/**
* Copyright 2010-present Facebook.
*
* 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.facebook.widget;
import android.content.Context;
import com.facebook.internal.FileLruCache;
import com.facebook.internal.Utility;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
class UrlRedirectCache {
static final String TAG = UrlRedirectCache.class.getSimpleName();
private static final String REDIRECT_CONTENT_TAG = TAG + "_Redirect";
private volatile static FileLruCache urlRedirectCache;
synchronized static FileLruCache getCache(Context context) throws IOException{
if (urlRedirectCache == null) {
urlRedirectCache = new FileLruCache(context.getApplicationContext(), TAG, new FileLruCache.Limits());
}
return urlRedirectCache;
}
static URL getRedirectedUrl(Context context, URL url) {
if (url == null) {
return null;
}
String urlString = url.toString();
URL finalUrl = null;
InputStreamReader reader = null;
try {
InputStream stream;
FileLruCache cache = getCache(context);
boolean redirectExists = false;
while ((stream = cache.get(urlString, REDIRECT_CONTENT_TAG)) != null) {
redirectExists = true;
// Get the redirected url
reader = new InputStreamReader(stream);
char[] buffer = new char[128];
int bufferLength;
StringBuilder urlBuilder = new StringBuilder();
while ((bufferLength = reader.read(buffer, 0, buffer.length)) > 0) {
urlBuilder.append(buffer, 0, bufferLength);
}
Utility.closeQuietly(reader);
// Iterate to the next url in the redirection
urlString = urlBuilder.toString();
}
if (redirectExists) {
finalUrl = new URL(urlString);
}
} catch (MalformedURLException e) {
// caching is best effort, so ignore the exception
} catch (IOException ioe) {
} finally {
Utility.closeQuietly(reader);
}
return finalUrl;
}
static void cacheUrlRedirect(Context context, URL fromUrl, URL toUrl) {
if (fromUrl == null || toUrl == null) {
return;
}
OutputStream redirectStream = null;
try {
FileLruCache cache = getCache(context);
redirectStream = cache.openPutStream(fromUrl.toString(), REDIRECT_CONTENT_TAG);
redirectStream.write(toUrl.toString().getBytes());
} catch (IOException e) {
// Caching is best effort
} finally {
Utility.closeQuietly(redirectStream);
}
}
}