Gorilla/sessions Study Notes

This is a creation in Article, where the information may have evolved or changed.

Simple examples

• First Call Newcookiestore to initialize a store and pass in a secret key to authenticate the session.
• In Handler , call store. Get () gets a session that already exists or (if it does not exist) creates a new one.
• Set the sesssion. value in values, session. Values are map[interface{}]interface{} types.
• Call session. Save () saves the session to the response.

  In the actual project, the session is called. Save (R,W) needs to detect the returned error and handle it.
  The Save () method must be called before writing to response, or the session cookie will not be sent to the client.

var store = sessions. Newcookiestore ([]byte ("Something-very-secret")) func MyHandler (w http. Responsewriter, R *http. Request) {session, Err: = store. Get (R, "S1") if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} FMT. PRINTLN (session) session. values["name"] = "Kingeastensun" session. Save (R, W)}func Multisessionhandler (w http. Responsewriter, R *http. Request) {session1, err: = store. Get (R, "S1") if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} FMT. Println (Session1) session1. values["name"] = "Kingeastensun" Session2, err: = store. Get (R, "S2") if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} FMT. Println (Session2) session2. values["name"] = "Kingeastensunyx" sessions. Save (R, W)}func main () {routes: = Mux. Newrouter () routes. Handlefunc ("/session", MyHandler) routes. Handlefunc ("/musession", MulTisessionhandler) http. Handle ("/", routes) HTTP. Listenandserve (": 8080", nil)}

Multi-session Processing

See Multisessionhandler, when saving, call

sessions.Save(r, w)

You can save Session1 and session2 at the same time.

Complex structural data

Type Mperson struct {FirstName string LastName string e-mail string age Int}type M Map[string]inter Face{}func init () {FMT. Println ("Init") gob. Register (&mperson{}) gob. Register (&m{})}var store = sessions. Newcookiestore ([]byte ("Something-very-secret")) Func Setmhandler (w http. Responsewriter, R *http. Request) {session, Err: = store. Get (R, "M") if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} MS: = Mperson{firstname: "King", LastName: "Eastersun"} session. Values["MS"] = ms M: = Make (map[string]interface{}) m["name"] = "Kingeasternsun" session. values["M"] = m err = session. Save (R, W) if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return}}func Getmhandler (w http. Responsewriter, R *http. Request) {session, Err: = store. Get (R, "M") if err! = Nil {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} MS: = Session. Values["MS"]//var person = &mperson{} if person, OK: = Ms. (*mperson); OK {fmt. PRINTLN (person)} else {http. Error (W, err. Error (), HTTP. Statusinternalservererror) return} m: = Session. values[' m ']//var mmap = m{} if mmap, OK: = M. (*m); OK {fmt. Println (mmap)} else {http. Error (W, err. Error (), HTTP. STATUSINTERNALSERVERERROR) return}}func main () {//FMT. Println (String (Securecookie. Generaterandomkey (+))//FMT. Println (String (Securecookie. Generaterandomkey (+)) Routes: = Mux. Newrouter () routes. Handlefunc ("/setm", Setmhandler) routes. Handlefunc ("/getm", Getmhandler) http. Handle ("/", routes) HTTP. Listenandserve (": 8080", nil)}

Error when setting

Browser error

The problem is

    m := make(map[string]interface{})    m["name"] = "kingeasternsun"

map[string]interface{} is not registered to the session, only Mpersion and M are registered in Init, although M is defined in the following way:

type M map[string]interface{}

But in Golang, this way of declaring, M and map[string]interface{} belong to different types.
Modify the Setmhandler as follows:

func SetMHandler(w http.ResponseWriter, r *http.Request) {    session, err := store.Get(r, "m")    if err != nil {        http.Error(w, err.Error(), http.StatusInternalServerError)        return    }    ms := MPerson{FirstName: "king", LastName: "eastersun"}    session.Values["ms"] = ms    m := M{}    m = make(map[string]interface{})    m["name"] = "kingeasternsun"    session.Values["m"] = m    err = session.Save(r, w)    if err != nil {        http.Error(w, err.Error(), http.StatusInternalServerError)        return    }}

Cookie Set Success

Cookie Set Success

Failed to get cookie

Double quotes are mistakenly written in the code as single quotes

    m := session.Values['m']    m := session.Values["m"]

Get Cookie Success

Replacement of key

In the project you may encounter the need to replace key, sessions can also be easily implemented

var store = sessions.NewCookieStore(    []byte("new-authentication-key"),    []byte("new-encryption-key"),    []byte("old-authentication-key"),    []byte("old-encryption-key"),)

Store through this method of creation, the new sessions will be created by a key pair, while the old sessions is read by the old key pair.

For all key pair, encryption key is optional, and if empty or omitted, it is not good to encrypt.

Postscript

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