feat: add migros products provider

Author: manuel-rw

GrocyScanner.Core/Providers/MigrosProductProvider.cs

@@ -0,0 +1,135 @@
+using System.Collections.Immutable;
+using System.Net.Http.Headers;
+using System.Text.Json;
+using GrocyScanner.Core.Models;
+using Microsoft.Extensions.Logging;
+
+namespace GrocyScanner.Core.Providers;
+
+public class MigrosProductProvider : IProductProvider
+{
+    private readonly IHttpClientFactory _httpClientFactory;
+    private readonly ILogger<MigrosProductProvider> _logger;
+
+    private string? _authorizationHeader;
+
+    public MigrosProductProvider(IHttpClientFactory httpClientFactory, ILogger<MigrosProductProvider> logger)
+    {
+        _httpClientFactory = httpClientFactory;
+        _logger = logger;
+    }
+
+    public async Task<Product?> GetProductByGtin(string gtin)
+    {
+        IReadOnlyList<int> productIds = await GetProductIds(gtin);
+
+        if (productIds.Count != 1)
+        {
+            _logger.LogError("Unexpected count for gtin {Gtin}: {Count}", gtin, productIds.Count);
+            return null;
+        }
+
+        return await GetProductByIdsAsync(gtin, productIds);
+    }
+
+    private async Task<Product?> GetProductByIdsAsync(string gtin, IEnumerable<int> productIds)
+    {
+        using HttpClient httpClient = _httpClientFactory.CreateClient();
+
+        HttpRequestMessage httpRequestMessage =
+            new(HttpMethod.Post, "https://www.migros.ch/product-display/public/v4/product-cards");
+        string requestJson =
+            @$"{{""offerFilter"":{{""ongoingOfferDate"":""{DateTime.Now:yyyy-MM-dd}T00:00:00"",""region"":""national"",""storeType"":""OFFLINE""}},""productFilter"":{{""uids"":[{string.Join(",", productIds)}]}}}}";
+        httpRequestMessage.Content = new StringContent(
+            requestJson,
+            MediaTypeHeaderValue.Parse("application/json"));
+        httpRequestMessage.Headers.Add("leshopch", await GetAndCreateAuthorizationHeader());
+        HttpResponseMessage httpResponseMessage = await httpClient.SendAsync(httpRequestMessage);
+        string content = await httpResponseMessage.Content.ReadAsStringAsync();
+        try
+        {
+            httpResponseMessage.EnsureSuccessStatusCode();
+            using JsonDocument jsonDocument = JsonDocument.Parse(content);
+
+            if (jsonDocument.RootElement.GetArrayLength() != 1)
+            {
+                _logger.LogError("Migros returned more than one product for the product ids {ProductId}", productIds);
+                return null;
+            }
+
+            JsonElement.ArrayEnumerator arrayEnumerator = jsonDocument.RootElement.EnumerateArray();
+            arrayEnumerator.MoveNext();
+
+            return new Product
+            {
+                Name = arrayEnumerator.Current.GetProperty("name").GetString()!,
+                Gtin = gtin,
+                Categories = ImmutableList<string>.Empty,
+                ImageUrl = GetImageFromJsonDocument(arrayEnumerator.Current)
+            };
+        }
+        catch (HttpRequestException httpRequestException)
+        {
+            _logger.LogError(httpRequestException,
+                "Failed to request product details for {ProductIds} at Migros: {Content}", productIds, content);
+            return null;
+        }
+    }
+
+    private async ValueTask<string> GetAndCreateAuthorizationHeader()
+    {
+        if (!string.IsNullOrEmpty(_authorizationHeader))
+        {
+            return _authorizationHeader;
+        }
+
+        using HttpClient httpClient = _httpClientFactory.CreateClient();
+        using HttpRequestMessage httpRequestMessage = new(HttpMethod.Get, "https://www.migros.ch/authentication/public/v1/api/guest?authorizationNotRequired=true");
+        HttpResponseMessage httpResponseMessage = await httpClient.SendAsync(httpRequestMessage);
+        httpResponseMessage.EnsureSuccessStatusCode();
+        var values = httpResponseMessage.Headers.GetValues("leshopch");
+        string authorizationToken = values.First();
+        _authorizationHeader = authorizationToken;
+        return authorizationToken;
+    }
+
+    private static string? GetImageFromJsonDocument(JsonElement jsonElement)
+    {
+        JsonElement imagesProperty = jsonElement.GetProperty("images");
+        return imagesProperty
+            .EnumerateArray()
+            .Select(element =>
+                element.GetProperty("url").GetString())
+            .FirstOrDefault(url => !string.IsNullOrEmpty(url));
+    }
+
+    private async Task<IReadOnlyList<int>> GetProductIds(string gtin)
+    {
+        using HttpClient httpClient = _httpClientFactory.CreateClient();
+
+        HttpRequestMessage httpRequestMessage =
+            new(HttpMethod.Post, "https://www.migros.ch/onesearch-oc-seaapi/public/v5/search");
+        httpRequestMessage.Content = new StringContent(
+            @$"{{""algorithm"":""DEFAULT"",""filters"":{{}},""language"":""en"",""productIds"":[],""query"":{gtin},""regionId"":""national"",""sortFields"":[],""sortOrder"":""asc""}}",
+            MediaTypeHeaderValue.Parse("application/json"));
+        httpRequestMessage.Headers.Add("leshopch", await GetAndCreateAuthorizationHeader());
+        HttpResponseMessage httpResponseMessage = await httpClient.SendAsync(httpRequestMessage);
+        string content = await httpResponseMessage.Content.ReadAsStringAsync();
+        try
+        {
+            httpResponseMessage.EnsureSuccessStatusCode();
+            using JsonDocument jsonDocument = JsonDocument.Parse(content);
+            JsonElement productIdsElement = jsonDocument.RootElement.GetProperty("productIds");
+            return productIdsElement.EnumerateArray().Select(jsonElement => jsonElement.GetInt32()).ToList();
+        }
+        catch (HttpRequestException httpRequestException)
+        {
+            _logger.LogError(httpRequestException, "Failed to request {Gtin} at Migros: {Content}", gtin, content);
+            return ImmutableList<int>.Empty;
+        }
+    }
+
+    public string Name => "Migros";
+    public string IconUri => "/migros-logo.png";
+    public string Country => "Switzerland";
+}

GrocyScanner.Service/Program.cs

@@ -21,6 +21,7 @@
 builder.Services.AddSingleton<IGtinValidator, GtinValidator>();
 builder.Services.AddSingleton<IProductProvider, OpenFoodFactsProductProvider>();
 builder.Services.AddSingleton<IProductProvider, CoopProductProvider>();
+builder.Services.AddSingleton<IProductProvider, MigrosProductProvider>();
 builder.Services.AddSingleton<IGrocyClient, GrocyClient>();
 builder.Services.AddSingleton<IGrocyQuantityUnit, GrocyQuantityUnitsMasterData>();
 builder.Services.AddSingleton<IGrocyLocations, GrocyLocationMasterData>();