/
writer.go
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/
writer.go
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// Copyright 2021 SpotHero
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package writer
import (
"net/http"
"github.com/gorilla/mux"
)
// StatusRecorder wraps the http ResponseWriter, allowing additional instrumentation and metrics
// capture before the response is returned to the client.
type StatusRecorder struct {
http.ResponseWriter
StatusCode int
}
// WriteHeader implements the http ResponseWriter WriteHeader interface. This function acts as a
// middleware which captures the StatusCode on the StatusRecorder and then delegates the actual
// work of writing the header to the underlying http ResponseWriter.
func (sr *StatusRecorder) WriteHeader(code int) {
sr.StatusCode = code
sr.ResponseWriter.WriteHeader(code)
}
// StatusRecorderMiddleware wraps the http.ResponseWriter with StatusRecorder so that downstream middlewares can
// utilize the outcome status code after the response completes. This middleware should be attached as early as
// possible.
func StatusRecorderMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
wrappedWriter := &StatusRecorder{ResponseWriter: w, StatusCode: http.StatusOK}
next.ServeHTTP(wrappedWriter, r)
})
}
// FetchRoutePathTemplate extracts the path template from a given request, or emptry string if none
// could be found.
func FetchRoutePathTemplate(r *http.Request) string {
routePath := ""
if route := mux.CurrentRoute(r); route != nil {
routePath, _ = route.GetPathTemplate()
}
return routePath
}