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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file contains the code snippets included in "Error Handling and Go."
package main
import (
"net/http"
"text/template"
)
type appError struct {
Error error
Message string
Code int
}
// STOP OMIT
type appHandler func(http.ResponseWriter, *http.Request) *appError
func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if e := fn(w, r); e != nil { // e is *appError, not error.
c := appengine.NewContext(r)
c.Errorf("%v", e.Error)
http.Error(w, e.Message, e.Code)
}
}
// STOP OMIT
func viewRecord(w http.ResponseWriter, r *http.Request) *appError {
c := appengine.NewContext(r)
key := datastore.NewKey(c, "Record", r.FormValue("id"), 0, nil)
record := new(Record)
if err := datastore.Get(c, key, record); err != nil {
return &appError{err, "Record not found", 404}
}
if err := viewTemplate.Execute(w, record); err != nil {
return &appError{err, "Can't display record", 500}
}
return nil
}
// STOP OMIT
func init() {
http.Handle("/view", appHandler(viewRecord))
}
type ap struct{}
func (ap) NewContext(*http.Request) *ctx { return nil }
type ctx struct{}
func (*ctx) Errorf(string, ...interface{}) {}
var appengine ap
type ds struct{}
func (ds) NewKey(*ctx, string, string, int, *int) string { return "" }
func (ds) Get(*ctx, string, *Record) error { return nil }
var datastore ds
type Record struct{}
var viewTemplate *template.Template
func main() {}
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