76 lines
2.9 KiB
C#
76 lines
2.9 KiB
C#
using Avalonia.Platform.Storage;
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using System.Text;
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namespace LehrerApp.Desktop.Services;
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public sealed record ExportFormat(string Label, string Extension, string MimeType)
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{
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public static ExportFormat Csv { get; } = new("CSV-Dateien", ".csv", "text/csv");
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public static ExportFormat Json { get; } = new("JSON-Dateien", ".json", "application/json");
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}
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public sealed record ExportFile(
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string DialogTitle,
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string SuggestedFileName,
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ExportFormat Format,
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ReadOnlyMemory<byte> Content)
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{
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public static ExportFile Csv(string dialogTitle, string suggestedFileName, string content) =>
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FromText(dialogTitle, suggestedFileName, ExportFormat.Csv, content, includeUtf8Bom: true);
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public static ExportFile Json(string dialogTitle, string suggestedFileName, string content) =>
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FromText(dialogTitle, suggestedFileName, ExportFormat.Json, content);
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private static ExportFile FromText(string dialogTitle, string suggestedFileName,
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ExportFormat format, string content, bool includeUtf8Bom = false)
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{
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var encoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: includeUtf8Bom);
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var preamble = encoding.GetPreamble();
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var text = encoding.GetBytes(content);
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var bytes = new byte[preamble.Length + text.Length];
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preamble.CopyTo(bytes, 0);
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text.CopyTo(bytes, preamble.Length);
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return new ExportFile(dialogTitle,
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EnsureExtension(SanitizeFileName(suggestedFileName), format.Extension), format, bytes);
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}
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private static string EnsureExtension(string fileName, string extension) =>
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fileName.EndsWith(extension, StringComparison.OrdinalIgnoreCase) ? fileName : fileName + extension;
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private static string SanitizeFileName(string fileName)
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{
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var invalidCharacters = Path.GetInvalidFileNameChars();
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return string.Concat(fileName.Select(character =>
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invalidCharacters.Contains(character) ? '_' : character));
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}
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}
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/// <summary>Zentrale Dateiauswahl und Stream-Ausgabe für alle Exportformate.</summary>
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public sealed class ExportService
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{
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public async Task<bool> SaveAsync(IStorageProvider storageProvider, ExportFile export)
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{
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var file = await storageProvider.SaveFilePickerAsync(new FilePickerSaveOptions
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{
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Title = export.DialogTitle,
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SuggestedFileName = export.SuggestedFileName,
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DefaultExtension = export.Format.Extension.TrimStart('.'),
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FileTypeChoices =
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[
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new FilePickerFileType(export.Format.Label)
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{
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Patterns = [$"*{export.Format.Extension}"],
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MimeTypes = [export.Format.MimeType],
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},
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],
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});
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if (file is null) return false;
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await using var stream = await file.OpenWriteAsync();
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if (stream.CanSeek) stream.SetLength(0);
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await stream.WriteAsync(export.Content);
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return true;
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}
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}
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