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I set a cookie from javascript such as:
setCookie("appointment", JSON.stringify({
appointmentDate: selectedDay.date,
appointmentStartMn: appointment.mnRange[0],
appointmentId: appointment.id || 0,
appointmentUserId: appointment.user.id || 0
})
);
After cookie is set I want to redirect the user to a booking page:
window.location.href = "https://localhost:8080/booking/"
The setCookie function:
function setCookie(cookieName, cookieValue) {
document.cookie = `${cookieName}=${cookieValue};secure;`;
}
I'd like to retrieve that cookie from my go backend but I can't figure out how to do this. I've read about this question since I've never used cookies before but the answers seems to tell that I don't have to do much aside from setting document.cookie.
In my browser storage I can see the cookie is indeed set as expected.
In my Go back end I want to print the cookie:
r.HandleFunc("/booking/", handler.serveTemplate)
func (handler *templateHandler) serveTemplate(w http.ResponseWriter, r *http.Request) {
c, err := r.Cookie("appointment")
if err != nil {
fmt.Println(err.Error())
} else {
fmt.Println(c.Value)
}
}
//output http: named cookie not present
What is the specific I am missing ? I think I'm confusing local/http cookie but how to achieve the reading of client set cookies?
UPDATE (see answer for more)
It has nothing to do with golang. My:
appointmentDate: selectedDay.date
What formatted as 2019-01-01 and - is not a valid character that can be send to the backend. It worked into my browser, but it needs to be URI encoded to be passed.
So this did the trick:
`${cookieName}=${encodeURIComponent(cookieValue)};secure;` + "path=/";`
And in go (didn't catch err here to save space):
cookie, _ := r.Cookie("appointment")
data, _ := url.QueryUnescape(cookie.Value)
795
The cookie value is the exact same string that was specified with Set-Cookie ; there is no further interpretation or encoding of the value. If there are multiple cookies for the given request, then they are separated by a semicolon and space, such as: Cookie: value1; value2; name1=value1.
A better way would be to encode your json into base64 for example. I made a working example...
main.go
package main
import (
"encoding/base64"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
)
// Contains everything about an appointment
type Appointment struct {
Date string `json:"appointmentDate"` // Contains date as string
StartMn string `json:"appointmentStartMn"` // Our startMn ?
ID int `json:"appointmentId"` // AppointmentId
UserID int `json:"appointmentUserId"` // UserId
}
func main() {
handler := http.NewServeMux()
// Main request
handler.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
fmt.Printf("Requested /\r\n")
// set typical headers
w.Header().Set("Content-Type", "text/html")
w.WriteHeader(http.StatusOK)
// Read file
b, _ := ioutil.ReadFile("index.html")
io.WriteString(w, string(b))
})
// booking request
handler.HandleFunc("/booking/", func(w http.ResponseWriter, r *http.Request) {
fmt.Printf("Requested /booking/\r\n")
// set typical headers
w.Header().Set("Content-Type", "text/html")
w.WriteHeader(http.StatusOK)
// Read cookie
cookie, err := r.Cookie("appointment")
if err != nil {
fmt.Printf("Cant find cookie :/\r\n")
return
}
fmt.Printf("%s=%s\r\n", cookie.Name, cookie.Value)
// Cookie data
data, err := base64.StdEncoding.DecodeString(cookie.Value)
if err != nil {
fmt.Printf("Error:", err)
}
var appointment Appointment
er := json.Unmarshal(data, &appointment)
if err != nil {
fmt.Printf("Error: ", er)
}
fmt.Printf("%s, %s, %d, %d\r\n", appointment.Date, appointment.StartMn, appointment.ID, appointment.UserID)
// Read file
b, _ := ioutil.ReadFile("booking.html")
io.WriteString(w, string(b))
})
// Serve :)
http.ListenAndServe(":8080", handler)
}
index.html
<html>
<head>
<title>Your page</title>
</head>
<body>
Setting cookie via Javascript
<script type="text/javascript">
window.onload = () => {
function setCookie(name, value, days) {
var expires = "";
if (days) {
var date = new Date();
date.setTime(date.getTime() + (days*24*60*60*1000));
expires = "; expires=" + date.toUTCString();
}
document.cookie = name + "=" + btoa((value || "")) + expires + "; path=/";
}
setCookie("appointment", JSON.stringify({
appointmentDate: "20-01-2019 13:06",
appointmentStartMn: "1-2",
appointmentId: 2,
appointmentUserId: 3
})
);
document.location = "/booking/";
}
</script>
</body>
booking.html
<html>
<head>
<title>Your page</title>
</head>
<body>
Your booking is okay :)
</body>
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