A Simple Login System - Howto

Report Issue Edit Page A Simple Login System Note This example is based on part of the transactions in v0.9 blogpost. Error checking has been omitted for brevity. Schema is assumed to be: // @upsert directive is important to detect conflicts. email: string @index(exact) @upsert . # @index(hash) would also work pass: password . // Create a new transaction. The deferred call to Discard // ensures that server-side resources are cleaned up. txn := client.NewTxn() defer txn.Discard(ctx) // Create and execute a query to looks up an email and checks if the password // matches. q := fmt.Sprintf(` { login_attempt(func: eq(email, %q)) { checkpwd(pass, %q) } } `, email, pass) resp, err := txn.Query(ctx, q) // Unmarshal the response into a struct. It will be empty if the email couldn't // be found. Otherwise it will contain a bool to indicate if the password matched. var login struct { Account []struct { Pass []struct { CheckPwd bool `json:"checkpwd"` } `json:"pass"` } `json:"login_attempt"` } err = json.Unmarshal(resp.GetJson(), &login); err != nil { // Now perform the upsert logic. if len(login.Account) == 0 { fmt.Println("Account doesn't exist! Creating new account.") mu := &protos.Mutation{ SetJson: []byte(fmt.Sprintf(`{ "email": %q, "pass": %q }`, email, pass)), } _, err = txn.Mutate(ctx, mu) // Commit the mutation, making it visible outside of the transaction. err = txn.Commit(ctx) } else if login.Account[0].Pass[0].CheckPwd { fmt.Println("Login successful!") } else { fmt.Println("Wrong email or password.") }

This is a companion discussion topic for the original entry at https://dgraph.io/docs/howto/login-system/