    = (DownloadManager) mActivity.getSystemService(Context.DOWNLOAD_SERVICE);
            manager.enqueue(request);
        }
        Toast.makeText(mActivity, R.string.download_pending, Toast.LENGTH_SHORT)
                .show();
    }

}