Java tutorial
/* * Copyright (C) 2008 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.kai; import android.content.ContentValues; import android.net.Uri; import android.net.http.AndroidHttpClient; import org.apache.http.HttpResponse; import org.apache.http.Header; import org.apache.http.client.methods.HttpHead; import java.io.IOException; import android.os.AsyncTask; import android.provider.Downloads; import android.webkit.MimeTypeMap; import android.webkit.URLUtil; /** * This class is used to pull down the http headers of a given URL so that * we can analyse the mimetype and make any correction needed before we give * the URL to the download manager. The ContentValues class holds the * content that would be provided to the download manager, so that on * completion of checking the mimetype, we can issue the download to * the download manager. * This operation is needed when the user long-clicks on a link or image and * we don't know the mimetype. If the user just clicks on the link, we will * do the same steps of correcting the mimetype down in * android.os.webkit.LoadListener rather than handling it here. * */ class FetchUrlMimeType extends AsyncTask<ContentValues, String, String> { BrowserActivity mActivity; ContentValues mValues; public FetchUrlMimeType(BrowserActivity activity) { mActivity = activity; } @Override public String doInBackground(ContentValues... values) { mValues = values[0]; // Check to make sure we have a URI to download String uri = mValues.getAsString(Downloads.COLUMN_URI); if (uri == null || uri.length() == 0) { return null; } // User agent is likely to be null, though the AndroidHttpClient // seems ok with that. AndroidHttpClient client = AndroidHttpClient.newInstance(mValues.getAsString(Downloads.COLUMN_USER_AGENT)); HttpHead request = new HttpHead(uri); String cookie = mValues.getAsString(Downloads.COLUMN_COOKIE_DATA); if (cookie != null && cookie.length() > 0) { request.addHeader("Cookie", cookie); } String referer = mValues.getAsString(Downloads.COLUMN_REFERER); if (referer != null && referer.length() > 0) { request.addHeader("Referer", referer); } HttpResponse response; String mimeType = null; try { response = client.execute(request); // We could get a redirect here, but if we do lets let // the download manager take care of it, and thus trust that // the server sends the right mimetype if (response.getStatusLine().getStatusCode() == 200) { Header header = response.getFirstHeader("Content-Type"); if (header != null) { mimeType = header.getValue(); final int semicolonIndex = mimeType.indexOf(';'); if (semicolonIndex != -1) { mimeType = mimeType.substring(0, semicolonIndex); } } } } catch (IllegalArgumentException ex) { request.abort(); } catch (IOException ex) { request.abort(); } finally { client.close(); } return mimeType; } @Override public void onPostExecute(String mimeType) { if (mimeType != null) { String url = mValues.getAsString(Downloads.COLUMN_URI); if (mimeType.equalsIgnoreCase("text/plain") || mimeType.equalsIgnoreCase("application/octet-stream")) { String newMimeType = MimeTypeMap.getSingleton() .getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(url)); if (newMimeType != null) { mValues.put(Downloads.COLUMN_MIME_TYPE, newMimeType); } } String filename = URLUtil.guessFileName(url, null, mimeType); mValues.put(Downloads.COLUMN_FILE_NAME_HINT, filename); } // Start the download final Uri contentUri = mActivity.getContentResolver().insert(Downloads.CONTENT_URI, mValues); mActivity.viewDownloads(contentUri); } }