我感到 panic :
C:\Users\loow\Desktop\USBWebserver v8.5\duplicate_submissions>go run server.go
2015/10/23 13:00:39 http: panic serving [::1]:63867: runtime error: invalid memo
ry address or nil pointer dereference
goroutine 5 [running]:
net/http.(*conn).serve.func1(0xc0820a1810, 0x3b55b8, 0xc082024040)
c:/go/src/net/http/server.go:1287 +0xbc
main.login(0x2990058, 0xc0820d4000, 0xc0820be1c0)
C:/Users/loow/Desktop/USBWebserver v8.5/duplicate_submissions/server.go:
27 +0x5a5
net/http.HandlerFunc.ServeHTTP(0x8326a8, 0x2990058, 0xc0820d4000, 0xc0820be1c0)
c:/go/src/net/http/server.go:1422 +0x41
net/http.(*ServeMux).ServeHTTP(0xc082062360, 0x2990058, 0xc0820d4000, 0xc0820be1
c0)
c:/go/src/net/http/server.go:1699 +0x184
net/http.serverHandler.ServeHTTP(0xc08200c360, 0x2990058, 0xc0820d4000, 0xc0820b
e1c0)
c:/go/src/net/http/server.go:1862 +0x1a5
net/http.(*conn).serve(0xc0820a1810)
c:/go/src/net/http/server.go:1361 +0xbf5
created by net/http.(*Server).Serve
c:/go/src/net/http/server.go:1910 +0x3fd
2015/10/23 13:00:39 http: panic serving [::1]:63868: runtime error: invalid memo
ry address or nil pointer dereference
goroutine 33 [running]:
net/http.(*conn).serve.func1(0xc082114000, 0x3b55b8, 0xc082112000)
c:/go/src/net/http/server.go:1287 +0xbc
main.login(0x2990058, 0xc0821140b0, 0xc0821200e0)
C:/Users/loow/Desktop/USBWebserver v8.5/duplicate_submissions/server.go:
27 +0x5a5
net/http.HandlerFunc.ServeHTTP(0x8326a8, 0x2990058, 0xc0821140b0, 0xc0821200e0)
c:/go/src/net/http/server.go:1422 +0x41
net/http.(*ServeMux).ServeHTTP(0xc082062360, 0x2990058, 0xc0821140b0, 0xc0821200
e0)
c:/go/src/net/http/server.go:1699 +0x184
net/http.serverHandler.ServeHTTP(0xc08200c360, 0x2990058, 0xc0821140b0, 0xc08212
00e0)
c:/go/src/net/http/server.go:1862 +0x1a5
net/http.(*conn).serve(0xc082114000)
c:/go/src/net/http/server.go:1361 +0xbf5
created by net/http.(*Server).Serve
c:/go/src/net/http/server.go:1910 +0x3fd
exit status 2
这段代码:
package main
import(
"fmt"
"net/http"
"html/template"
"log"
"time"
"crypto/md5"
"io"
"strconv"
)
func loginForm(w http.ResponseWriter, r *http.Request){
}
func login(w http.ResponseWriter, r *http.Request){
fmt.Println(r.Method)
if r.Method == "GET"{
cruTime := time.Now().Unix()
h := md5.New()
io.WriteString(h,strconv.FormatInt(cruTime,10))
token := fmt.Sprintf("%x", h.Sum(nil))
fmt.Println(token)
t, err := template.ParseFiles("templates/index.gtpl")
fmt.Println(err.Error())
err = t.Execute(w, token)
fmt.Println(err.Error())
} else{
r.ParseForm()
token := r.Form.Get("token")
if token != ""{
fmt.Println(token)
} else{
fmt.Println("There is no token")
}
fmt.Println("username length: ", len(r.Form["username"][0]))
fmt.Println("username: ", template.HTMLEscapeString(r.Form.Get("username")))
fmt.Println("password: ", template.HTMLEscapeString(r.Form.Get("password")))
template.HTMLEscape(w, []byte(r.Form.Get("username")))
}
}
func main(){
http.HandleFunc("/", loginForm)
http.HandleFunc("/login", login)
err := http.ListenAndServe(":9090", nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
我无法解决它，我尝试了在stackoverflow中找到的所有内容。问题是什么？没有错误，并且惊慌地说是t的问题，err == template.ParseFiles(“templates/index.gtpl”)。
有模板文件:
<input type="checkbox" name="interest" value="football">Football
<input type="checkbox" name="interest" value="basketball">Basketball
<input type="checkbox" name="interest" value="tennis">Tennis
Username: <input type="text" name="username">
Password: <input type="password" name="password">
<input type="hidden" name="token" value="{{.}}">
<input type="submit" value="Login">
最佳答案
紧急堆栈跟踪为您提供以下信息:
2015/10/23 13:00:39 http: panic serving [::1]:63868: runtime error: invalid memory address or nil pointer dereference goroutine 33 [running]:
这意味着您正在尝试访问不存在的内容(无指针)。
那么来自文件的第一行就是这个:
v8.5/duplicate_submissions/server.go:27
那里:
26: t, err := template.ParseFiles("templates/index.gtpl")
27: fmt.Println(err.Error())
28: err = t.Execute(w, token)
这意味着err为零。
解决方案
如果收到错误，则无法继续该过程。这就是为什么您不能仅打印出错误的原因。为了正常停止该过程，您需要返回HTTP状态代码，然后返回。对于上述情况，您可以返回代码500(内部服务器错误)。
t, err := template.ParseFiles("templates/index.gtpl")
if err != nil {
fmt.Println(err) // Ugly debug output
w.WriteHeader(http.StatusInternalServerError) // Proper HTTP response
return
}
对于template.ParseFiles和t.Execute也必须这样做。
顺便说一句，这就是所谓的“逗号确定”模式
关于http - 去http紧急服务，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/33300868/