Define and use an auth context structure

auth/imap.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"context"
 	"log"
 	"net/http"
 
@@ -54,6 +55,12 @@ func (prov *IMAPProvider) doAuth(next http.Handler,
 		return
 	}
 
+	authCtx := AuthContext{
+		AuthMethod: "imap",
+		UserName:   user,
+	}
+	ctx := context.WithValue(r.Context(), AuthCtxKey, &authCtx)
+	r = r.WithContext(ctx)
 	next.ServeHTTP(w, r)
 }