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package main |
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import ( |
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"io/ioutil" |
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"log" |
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"strings" |
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"net/http" |
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"encoding/json" |
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"fmt" |
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"time" |
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"github.com/codegangsta/negroni" |
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"github.com/dgrijalva/jwt-go" |
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"os" |
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) |
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//RSA KEYS AND INITIALISATION |
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const ( |
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privKeyPath = "path/to/keys/app.rsa" |
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pubKeyPath = "path/to/keys/app.rsa.pub" |
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) |
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var VerifyKey, SignKey []byte |
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func initKeys(){ |
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var err error |
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SignKey, err = ioutil.ReadFile(privKeyPath) |
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if err != nil { |
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log.Fatal("Error reading private key") |
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return |
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} |
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VerifyKey, err = ioutil.ReadFile(pubKeyPath) |
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if err != nil { |
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log.Fatal("Error reading public key") |
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return |
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} |
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} |
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//STRUCT DEFINITIONS |
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type UserCredentials struct { |
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Username string `json:"username"` |
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Password string `json:"password"` |
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} |
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type User struct { |
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ID int `json:"id"` |
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Name string `json:"name"` |
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Username string `json:"username"` |
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Password string `json:"password"` |
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} |
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type Response struct { |
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Data string `json:"data"` |
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} |
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type Token struct { |
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Token string `json:"token"` |
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} |
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//SERVER ENTRY POINT |
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func StartServer(){ |
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//PUBLIC ENDPOINTS |
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http.HandleFunc("/login", LoginHandler) |
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//PROTECTED ENDPOINTS |
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http.Handle("/resource/", negroni.New( |
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negroni.HandlerFunc(ValidateTokenMiddleware), |
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negroni.Wrap(http.HandlerFunc(ProtectedHandler)), |
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)) |
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log.Println("Now listening...") |
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http.ListenAndServe(":8000", nil) |
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} |
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func main() { |
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initKeys() |
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StartServer() |
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} |
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////////////////////////////////////////// |
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/////////////ENDPOINT HANDLERS//////////// |
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///////////////////////////////////////// |
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func ProtectedHandler(w http.ResponseWriter, r *http.Request){ |
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response := Response{"Gained access to protected resource"} |
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JsonResponse(response, w) |
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} |
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func LoginHandler(w http.ResponseWriter, r *http.Request) { |
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var user UserCredentials |
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//decode request into UserCredentials struct |
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err := json.NewDecoder(r.Body).Decode(&user) |
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if err != nil { |
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w.WriteHeader(http.StatusForbidden) |
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fmt.Fprintf(w, "Error in request") |
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return |
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} |
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fmt.Println(user.Username, user.Password) |
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//validate user credentials |
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if strings.ToLower(user.Username) != "alexcons" { |
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if user.Password != "kappa123" { |
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w.WriteHeader(http.StatusForbidden) |
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fmt.Println("Error logging in") |
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fmt.Fprint(w, "Invalid credentials") |
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return |
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} |
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} |
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//create a rsa 256 signer |
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signer := jwt.New(jwt.GetSigningMethod("RS256")) |
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//set claims |
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signer.Claims["iss"] = "admin" |
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signer.Claims["exp"] = time.Now().Add(time.Minute * 20).Unix() |
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signer.Claims["CustomUserInfo"] = struct { |
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Name string |
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Role string |
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}{user.Username, "Member"} |
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tokenString, err := signer.SignedString(SignKey) |
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if err != nil { |
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w.WriteHeader(http.StatusInternalServerError) |
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fmt.Fprintln(w, "Error while signing the token") |
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log.Printf("Error signing token: %v\n", err) |
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} |
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//create a token instance using the token string |
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response := Token{tokenString} |
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JsonResponse(response, w) |
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} |
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//AUTH TOKEN VALIDATION |
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func ValidateTokenMiddleware(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) { |
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//validate token |
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token, err := jwt.ParseFromRequest(r, func(token *jwt.Token) (interface{}, error){ |
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return VerifyKey, nil |
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}) |
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if err == nil { |
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if token.Valid{ |
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next(w, r) |
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} else { |
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w.WriteHeader(http.StatusUnauthorized) |
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fmt.Fprint(w, "Token is not valid") |
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} |
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} else { |
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w.WriteHeader(http.StatusUnauthorized) |
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fmt.Fprint(w, "Unauthorised access to this resource") |
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} |
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} |
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//HELPER FUNCTIONS |
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func JsonResponse(response interface{}, w http.ResponseWriter) { |
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json, err := json.Marshal(response) |
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if err != nil { |
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http.Error(w, err.Error(), http.StatusInternalServerError) |
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return |
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} |
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w.WriteHeader(http.StatusOK) |
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w.Header().Set("Content-Type", "application/json") |
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w.Write(json) |
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} |
thealexcons created this gist