View source for Log in

After you've [[First_app|initialized]], you can use Volt to control who is allowed to use your app. Only users who have registered will be able to log into your app.

== Checking if user is logged in ==

Use the <code>$volt.auth.isLoggedIn()</code> to check if a user is logged in:

  <syntaxhighlight lang="JavaScript">
  if ($volt.auth.isLoggedIn()) {
    // Ok to do processing
  } else {
    // ask user to log in
  }
  </syntaxhighlight>

  <syntaxhighlight lang="basic">
  If $volt.auth.isLoggedIn() Then
    'Ok to do processing
  Else
    'ask user to log in
  End If
  </syntaxhighlight>

== Logging In ==

Logging in identifies your user to the Volt server. Here is a typical log in screen:

[[File:Logging-in-and-out.png]]

Once you have have obtained the user's email and password (either from a screen like the above or otherwise), you can call the <code>$volt.auth.login()</code> function to log the user in.

The syntax of the function is:

'''$volt.auth.login'''(''email'', ''password'', ''appId'', ''callback'')

* ''email'' - string, required. The email address of the user.
* ''password'' - string, required. The user's password.
* ''appId'' - string, optional. The Volt ID of the app to sign into. If not supplied, defaults to value set in <code>$volt.init(appId)</code>.
* ''callback'' - function(error, data), required. The function in your app to call when the login is complete (or fails).

  <syntaxhighlight lang="JavaScript">
  butSignOn.onclick = function () {
    $volt.auth.login(inpEmail.value, inpPassword.value, signOnCallback);
  }

  function signOnCallback(error, data) {
    if (error) {
      if (!data) {
        data = { message: 'Network Error' };
      }
      alert(data.message);
    } else {
      alert('User successfully logged in');
    }
  }
  </syntaxhighlight>

  <syntaxhighlight lang="basic">
  Sub butSignOn.onclick()
    $volt.auth.login(inpEmail.value, inpPassword.value, signOnCallback);
  End Sub

  Function signOnCallback(error, data)
    If error Then
      If (!data) Then data = { message: "Network Error" }
      MsgBox data.message
    Else
      MsgBox "User successfully logged in"
    End If
  End Sub
  </syntaxhighlight>

Once the user is logged in, he stays logged in. The info is save to localStorage so the next time the app is run, the user does not have to log in again.

== Logging Out ==

You can log your user out by using <code>$volt.auth.logout()</code>:

  <syntaxhighlight lang="JavaScript">
  $volt.auth.logout();
  </syntaxhighlight>

  <syntaxhighlight lang="basic">
  $volt.auth.logout()
  </syntaxhighlight>

== AppStudio Users ==

[https://www.nsbasic.com/ AppStudio] includes a form for handling login duties, called frmSignOn. If you include it in your app, you can call it as follows:

  <syntaxhighlight lang="JavaScript">
  butSignIn.onclick = function() {
    showSignIn(signInCallback);
  };

  function signInCallback() {
    butSignIn.disabled = true;
    NSB.MsgBox('SignIn successful.');
  }
  </syntaxhighlight>

  <syntaxhighlight lang="basic">
  Function butSignIn_onclick()
    showSignIn(signInCallback)
  End Function

  Function signInCallback()
    butSignIn.disabled = True
    MsgBox "SignIn successful."
  End Function
  </syntaxhighlight>

== Reference ==

* JavaScript API
** [[https://docs.voltcloud.io/client/$volt.auth.html#.isLoggedIn https://docs.voltcloud.io/client/$volt.auth.html#.isLoggedIn]]
** [[https://docs.voltcloud.io/client/$volt.auth.html#.login https://docs.voltcloud.io/client/$volt.auth.html#.login]]
** [[https://docs.voltcloud.io/client/$volt.auth.html#.logout https://docs.voltcloud.io/client/$volt.auth.html#.logout]]
* REST API: [[https://docs.voltcloud.io/api/#authentication-login-post https://docs.voltcloud.io/api/#authentication-login-post]]