src/Search/Controllers/SearchController.cs

@@ -6,7 +6,9 @@ using Coscine.SemanticSearch.Clients;
 using Coscine.SemanticSearch.Core;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -41,31 +43,43 @@ namespace Coscine.Api.Search.Controllers
             _searchClient = new ElasticsearchSearchClient(elasticsearchServer, elasticsearchPort);
         }
 
-
         /// <summary>
         /// Search Elasticsearch
         /// </summary>
-        /// <param name="query">Elasticsearch query</param>
-        /// <param name="user">Specify user or only public metadata records could be found</param>
-        /// <param name="adv">Set true for advanced Elasticsearch search syntax</param>
-        /// <param name="languages">Set the used languages</param>
+        /// <param name="searchParameters"></param>
         /// <returns>Search results</returns>
-        [HttpGet("[controller]/{query?}/{user?}/{adv?}/{languages?}")]
-        public async Task<ActionResult<SearchResult>> SearchAsync(string query = "*", bool user = true, bool adv = false, [System.Web.Http.FromUri] string[] languages = null)
+        [HttpGet("[controller]/")]
+        public async Task<ActionResult<IEnumerable<ItemSearchResult>>> SearchAsync([FromQuery] SearchParameters searchParameters = null)
         {
+            if (searchParameters is null)
+            {
+                searchParameters = new SearchParameters();
+            }
+
             var currentUser = _authenticator.GetUser();
-            if (languages is null || languages.Length == 0)
+            if (searchParameters.IncludedLanguages is null || !searchParameters.IncludedLanguages.Any())
             {
-                languages = _defaultLanguages;
+                searchParameters.IncludedLanguages = _defaultLanguages;
             }
 
             try
             {
-                var items = await Searchers.SearchForItemsAsync(currentUser.Id, query, adv, includePrivateRecords: user, _connector, _searchClient, languages.ToList());
-                var res = new SearchResult()
+                var items = await Searchers.SearchForItemsAsync(currentUser.Id, searchParameters.SearchQuery, searchParameters.UseAdvancedSyntax, includePrivateRecords: searchParameters.IncludeUsers, _connector, _searchClient, searchParameters.IncludedLanguages.ToList());
+
+                var res = PagedList<ItemSearchResult>.ToPagedList(items, searchParameters.PageNumber, searchParameters.PageSize);
+
+                var metadata = new
                 {
-                    Items = items,
+                    res.TotalCount,
+                    res.PageSize,
+                    res.CurrentPage,
+                    res.TotalPages,
+                    res.HasNext,
+                    res.HasPrevious
                 };
+
+                Response.Headers.Add("X-Pagination", JsonConvert.SerializeObject(metadata));
+
                 return res;
             }
             catch (Exception e)
@@ -74,4 +88,4 @@ namespace Coscine.Api.Search.Controllers
             }
         }
     }
-}
+}
\ No newline at end of file

src/Search/Helpers/PagedList.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Coscine.Api.Search.Helpers;
+
+/// <summary>
+/// Helper class for paged results
+/// </summary>
+/// <typeparam name="T"></typeparam>
+public class PagedList<T> : List<T>
+{
+    /// <summary>
+    /// The current page
+    /// </summary>
+    public int CurrentPage { get; }
+
+    /// <summary>
+    /// Total pages
+    /// </summary>
+    public int TotalPages { get; }
+
+    /// <summary>
+    /// The site of a page
+    /// </summary>
+    public int PageSize { get; }
+
+    /// <summary>
+    /// Total amount of results
+    /// </summary>
+    public int TotalCount { get; }
+
+    /// <summary>
+    /// Has a previous pages
+    /// </summary>
+    public bool HasPrevious => CurrentPage > 1;
+
+    /// <summary>
+    /// Has a following page
+    /// </summary>
+    public bool HasNext => CurrentPage < TotalPages;
+
+    /// <summary>
+    /// Create a paged list
+    /// </summary>
+    /// <param name="items"></param>
+    /// <param name="count"></param>
+    /// <param name="pageNumber"></param>
+    /// <param name="pageSize"></param>
+    public PagedList(IEnumerable<T> items, int count, int pageNumber, int pageSize)
+    {
+        TotalCount = count;
+        PageSize = pageSize;
+        CurrentPage = pageNumber;
+        TotalPages = (int)Math.Ceiling(count / (double)pageSize);
+        AddRange(items);
+    }
+
+    /// <summary>
+    /// Create a paged list
+    /// </summary>
+    /// <param name="source"></param>
+    /// <param name="pageNumber"></param>
+    /// <param name="pageSize"></param>
+    /// <returns></returns>
+    // source should better be IQueryable
+    public static PagedList<T> ToPagedList(IEnumerable<T> source, int pageNumber, int pageSize)
+    {
+        var count = source.Count();
+        var items = source.Skip((pageNumber - 1) * pageSize).Take(pageSize).ToList();
+        return new PagedList<T>(items, count, pageNumber, pageSize);
+    }
+}
\ No newline at end of file

src/Search/Models/QueryStringParameters.cs

+namespace Coscine.Api.Search.Models
+{
+    /// <summary>
+    /// Parameters for pagination of the search
+    /// </summary>
+    public class QueryStringParameters
+    {
+        private const int maxPageSize = 50;
+
+        /// <summary>
+        /// The requested page number
+        /// </summary>
+        public int PageNumber { get; set; } = 1;
+
+        private int _pageSize = 10;
+
+        /// <summary>
+        /// The size of a page
+        /// </summary>
+        public int PageSize
+        {
+            get
+            {
+                return _pageSize;
+            }
+            set
+            {
+                _pageSize = (value > maxPageSize) ? maxPageSize : value;
+            }
+        }
+    }
+}
\ No newline at end of file

src/Search/Models/SearchParameters.cs

+using System.Collections.Generic;
+
+namespace Coscine.Api.Search.Models
+{
+    /// <summary>
+    /// Parameters and filters for the search
+    /// </summary>
+    public class SearchParameters : QueryStringParameters
+    {
+        /// <summary>
+        /// The actual search query
+        /// </summary>
+        public string SearchQuery { get; set; } = "*";
+
+        /// <summary>
+        /// Specify user or only public metadata records could be found
+        /// </summary>
+        public bool IncludeUsers { get; set; } = true;
+
+        /// <summary>
+        /// Set true for advanced Elasticsearch search syntax
+        /// </summary>
+        public bool UseAdvancedSyntax { get; set; }
+
+        /// <summary>
+        /// Set the used languages
+        /// </summary>
+        public IEnumerable<string> IncludedLanguages { get; set; }
+    }
+}
\ No newline at end of file

src/Search/Models/SearchResult.cs

-using System.Collections.Generic;
+using Coscine.Api.Search.Helpers;
 
 namespace Coscine.Api.Search.Models
 {
@@ -10,6 +10,6 @@ namespace Coscine.Api.Search.Models
         /// <summary>
         /// Search result files
         /// </summary>
-        public IEnumerable<ItemSearchResult> Items { get; set; }
+        public PagedList<ItemSearchResult> Items { get; set; }
     }
-}
+}
\ No newline at end of file

src/Search/Search.csproj

@@ -5,7 +5,7 @@
 		<AssemblyName>Coscine.Api.Search</AssemblyName>
 		<GenerateDocumentationFile>true</GenerateDocumentationFile>
 		<TargetFramework>net6.0</TargetFramework>
-		<Version>1.5.0</Version>
+		<Version>1.6.0</Version>
 	</PropertyGroup>
 	<PropertyGroup>
 		<Authors>RWTH Aachen University</Authors>