Module page.codeberg.friedolyn.Friedolyn

Package page.codeberg.friedolyn.client

Class HeadlessBrowser

java.lang.Object

page.codeberg.friedolyn.client.FriedolinClient

page.codeberg.friedolyn.client.HeadlessBrowser

public class HeadlessBrowser
extends FriedolinClient

An alternative to the default Client that uses a browser without a graphical user interface to interact with the University of Jena's Friedolin system. Therefore, this class is very resource-intensive and should only be used if the hardware is capable of running a headless browser. NOT recommended for use on devices like a Raspberry Pi.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	HeadlessBrowser.FetchClearname
class	HeadlessBrowser.FetchEmailAddress
class	HeadlessBrowser.Login

Nested classes/interfaces inherited from class page.codeberg.friedolyn.client.FriedolinClient

FriedolinClient.HTTP_REQUEST_TYPE, FriedolinClient.InternetConnectivityStatus

Field Summary

Fields

Modifier and Type	Field	Description
private @NonNull Configuration	configuration	The configuration with all parameters required to log in at the University of Jena's Friedolin system.
static final @NonNull URL	DNS_OVER_HTTPS_URL
private final @NonNull org.openqa.selenium.WebDriver	DRIVER	The Selenium web driver, i.e.
private final @NonNull ReentrantLock	IS_LOGGED_IN_LOCK
private @NonNull Expiring<Boolean>	isLoggedIn	Whether the headless browser is currently logged in at the University of Jena's Friedolin system.

Fields inherited from class page.codeberg.friedolyn.client.FriedolinClient

SESSION_LIFETIME

Constructor Summary

Constructors

Constructor	Description
HeadlessBrowser(@NonNull Configuration configuration)	Creates a new headless browser instance with the provided configuration.

Method Summary

Modifier and Type	Method	Description
private boolean	acceptObligationOfUse()	Accepts the obligation of use in order to access the grade table.
@NonNull FriedolinClient.InternetConnectivityStatus	checkInternetConnectivity()	Checks whether the DRIVER has internet access.
boolean	checkLoginStatus()	Checks whether the headless browser is currently logged in at the University of Jena's Friedolin system and updates the isLoggedIn field accordingly.
boolean	fetchGrades(@NonNull String... degrees)	Fetches the student's grades from the University of Jena's Friedolin system, using the credentials specified in the Configuration previously set via FriedolinClient.setConfiguration(Configuration) (or the constructor).
private boolean	fetchGradesForDegree(@NonNull String degree)	Fetches the grades for the specified degree.
void	finish()	Exits the headless browser.
@NonNull HeadlessBrowser.FetchClearname	getFetchClearnameTask()
@NonNull HeadlessBrowser.FetchEmailAddress	getFetchEmailAddressTask()
@NonNull HeadlessBrowser.Login	getLoginTask()
void	setConfiguration(@NonNull Configuration configuration)	Updates the preferences that determine the behaviour of this client with a deep copy of the given configuration (not the actual reference, for security reasons).
void	setConfigurationReference(@NonNull Configuration configuration)	Updates the preferences that determine the behaviour of this client with the exact reference of the given Configuration (instead of just a deep copy).

Methods inherited from class page.codeberg.friedolyn.client.FriedolinClient

buildURL, decodeQuery, encodeParameters, fetchEmailAddress, fetchStudentClearname, getConfiguration, getIsLoggedIn, login, saveResponse, stripAnchor

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DNS_OVER_HTTPS_URL

@NonNull
public static final @NonNull URL DNS_OVER_HTTPS_URL

configuration

@NonNull
private @NonNull Configuration configuration

The configuration with all parameters required to log in at the University of Jena's Friedolin system.

DRIVER

@NonNull
private final @NonNull org.openqa.selenium.WebDriver DRIVER

The Selenium web driver, i.e. the headless browser.

isLoggedIn

@NonNull
private @NonNull Expiring<Boolean> isLoggedIn

Whether the headless browser is currently logged in at the University of Jena's Friedolin system.

IS_LOGGED_IN_LOCK

@NonNull
private final @NonNull ReentrantLock IS_LOGGED_IN_LOCK

Constructor Details

HeadlessBrowser

public HeadlessBrowser(@NonNull
 @NonNull Configuration configuration)

Creates a new headless browser instance with the provided configuration. Since an entire browser is started, it is strongly recommended to execute the construction of this object in a separate thread when the constructor is invoked from a graphical user interface.

