Extends OpenAPISpecGeneratorPlugin to include default values for parameters (#1323)

* refactor: Fix null exception as key cannot be null

* feat: Add IncludeParameters property to list params be included with their values as defaults

* refactor: Use deconstruction

* feat: Add matched IncludeParameters into spec with their default values

* Fix includeParameters description

* Update openapispecgeneratorplugin.schema.json

Co-authored-by: Copilot <[email protected]>

* fix: Update null check to use pattern matching for query parameters

---------

Co-authored-by: Waldek Mastykarz <[email protected]>
Co-authored-by: Copilot <[email protected]>

Author: 3 people

DevProxy.Plugins/Generation/OpenApiSpecGeneratorPlugin.cs

@@ -9,6 +9,7 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
 using Microsoft.OpenApi;
+using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Extensions;
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Models;
@@ -56,6 +57,7 @@ public sealed class OpenApiSpecGeneratorPluginConfiguration
     public SpecFormat SpecFormat { get; set; } = SpecFormat.Json;
     public SpecVersion SpecVersion { get; set; } = SpecVersion.v3_0;
     public bool IgnoreResponseTypes { get; set; }
+    public IEnumerable<string> IncludeParameters { get; set; } = [];
 }
 
 public sealed class OpenApiSpecGeneratorPlugin(
@@ -319,21 +321,35 @@ private void SetParametersFromQueryString(OpenApiOperation operation, NameValueC
         }
 
         Logger.LogDebug("  Processing query string parameters...");
-#pragma warning disable IDE0004
-        var dictionary = (queryParams.AllKeys as string[]).ToDictionary(k => k, k => queryParams[k] as object);
-#pragma warning restore IDE0004
+        var dictionary = queryParams.AllKeys
+            .Where(k => k is not null).Cast<string>()
+            .ToDictionary(k => k, k => queryParams[k] as object);
 
-        foreach (var parameter in dictionary)
+        foreach (var (key, value) in dictionary)
         {
-            operation.Parameters.Add(new()
+            var isRequired = Configuration.IncludeParameters.Any(p => string.Equals(p, key, StringComparison.Ordinal));
+
+            OpenApiParameter parameter = new()
             {
-                Name = parameter.Key,
+                Name = key,
                 In = ParameterLocation.Query,
-                Required = false,
+                Required = isRequired,
                 Schema = new() { Type = "string" }
-            });
-            Logger.LogDebug("    Added query string parameter {ParameterKey}", parameter.Key);
+            };
+            SetParameterDefault(parameter, value);
+
+            operation.Parameters.Add(parameter);
+            Logger.LogDebug("    Added query string parameter {ParameterKey}", key);
+        }
+    }
+
+    private static void SetParameterDefault(OpenApiParameter parameter, object? value)
+    {
+        if (!parameter.Required || value is null)
+        {
+            return;
         }
+        parameter.Schema.Default = new OpenApiString(value.ToString());
     }
 
     private void SetResponseFromSession(OpenApiOperation operation, Response response)

schemas/v1.0.0/openapispecgeneratorplugin.schema.json

@@ -30,6 +30,14 @@
         "Yaml"
       ],
       "description": "Specifies the format of the generated OpenAPI spec. Allowed values: 'Json' or 'Yaml'. Default: 'Json'."
+    },
+    "includeParameters": {
+      "type": "array",
+      "items": {
+        "type": "string"
+      },
+      "description": "Defines the list of query string parameters to include in the generated OpenAPI spec, along with their default values. Default: []",
+      "default": []
     }
   },
   "additionalProperties": false