caddy/modules/caddyhttp/staticerror.go

116 lines
3.3 KiB
Go

// Copyright 2015 Matthew Holt and The Caddy Authors
//
// 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 caddyhttp
import (
"fmt"
"net/http"
"strconv"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
)
func init() {
caddy.RegisterModule(StaticError{})
}
// StaticError implements a simple handler that returns an error.
// This handler returns an error value, but does not write a response.
// This is useful when you want the server to act as if an error
// occurred; for example, to invoke your custom error handling logic.
//
// Since this handler does not write a response, the error information
// is for use by the server to know how to handle the error.
type StaticError struct {
// The error message. Optional. Default is no error message.
Error string `json:"error,omitempty"`
// The recommended HTTP status code. Can be either an integer or a
// string if placeholders are needed. Optional. Default is 500.
StatusCode WeakString `json:"status_code,omitempty"`
}
// CaddyModule returns the Caddy module information.
func (StaticError) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.handlers.error",
New: func() caddy.Module { return new(StaticError) },
}
}
// UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax:
//
// error [<matcher>] <status>|<message> [<status>] {
// message <text>
// }
//
// If there is just one argument (other than the matcher), it is considered
// to be a status code if it's a valid positive integer of 3 digits.
func (e *StaticError) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
d.Next() // consume directive name
args := d.RemainingArgs()
switch len(args) {
case 1:
if len(args[0]) == 3 {
if num, err := strconv.Atoi(args[0]); err == nil && num > 0 {
e.StatusCode = WeakString(args[0])
break
}
}
e.Error = args[0]
case 2:
e.Error = args[0]
e.StatusCode = WeakString(args[1])
default:
return d.ArgErr()
}
for d.NextBlock(0) {
switch d.Val() {
case "message":
if e.Error != "" {
return d.Err("message already specified")
}
if !d.AllArgs(&e.Error) {
return d.ArgErr()
}
default:
return d.Errf("unrecognized subdirective '%s'", d.Val())
}
}
return nil
}
func (e StaticError) ServeHTTP(w http.ResponseWriter, r *http.Request, _ Handler) error {
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
statusCode := http.StatusInternalServerError
if codeStr := e.StatusCode.String(); codeStr != "" {
intVal, err := strconv.Atoi(repl.ReplaceAll(codeStr, ""))
if err != nil {
return Error(http.StatusInternalServerError, err)
}
statusCode = intVal
}
return Error(statusCode, fmt.Errorf("%s", repl.ReplaceKnown(e.Error, "")))
}
// Interface guard
var (
_ MiddlewareHandler = (*StaticError)(nil)
_ caddyfile.Unmarshaler = (*StaticError)(nil)
)