ContainerImage.Pinniped/internal/httputil/httperr/httperr.go

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// Copyright 2020 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package httperr contains some helpers for nicer error handling in http.Handler implementations.
package httperr
import (
"fmt"
"net/http"
)
// Responder represents an error that can emit a useful HTTP error response to an http.ResponseWriter.
type Responder interface {
error
Respond(http.ResponseWriter)
}
// New returns a Responder that emits the given HTTP status code and message.
func New(code int, msg string) error {
return httpErr{code: code, msg: msg}
}
// Newf returns a Responder that emits the given HTTP status code and fmt.Sprintf formatted message.
func Newf(code int, format string, args ...interface{}) error {
return httpErr{code: code, msg: fmt.Sprintf(format, args...)}
}
// Wrap returns a Responder that emits the given HTTP status code and message, and also wraps an internal error.
func Wrap(code int, msg string, cause error) error {
return httpErr{code: code, msg: msg, cause: cause}
}
type httpErr struct {
code int
msg string
cause error
}
func (e httpErr) Error() string {
if e.cause != nil {
return fmt.Sprintf("%s: %v", e.msg, e.cause)
}
return e.msg
}
func (e httpErr) Respond(w http.ResponseWriter) {
// http.Error is important here because it prevents content sniffing by forcing text/plain.
http.Error(w, http.StatusText(e.code)+": "+e.msg, e.code)
}
func (e httpErr) Unwrap() error {
return e.cause
}
// HandlerFunc is like http.HandlerFunc, but with a function signature that allows easier error handling.
type HandlerFunc func(http.ResponseWriter, *http.Request) error
func (f HandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch err := f(w, r).(type) {
case nil:
return
case Responder:
err.Respond(w)
default:
http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
}
}