Parameters:

configuration - The configuration with all parameters required to log in at the University of Jena's Friedolin system.

Method Details

finish

public void finish()

Exits the headless browser. This method should be called when the headless browser is no longer needed but the application is still running, in order not to waste resources longer than necessary. Yes, Java has a garbage collector, but there may be situations where the parent of this object is still in use but does not need the headless browser anymore.

Specified by:

finish in class FriedolinClient

getLoginTask

@NonNull
public @NonNull HeadlessBrowser.Login getLoginTask()

Specified by:

getLoginTask in class FriedolinClient

Returns:

A Task that can be executed in a different Thread to log in to Friedolin.

setConfiguration

public void setConfiguration(@NonNull
 @NonNull Configuration configuration)

Updates the preferences that determine the behaviour of this client with a deep copy of the given configuration (not the actual reference, for security reasons).

Specified by:

setConfiguration in class FriedolinClient

Parameters:

configuration - The new configuration to use.

See Also:

• setConfigurationReference(Configuration)

Implementation Note:

It is required that a deep copy of the given configuration is stored.

setConfigurationReference

public void setConfigurationReference(@NonNull
 @NonNull Configuration configuration)

Updates the preferences that determine the behaviour of this client with the exact reference of the given Configuration (instead of just a deep copy).

Specified by:

setConfigurationReference in class FriedolinClient

Parameters:

configuration - The new configuration to use.

See Also:

• setConfiguration(Configuration)

Implementation Note:

It is required to store the exact object instance instead of calling copy().

fetchGradesForDegree

private boolean fetchGradesForDegree(@NonNull
 @NonNull String degree)
                              throws IllegalArgumentException

Fetches the grades for the specified degree. IMPORTANT: It is absolutely REQUIRED that the currently opened page is the course list page.

Parameters:

degree - The degree to fetch the grades for.

Returns:

true if the grades could be fetched, false otherwise.

Throws:

IllegalArgumentException - If the student is not enrolled in the specified degree.

fetchGrades

public boolean fetchGrades(@NonNull
 @NonNull String... degrees)
                    throws IllegalArgumentException

Fetches the student's grades from the University of Jena's Friedolin system, using the credentials specified in the Configuration previously set via FriedolinClient.setConfiguration(Configuration) (or the constructor).

Specified by:

fetchGrades in class FriedolinClient

Parameters:

degrees - The academic degrees to fetch the grades for. If none are specified, all degrees present in

invalid reference

Configuration#getAcademicDegrees()

will be fetched.

Returns:

true if the grades were fetched successfully, false otherwise.

Throws:

IllegalArgumentException - If any of the given degrees is not present in the configuration.

acceptObligationOfUse

private boolean acceptObligationOfUse()

Accepts the obligation of use in order to access the grade table.

Returns:

true if the obligation of use could be accepted, false otherwise.

getFetchClearnameTask

@NonNull
public @NonNull HeadlessBrowser.FetchClearname getFetchClearnameTask()

Specified by:

getFetchClearnameTask in class FriedolinClient

Returns:

A Task that can be executed in a different Thread to fetch the student's real name (e.g. Edward Snowden) from the University of Jena's Friedolin system.

getFetchEmailAddressTask

@NonNull
public @NonNull HeadlessBrowser.FetchEmailAddress getFetchEmailAddressTask()

Specified by:

getFetchEmailAddressTask in class FriedolinClient

Returns:

A Task that can be executed in a different Thread to fetch the student's email address (e.g. edward.snowden@uni-jena.de).

checkLoginStatus

public boolean checkLoginStatus()

Checks whether the headless browser is currently logged in at the University of Jena's Friedolin system and updates the isLoggedIn field accordingly.

Returns:

true if the headless browser is currently logged in, false otherwise.

checkInternetConnectivity

@NonNull
public @NonNull FriedolinClient.InternetConnectivityStatus checkInternetConnectivity()

Checks whether the DRIVER has internet access.

Specified by:

checkInternetConnectivity in class FriedolinClient

Returns:

The internet connectivity status of the DRIVER.

See Also:

• Client.checkInternetConnectivity()
• checkInternetConnectivity()

Implementation Note:

In order to rule out DNS issues, we first try to connect to 116.202.120.166 (i.e. web-fsn-02 of the Tor Project). Then, we connect to codeberg.org to take DNS into consideration.