Get existing gorilla sessions

I am trying to set a gorilla session and then retreive the value again. I am doing the following just as a test.

//create session and store in http Cookies
session, err := store.Get(req, "session")
if err != nil {
	errCode = http.StatusInternalServerError
	return
}

//save a value
session.Values["user_id"] = userTuple.UserId
err = session.Save(req, w)
if err != nil {
	errCode = http.StatusInternalServerError
	return
}

//try to get the same session that was just created
nr := http.Request{Header: w.Header()}
session, err = store.Get(&nr, "session")
if err != nil {
	errCode = http.StatusInternalServerError
	return
} else if session.IsNew {
	log.Println("New session created instead of old one.")
}

This is a snippet out of a larger HTTP handler. But the relavent parts are posted and the the second call to store.Get() is not returning an existing session, but a brand new one. Hence, when the handler this code is in is executed, the log statements is printed to console.

Why am I getting a new session in this case instead of the one I had already created and saved?

I feel like I already answered this question. You are misusing this pkg. Behind the scenes the context package is used to store state for a request, by creating a new, incomplete http.Request, the context package returns an empty state with no session info.

check out this code to see what i'm talking about.

The following code won't work because the actual season values are saved inside the cookie that is written to ResponseWriter, copying:

nr := http.Request{Header: w.Header()}
session, err = store.Get(&nr, "session")

The code for saving is https://github.com/gorilla/sessions/blob/master/store.go#L101

And it stores season id based on the request pointer for some odd reason, check https://github.com/gorilla/context/blob/master/context.go#L31.

You'd have to reload the page to access the new cookies.

I don't think this has anything to do with gorilla/sessions, but with how you're constructing that request struct.

When you call session.Save(r, w), w.Header() will now contain a map like the following:

map[string][]string{
  // ...
  "Set-Cookie": []string{/* ... */}
  // ...
}

You should replace that Set-Cookie header with a Cookie header - otherwise, gorilla/sessions won't see any cookies in the request, and will assume that the request didn't have a session cookie.

But yeah, like @OneOfOne mentioned, you'd usually just call http.Redirect and have the browser do that Set-Cookie-Cookie replacement for you.