Middleware
A middleware wraps an HTTP request to add additional logic before or after the request has been handled. A middleware can be any struct that implements the chttp.Middleware interface.
type Middleware interface {
Handle(next http.Handler) http.Handler
}
If you have a simple function, you can use the chttp.HandleMiddleware function to create a middleware out of it.

Request Logger Middleware

This is an example middleware that logs each incoming HTTP request.
func NewRequestLoggerMiddleware(logger clogger.Logger) *RequestLoggerMiddleware {
return &RequestLoggerMiddleware{logger: logger}
}
type RequestLoggerMiddleware struct {
logger clogger.Logger
}
func (mw *RequestLoggerMiddleware) Handle(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
mw.logger.WithTags(map[string]interface{}{
"url": r.URL.Path,
"method": r.Method
}).Info("Handling HTTP Request..")
next.ServeHTTP(w, r)
}
}

Route Middlewares

The chttp.Route struct accepts a list of middlewares that will be executed, in order, for each request that matches the route.
func (ro *Router) Routes() []chttp.Route {
return []chttp.Route{
{
Path: "/rockets/{id}/launch",
Methods: []string{http.MethodPost},
Middlewares: []chttp.Middleware{ro.requestLoggerMW},
Handler: ro.HandleRocketLaunch,
},
}
}

Global Middlewares

In pkg/app/handler.go, you can pass a list of middlewares to the chttp.NewHandler function. These middlewares will be executed on all requests handled by this handler.
pkg/app/handler.go
func NewHTTPHandler(p NewHTTPHandlerParams) http.Handler {
return chttp.NewHandler(chttp.NewHandlerParams{
GlobalMiddlewares: []chttp.Middleware{
p.RequestLoggerMW,
},
...
})
}
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