62 lines
2.0 KiB
C#
62 lines
2.0 KiB
C#
using System.Security.Cryptography;
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using System.Text;
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using System.Text.Json;
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namespace CampusErrand.Services;
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/// <summary>
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/// 腾讯 IM 服务，负责生成 UserSig
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/// </summary>
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public class TencentIMService
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{
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private readonly long _sdkAppId;
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private readonly string _secretKey;
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public TencentIMService(IConfiguration configuration)
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{
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var config = configuration.GetSection("TencentIM");
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_sdkAppId = config.GetValue<long>("SDKAppId");
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_secretKey = config["SecretKey"]!;
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}
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public long SDKAppId => _sdkAppId;
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/// <summary>
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/// 生成 UserSig
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/// </summary>
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/// <param name="userId">用户标识</param>
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/// <param name="expireSeconds">有效期（秒），默认7天</param>
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public string GenerateUserSig(string userId, int expireSeconds = 604800)
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{
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var now = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
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var obj = new Dictionary<string, object>
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{
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["TLS.ver"] = "2.0",
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["TLS.identifier"] = userId,
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["TLS.sdkappid"] = _sdkAppId,
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["TLS.expire"] = expireSeconds,
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["TLS.time"] = now
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};
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var contentToSign = $"TLS.identifier:{userId}\nTLS.sdkappid:{_sdkAppId}\nTLS.time:{now}\nTLS.expire:{expireSeconds}\n";
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using var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(_secretKey));
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var sig = hmac.ComputeHash(Encoding.UTF8.GetBytes(contentToSign));
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obj["TLS.sig"] = Convert.ToBase64String(sig);
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var jsonBytes = Encoding.UTF8.GetBytes(JsonSerializer.Serialize(obj));
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// zlib 压缩
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using var output = new MemoryStream();
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using (var zlib = new System.IO.Compression.ZLibStream(output, System.IO.Compression.CompressionLevel.Optimal))
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{
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zlib.Write(jsonBytes, 0, jsonBytes.Length);
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}
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// Base64 URL 安全编码
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return Convert.ToBase64String(output.ToArray())
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.Replace('+', '*')
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.Replace('/', '-')
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.Replace('=', '_');
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}
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}
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