Flutter authentication with email and password without using Firebase - flutter

Question

Is it possible to achive authentication with email and password in flutter without using firebase? I have searched around Stackoverflow and internet in general and found nothing about this.
I am creating a simple authentication class this is what I have done at the moment:
class User {
bool isAuthenticated = false;
late String userid;
late String username;
late String email;
late DateTime expireDate; // this variable is used to make the user re-authenticate when today is expireDate
User(bool isAuthenticated, String userid, String username, String email) {
this.isAuthenticated = isAuthenticated;
this.userid = userid;
this.username = username;
this.email = email;
this.expireDate = new DateTime.now().add(new Duration(days: 30));
}
}
class Authentication {
Future<User> signin(String email, String password) {}
void signup(String username, String email, String password) {}
}
EDIT #1: I know how to setup a cookie/token based authentication server I have my own repos on that topic: cookie authentication, token authentication but I don't know how to handle the tokens/cookies in flutter.

Answer 1

This answer is based of #edit1. Since you mentioned that you already know how to set up tokens on the server side you're half way done. Here's a few assumptions I'm making, you already know js/php and worked with JSON output, The database already has a column and table that keeps track of sessions and user_id.
Since you know how Cookies are built this should be relatively easy cause i built it around similar architecture. We has to use the local memory that app's provide access to. There are two packages in flutter that allow u to do this, you can use either:
shared_preferences package link
flutter_secure_storage package link
The main difference is if you want to store 'tokens' or data you want secure you would obviously use flutter_secure_storage. I'm going to use this for code example. And yes the data is saved even after the app is closed.
Setting up Tokens(flutter):
Setting up User Class
When using firebase we generally take for granted the user class that comes with flutter_auth but that is basically what we have to build. A user class with all the data u want to store and then a function called authenticate.
class AppUser{
final _storage = new FlutterSecureStorage();
//below class is mentioned in the next part
AuthApi api = new AuthApi();
//constructor
AppUser(){
//ur data;
};
Future<bool> authenticate(email, password) async {
//this is the api mentioned in next part
http.Response res = await api.login(email, password);
Map<String, dynamic> jsonRes = jsonDecode(res.body);
if (jsonRes["error"]) {
return false;
}
_setToken(jsonRes["token"]);
_setUID(jsonRes["user-id"].toString());
_setAuthState(true);
return true;
}
Future<void> _setToken(String val) async {
//how to write to safe_storage
await _storage.write(key: 'token', value: val);
}
Future<void> _setUID(String val) async {
await _storage.write(key: 'user_id', value: val);
}
//you can stream this or use it in a wrapper to help navigate
Future<bool> isAuthenticated() async {
bool authState = await _getAuthState();
return authState;
}
Future<void> _getAuthState() async {
//how to read from safe_storage u can use the same to read token later just replace 'state' with 'token'
String myState = (await _storage.read(key: 'state')).toString();
//returns boolean true or false
return myState.toLowerCase() == 'true';
}
Future<void> _setAuthState(bool liveAuthState) async {
await _storage.write(key: 'state', value: liveAuthState.toString());
}
}
and assuming ur going to authenticate on a button press so it would look like
onPressed(){
AuthUser user = new AuthUser();
if(user.authenticate(email, password)){
//if logged in. Prolly call Navigator.
}else{
//handle error
}
}
Setting up api calls
Oka so this is calling a Node express API, and the json output looks like
//if successful
{"status":200, "error": false, "token": "sha256token", "user-id": "uid"}
we need to create a class that will give us an output for making this call hence the AuthApi class
class AuthApi {
//this is the login api and it returns the above JSON
Future<http.Response> login(String email, String password){
return http.post(
Uri.parse(ip + '/api/auth/login'),
headers: <String, String>{
'Content-Type': 'application/json',
},
body: jsonEncode(<String, String>{
"email": email,
"password": password,
}),
);
}
}
Thank you for clarifying what u needed, it helped answer better.

Answer 2

You can use Nodejs & express to create your own API and MongoDB or any other DB to act as a persistent DB. I am attaching my github repo link which has minimum code required to setup a email/password auth in mongodb
Github
EDIT :
I have little to no idea about sessions but for tokens there are packages in pub.dev which lets you decode the tokens. jwt-decoder.
You can check the expiry time of the token using this package and for storing them you can use secure_storage
I had a look at your token authentication repo. I would suggest you to verify the token when you get them and not just blindly trust them.

Answer 3

Yes it is Totally possible to create Authentication without Firebase, but it becomes a-lot more difficult and there are multiple solutions.
What firebase provides:
Server space with no down time
Complete set of Api's including authentication with various methods
Strong security(built by google)
Ease of use and setup with great documentation
The reason I bring these up is cause the alternative ur looking for is very difficult for a programer who's relatively new and can feel like you are building multiple applications at a time. It's definitely a learning curve. Also I'm assuming u don't just want local authentication cause thats kinda pointless.
Creating ur own backend involves:
Setting up a server(usually ubuntu)(and either on a raspi or a host like amazon, digital ocean, etc)
Setting up a database with tables(mysql, sql, mongoDB)
Creating communication API's (php, Node.js)
So here's what i'd recommend for getting into backend dev,
use LAMP architecture : Linux, Apache, MySQL, PHP
Setting up Lamp isn't too hard heres a link i followed:
https://www.digitalocean.com/community/tutorials/how-to-install-linux-apache-mysql-php-lamp-stack-on-ubuntu-16-04
After u set up ur back end, then u have to create api calls from flutter.
The call (if u created an auth.php where people can login) would look something like:
http://ip:8080/auth.php?email="example#gmail.com"&pass="123456"
I understand why you feel like you didn't find solutions, i was there too but there are tons,LAMP is one of the more easier ones. If u are still interested i'd recommend checking out System Design courses.