How to get specific data from Realtime Database in flutter? - firebase

I have fetched the snapshot values named as name and role and I store
them as userName and user role.
I want to access the same data in the same widget but it cannot recognize. Please help

You have to declare (and initialize userName and userRole variables if you are using newer versions of dart) before the Widget. Something like:
String userName = "", userRole = "";
or
late String userName, userRole;

Related

how to store a value from database to a global variable and use it everywhere we need it

I don't know if this is the way to ask this, also I want to achieve this without state management.
so here's the code that getting user is from firebase
final docUsers = FirebaseFirestore.instance.collection('users').doc();
final userObject = Users(
id: docUsers.id,
name: userName,
email: emailAdress,
password: password,
);
await docUsers.set(userObject.toJson());
userID = docUsers.id;
userID = docUsers.id; the user id is the global variable here, so I assigned the value to the global variable when the id received. but when it using its shows the value is null, how to achieve this without statemanagement (I meant bloc, provider and like many others. not the "state management").
so how can I achieve that?
Could you show how and when your value is NULL?
But this might help:
class MyGlobalVariables {
static String userId = '123';
}
MyGlobalVariables.userId = 'abc';
print( MyGlobalVariables.userId ); // = abc
It looks like you want to create entries for new users of your App in the database. If this is the case, one would want to use Firebase Authentication for dealing with that:
https://firebase.google.com/docs/auth/

Unique field in Firestore database + Flutter

I'm trying to implement a normal authentication system in my app, but I'd like to create a new field for each user that is the "uniqueName" so users can search and add each other in their friends list. I was thinking of adding a textField in the signup form for the uniqueName and updating my User class adding a new String in this way:
class User {
String email;
String name;
String uniqueName;
String userID;
String profilePictureURL;
String appIdentifier;
...
}
Now, since I have this method for the email&password signup:
static firebaseSignUpWithEmailAndPassword(String emailAddress,String password,File? image,String name,) async {
try {
auth.UserCredential result = await auth.FirebaseAuth.instance
.createUserWithEmailAndPassword(
email: emailAddress, password: password);
String profilePicUrl = '';
if (image != null) {
await updateProgress('Uploading image, Please wait...');
profilePicUrl =
await uploadUserImageToFireStorage(image, result.user?.uid ?? '');
}
User user = User(
email: emailAddress,
name: name,
userID: result.user?.uid ?? '',
profilePictureURL: profilePicUrl);
String? errorMessage = await firebaseCreateNewUser(user);
if (errorMessage == null) {
return user;
} else {
return 'Couldn\'t sign up for firebase, Please try again.';
}
}
how do I have to modify it in order to add this new field in the registration? Since I have to check that the uniqueName insert by the user is effectively unique before creating a new user in the database, what can I do?
Furthermore, I think that it would be cool if this check is made concurrently to the filling of the form, how can I do it? (this is not necessary)
Thanks everyone for the answers
You have to save your users in a collection, then check if uniqueName already exists in the collection. If it exists, return error.
Then when a new user account is created, save the uniqueName.
// this function checks if uniqueName already exists
Future<bool> isDuplicateUniqueName(String uniqueName) async {
QuerySnapshot query = await FirebaseFirestore.instance
.collection('PATH_TO_USERS_COLLECTION')
.where('uniqueName', isEqualTo: uniqueName)
.get();
return query.docs.isNotEmpty;
}
// call the above function inside here.
static firebaseSignUpWithEmailAndPassword(String emailAddress, String password, File? image, String name,) async {
if (await isDuplicateUniqueName(name)) {
// UniqueName is duplicate
// return 'Unique name already exists';
}
// ... the rest of your code. Go ahead and create an account.
// remember to save the uniqueName to users collection.
I suggest doing the following steps:
Create your own users collection (for example users) in Firestore, which you might have done already. (I don't think that User is a good class name, since Firebase Authentication is using the same name. Try MyUser or something.)
Add authentication triggers that will ensure that whenever a Firebase user is added or deleted, it will also be added to or deleted from users collection, use Firebase uid as identifier.
Create a solution to check whether a uniqueName already exists in users collection. You can use a Firestore query, but in this case you have to allow unauthenticated access to read users, at least uniqueName field. (Since the user is not authenticated yet at this point.) A Firebase Cloud Function is another option.
When users enter their desired uniqueName, run the check before creating Firebase user. You can do it when user enters this or when you start the signup process.
If uniqueName is unique, you can try to create Firebase user. Be aware, this step can also fail (for example e-mail name taken etc.). Your users document will be created by the authentication trigger you set up in step 2.
Finally, you have to store this uniqueName in users collection. At this point you will have uid of the newly created Firebase user, so you can use Firestore set command with merge option set to true, so you don't overwrite other data.
It is important to note that you can't guarantee that the Firebase trigger already created the new document in users by the time you arrive to point 6, it is very likely that the trigger is still working or not even started yet. That's why you have to use set both in the authentication trigger and in your own code that sets uniqueName: which "arrives" first, will create the document, and the second will update it.
Also, for the same reason, you have to allow inserts and updates into users collection with Firestore rules. This might sound a little scary, but keep in mind that this is only your own user list to keep track of uniqueName, and authentication is based not on this, but on Firebase Authentication's user management which is well protected.
Last comment: this is not a 100% solution. It is quite unlikely, but theoretically can happen, that some else reserves a uniqueName between you check whether it's unique and the user is actually created. To mitigate this, it is a good idead to make the check just before Firebase user is created. Even in this case a slight chance remains for duplicates.

