Middlewares

caution

The middleware API is experimental and may change in the future.

info

If you are looking for a way how to use net/http middlewares with ogen, check out the Using net/http middlewares section.

ogen provides a high-level middleware API that allows you to perform custom logic before and after the request is handled by the server.

Unlike the net/http middleware, ogen middleware gets an already parsed and validated request, and must return a typed response.

package middlewares

import (
    "go.uber.org/zap"
    "go.uber.org/zap/zapcore"

    "github.com/ogen-go/ogen/middleware"
)

func Logging(logger *zap.Logger) middleware.Middleware {
    return func(
        req middleware.Request,
        next func(req middleware.Request) (middleware.Response, error),
    ) (middleware.Response, error) {
        logger := logger.With(
            zap.String("operation", req.OperationName),
            zap.String("operationId", req.OperationID),
        )
        logger.Info("Handling request")
        resp, err := next(req)
        if err != nil {
            logger.Error("Fail", zap.Error(err))
        } else {
            var fields []zapcore.Field
            // Some response types may have a status code.
            // ogen provides a getter for it.
            //
            // You can write your own interface to match any response type.
            if tresp, ok := resp.Type.(interface{ GetStatusCode() int }); ok {
                fields = []zapcore.Field{
                    zap.Int("status_code", tresp.GetStatusCode()),
                }
            }
            logger.Info("Success", fields...)
        }
        return resp, err
    }
}