/*
* Copyright 2011 ZXing authors
*
* 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.google.zxing.client.android;
import android.util.Log;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
/**
* Utility methods for retrieving content over HTTP using the more-supported {@code java.net} classes
* in Android.
*/
public final class HttpHelper {
private static final String TAG = HttpHelper.class.getSimpleName();
private static final Collection<String> REDIRECTOR_DOMAINS = new HashSet<String>(Arrays.asList(
"amzn.to", "bit.ly", "bitly.com", "fb.me", "goo.gl", "is.gd", "j.mp", "lnkd.in", "ow.ly",
"R.BEETAGG.COM", "r.beetagg.com", "SCN.BY", "su.pr", "t.co", "tinyurl.com", "tr.im"
));
private HttpHelper() {
}
public enum ContentType {
/** HTML-like content type, including HTML, XHTML, etc. */
HTML,
/** JSON content */
JSON,
/** Plain text content */
TEXT,
}
/**
* Downloads the entire resource instead of part.
*
* @see #downloadViaHttp(String, HttpHelper.ContentType, int)
*/
public static CharSequence downloadViaHttp(String uri, ContentType type) throws IOException {
return downloadViaHttp(uri, type, Integer.MAX_VALUE);
}
/**
* @param uri URI to retrieve
* @param type expected text-like MIME type of that content
* @param maxChars approximate maximum characters to read from the source
* @return content as a {@code String}
* @throws IOException if the content can't be retrieved because of a bad URI, network problem, etc.
*/
public static CharSequence downloadViaHttp(String uri, ContentType type, int maxChars) throws IOException {
String contentTypes;
switch (type) {
case HTML:
contentTypes = "application/xhtml+xml,text/html,text/*,*/*";
break;
case JSON:
contentTypes = "application/json,text/*,*/*";
break;
case TEXT:
default:
contentTypes = "text/*,*/*";
}
return downloadViaHttp(uri, contentTypes, maxChars);
}
private static CharSequence downloadViaHttp(String uri, String contentTypes, int maxChars) throws IOException {
Log.i(TAG, "Downloading " + uri);
URL url = new URL(uri);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection)) {
throw new IOException();
}
HttpURLConnection connection = (HttpURLConnection) conn;
connection.setRequestProperty("Accept", contentTypes);
connection.setRequestProperty("Accept-Charset", "utf-8,*");
connection.setRequestProperty("User-Agent", "ZXing (Android)");
try {
try {
connection.connect();
} catch (NullPointerException npe) {
// this is an Android bug: http://code.google.com/p/android/issues/detail?id=16895
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(npe);
} catch (IllegalArgumentException iae) {
// Also seen this in the wild, not sure what to make of it. Probably a bad URL
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(iae);
}
int responseCode;
try {
responseCode = connection.getResponseCode();
} catch (NullPointerException npe) {
// this is maybe this Android bug: http://code.google.com/p/android/issues/detail?id=15554
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(npe);
}
if (responseCode != HttpURLConnection.HTTP_OK) {
throw new IOException("Bad HTTP response: " + responseCode);
}
Log.i(TAG, "Consuming " + uri);
return consume(connection, maxChars);
} finally {
connection.disconnect();
}
}
private static String getEncoding(URLConnection connection) {
String contentTypeHeader = connection.getHeaderField("Content-Type");
if (contentTypeHeader != null) {
int charsetStart = contentTypeHeader.indexOf("charset=");
if (charsetStart >= 0) {
return contentTypeHeader.substring(charsetStart + "charset=".length());
}
}
return "UTF-8";
}
private static CharSequence consume(URLConnection connection, int maxChars) throws IOException {
String encoding = getEncoding(connection);
StringBuilder out = new StringBuilder();
Reader in = null;
try {
in = new InputStreamReader(connection.getInputStream(), encoding);
char[] buffer = new char[1024];
int charsRead;
while (out.length() < maxChars && (charsRead = in.read(buffer)) > 0) {
out.append(buffer, 0, charsRead);
}
} finally {
if (in != null) {
try {
in.close();
} catch (IOException ioe) {
// continue
} catch (NullPointerException npe) {
// another apparent Android / Harmony bug; continue
}
}
}
return out;
}
public static URI unredirect(URI uri) throws IOException {
if (!REDIRECTOR_DOMAINS.contains(uri.getHost())) {
return uri;
}
URL url = uri.toURL();
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection)) {
throw new IOException();
}
HttpURLConnection connection = (HttpURLConnection) conn;
connection.setInstanceFollowRedirects(false);
connection.setDoInput(false);
connection.setRequestMethod("HEAD");
connection.setRequestProperty("User-Agent", "ZXing (Android)");
try {
try {
connection.connect();
} catch (NullPointerException npe) {
// this is an Android bug: http://code.google.com/p/android/issues/detail?id=16895
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(npe);
} catch (IllegalArgumentException iae) {
// Also seen this in the wild, not sure what to make of it. Probably a bad URL
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(iae);
}
int responseCode;
try {
responseCode = connection.getResponseCode();
} catch (NullPointerException npe) {
// this is maybe this Android bug: http://code.google.com/p/android/issues/detail?id=15554
Log.w(TAG, "Bad URI? " + uri);
throw new IOException(npe);
}
switch (responseCode) {
case HttpURLConnection.HTTP_MULT_CHOICE:
case HttpURLConnection.HTTP_MOVED_PERM:
case HttpURLConnection.HTTP_MOVED_TEMP:
case HttpURLConnection.HTTP_SEE_OTHER:
case 307: // No constant for 307 Temporary Redirect ?
String location = connection.getHeaderField("Location");
if (location != null) {
try {
return new URI(location);
} catch (URISyntaxException e) {
// nevermind
}
}
}
return uri;
} finally {
connection.disconnect();
}
}
}