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C# 8.0 のnull許容参照型を有効化
[opentween/open-tween.git] / OpenTween / Thumbnail / Services / SimpleThumbnailService.cs
1 // OpenTween - Client of Twitter
2 // Copyright (c) 2012 kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
3 // All rights reserved.
4 //
5 // This file is part of OpenTween.
6 //
7 // This program is free software; you can redistribute it and/or modify it
8 // under the terms of the GNU General Public License as published by the Free
9 // Software Foundation; either version 3 of the License, or (at your option)
10 // any later version.
11 //
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 // for more details.
16 //
17 // You should have received a copy of the GNU General Public License along
18 // with this program. If not, see <http://www.gnu.org/licenses/>, or write to
19 // the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
20 // Boston, MA 02110-1301, USA.
21
22 #nullable enable
23
24 using System;
25 using System.Collections.Generic;
26 using System.Linq;
27 using System.Net.Http;
28 using System.Text;
29 using System.Text.RegularExpressions;
30 using System.Threading;
31 using System.Threading.Tasks;
32 using OpenTween.Models;
33
34 namespace OpenTween.Thumbnail.Services
35 {
36     /// <summary>
37     /// 正規表現によるURLの単純な置換でサムネイルURLを生成する
38     /// </summary>
39     class SimpleThumbnailService : IThumbnailService
40     {
41         protected Regex regex;
42         protected string thumb_replacement;
43         protected string? fullsize_replacement;
44
45         public SimpleThumbnailService(string pattern, string replacement)
46             : this(pattern, replacement, null)
47         {
48         }
49
50         public SimpleThumbnailService(string pattern, string replacement, string? file_replacement)
51         {
52             this.regex = new Regex(pattern, RegexOptions.IgnoreCase);
53             this.thumb_replacement = replacement;
54             this.fullsize_replacement = file_replacement;
55         }
56
57         public override Task<ThumbnailInfo?> GetThumbnailInfoAsync(string url, PostClass post, CancellationToken token)
58         {
59             return Task.Run(() =>
60             {
61                 var thumbnailUrl = this.ReplaceUrl(url);
62                 if (thumbnailUrl == null) return null;
63
64                 return new ThumbnailInfo
65                 {
66                     MediaPageUrl = url,
67                     ThumbnailImageUrl = thumbnailUrl,
68                     TooltipText = null,
69                     FullSizeImageUrl = ReplaceUrl(url, this.fullsize_replacement)
70                 };
71             }, token);
72         }
73
74         protected string? ReplaceUrl(string url)
75             => this.ReplaceUrl(url, this.thumb_replacement);
76
77         protected string? ReplaceUrl(string url, string? replacement)
78         {
79             if (replacement == null) return null;
80             var match = this.regex.Match(url);
81
82             return match.Success ? match.Result(replacement) : null;
83         }
84     }
85 }