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