feat: externalize pagination settings to configurable options and apply them across endpoints

Author: aalmada

src/ApiService/BookStore.ApiService/Endpoints/AuthorEndpoints.cs

@@ -4,6 +4,7 @@
 using Marten.Pagination;
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
 
 namespace BookStore.ApiService.Endpoints;
 
@@ -26,9 +27,10 @@ public static RouteGroupBuilder MapAuthorEndpoints(this RouteGroupBuilder group)
 
     static async Task<Ok<IPagedList<AuthorProjection>>> GetAuthors(
         [FromServices] IQuerySession session,
+        [FromServices] IOptions<PaginationOptions> paginationOptions,
         [AsParameters] PagedRequest request)
     {
-        var paging = request.Normalize();
+        var paging = request.Normalize(paginationOptions.Value);
 
         // Use Marten's native pagination for optimal performance
         var pagedList = await session.Query<AuthorProjection>()

src/ApiService/BookStore.ApiService/Endpoints/BookEndpoints.cs

@@ -4,6 +4,7 @@
 using Marten.Pagination;
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
 using Npgsql;
 
 namespace BookStore.ApiService.Endpoints;
@@ -29,10 +30,11 @@ public static RouteGroupBuilder MapBookEndpoints(this RouteGroupBuilder group)
 
     static async Task<Ok<PagedListDto<BookSearchProjection>>> SearchBooks(
         [FromServices] IQuerySession session,
+        [FromServices] IOptions<PaginationOptions> paginationOptions,
         [AsParameters] PagedRequest request,
         [FromQuery] string? search = null)
     {
-        var paging = request.Normalize();
+        var paging = request.Normalize(paginationOptions.Value);
 
         if (string.IsNullOrWhiteSpace(search))
         {

src/ApiService/BookStore.ApiService/Endpoints/CategoryEndpoints.cs

@@ -5,6 +5,7 @@
 using Marten.Pagination;
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
 
 namespace BookStore.ApiService.Endpoints;
 
@@ -29,10 +30,11 @@ public static RouteGroupBuilder MapCategoryEndpoints(this RouteGroupBuilder grou
 
     static async Task<IResult> GetCategories(
         [FromServices] IQuerySession session,
+        [FromServices] IOptions<PaginationOptions> paginationOptions,
         [AsParameters] PagedRequest request,
         HttpContext context)
     {
-        var paging = request.Normalize();
+        var paging = request.Normalize(paginationOptions.Value);
         var language = GetPreferredLanguage(context);
 
         // Use Marten's native pagination for optimal performance

src/ApiService/BookStore.ApiService/Endpoints/PublisherEndpoints.cs

@@ -4,6 +4,7 @@
 using Marten.Pagination;
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
 
 namespace BookStore.ApiService.Endpoints;
 
@@ -26,9 +27,10 @@ public static RouteGroupBuilder MapPublisherEndpoints(this RouteGroupBuilder gro
 
     static async Task<Ok<IPagedList<PublisherProjection>>> GetPublishers(
         [FromServices] IQuerySession session,
+        [FromServices] IOptions<PaginationOptions> paginationOptions,
         [AsParameters] PagedRequest request)
     {
-        var paging = request.Normalize();
+        var paging = request.Normalize(paginationOptions.Value);
 
         // Use Marten's native pagination for optimal performance
         var pagedList = await session.Query<PublisherProjection>()

src/ApiService/BookStore.ApiService/Models/Pagination.cs

@@ -6,9 +6,9 @@ namespace BookStore.ApiService.Models;
 public record PagedRequest
 {
     /// <summary>
-    /// Maximum number of items allowed per page
+    /// Default page number (1-based)
     /// </summary>
-    public const int MaxPageSize = 100;
+    public const int DefaultPage = 1;
 
     /// <summary>
     /// Page number (1-based)
@@ -21,18 +21,19 @@ public record PagedRequest
     public int? PageSize { get; init; }
 
     /// <summary>
-    /// Validates and normalizes pagination parameters
+    /// Validates and normalizes pagination parameters using configuration options
     /// </summary>
-    public PagedRequest Normalize()
+    public PagedRequest Normalize(PaginationOptions options)
     {
-        var page = int.Max(1, Page ?? 1);
-        var pageSize = int.Clamp(PageSize ?? 20, 1, MaxPageSize);
+        var page = int.Max(DefaultPage, Page ?? DefaultPage);
+        var pageSize = int.Clamp(PageSize ?? options.DefaultPageSize, 1, options.MaxPageSize);
 
         return this with { Page = page, PageSize = pageSize };
     }
 
     /// <summary>
-    /// Calculates the number of items to skip
+    /// Calculates the number of items to skip using configuration options
     /// </summary>
-    public int Skip => ((Page ?? 1) - 1) * (PageSize ?? 20);
+    public int GetSkip(PaginationOptions options) => 
+        ((Page ?? DefaultPage) - 1) * (PageSize ?? options.DefaultPageSize);
 }

src/ApiService/BookStore.ApiService/Models/PaginationOptions.cs

@@ -0,0 +1,32 @@
+namespace BookStore.ApiService.Models;
+
+/// <summary>
+/// Configuration options for pagination
+/// </summary>
+public sealed class PaginationOptions
+{
+    /// <summary>
+    /// Configuration section name
+    /// </summary>
+    public const string SectionName = "Pagination";
+
+    /// <summary>
+    /// Default value for page size when not specified
+    /// </summary>
+    public const int DefaultPageSizeValue = 20;
+
+    /// <summary>
+    /// Default value for maximum number of items allowed per page
+    /// </summary>
+    public const int MaxPageSizeValue = 100;
+
+    /// <summary>
+    /// Default page size when not specified
+    /// </summary>
+    public int DefaultPageSize { get; init; } = DefaultPageSizeValue;
+
+    /// <summary>
+    /// Maximum number of items allowed per page
+    /// </summary>
+    public int MaxPageSize { get; init; } = MaxPageSizeValue;
+}

src/ApiService/BookStore.ApiService/Program.cs

@@ -42,6 +42,10 @@
 // Add services to the container.
 builder.Services.AddProblemDetails();
 
+// Configure pagination options
+builder.Services.Configure<BookStore.ApiService.Models.PaginationOptions>(
+    builder.Configuration.GetSection(BookStore.ApiService.Models.PaginationOptions.SectionName));
+
 // Configure OpenAPI with metadata
 builder.Services.AddOpenApi(options => options.AddBookStoreApiDocumentation());
 

src/ApiService/BookStore.ApiService/appsettings.json

@@ -22,5 +22,9 @@
       }
     }
   },
-  "AllowedHosts": "*"
-}
+  "AllowedHosts": "*",
+  "Pagination": {
+    "DefaultPageSize": 20,
+    "MaxPageSize": 100
+  }
+}