StopShopping/StopShopping.OpenPlatform/TencentLocationApi/TencentDistrictService.cs

using System.Text.Json;
using System.Threading.RateLimiting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Polly;
using Polly.RateLimiting;
using Polly.Timeout;
using StopShopping.OpenPlatform.Extensions;

namespace StopShopping.OpenPlatform.TencentLocationApi;

public class TencentDistrictService : IDistrictService
{
    public TencentDistrictService(
        IHttpClientFactory httpClientFactory,
        IOptions<OpenPlatformOptions> openPlatformOptions,
        ILogger<TencentDistrictService> logger)
    {
        _httpContextFactory = httpClientFactory;
        _options = openPlatformOptions.Value;
        _logger = logger;

        _pipeline = new ResiliencePipelineBuilder()
            .AddRetry(new Polly.Retry.RetryStrategyOptions
            {
                Delay = TimeSpan.FromSeconds(2),
                MaxRetryAttempts = 5,
                ShouldHandle = (arg) =>
                    ValueTask.FromResult(arg.Outcome.Exception is
                        TimeoutRejectedException or RateLimiterRejectedException)
            })
            .AddRateLimiter(new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueLimit = int.MaxValue,
                SegmentsPerWindow = 5,
                Window = TimeSpan.FromSeconds(1)
            }))
            .AddTimeout(TimeSpan.FromSeconds(20))
            .Build();
    }

    private readonly IHttpClientFactory _httpContextFactory;
    private readonly OpenPlatformOptions _options;
    private readonly ILogger<TencentDistrictService> _logger;

    private readonly ResiliencePipeline _pipeline;

    public async Task<DistrictResponse?> GetChildrenAsync(string code, CancellationToken cancellationToken = default)
    {
        var uri = new Uri(
            string.Format("{0}?key={1}&id={2}"
                , _options.TencentDistrict.GetChildrenUrl!
                , Uri.EscapeDataString(_options.TencentDistrict.SecretKey!)
                , code));

        var districts = await Get<District[]?>(uri, cancellationToken);

        if (null == districts)
            return null;

        DistrictResponse response = new()
        {
            IsSucced = districts.Status == 0,
            Message = $"{districts.Status}:{districts.Message}",
            Districts = districts.Result
                ?.FirstOrDefault()
                ?.Select(Cast)
                .ToList()
        };

        return response;
    }

    public async Task<DistrictResponse?> GetTop3LevelDistrictsAsync(CancellationToken cancellationToken = default)
    {
        var uri = new Uri(
            string.Format("{0}?key={1}&struct_type=1"
                , _options.TencentDistrict.Top3LevelUrl!
                , _options.TencentDistrict.SecretKey!)
        );

        var districts = await Get<District>(uri, cancellationToken);

        if (null == districts)
            return null;

        DistrictResponse response = new()
        {
            IsSucced = districts.Status == 0,
            Message = $"{districts.Status}:{districts.Message}",
            Districts = null != districts.Result
                ? [.. RecurCast(districts.Result)] : null
        };

        return response;
    }

    private async Task<ResponseDistrict<T>?> Get<T>(Uri uri, CancellationToken cancellationToken = default)
    {
        using var httpClient = _httpContextFactory.CreateClient();


        var districts = await _pipeline.ExecuteAsync(async (token) =>
        {
            var jsonStream = await httpClient.GetStreamAsync(uri, token);

            try
            {
                return await JsonSerializer.DeserializeAsync<ResponseDistrict<T>>(
                   jsonStream, cancellationToken: token);
            }
            catch (JsonException e)
            {
                _logger.LogError("序列化异常：{Path}", e.Path);
                return null;
            }
        }, cancellationToken);

        if (null == districts)
        {
            _logger.LogError("接口请求失败:{Url}", uri.ToString());
            return null;
        }

        return districts;
    }

    private IEnumerable<DistrictResponse.District> RecurCast(District[] districts)
    {
        foreach (var d in districts)
        {
            var cd = Cast(d);
            if (d.Districts?.Length > 0)
                cd.Districts = [.. RecurCast(d.Districts!)];

            yield return cd;
        }
    }

    private DistrictResponse.District Cast(District d)
    {
        return new DistrictResponse.District
        {
            Code = d.Id,
            FullName = d.FullName,
            Latitude = d.Location.Latitude,
            Level = d.Level,
            Longitude = d.Location.Longitude,
            Name = d.Name,
            PinYin = d.PinYin?.Length > 0 ? string.Join(',', d.PinYin) : null,
        };
    }
}