openapi3filter: apply default values of an array in a query param with exploded = false (#1054)

* issue1053: apply default values of an array in a query param with exploded set to false

* issue1053: apply default values of an array in a query param with exploded set to false

* issue1053: apply default values of an array in a query param with exploded set to false

* add test case with explode set to true

* refactor code

Author: nhochstr

openapi3filter/issue991_test.go

@@ -9,8 +9,12 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestValidateRequestDefault(t *testing.T) {
-	const spec = `
+func generateSpec(explode bool) string {
+	explodeStr := "false"
+	if explode {
+		explodeStr = "true"
+	}
+	return `
 openapi: 3.0.0
 info:
   title: 'Validator'
@@ -29,6 +33,7 @@ components:
       in: query
       name: type
       required: false
+      explode: ` + explodeStr + `
       description: Type parameter
       schema:
         type: array
@@ -43,9 +48,9 @@ components:
             - B
             - C
 `
+}
 
-	router := setupTestRouter(t, spec)
-
+func TestValidateRequestDefault(t *testing.T) {
 	type args struct {
 		url      string
 		expected []string
@@ -55,42 +60,57 @@ components:
 		args                 args
 		expectedModification bool
 		expectedErr          error
+		spec                 string
 	}{
 		{
-			name: "Valid request without type parameters set",
+			name: "Valid request without type parameters set and explode is false",
 			args: args{
 				url:      "/category",
-				expected: []string{"A", "B", "C"},
+				expected: []string{"A,B,C"},
 			},
 			expectedModification: false,
 			expectedErr:          nil,
+			spec:                 generateSpec(false),
 		},
 		{
-			name: "Valid request with 1 type parameters set",
+			name: "Valid request with 1 type parameters set and explode is false",
 			args: args{
 				url:      "/category?type=A",
 				expected: []string{"A"},
 			},
 			expectedModification: false,
 			expectedErr:          nil,
+			spec:                 generateSpec(false),
 		},
 		{
-			name: "Valid request with 2 type parameters set",
+			name: "Valid request with 2 type parameters set and explode is false",
 			args: args{
 				url:      "/category?type=A&type=C",
 				expected: []string{"A", "C"},
 			},
 			expectedModification: false,
 			expectedErr:          nil,
+			spec:                 generateSpec(false),
 		},
 		{
-			name: "Valid request with 1 type parameters set out of enum",
+			name: "Valid request with 1 type parameters set out of enum and explode is false",
 			args: args{
 				url:      "/category?type=X",
 				expected: nil,
 			},
 			expectedModification: false,
 			expectedErr:          &RequestError{},
+			spec:                 generateSpec(false),
+		},
+		{
+			name: "Valid request without type parameters set and explode is true",
+			args: args{
+				url:      "/category",
+				expected: []string{"A", "B", "C"},
+			},
+			expectedModification: false,
+			expectedErr:          nil,
+			spec:                 generateSpec(true),
 		},
 	}
 	for _, tc := range tests {
@@ -99,6 +119,7 @@ components:
 			req, err := http.NewRequest(http.MethodGet, tc.args.url, nil)
 			require.NoError(t, err)
 
+			router := setupTestRouter(t, tc.spec)
 			route, pathParams, err := router.FindRoute(req)
 			require.NoError(t, err)
 

openapi3filter/validate_request.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"sort"
+	"strings"
 
 	"github.com/getkin/kin-openapi/openapi3"
 )
@@ -111,15 +112,26 @@ func appendToQueryValues[T any](q url.Values, parameterName string, v []T) {
 	}
 }
 
+func joinValues(values []any, sep string) string {
+	strValues := make([]string, len(values))
+	for i, v := range values {
+		strValues[i] = fmt.Sprintf("%v", v)
+	}
+	return strings.Join(strValues, sep)
+}
+
 // populateDefaultQueryParameters populates default values inside query parameters, while ensuring types are respected
-func populateDefaultQueryParameters(q url.Values, parameterName string, value any) {
+func populateDefaultQueryParameters(q url.Values, parameterName string, value any, explode bool) {
 	switch t := value.(type) {
 	case []any:
-		appendToQueryValues(q, parameterName, t)
+		if explode {
+			appendToQueryValues(q, parameterName, t)
+		} else {
+			q.Add(parameterName, joinValues(t, ","))
+		}
 	default:
 		q.Add(parameterName, fmt.Sprintf("%v", value))
 	}
-
 }
 
 // ValidateParameter validates a parameter's value by JSON schema.
@@ -175,7 +187,8 @@ func ValidateParameter(ctx context.Context, input *RequestValidationInput, param
 				// Next check `parameter.Required && !found` will catch this.
 			case openapi3.ParameterInQuery:
 				q := req.URL.Query()
-				populateDefaultQueryParameters(q, parameter.Name, value)
+				explode := parameter.Explode != nil && *parameter.Explode
+				populateDefaultQueryParameters(q, parameter.Name, value, explode)
 				req.URL.RawQuery = q.Encode()
 			case openapi3.ParameterInHeader:
 				req.Header.Add(parameter.Name, fmt.Sprintf("%v", value))