Need to enter more data for user sign up in Firebase

I'm new to Firebase. I was looking at the Firebase documentation and it seems good. But one thing I've noticed is that when I register/sign up my users, I can only get their email ID and password.
However, for my app, I need my users to enter more details like name, address, phone, and some other details. How can I do this?
I thought maybe I can use the real time database, but then I didn't know how to match the users with their respective details from the realtime database. Please give me some ideas on how to do this.
You're right.
In order to save some user data, you will have to use Realtime Database. There are few properties you can assign to user like email, photoURL, displayName but for more than that you have to use database.
Hope it helps, here is a way I am doing it:
I created "users" node in database and every time new user registers, new entry with his uid gets inserted. Check screenshot below:
So every time you need to get user data, just call child at "users" node with given "current user uid".
On Success of registration , get all the details and update/create the information in firebase database.
final String emailId = mEditTextEmail.getText().toString() ;
String password = mEditTextPassword.getText().toString() ;
firebaseRef.createUser(emailId, password, new Firebase.ValueResultHandler<Map<String,Object>>() {
#Override
public void onSuccess(Map<String, Object> stringObjectMap) {
User user = new User();
user.setUid(stringObjectMap.get("uid").toString());
user.setEmail(emailId);
user.setProfileStatus(User.NEW);
firebaseRef.child("Users").child(user.getUid()).setValue(user);
mProgressBar.setVisibility(View.GONE);
Intent intent = new Intent(SignupActivity.this,LoginActivity.class);
intent.putExtra("email",mEditTextEmail.getText().toString());
startActivity(intent);
Toast.makeText(getBaseContext(),"You are Successfully Registered in",Toast.LENGTH_SHORT).show();
Toast.makeText(getBaseContext(),"Login to continue..",Toast.LENGTH_SHORT).show();
}

WebSecurity.ChangePassword returning FALSE value

I can't figure out why my WebSecurity.ChangePassword is not working. Here's the piece of code I'm working on.
if (WebSecurity.ChangePassword(USER, oldpass, password)) {
Response.Redirect("~/SuperAdmin");
return;
}else {
ModelState.AddFormError(USER);
// I put the each WebSecurity.ChangePassword parameter to this parameter to check whether
//each parameter valid or not (print it out)
}
and for each parameter of WebSecurity.ChangePassword, I retrieve it from the database as follows
if(IsPost){
Validation.RequireField("email", "Masukkan email");
Validation.RequireField("password", "Masukkan Password");
Validation.RequireField("userid", "user ID tidak ada!");
email = Request.Form["email"];
password = Request.Form["password"];
userId = Request.Form["userId"];
if(Validation.IsValid()){
var db = Database.Open("StarterSite");
var updateCommand2 = "UPDATE UserProfile SET Email=#0 WHERE UserId=#1";
db.Execute(updateCommand2, email,userId);
var USER = db.QueryValue("SELECT a.Email FROM UserProfile a, webpages_Membership b WHERE a.UserId=b.UserId AND a.UserId= #0", userId);
var oldpass = db.QueryValue("SELECT Password FROM webpages_Membership WHERE UserId = #0", userId);
Can anyone tell me what seems to be the problem here? Thanks in advance
The WebPages Membership has everything built you do not need to get the users email address and password (I am guessing the email address is the username right?) The ChangePassword method takes 3 arguments. which is UserName, CurrentPassword, NewPassword.
The reason your getting false is because your getting the old password from the database based on the users current Id, but the old password does not match the users current password because old one is encrypted and you're not encrypting the one they submit (in fact you don't even have a field for them to enter their current password).
The WebPages Membership provider will do all the updating you do not need open the database and update the users password, the weird thing you're doing is telling the user to enter a new password but not asking for the current one! Here see this for more information:
http://www.thecodingguys.net/reference/asp/websecurity-changepassword
Make sure the user you are trying to change password for is not LockedOut. You can check it by this
select * from aspnet_membership
where
IsLockedOut = 1

