Matterhorn.Login

This module provides the login interface for Matterhorn.

• Overview

The interface provides a set of form fields for the user to use to enter their server information and credentials. The user enters this information and presses Enter, and then this module attempts to connect to the server. The module's main function, interactiveGetLoginSession, returns the result of that connection attempt, if any.

• Details

The interactiveGetLoginSession function takes the Matterhorn configuration's initial connection information as input. If the configuration provided a complete set of values needed to make a login attempt, this module goes ahead and immediately makes a login attempt before even showing the user the login form. This case is the case where the configuration provided all four values needed: server host name, port, username, and password. When the interface immediately makes a login attempt under these conditions, this is referred to as an "initial" attempt in various docstrings below. Otherwise, the user is prompted to fill out the form to enter any missing values. On pressing Enter, a login attempt is made.

A status message about whether a connection is underway is shown in both cases: in the case where the user has edited the credentials and pressed Enter, and in the case where the original credentials provided to interactiveGetLoginSession caused an initial connection attempt.

The "initial" login case is special because in addition to not showing the form, we want to ensure that the "connecting to..." status message that is shown is shown long enough for the user to see what is happening (rather than just flashing by in the case of a fast server connection). For this usability reason, we have a "startup timer" thread: the thread waits a specified number of milliseconds (see startupTimerMilliseconds below) and then notifies the interface that it has timed out. If there is an initial connection attempt underway that succeeds *before* the timer fires, we wait until the timer fires before quitting the Login application and returning control to Matterhorn. This ensures that the "connecting to..." message stays on the screen long enough to not be jarring, and to show the user what is happening. If the connection fails before the timer fires, we just resume normal operation and show the login form so the user can intervene.

Documentation

data LoginAttempt

The result of an authentication attempt.

Constructors

AttemptFailed AuthenticationException

The attempt failed with the corresponding error.

AttemptSucceeded ConnectionInfo ConnectionData Session User (Maybe Text)

The attempt succeeded.

interactiveGetLoginSession

Arguments

:: Vty

The initial terminal state handle to use.

-> IO Vty

An action to build a new state handle if one is needed. (In practice this never fires since the login app doesn't use suspendAndResume, but we need it to satisfy the Brick API.)

-> (ConnectionData -> ConnectionData)

The function to set the logger on connection handles.

-> LogManager

The log manager used to do logging.

-> ConnectionInfo

Initial connection info to use to populate the login form. If the connection info provided here is fully populated, an initial connection attempt is made without first getting the user to hit Enter.

-> IO (Maybe LoginAttempt, Vty)

The main function of this module: interactively present a login interface, get the user's input, and attempt to log into the user's specified mattermost server.

This always returns the final terminal state handle. If the user makes no login attempt, this returns Nothing. Otherwise it returns Just the result of the latest attempt.