65 lines
2.3 KiB
C#
65 lines
2.3 KiB
C#
using SixLabors.ImageSharp;
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using System.Text.Json;
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using System.Text.Json.Nodes;
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namespace IM_API.Tools
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{
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public static class UrlTools
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{
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public static string GetFullUrl(string objectName, string provider, string? baseUrl)
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{
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return provider switch
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{
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"Local" => $"{baseUrl}/uploads/files/{objectName}",
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_ => "http://baidu.com",
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};
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}
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public static async Task<(int width, int height)> GetImageWH(string url)
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{
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using var httpClient = new HttpClient();
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var stream = await httpClient.GetStreamAsync(url);
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var info = await Image.IdentifyAsync(stream);
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return (info.Width, info.Height);
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}
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public static string ProcessMessageUrl(string contentJson, string? localBaseUrl)
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{
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// 1. 解析 JSON 文档（比反序列化快得多）
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using var doc = JsonDocument.Parse(contentJson);
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var root = doc.RootElement;
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// 2. 获取 Provider 字段
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string provider = root.GetProperty("provider").GetString();
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// 3. 根据 Provider 决定前缀
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string prefix = GetFullUrl("", provider, localBaseUrl);
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// 4. 重新组装（如果只是为了给前端看，建议直接返回带前缀的对象或字符串）
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// 这里推荐用 JsonNode 方便修改并返回字符串
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var node = JsonNode.Parse(contentJson);
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node["url"] = $"{prefix}{node["url"]}";
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node["thumb"] = $"{prefix}{node["thumb"]}";
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return node.ToJsonString();
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}
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public static Stream Base64ToStream(string base64String)
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{
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if (string.IsNullOrEmpty(base64String))
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throw new ArgumentNullException(nameof(base64String));
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// 1. 自动处理可能存在的 Base64 Data URL 前缀
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string base64Data = base64String.Contains(",")
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? base64String.Split(',')[1]
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: base64String;
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// 2. 解码为字节数组
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byte[] bytes = Convert.FromBase64String(base64Data);
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// 3. 包装进 MemoryStream
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// 注意：这里直接把 Position 设为 0，符合“方法a”产生即用的原则
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return new MemoryStream(bytes);
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}
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}
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}
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