SAMLObserver

open class SAMLObserver

extension SAMLObserver: SAPURLSessionObserving

SAMLObserver

The use of this component is the SDK-suggested way of implementing SAML authentication in the application. The SAMLObserver intercepts requests provided by SAPURLSession and looks for SAML challenge indicating HTTP responses. Upon detecting a SAML challenge, it uses its SAMLAuthenticator to authenticate and resend the original request when the authentication is successful. The caller does not notice anything from the authentication flow.

SAML implementation is based on session cookies, so no additional values/tokens need to be stored. The SAML observer must be on the same url session as the other requests sent to the SAML protected server.

Usage

SDK-suggested usage

The SDK-suggested way of using the SAMLObserver is to use its convenience initializer which takes a SAPcpms settings parameters as parameter. This is most favorable when the authentication happens against SAPcpms.

Example:

// Create the SAPcpms settings parameter.
let settingsParameters: SAPcpmsSettingsParameters = <#Settings parameter#>

// Create the observer with the suitable initializer
let observer = SAMLObserver(settingsParameters: settingsParameters)

// Register the observer to an instance of `SAPURLSession`
sapURLSession.register(observer)

A SAPURLSession is required to register the observer. Be aware that an observer instance can be registered to the same SAPURLSession instance only once! Multiple registration will result in application termination!

Customization

There can be scenarios where the SDK supplied convenience implementation is not sufficient. The SDK supports multiple level of customizations. You can find examples at the Authentication section.

Detecting SAML challenges

SAPcpms signals SAML challenges through HTTP response headers. The default SAML challenge implemented by SAPcpms:

• HTTP response status code 200
• Custom header name “com.sap.cloud.security.login” with value “login-request”

The default SAMLObserver looks for these conditions on every received response to determine if there was a SAML challenge.

Overriding the default challenge detection logic

If your landscape signals SAML challenges differently then you need to customize the challenge detection logic. The SDK supports this kind of customization through the sub-classing of SAMLObserver and the overriding of the dedicated challenge detection method.

class MySAMLObserver: SAMLObserver {
    // Override the default challenge detection method
    override func isChallenge(dataTask: SAPURLSessionTask, response: URLResponse) -> Bool {
        // Determine if the response contains a SAML challenge
        // Return a boolean value accordingly.
        // return true - the repsonse is a SAML challenge and authentication must take place
        // return false - the response is not a SAML challenge, continue normally
    }
}

// Create your observer with one of the available initializers
let mySAMLObserver = MySAMLObserver(settingsParameter: <#your SAPcpmsSettingsParameters#>)

// Register the created observer to an instance of the SAPURLSession
sapURLSession.register(mySAMLObserver)

Note - regarding the main thread

The observer is aware of the application state, and does not allow to run UI-required authentication in background state. It uses the main thread synchronously to read the UIApplication.shared.applicationState property.

Do not use the main thread to wait (block) for a network request which goes through this observer!

The use of this component is the SDK-suggested way of implementing SAML authentication in the application. The SAMLObserver intercepts requests provided by SAPURLSession and looks for SAML challenge indicating HTTP responses. Upon detecting a SAML challenge, it uses its SAMLAuthenticator to authenticate and resend the original request when the authentication is successful. The caller does not notice anything from the authentication flow.

Example use:

// create or acquire the SAPURLSession instance
let sapURLSession = SAPURLSession()

// perform other steps to initialize the session and the application

// create the SAPcpms settings parameter
let settingsParameters = SAPcpmsSettingsParameters(backendURL: <#your backendURL#>, applicationID: <#your applicationID#>)

// create the SAML observer
let samlObserver = SAMLObserver(settingsParameters: settingsParameters)

// register the observer on the URL session
sapURLSession.register(samlObserver)

// start to create requests