114 lines
3.2 KiB
C#
114 lines
3.2 KiB
C#
using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using System.Net.Http;
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namespace FileManager
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{
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public enum PictureSize { _80x80, _300x300, _500x500 }
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public struct PictureDefinition
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{
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public string PictureId { get; }
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public PictureSize Size { get; }
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public PictureDefinition(string pictureId, PictureSize pictureSize)
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{
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PictureId = pictureId;
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Size = pictureSize;
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}
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}
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public static class PictureStorage
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{
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// not customizable. don't move to config
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private static string ImagesDirectory { get; }
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= new DirectoryInfo(Configuration.Instance.LibationFiles).CreateSubdirectory("Images").FullName;
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private static string getPath(PictureDefinition def)
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=> Path.Combine(ImagesDirectory, $"{def.PictureId}{def.Size}.jpg");
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private static System.Timers.Timer timer { get; }
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static PictureStorage()
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{
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timer = new System.Timers.Timer(700)
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{
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AutoReset = true,
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Enabled = true
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};
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timer.Elapsed += (_, __) => timerDownload();
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}
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public static event EventHandler<string> PictureCached;
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private static Dictionary<PictureDefinition, byte[]> cache { get; } = new Dictionary<PictureDefinition, byte[]>();
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public static (bool isDefault, byte[] bytes) GetPicture(PictureDefinition def)
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{
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if (!cache.ContainsKey(def))
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{
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var path = getPath(def);
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cache[def]
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= File.Exists(path)
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? File.ReadAllBytes(path)
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: null;
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}
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return (cache[def] == null, cache[def] ?? getDefaultImage(def.Size));
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}
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private static Dictionary<PictureSize, byte[]> defaultImages { get; } = new Dictionary<PictureSize, byte[]>();
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public static void SetDefaultImage(PictureSize pictureSize, byte[] bytes)
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=> defaultImages[pictureSize] = bytes;
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private static byte[] getDefaultImage(PictureSize size)
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=> defaultImages.ContainsKey(size)
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? defaultImages[size]
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: new byte[0];
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// necessary to avoid IO errors. ReadAllBytes and WriteAllBytes can conflict in some cases, esp when debugging
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private static bool isProcessing;
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private static void timerDownload()
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{
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// must live outside try-catch, else 'finally' can reset another thread's lock
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if (isProcessing)
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return;
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try
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{
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isProcessing = true;
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var def = cache
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.Where(kvp => kvp.Value is null)
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.Select(kvp => kvp.Key)
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// 80x80 should be 1st since it's enum value == 0
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.OrderBy(d => d.PictureId)
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.FirstOrDefault();
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// no more null entries. all requsted images are cached
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if (string.IsNullOrWhiteSpace(def.PictureId))
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return;
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var bytes = downloadBytes(def);
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saveFile(def, bytes);
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cache[def] = bytes;
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PictureCached?.Invoke(nameof(PictureStorage), def.PictureId);
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}
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finally
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{
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isProcessing = false;
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}
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}
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private static HttpClient imageDownloadClient { get; } = new HttpClient();
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private static byte[] downloadBytes(PictureDefinition def)
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{
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var sz = def.Size.ToString().Split('x')[1];
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return imageDownloadClient.GetByteArrayAsync("ht" + $"tps://images-na.ssl-images-amazon.com/images/I/{def.PictureId}._SL{sz}_.jpg").Result;
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}
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private static void saveFile(PictureDefinition def, byte[] bytes)
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{
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var path = getPath(def);
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File.WriteAllBytes(path, bytes);
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}
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}
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}
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