Start work on the user count endpoint

src/Keycloak.AuthServices.Sdk/Admin/ApiUrls.cs

@@ -19,6 +19,8 @@ internal static class ApiUrls
 
     internal const string GetUser = $"{GetRealm}/users/{{id}}";
 
+    internal const string GetUserCount = $"{GetRealm}/users/count";
+
     internal const string CreateUser = $"{GetRealm}/users";
 
     internal const string UpdateUser = $"{GetRealm}/users/{{id}}";

src/Keycloak.AuthServices.Sdk/Admin/IKeycloakUserClient.cs

@@ -40,6 +40,41 @@ async Task<IEnumerable<UserRepresentation>> GetUsersAsync(
             ?? Enumerable.Empty<UserRepresentation>();
     }
 
+    /// <summary>
+    /// Get the integer amount of users on the realm that match the provided <see cref="GetUserCountRequestParameters"/>.
+    ///
+    /// Note that the response is not JSON, but simply the integer value as a string.
+    /// </summary>
+    /// <param name="realm">Realm name (not ID).</param>
+    /// <param name="parameters">Optional query parameters.</param>
+    /// <param name="cancellationToken"></param>
+    /// <returns>An integer amount of users</returns>
+    Task<HttpResponseMessage> GetUserCountWithResponseAsync(
+        string realm,
+        GetUserCountRequestParameters? parameters = default,
+        CancellationToken cancellationToken = default
+    );
+
+    /// <summary>
+    /// Get the integer amount of users on the realm that match the provided <see cref="GetUserCountRequestParameters"/>.
+    /// </summary>
+    /// <param name="realm">Realm name (not ID).</param>
+    /// <param name="parameters">Optional query parameters.</param>
+    /// <param name="cancellationToken"></param>
+    /// <returns>An integer amount of users</returns>
+    async Task<int> GetUserCountAsync(
+        string realm,
+        GetUserCountRequestParameters? parameters = default,
+        CancellationToken cancellationToken = default
+    )
+    {
+        var response = await this.GetUserCountWithResponseAsync(realm, parameters, cancellationToken);
+        var stringContent = await response.Content.ReadAsStringAsync(cancellationToken);
+#pragma warning disable CA1305 // Specify IFormatProvider
+        return Convert.ToInt32(stringContent);
+#pragma warning restore CA1305 // Specify IFormatProvider
+    }
+
     /// <summary>
     /// Get representation of a user.
     /// </summary>

src/Keycloak.AuthServices.Sdk/Admin/KeycloakClient.cs

@@ -11,7 +11,7 @@
 /// <summary>
 /// Represents a client for interacting with the Keycloak Admin API.
 /// </summary>
-public partial class KeycloakClient : IKeycloakClient
+public class KeycloakClient : IKeycloakClient
 {
     private readonly HttpClient httpClient;
 
@@ -94,7 +94,42 @@ public async Task<HttpResponseMessage> GetUsersWithResponseAsync(
 
         var responseMessage = await this.httpClient.GetAsync(path + query, cancellationToken);
 
-        return responseMessage!;
+        return responseMessage;
+    }
+
+    /// <inheritdoc/>
+    public async Task<HttpResponseMessage> GetUserCountWithResponseAsync(
+        string realm,
+        GetUserCountRequestParameters? parameters = default,
+        CancellationToken cancellationToken = default
+    )
+    {
+        var path = ApiUrls.GetUserCount.WithRealm(realm);
+
+        var query = string.Empty;
+
+        if (parameters is not null)
+        {
+            var queryParameters = new List<KeyValuePair<string, string?>>()
+            {
+                new("email", parameters.Email),
+                new("emailVerified", parameters.EmailVerified?.ToString()),
+                new("enabled", parameters.Enabled?.ToString()),
+                new("firstName", parameters.FirstName),
+                new("lastName", parameters.LastName),
+                new("q", parameters.Query),
+                new("search", parameters.Search),
+                new("username", parameters.Username)
+            };
+
+            query = new QueryBuilder(queryParameters.Where(q => q.Value is not null)!)
+                .ToQueryString()
+                .ToString();
+        }
+
+        var responseMessage = await this.httpClient.GetAsync(path + query, cancellationToken);
+
+        return responseMessage;
     }
 
     /// <inheritdoc/>

src/Keycloak.AuthServices.Sdk/Admin/Requests/Users/GetUserCountRequestParameters.cs

@@ -0,0 +1,50 @@
+namespace Keycloak.AuthServices.Sdk.Admin.Requests.Users;
+
+/// <summary>
+/// Optional request parameters for the <see cref="IKeycloakClient.GetUserCountAsync"/> endpoint.
+/// If these are not specified, the total amount of users in the provided realm will be returned, otherwise, the amount
+/// of users in the realm that match the criteria defined in these parameters will be returned.
+/// </summary>
+public class GetUserCountRequestParameters
+{
+    /// <summary>
+    /// An optional filter for a user's email.
+    /// </summary>
+    public string? Email { get; init; }
+
+    /// <summary>
+    /// Whether a user's email has to be verified to be included.
+    /// </summary>
+    public bool? EmailVerified { get; init; }
+
+    /// <summary>
+    /// Whether a user has to be enabled to be included.
+    /// </summary>
+    public bool? Enabled { get; init; }
+
+    /// <summary>
+    /// An optional filter for a user's first name.
+    /// </summary>
+    public string? FirstName { get; init; }
+
+    /// <summary>
+    /// An optional filter for a user's last name.
+    /// </summary>
+    public string? LastName { get; init; }
+
+    /// <summary>
+    /// An optional query to search for custom attributes, in the format "<c>key1:value2 key2:value2</c>".
+    /// </summary>
+    public string? Query { get; init; }
+
+    /// <summary>
+    /// An optional search string for all the fields of a user.
+    /// Default search behavior is prefix-based (e.g., foo or foo*). Use foo for infix search and "foo" for exact search.
+    /// </summary>
+    public string? Search { get; init; }
+
+    /// <summary>
+    /// An optional filter for a user's username.
+    /// </summary>
+    public string? Username { get; init; }
+}