Storing DotNetOpenAuth information and user info retrieval

This question is a bit of a structural/design question as I'm having trouble working out the best way to perform the task.
In my MVC app, I am using DotNetOpenAuth (3.4) as my login information provider and just using the standard FormsAuthentication for cookies etc.
The current user table in the DB has:
UserId (PK, uniqueidentifier)
OpenIdIdentifier (nvarchar(255))
OpenIdDisplay (nvarchar(255))
Displayname (nvarchar(50))
Email (nvarchar(50))
PhoneNumber (nvarchar(50))
As the UserId is the clear identifier for a user (they should be able to change their OpenId provider at a later date), it is the key that other tables link to (for a user).
This is the current code, that on a successfull authentication, creates a temporary user and redirects to Create Action.
switch (response.Status)
{
case AuthenticationStatus.Authenticated:
FormsAuthentication.SetAuthCookie(response.ClaimedIdentifier, false);
var users = new UserRepository();
if (!users.IsOpenIdAssociated(response.ClaimedIdentifier))
{
var newUser = new DueDate.Models.User();
newUser.OpenIdIdentifer = response.ClaimedIdentifier;
newUser.OpenIdDisplay = response.FriendlyIdentifierForDisplay;
TempData["newUser"] = newUser;
return this.RedirectToAction("Create");
}
And now for the crux of the question:
Is the response.ClaimedIdentifier the correct piece of information to be storing against a user?
Is FormAuthentication.SetAuthCookie the preferred way to forms authentication? Or is there a better way?
When I call SetAuthCookie, there is no data relating to the user except for the ClaimedIdentifier. If I'm consistently referring to their UserId, is a better idea to create the user, then store that UserId in the cookie instead of the ClaimedIdentifier?
If I'm using that UserId in a number of places, how do I either retrieve it from the cookie, or store it somewhere else more logical/useful?
A bit long winded but I've been having trouble trying to work out the best way to do this/
1.Is the response.ClaimedIdentifier the correct piece of information to be storing against a user?
Yes. And make sure the column you store it in the database with is case sensitive. Here is a table schema that demonstrates how to make sure it is case sensitive. This comes out of the DotNetOpenAuth project template's database schema. The "CS" bit of the specified collation stand for Case Sensitive.
CREATE TABLE [dbo].[AuthenticationToken] (
[AuthenticationTokenId] INT IDENTITY (1, 1) NOT NULL,
[UserId] INT NOT NULL,
[OpenIdClaimedIdentifier] NVARCHAR (250) COLLATE SQL_Latin1_General_CP1_CS_AS NOT NULL,
[OpenIdFriendlyIdentifier] NVARCHAR (250) NULL,
[CreatedOn] DATETIME NOT NULL,
[LastUsed] DATETIME NOT NULL,
[UsageCount] INT NOT NULL
);
2.Is FormAuthentication.SetAuthCookie the preferred way to forms authentication? Or is there a better way?
For MVC apps it definitely is, since you still can return your preferred ActionResult from the method.
3.When I call SetAuthCookie, there is no data relating to the user except for the ClaimedIdentifier. If I'm consistently referring to their UserId, is a better idea to create the user, then store that UserId in the cookie instead of the ClaimedIdentifier?
That sounds like personal preference. But I would typically go with user_id, since it might result in a faster database lookup every time an HTTP request comes in that requires you to look up any user information.
4.If I'm using that UserId in a number of places, how do I either retrieve it from the cookie, or store it somewhere else more logical/useful?
FormsAuthentication does provide a way to store more information in its encrypted cookie than just username, but it is harder than you'd expect to use it. This snippet comes out of DotNetOpenAuth's web SSO RP sample:
const int TimeoutInMinutes = 100; // TODO: look up the right value from the web.config file
var ticket = new FormsAuthenticationTicket(
2, // magic number used by FormsAuth
response.ClaimedIdentifier, // username
DateTime.Now,
DateTime.Now.AddMinutes(TimeoutInMinutes),
false, // "remember me"
"your extra data goes here");
HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, FormsAuthentication.Encrypt(ticket));
Response.SetCookie(cookie);
Response.Redirect(Request.QueryString["ReturnUrl"] ?? FormsAuthentication.DefaultUrl);
Then you can get at that extra data in a future HTTP request with this:
var cookie = HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName];
if (cookie != null) {
var ticket = FormsAuthentication.Decrypt(cookie.Value);
if (!string.IsNullOrEmpty(ticket.UserData)) {
// do something cool with the extra data here
}
}

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