expose current version to the api as well

Author: GreemDev

src/Client/UpdateClient/UpdateClient.Versioning.cs

@@ -25,6 +25,28 @@ public partial class UpdateClient
 
         return await resp.Content.ReadAsStringAsync();
     }
+    
+    /// <summary>
+    ///     Query the current version for a release channel.
+    /// </summary>
+    /// <param name="rc">The target release channel.</param>
+    /// <returns>Plain version string if request success; null if non-200 series HTTP status code or if not configured to support this endpoint.</returns>
+    public async Task<string?> GetCurrentVersionAsync(ReleaseChannel rc)
+    {
+        var httpRequest = new HttpRequestMessage(HttpMethod.Get,
+            $"{Constants.FullRouteName_Api_Versioning}/{Constants.RouteName_Api_Versioning_GetCurrentVersion}?rc={rc.QueryStringValue}");
+
+        var resp = await _http.SendAsync(httpRequest);
+
+        if (!resp.IsSuccessStatusCode)
+        {
+            Log("Getting current version failed: received status code {0}; content body: {1}",
+                [Enum.GetName(resp.StatusCode) ?? $"{(int)resp.StatusCode}", await resp.Content.ReadAsStringAsync()]);
+            return null;
+        }
+
+        return await resp.Content.ReadAsStringAsync();
+    }
 
     /// <summary>
     ///     Requests the configured update server to increment its version for a given release channel.

src/Common/Constants.cs

@@ -20,6 +20,7 @@ internal static class Constants
     public const string RouteName_Api_Version = "version";
     public const string RouteName_Api_Versioning = "versioning";
     public const string RouteName_Api_Versioning_GetNextVersion = "next";
+    public const string RouteName_Api_Versioning_GetCurrentVersion = "current";
     public const string RouteName_Api_Versioning_AdvanceVersion = "advance";
     public const string RouteName_Api_Versioning_IncrementVersion = "increment";
     public const string RouteName_Api_Meta = "meta";

src/Server/Controllers/Api/v1/Admin/VersioningController.cs

@@ -34,6 +34,24 @@ public async Task<ActionResult<string>> GetNext([FromQuery] string rc)
         return Ok(versionProviderService.GetNextVersion(releaseChannel));
     }
 
+    [HttpGet(Constants.RouteName_Api_Versioning_GetCurrentVersion)]
+    public async Task<ActionResult<string>> GetCurrent([FromQuery] string rc)
+    {
+        if (!rc.TryParseAsReleaseChannel(out var releaseChannel))
+            return Problem(
+                $"Unknown release channel '{rc}'; valid are '{Constants.StableRoute}' and '{Constants.CanaryRoute}'",
+                statusCode: 404);
+
+        var versionProviderService = HttpContext.RequestServices
+            .GetService<VersionProviderService>();
+
+        if (versionProviderService is null)
+            return Problem("This instance of Ryubing UpdateServer is not configured to support this endpoint.",
+                statusCode: 418);
+
+        return Ok(versionProviderService.GetCurrentVersion(releaseChannel));
+    }
+
     [HttpPatch(Constants.RouteName_Api_Versioning_IncrementVersion)]
     [ProducesResponseType(StatusCodes.Status401Unauthorized)]
     [ProducesResponseType(StatusCodes.Status418ImATeapot)]