FetchUrlMimeType.java revision f08809b2cf7e502fef5965691a7fb6d7cf0322af 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.browser;
18
19import android.content.ContentValues;
20import android.net.Uri;
21import com.android.common.AndroidHttpClient;
22
23import org.apache.http.HttpResponse;
24import org.apache.http.Header;
25import org.apache.http.client.methods.HttpHead;
26
27import java.io.IOException;
28
29import android.os.AsyncTask;
30import android.provider.Downloads;
31import android.webkit.MimeTypeMap;
32import android.webkit.URLUtil;
33
34/**
35 * This class is used to pull down the http headers of a given URL so that
36 * we can analyse the mimetype and make any correction needed before we give
37 * the URL to the download manager. The ContentValues class holds the
38 * content that would be provided to the download manager, so that on
39 * completion of checking the mimetype, we can issue the download to
40 * the download manager.
41 * This operation is needed when the user long-clicks on a link or image and
42 * we don't know the mimetype. If the user just clicks on the link, we will
43 * do the same steps of correcting the mimetype down in
44 * android.os.webkit.LoadListener rather than handling it here.
45 *
46 */
47class FetchUrlMimeType extends AsyncTask<ContentValues, String, String> {
48
49    BrowserActivity mActivity;
50    ContentValues mValues;
51
52    public FetchUrlMimeType(BrowserActivity activity) {
53        mActivity = activity;
54    }
55
56    @Override
57    public String doInBackground(ContentValues... values) {
58        mValues = values[0];
59
60        // Check to make sure we have a URI to download
61        String uri = mValues.getAsString(Downloads.Impl.COLUMN_URI);
62        if (uri == null || uri.length() == 0) {
63            return null;
64        }
65
66        // User agent is likely to be null, though the AndroidHttpClient
67        // seems ok with that.
68        AndroidHttpClient client = AndroidHttpClient.newInstance(
69                mValues.getAsString(Downloads.Impl.COLUMN_USER_AGENT));
70        HttpHead request = new HttpHead(uri);
71
72        String cookie = mValues.getAsString(Downloads.Impl.COLUMN_COOKIE_DATA);
73        if (cookie != null && cookie.length() > 0) {
74            request.addHeader("Cookie", cookie);
75        }
76
77        String referer = mValues.getAsString(Downloads.Impl.COLUMN_REFERER);
78        if (referer != null && referer.length() > 0) {
79            request.addHeader("Referer", referer);
80        }
81
82        HttpResponse response;
83        String mimeType = null;
84        try {
85            response = client.execute(request);
86            // We could get a redirect here, but if we do lets let
87            // the download manager take care of it, and thus trust that
88            // the server sends the right mimetype
89            if (response.getStatusLine().getStatusCode() == 200) {
90                Header header = response.getFirstHeader("Content-Type");
91                if (header != null) {
92                    mimeType = header.getValue();
93                    final int semicolonIndex = mimeType.indexOf(';');
94                    if (semicolonIndex != -1) {
95                        mimeType = mimeType.substring(0, semicolonIndex);
96                    }
97                }
98            }
99        } catch (IllegalArgumentException ex) {
100            request.abort();
101        } catch (IOException ex) {
102            request.abort();
103        } finally {
104            client.close();
105        }
106
107        return mimeType;
108    }
109
110   @Override
111    public void onPostExecute(String mimeType) {
112       if (mimeType != null) {
113           String url = mValues.getAsString(Downloads.Impl.COLUMN_URI);
114           if (mimeType.equalsIgnoreCase("text/plain") ||
115                   mimeType.equalsIgnoreCase("application/octet-stream")) {
116               String newMimeType =
117                       MimeTypeMap.getSingleton().getMimeTypeFromExtension(
118                           MimeTypeMap.getFileExtensionFromUrl(url));
119               if (newMimeType != null) {
120                   mValues.put(Downloads.Impl.COLUMN_MIME_TYPE, newMimeType);
121               }
122           }
123           String filename = URLUtil.guessFileName(url,
124                   null, mimeType);
125           mValues.put(Downloads.Impl.COLUMN_FILE_NAME_HINT, filename);
126       }
127
128       // Start the download
129       final Uri contentUri =
130           mActivity.getContentResolver().insert(Downloads.Impl.CONTENT_URI, mValues);
131    }
132
133}
134