✨ Add simple service for parsing SUZ Canteena page

Packages.props

@@ -24,5 +24,6 @@
         <PackageReference Update="xunit.runner.visualstudio" Version="2.4.5" />
         <PackageReference Update="Shouldly" Version="4.1.0" />
         <PackageReference Update="Html2Markdown" Version="5.1.0.703" />
+        <PackageReference Update="HtmlAgilityPack" Version="1.11.46" />
     </ItemGroup>
 </Project>

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "6.0.100",
+    "version": "6.0",
     "rollForward": "latestMinor"
   }
 }

src/HonzaBotner.Services.Contract/Dto/CanteenDishDto.cs

@@ -0,0 +1,9 @@
+namespace HonzaBotner.Services.Contract.Dto;
+
+public record CanteenDishDto(
+    string DishType,
+    string Name,
+    string Amount,
+    string StudentPrice,
+    string OtherPrice,
+    string PhotoLink = "");

src/HonzaBotner.Services.Contract/Dto/CanteenDto.cs

@@ -0,0 +1,5 @@
+using System.Collections.Generic;
+
+namespace HonzaBotner.Services.Contract.Dto;
+
+public record CanteenDto(int Id, string Name, bool Open, IReadOnlyList<CanteenDishDto>? TodayDishes = null);

src/HonzaBotner.Services.Contract/ICanteenService.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Threading;
+using System.Threading.Tasks;
+using HonzaBotner.Services.Contract.Dto;
+
+namespace HonzaBotner.Services.Contract;
+
+public interface ICanteenService
+{
+    Task<IList<CanteenDto>> ListCanteensAsync(bool onlyOpen = false, CancellationToken cancellationToken = default);
+    Task<CanteenDto> GetCurrentMenuAsync(CanteenDto canteen, CancellationToken cancellationToken = default);
+}

src/HonzaBotner.Services.Test/SuzCanteenServiceTest.cs

@@ -0,0 +1,54 @@
+using System.Collections.Immutable;
+using System.Linq;
+using System.Net.Http;
+using HonzaBotner.Services.Contract;
+using HonzaBotner.Services.Contract.Dto;
+using Xunit;
+
+namespace HonzaBotner.Services.Test;
+
+public class SuzCanteenServiceTest
+{
+    private static readonly CanteenDto Technicka = new(3, "Technická menza", true);
+
+    [Fact]
+    public async void ListCanteens()
+    {
+        ICanteenService canteenService = new SuzCanteenService(new HttpClient()); // TODO: Init
+
+        var canteens = (await canteenService.ListCanteensAsync()).ToList();
+
+        Assert.NotEmpty(canteens);
+        Assert.All(canteens, dto =>
+        {
+            Assert.NotEmpty(dto.Name);
+            Assert.NotEqual(0, dto.Id);
+        });
+
+        Assert.Contains(Technicka, canteens);
+    }
+
+    [Fact]
+    public async void GetCurrentMenu()
+    {
+        ICanteenService canteenService = new SuzCanteenService(new HttpClient()); // TODO: Init
+        var canteens = await canteenService.ListCanteensAsync(true);
+
+        foreach (CanteenDto canteen in canteens)
+        {
+            var canteenWithMenu = await canteenService.GetCurrentMenuAsync(canteen);
+            // Method modifies only today dishes
+            Assert.Equal(canteen, canteenWithMenu with { TodayDishes = canteen.TodayDishes });
+            Assert.NotNull(canteenWithMenu);
+
+            foreach (var dish in canteenWithMenu.TodayDishes!)
+            {
+                Assert.NotEmpty(dish.DishType);
+                Assert.NotEqual("Jiné", dish.DishType);
+                Assert.NotEmpty(dish.Name);
+                Assert.NotEmpty(dish.StudentPrice);
+                Assert.NotEmpty(dish.OtherPrice);
+            }
+        }
+    }
+}

src/HonzaBotner.Services/HonzaBotner.Services.csproj

@@ -6,6 +6,7 @@
     <PackageReference Include="Microsoft.Extensions.Http" />
     <PackageReference Include="Microsoft.Extensions.Options" />
     <PackageReference Include="Html2Markdown" />
+    <PackageReference Include="HtmlAgilityPack" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\HonzaBotner.Database\HonzaBotner.Database.csproj" />

