I'm new to Golang and I'm trying to create a simple web server but I'm getting an error in a GET request. This is the code:
import (
"fmt"
"html/template"
"log"
"net/http"
"strings"
)
func sayhelloName(w http.ResponseWriter, r *http.Request) {
r.ParseForm()
fmt.Println(r.Form) // print information on server side.
fmt.Println("path", r.URL.Path)
fmt.Println("scheme", r.URL.Scheme)
fmt.Println(r.Form["url_long"])
for k, v := range r.Form {
fmt.Println("key:", k)
fmt.Println("val:", strings.Join(v, ""))
}
fmt.Fprintf(w, "Hello Worrld!") // write data to response
}
func login(w http.ResponseWriter, r *http.Request) {
fmt.Println("method:", r.Method) //get request method
if r.Method == "GET" {
t, _ := template.ParseFiles("login.gtpl")
t.Execute(w, nil)
} else {
r.ParseForm()
// logic part of log in
fmt.Println("username:", r.Form["username"])
fmt.Println("password:", r.Form["password"])
}
}
func main() {
http.HandleFunc("/", sayhelloName) // setting router rule
http.HandleFunc("/login", login)
err := http.ListenAndServe(":9090", nil) // setting listening port
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
sayhelloName works but not the login function. This is the output error:
method: GET
2015/10/18 12:46:28 http: panic serving 127.0.0.1:51714: runtime error: invalid memory address or nil pointer dereference
goroutine 6 [running]:
net/http.(*conn).serve.func1(0x1247aa20, 0xaf5380, 0x12490390)
c:/go/src/net/http/server.go:1287 +0xa2
html/template.(*Template).escape(0x0, 0x0, 0x0)
c:/go/src/html/template/template.go:79 +0x37
html/template.(*Template).Execute(0x0, 0xaf54e8, 0x12530080, 0x0, 0x0, 0x0, 0x0)
c:/go/src/html/template/template.go:101 +0x2b
main.login(0xaf5468, 0x12530080, 0x124f6620)
C:/Users/Fabio/Go/hello.go:30 +0x209
net/http.HandlerFunc.ServeHTTP(0x7462e4, 0xaf5468, 0x12530080, 0x124f6620)
c:/go/src/net/http/server.go:1422 +0x34
net/http.(*ServeMux).ServeHTTP(0x1252a020, 0xaf5468, 0x12530080, 0x124f6620)
c:/go/src/net/http/server.go:1699 +0x133
net/http.serverHandler.ServeHTTP(0x12476480, 0xaf5468, 0x12530080, 0x124f6620)
c:/go/src/net/http/server.go:1862 +0x156
net/http.(*conn).serve(0x1247aa20)
c:/go/src/net/http/server.go:1361 +0xc05
created by net/http.(*Server).Serve
c:/go/src/net/http/server.go:1910 +0x343
login.gptl it's in the same folder of source code file
Always handle your errors
t, _ := template.ParseFiles("login.gtpl")
What if this fails? Then t is nil and you get the same error