downloaderV2, download single tile

2026-04-22 09:06:38 +00:00 · 2025-10-28 15:10:50 +01:00
parent 7b24c1d720
commit 12f3bf890a
2 changed files with 179 additions and 20 deletions
@@ -0,0 +1,148 @@
+using System.Net.Http.Json;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Newtonsoft.Json;
+using SatelliteProvider.Common.Configs;
+using SatelliteProvider.Common.DTO;
+using SatelliteProvider.Common.Utils;
+
+namespace SatelliteProvider.Services;
+
+public record DownloadedTileInfoV2(int X, int Y, int ZoomLevel, double CenterLatitude, double CenterLongitude, string FilePath, double TileSizeMeters);
+
+public class GoogleMapsDownloaderV2
+{
+    private const string TILE_URL_TEMPLATE = "https://mt{0}.google.com/vt/lyrs=s&x={1}&y={2}&z={3}&token={4}";
+    private const string USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.0.0 Safari/537.36";
+    private const int TILE_SIZE_PIXELS = 256;
+    private static readonly int[] ALLOWED_ZOOM_LEVELS = { 15, 16, 17, 18, 19 };
+    
+    private readonly ILogger<GoogleMapsDownloaderV2> _logger;
+    private readonly string _apiKey;
+    private readonly string _tilesDirectory;
+    private readonly IHttpClientFactory _httpClientFactory;
+
+    public GoogleMapsDownloaderV2(
+        ILogger<GoogleMapsDownloaderV2> logger, 
+        IOptions<MapConfig> mapConfig, 
+        IOptions<StorageConfig> storageConfig, 
+        IHttpClientFactory httpClientFactory)
+    {
+        _logger = logger;
+        _apiKey = mapConfig.Value.ApiKey;
+        _tilesDirectory = storageConfig.Value.TilesDirectory;
+        _httpClientFactory = httpClientFactory;
+    }
+
+    private record SessionResponse(string Session);
+
+    private async Task<string?> GetSessionToken()
+    {
+        var url = $"https://tile.googleapis.com/v1/createSession?key={_apiKey}";
+        using var httpClient = _httpClientFactory.CreateClient();
+        try
+        {
+            var str = JsonConvert.SerializeObject(new { mapType = "satellite" });
+            var response = await httpClient.PostAsync(url, new StringContent(str));
+            response.EnsureSuccessStatusCode();
+            var sessionResponse = await response.Content.ReadFromJsonAsync<SessionResponse>();
+            return sessionResponse?.Session;
+        }
+        catch (Exception e)
+        {
+            _logger.LogError(e, "Failed to get session token");
+            throw;
+        }
+    }
+
+    public async Task<DownloadedTileInfoV2> DownloadSingleTileAsync(double latitude, double longitude, int zoomLevel, CancellationToken token = default)
+    {
+        if (!ALLOWED_ZOOM_LEVELS.Contains(zoomLevel))
+        {
+            throw new ArgumentException($"Zoom level {zoomLevel} is not allowed. Allowed zoom levels are: {string.Join(", ", ALLOWED_ZOOM_LEVELS)}", nameof(zoomLevel));
+        }
+
+        var geoPoint = new GeoPoint(latitude, longitude);
+        var (tileX, tileY) = GeoUtils.WorldToTilePos(geoPoint, zoomLevel);
+
+        _logger.LogInformation("Downloading single tile at ({Lat}, {Lon}), zoom {Zoom}, tile coordinates ({X}, {Y})", 
+            latitude, longitude, zoomLevel, tileX, tileY);
+
+        var sessionToken = await GetSessionToken();
+        var server = 0;
+        var url = string.Format(TILE_URL_TEMPLATE, server, tileX, tileY, zoomLevel, sessionToken);
+
+        Directory.CreateDirectory(_tilesDirectory);
+
+        var timestamp = DateTime.UtcNow.ToString("yyyyMMddHHmmss");
+        var fileName = $"raw_tile_{zoomLevel}_{tileX}_{tileY}_{timestamp}.jpg";
+        var filePath = Path.Combine(_tilesDirectory, fileName);
+
+        using var httpClient = _httpClientFactory.CreateClient();
+        httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(USER_AGENT);
+
+        var response = await httpClient.GetAsync(url, token);
+        response.EnsureSuccessStatusCode();
+
+        _logger.LogInformation("=== HTTP Response Headers from Google Maps ===");
+        _logger.LogInformation("Status Code: {StatusCode}", response.StatusCode);
+        
+        foreach (var header in response.Headers)
+        {
+            _logger.LogInformation("Header: {Key} = {Value}", header.Key, string.Join(", ", header.Value));
+        }
+        
+        foreach (var header in response.Content.Headers)
+        {
+            _logger.LogInformation("Content Header: {Key} = {Value}", header.Key, string.Join(", ", header.Value));
+        }
+        
+        if (response.Headers.ETag != null)
+        {
+            _logger.LogInformation("*** ETag Found: {ETag}", response.Headers.ETag.Tag);
+        }
+        
+        if (response.Content.Headers.LastModified.HasValue)
+        {
+            _logger.LogInformation("*** Last-Modified Found: {LastModified}", response.Content.Headers.LastModified.Value);
+        }
+        
+        if (response.Headers.CacheControl != null)
+        {
+            _logger.LogInformation("*** Cache-Control: MaxAge={MaxAge}, Public={Public}, Private={Private}, MustRevalidate={MustRevalidate}", 
+                response.Headers.CacheControl.MaxAge,
+                response.Headers.CacheControl.Public,
+                response.Headers.CacheControl.Private,
+                response.Headers.CacheControl.MustRevalidate);
+        }
+        
+        _logger.LogInformation("=== End of Headers ===");
+
+        var imageBytes = await response.Content.ReadAsByteArrayAsync(token);
+        await File.WriteAllBytesAsync(filePath, imageBytes, token);
+
+        var tileCenter = GeoUtils.TileToWorldPos(tileX, tileY, zoomLevel);
+        var tileSizeMeters = CalculateTileSizeInMeters(zoomLevel, tileCenter.Lat);
+
+        _logger.LogInformation("Downloaded tile to {FilePath}, size: {Size:F2} meters", filePath, tileSizeMeters);
+
+        return new DownloadedTileInfoV2(
+            tileX,
+            tileY,
+            zoomLevel,
+            tileCenter.Lat,
+            tileCenter.Lon,
+            filePath,
+            tileSizeMeters
+        );
+    }
+
+    private static double CalculateTileSizeInMeters(int zoomLevel, double latitude)
+    {
+        const double EARTH_CIRCUMFERENCE_METERS = 40075016.686;
+        var latRad = latitude * Math.PI / 180.0;
+        var metersPerPixel = (EARTH_CIRCUMFERENCE_METERS * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * TILE_SIZE_PIXELS);
+        return metersPerPixel * TILE_SIZE_PIXELS;
+    }
+}
+