Java tutorial
/* * Copyright (C) 2009 University of Washington * * 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 org.odk.collect.android.tasks; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.protocol.HttpContext; import org.javarosa.xform.parse.XFormParser; import org.kxml2.kdom.Element; import org.odk.collect.android.R; import org.odk.collect.android.application.Collect; import org.odk.collect.android.listeners.FormDownloaderListener; import org.odk.collect.android.logic.FormDetails; import org.odk.collect.android.provider.FormsProviderAPI.FormsColumns; import org.odk.collect.android.utilities.DocumentFetchResult; import org.odk.collect.android.utilities.FileUtils; import org.odk.collect.android.utilities.WebUtils; import android.content.ContentValues; import android.database.Cursor; import android.net.Uri; import android.os.AsyncTask; import android.util.Log; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.MalformedURLException; import java.net.SocketTimeoutException; import java.net.URI; import java.net.URISyntaxException; import java.net.URL; import java.util.ArrayList; import java.util.HashMap; import java.util.List; /** * Background task for downloading a given list of forms. We assume right now that the forms are * coming from the same server that presented the form list, but theoretically that won't always be * true. * * @author msundt * @author carlhartung */ public class DownloadFormsTask extends AsyncTask<ArrayList<FormDetails>, String, HashMap<String, String>> { private static final String t = "DownlaodFormsTask"; private static final String MD5_COLON_PREFIX = "md5:"; private FormDownloaderListener mStateListener; private static final String NAMESPACE_OPENROSA_ORG_XFORMS_XFORMS_MANIFEST = "http://openrosa.org/xforms/xformsManifest"; private boolean isXformsManifestNamespacedElement(Element e) { return e.getNamespace().equalsIgnoreCase(NAMESPACE_OPENROSA_ORG_XFORMS_XFORMS_MANIFEST); } @Override protected HashMap<String, String> doInBackground(ArrayList<FormDetails>... values) { ArrayList<FormDetails> toDownload = values[0]; int total = toDownload.size(); int count = 1; HashMap<String, String> result = new HashMap<String, String>(); for (int i = 0; i < total; i++) { FormDetails fd = toDownload.get(i); publishProgress(fd.formName, Integer.valueOf(count).toString(), Integer.valueOf(total).toString()); String message = ""; try { // get the xml file // if we've downloaded a duplicate, this gives us the file File dl = downloadXform(fd.formName, fd.downloadUrl); String[] projection = { FormsColumns._ID, FormsColumns.FORM_FILE_PATH }; String[] selectionArgs = { dl.getAbsolutePath() }; String selection = FormsColumns.FORM_FILE_PATH + "=?"; Cursor alreadyExists = Collect.getInstance().getContentResolver().query(FormsColumns.CONTENT_URI, projection, selection, selectionArgs, null); Uri uri = null; if (alreadyExists.getCount() <= 0) { // doesn't exist, so insert it ContentValues v = new ContentValues(); v.put(FormsColumns.FORM_FILE_PATH, dl.getAbsolutePath()); HashMap<String, String> formInfo = FileUtils.parseXML(dl); v.put(FormsColumns.DISPLAY_NAME, formInfo.get(FileUtils.TITLE)); v.put(FormsColumns.MODEL_VERSION, formInfo.get(FileUtils.MODEL)); v.put(FormsColumns.UI_VERSION, formInfo.get(FileUtils.UI)); v.put(FormsColumns.JR_FORM_ID, formInfo.get(FileUtils.FORMID)); v.put(FormsColumns.SUBMISSION_URI, formInfo.get(FileUtils.SUBMISSIONURI)); uri = Collect.getInstance().getContentResolver().insert(FormsColumns.CONTENT_URI, v); } else { alreadyExists.moveToFirst(); uri = Uri.withAppendedPath(FormsColumns.CONTENT_URI, alreadyExists.getString(alreadyExists.getColumnIndex(FormsColumns._ID))); } if (fd.manifestUrl != null) { Cursor c = Collect.getInstance().getContentResolver().query(uri, null, null, null, null); if (c.getCount() > 0) { // should be exactly 1 c.moveToFirst(); String error = downloadManifestAndMediaFiles( c.getString(c.getColumnIndex(FormsColumns.FORM_MEDIA_PATH)), fd, count, total); if (error != null) { message += error; } } } else { // TODO: manifest was null? Log.e(t, "Manifest was null. PANIC"); } } catch (SocketTimeoutException se) { se.printStackTrace(); message += se.getMessage(); } catch (Exception e) { e.printStackTrace(); message += e.getMessage(); } count++; if (message.equalsIgnoreCase("")) { message = Collect.getInstance().getString(R.string.success); } result.put(fd.formName, message); } return result; } /** * Takes the formName and the URL and attempts to download the specified file. Returns a file * object representing the downloaded file. * * @param formName * @param url * @return * @throws Exception */ private File downloadXform(String formName, String url) throws Exception { File f = null; // clean up friendly form name... String rootName = formName.replaceAll("[^\\p{L}\\p{Digit}]", " "); rootName = rootName.replaceAll("\\p{javaWhitespace}+", " "); rootName = rootName.trim(); // proposed name of xml file... String path = Collect.FORMS_PATH + "/" + rootName + ".xml"; int i = 2; f = new File(path); while (f.exists()) { path = Collect.FORMS_PATH + "/" + rootName + "_" + i + ".xml"; f = new File(path); i++; } downloadFile(f, url); // we've downloaded the file, and we may have renamed it // make sure it's not the same as a file we already have String[] projection = { FormsColumns.FORM_FILE_PATH }; String[] selectionArgs = { FileUtils.getMd5Hash(f) }; String selection = FormsColumns.MD5_HASH + "=?"; Cursor c = Collect.getInstance().getContentResolver().query(FormsColumns.CONTENT_URI, projection, selection, selectionArgs, null); if (c.getCount() > 0) { // Should be at most, 1 c.moveToFirst(); // delete the file we just downloaded, because it's a duplicate f.delete(); // set the file returned to the file we already had f = new File(c.getString(c.getColumnIndex(FormsColumns.FORM_FILE_PATH))); } c.close(); return f; } /** * Common routine to download a document from the downloadUrl and save the contents in the file * 'f'. Shared by media file download and form file download. * * @param f * @param downloadUrl * @throws Exception */ private void downloadFile(File f, String downloadUrl) throws Exception { URI uri = null; try { URL url = new URL(downloadUrl); uri = url.toURI(); } catch (MalformedURLException e) { e.printStackTrace(); throw e; } catch (URISyntaxException e) { e.printStackTrace(); throw e; } // get shared HttpContext so that authentication and cookies are retained. HttpContext localContext = Collect.getInstance().getHttpContext(); HttpClient httpclient = WebUtils.createHttpClient(WebUtils.CONNECTION_TIMEOUT); // set up request... HttpGet req = WebUtils.createOpenRosaHttpGet(uri); HttpResponse response = null; try { response = httpclient.execute(req, localContext); int statusCode = response.getStatusLine().getStatusCode(); if (statusCode != 200) { String errMsg = Collect.getInstance().getString(R.string.file_fetch_failed, f.getAbsolutePath(), response.getStatusLine().getReasonPhrase(), statusCode); Log.e(t, errMsg); throw new Exception(errMsg); } // write connection to file InputStream is = null; OutputStream os = null; try { is = response.getEntity().getContent(); os = new FileOutputStream(f); byte buf[] = new byte[1024]; int len; while ((len = is.read(buf)) > 0) { os.write(buf, 0, len); } os.flush(); } finally { if (os != null) { try { os.close(); } catch (Exception e) { } } if (is != null) { try { is.close(); } catch (Exception e) { } } } } catch (Exception e) { e.printStackTrace(); throw e; } } private static class MediaFile { final String filename; final String hash; final String downloadUrl; MediaFile(String filename, String hash, String downloadUrl) { this.filename = filename; this.hash = hash; this.downloadUrl = downloadUrl; } } private String downloadManifestAndMediaFiles(String mediaPath, FormDetails fd, int count, int total) { if (fd.manifestUrl == null) return null; publishProgress(Collect.getInstance().getString(R.string.fetching_manifest, fd.formName), Integer.valueOf(count).toString(), Integer.valueOf(total).toString()); List<MediaFile> files = new ArrayList<MediaFile>(); // get shared HttpContext so that authentication and cookies are retained. HttpContext localContext = Collect.getInstance().getHttpContext(); HttpClient httpclient = WebUtils.createHttpClient(WebUtils.CONNECTION_TIMEOUT); DocumentFetchResult result = WebUtils.getXmlDocument(fd.manifestUrl, localContext, httpclient); if (result.errorMessage != null) { return result.errorMessage; } String errMessage = Collect.getInstance().getString(R.string.access_error, fd.manifestUrl); if (!result.isOpenRosaResponse) { errMessage += Collect.getInstance().getString(R.string.manifest_server_error); Log.e(t, errMessage); return errMessage; } // Attempt OpenRosa 1.0 parsing Element manifestElement = result.doc.getRootElement(); if (!manifestElement.getName().equals("manifest")) { errMessage += Collect.getInstance().getString(R.string.root_element_error, manifestElement.getName()); Log.e(t, errMessage); return errMessage; } String namespace = manifestElement.getNamespace(); if (!isXformsManifestNamespacedElement(manifestElement)) { errMessage += Collect.getInstance().getString(R.string.root_namespace_error, namespace); Log.e(t, errMessage); return errMessage; } int nElements = manifestElement.getChildCount(); for (int i = 0; i < nElements; ++i) { if (manifestElement.getType(i) != Element.ELEMENT) { // e.g., whitespace (text) continue; } Element mediaFileElement = (Element) manifestElement.getElement(i); if (!isXformsManifestNamespacedElement(mediaFileElement)) { // someone else's extension? continue; } String name = mediaFileElement.getName(); if (name.equalsIgnoreCase("mediaFile")) { String filename = null; String hash = null; String downloadUrl = null; // don't process descriptionUrl int childCount = mediaFileElement.getChildCount(); for (int j = 0; j < childCount; ++j) { if (mediaFileElement.getType(j) != Element.ELEMENT) { // e.g., whitespace (text) continue; } Element child = mediaFileElement.getElement(j); if (!isXformsManifestNamespacedElement(child)) { // someone else's extension? continue; } String tag = child.getName(); if (tag.equals("filename")) { filename = XFormParser.getXMLText(child, true); if (filename != null && filename.length() == 0) { filename = null; } } else if (tag.equals("hash")) { hash = XFormParser.getXMLText(child, true); if (hash != null && hash.length() == 0) { hash = null; } } else if (tag.equals("downloadUrl")) { downloadUrl = XFormParser.getXMLText(child, true); if (downloadUrl != null && downloadUrl.length() == 0) { downloadUrl = null; } } } if (filename == null || downloadUrl == null || hash == null) { errMessage += Collect.getInstance().getString(R.string.manifest_tag_error, Integer.toString(i)); Log.e(t, errMessage); return errMessage; } files.add(new MediaFile(filename, hash, downloadUrl)); } } // OK we now have the full set of files to download... Log.i(t, "Downloading " + files.size() + " media files."); int mediaCount = 0; if (files.size() > 0) { FileUtils.createFolder(mediaPath); File mediaDir = new File(mediaPath); for (MediaFile toDownload : files) { if (isCancelled()) { return "cancelled"; } ++mediaCount; publishProgress( Collect.getInstance().getString(R.string.form_download_progress, fd.formName, mediaCount, files.size()), Integer.valueOf(count).toString(), Integer.valueOf(total).toString()); try { File mediaFile = new File(mediaDir, toDownload.filename); String currentFileHash = FileUtils.getMd5Hash(mediaFile); String downloadFileHash = toDownload.hash.substring(MD5_COLON_PREFIX.length()); if (!mediaFile.exists()) { downloadFile(mediaFile, toDownload.downloadUrl); } else { if (!currentFileHash.contentEquals(downloadFileHash)) { // if the hashes match, it's the same file // otherwise delete our current one and replace it with the new one mediaFile.delete(); downloadFile(mediaFile, toDownload.downloadUrl); } else { // exists, and the hash is the same // no need to download it again } } } catch (Exception e) { return e.getLocalizedMessage(); } } } return null; } @Override protected void onPostExecute(HashMap<String, String> value) { synchronized (this) { if (mStateListener != null) { mStateListener.formsDownloadingComplete(value); } } } @Override protected void onProgressUpdate(String... values) { synchronized (this) { if (mStateListener != null) { // update progress and total mStateListener.progressUpdate(values[0], new Integer(values[1]).intValue(), new Integer(values[2]).intValue()); } } } public void setDownloaderListener(FormDownloaderListener sl) { synchronized (this) { mStateListener = sl; } } }