feat(redirect): handle the case of redirect on filedownloader self

Closes #611

library/src/main/java/com/liulishuo/filedownloader/connection/RedirectHandler.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2015 LingoChamp Inc.
+ *
+ * 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.liulishuo.filedownloader.connection;
+
+import com.liulishuo.filedownloader.download.CustomComponentHolder;
+import com.liulishuo.filedownloader.util.FileDownloadLog;
+import com.liulishuo.filedownloader.util.FileDownloadUtils;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Handle redirect case.
+ */
+public class RedirectHandler {
+
+    private final static int MAX_REDIRECT_TIMES = 10;
+
+    /**
+     * The target resource resides temporarily under a different URI and the user agent MUST NOT
+     * change the request method if it performs an automatic redirection to that URI.
+     */
+    private final static int HTTP_TEMPORARY_REDIRECT = 307;
+    /**
+     * The target resource has been assigned a new permanent URI and any future references to this
+     * resource ought to use one of the enclosed URIs.
+     */
+    private final static int HTTP_PERMANENT_REDIRECT = 308;
+
+
+    public static FileDownloadConnection process(final Map<String, List<String>> requestHeaderFields,
+                                                 final FileDownloadConnection connection,
+                                                 List<String> redirectedUrlList)
+            throws IOException, IllegalAccessException {
+
+        int code = connection.getResponseCode();
+        String location = connection.getResponseHeaderField("Location");
+
+        List<String> redirectLocationList = new ArrayList<>();
+        int redirectTimes = 0;
+        FileDownloadConnection redirectConnection = connection;
+
+        while (isRedirect(code)) {
+            if (location == null) {
+                throw new IllegalAccessException(FileDownloadUtils.
+                        formatString("receive %d (redirect) but the location is null with response [%s]",
+                                code, redirectConnection.getResponseHeaderFields()));
+            }
+
+            if (FileDownloadLog.NEED_LOG) {
+                FileDownloadLog.d(RedirectHandler.class, "redirect to %s with %d, %s",
+                        location, code, redirectLocationList);
+            }
+
+            redirectConnection =
+                    buildRedirectConnection(requestHeaderFields, location);
+            redirectLocationList.add(location);
+
+            if (redirectConnection != null) redirectConnection.ending();
+
+            redirectConnection.execute();
+            code = redirectConnection.getResponseCode();
+            location = redirectConnection.getResponseHeaderField("Location");
+
+            if (++redirectTimes >= MAX_REDIRECT_TIMES) {
+                throw new IllegalAccessException(
+                        FileDownloadUtils.formatString("redirect too many times! %s", redirectLocationList));
+            }
+        }
+
+        if (redirectedUrlList != null) {
+            redirectedUrlList.addAll(redirectLocationList);
+        }
+
+        return redirectConnection;
+    }
+
+    private static boolean isRedirect(int code) {
+        return code == HttpURLConnection.HTTP_MOVED_PERM
+                || code == HttpURLConnection.HTTP_MOVED_TEMP
+                || code == HttpURLConnection.HTTP_SEE_OTHER
+                || code == HttpURLConnection.HTTP_MULT_CHOICE
+                || code == HTTP_TEMPORARY_REDIRECT
+                || code == HTTP_PERMANENT_REDIRECT;
+    }
+
+    private static FileDownloadConnection buildRedirectConnection(Map<String, List<String>> requestHeaderFields,
+                                                                  String newUrl) throws IOException {
+        FileDownloadConnection redirectConnection = CustomComponentHolder.getImpl().
+                createConnection(newUrl);
+
+        String name;
+        List<String> list;
+
+        Set<Map.Entry<String, List<String>>> entries = requestHeaderFields.entrySet();
+        for (Map.Entry<String, List<String>> e : entries) {
+            name = e.getKey();
+            list = e.getValue();
+            if (list != null) {
+                for (String value : list) {
+                    redirectConnection.addHeader(name, value);
+                }
+            }
+        }
+
+        return redirectConnection;
+    }
+}

library/src/main/java/com/liulishuo/filedownloader/download/ConnectTask.java

@@ -19,11 +19,13 @@
 import android.text.TextUtils;
 
 import com.liulishuo.filedownloader.connection.FileDownloadConnection;
+import com.liulishuo.filedownloader.connection.RedirectHandler;
 import com.liulishuo.filedownloader.model.FileDownloadHeader;
 import com.liulishuo.filedownloader.util.FileDownloadLog;
 import com.liulishuo.filedownloader.util.FileDownloadUtils;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -42,6 +44,7 @@ public class ConnectTask {
     private String etag;
 
     private Map<String, List<String>> requestHeader;
+    private List<String> redirectedUrlList;
 
 
     private ConnectTask(ConnectionProfile profile,
@@ -53,8 +56,8 @@ private ConnectTask(ConnectionProfile profile,
         this.profile = profile;
     }
 
-    FileDownloadConnection connect() throws IOException {
-        final FileDownloadConnection connection = CustomComponentHolder.getImpl().createConnection(url);
+    FileDownloadConnection connect() throws IOException, IllegalAccessException {
+        FileDownloadConnection connection = CustomComponentHolder.getImpl().createConnection(url);
 
         addUserRequiredHeader(connection);
         addRangeHeader(connection);
@@ -69,6 +72,8 @@ FileDownloadConnection connect() throws IOException {
         }
 
         connection.execute();
+        redirectedUrlList = new ArrayList<>();
+        connection = RedirectHandler.process(requestHeader, connection, redirectedUrlList);
 
         return connection;
     }
@@ -123,6 +128,14 @@ boolean isRangeNotFromBeginning(){
         return profile.currentOffset > 0;
     }
 
+    String getFinalRedirectedUrl() {
+        if (redirectedUrlList != null && !redirectedUrlList.isEmpty()) {
+            return redirectedUrlList.get(redirectedUrlList.size() - 1);
+        }
+
+        return null;
+    }
+
     public Map<String, List<String>> getRequestHeader() {
         return requestHeader;
     }

library/src/main/java/com/liulishuo/filedownloader/download/DownloadLaunchRunnable.java

@@ -108,6 +108,8 @@ public class DownloadLaunchRunnable implements Runnable, ProcessCallback {
     private volatile boolean alive;
     private volatile boolean paused;
 
+    private String redirectedUrl;
+
     private DownloadLaunchRunnable(FileDownloadModel model, FileDownloadHeader header,
                                    IThreadPoolMonitor threadPoolMonitor,
                                    final int minIntervalMillis, int callbackProgressMaxCount,
@@ -458,6 +460,7 @@ private void handleFirstConnected(Map<String, List<String>> requestHeader,
             throw new RetryDirectly();
         }
 
+        redirectedUrl = connectTask.getFinalRedirectedUrl();
         if (acceptPartial || onlyFromBeginning) {
             final long contentLength = FileDownloadUtils.findContentLength(id, connection);
 
@@ -548,7 +551,7 @@ private void fetchWithMultipleConnectionFromBeginning(final long totalLength, fi
     private void fetchWithMultipleConnection(final List<ConnectionModel> connectionModelList) throws InterruptedException {
         final int id = model.getId();
         final String etag = model.getETag();
-        final String url = model.getUrl();
+        final String url = redirectedUrl != null ? redirectedUrl : model.getUrl();
         final String path = model.getTempFilePath();
 
         if (FileDownloadLog.NEED_LOG) {