grpc-ecosystem/grpc-gateway · error

invalid header parameter type: %+v

Error message

invalid header parameter type: %+v

What it means

Schema-mapping error in genopenapi renderServices: an openapi_options HeaderParameter has a type enum value outside the known STRING/NUMBER/INTEGER/BOOLEAN set, so the generator cannot map it to an OpenAPI parameter type. The failing input is the header parameter option with the unsupported type value.

Source

Thrown at protoc-gen-openapiv2/internal/genopenapi/template.go:2190

							param := openapiParameterObject{
								In:          "header",
								Name:        header.Name,
								Description: header.Description,
								Required:    header.Required,
								Format:      header.Format,
							}

							switch header.Type {
							case openapi_options.HeaderParameter_STRING:
								param.Type = "string"
							case openapi_options.HeaderParameter_NUMBER:
								param.Type = "number"
							case openapi_options.HeaderParameter_INTEGER:
								param.Type = "integer"
							case openapi_options.HeaderParameter_BOOLEAN:
								param.Type = "boolean"
							default:
								return fmt.Errorf("invalid header parameter type: %+v", header.Type)
							}

							operationObject.Parameters = append(operationObject.Parameters, param)
						}
					}

					// TODO(ivucica): add remaining fields of operation object
				}

				switch b.HTTPMethod {
				case "DELETE":
					pathItemObject.Delete = operationObject
				case "GET":
					pathItemObject.Get = operationObject
				case "POST":
					pathItemObject.Post = operationObject
				case "PUT":
					pathItemObject.Put = operationObject

View on GitHub (pinned to a58a4436a3)

Solutions

1. Set the header parameter's type to one of STRING, NUMBER, INTEGER, or BOOLEAN in the openapiv2 options.
2. Regenerate if a newer plugin supports additional header types.

When it happens

Trigger: Thrown at protoc-gen-openapiv2/internal/genopenapi/template.go:2190 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grpc-ecosystem/grpc-gateway@a58a4436a3 (2026-09-02). Data as JSON: /api/errors/851fe7b93f694d11. Report an issue: GitHub.