src/HonzaBotner.Services/SuzCanteenService.cs

@@ -0,0 +1,114 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using HonzaBotner.Services.Contract;
+using HonzaBotner.Services.Contract.Dto;
+using HtmlAgilityPack;
+
+namespace HonzaBotner.Services;
+
+public class SuzCanteenService: ICanteenService
+{
+    private readonly HttpClient _httpClient;
+
+    public SuzCanteenService(HttpClient httpClient)
+    {
+        _httpClient = httpClient;
+    }
+
+    public async Task<IList<CanteenDto>> ListCanteensAsync(bool onlyOpen = false, CancellationToken cancellationToken = default)
+    {
+        const string url = "https://agata.suz.cvut.cz/jidelnicky/index.php";
+        string pageContent = await _httpClient.GetStringAsync(url, cancellationToken);
+
+        var htmlDoc = new HtmlDocument();
+        htmlDoc.LoadHtml(pageContent);
+
+        var canteens = htmlDoc.DocumentNode.SelectNodes("//ul[@id='menzy']/li/a")
+            .Select(node =>
+            {
+                int.TryParse(node.Id.Replace("podSh", ""), out int id);
+                bool open = node.SelectSingleNode($"{node.XPath}/img")
+                    .GetAttributeValue("src", "closed").Contains("Otevreno");
+                string name = node.InnerText.Trim();
+                return new CanteenDto(id, name, open);
+            });
+
+        if (onlyOpen)
+            return canteens.Where(c => c.Open).ToList();
+        return canteens.ToList();
+    }
+
+    public async Task<CanteenDto> GetCurrentMenuAsync(CanteenDto canteen, CancellationToken cancellationToken = default)
+    {
+        const string url = "https://agata.suz.cvut.cz/jidelnicky/index.php?clPodsystem={0}";
+        string pageContent = await _httpClient.GetStringAsync(string.Format(url, canteen.Id), cancellationToken);
+
+        var htmlDoc = new HtmlDocument();
+        htmlDoc.LoadHtml(pageContent);
+
+        var rows = htmlDoc.DocumentNode
+            .SelectNodes("//div[@class='data']/table[@class='table table-condensed']/tbody/tr");
+        if (rows is null)
+        {
+            // TODO: Log and maybe say something to user?
+            return canteen with { TodayDishes = ArraySegment<CanteenDishDto>.Empty};
+        }
+
+        var dishes = new List<CanteenDishDto>();
+
+        string currentDishType = "Jiné";
+
+        foreach (var row in rows)
+        {
+            if (row is null) continue;
+
+            var th = row.ChildNodes["th"];
+            if (th is not null)
+            {
+                currentDishType = th.InnerText.Trim();
+                continue;
+            }
+
+            var tds = row.SelectNodes("td");
+            if (tds is null) continue;
+
+            string amount = TrimHtml(tds[1].InnerText);
+            string name = TrimHtml(tds[2].InnerText);
+            string photo = ParsePhoto(tds[4]);
+
+            string studentPrice = TrimHtml(tds[5].InnerText);
+            string otherPrice = TrimHtml(tds[6].InnerText);
+
+            dishes.Add(new CanteenDishDto(currentDishType, name, amount, studentPrice, otherPrice, photo));
+        }
+
+
+        return canteen with { TodayDishes = dishes };
+    }
+
+
+    private static string ParsePhoto(HtmlNode node)
+    {
+        var photo = node.Descendants("a")?.FirstOrDefault();
+
+        if (photo is null)
+        {
+            return string.Empty;
+        }
+
+        string link = photo.GetAttributeValue("href", string.Empty);
+
+        if (string.IsNullOrEmpty(link)) return link;
+
+        return $"https://agata.suz.cvut.cz/jidelnicky/{link}";
+    }
+
+    private static string TrimHtml(string text)
+    {
+        return text.Replace("&nbsp;", " ").Trim();
+    }
+}