Accessing credentials from user Java code

You can access credentials from user Java™ code by editing the Java Compute Node Class in a JavaCompute node.

Before you begin

Create a JavaCompute node in your message flow.

Procedure

Enable credential lookups from user Java code by completing the following steps:

  1. Create Java code for a JavaCompute node as described in Creating Java code for a JavaCompute node.
  2. Add user code to implement your required lookup method on MbCredential by adapting one of the following patterns:
    • Use and adapt the following pattern if you have no requirement for updates or performance from caching: 
      
// ----------------------------------------------------------
// Add user code below
{
// Lookup pattern 1, don't care about updates or performance from caching,
// lookup on each use, minimal exception handling

String username;
char[] password;

outerLoop : while (true) {
MbCredential myCred;
try {
myCred = MbCredential.getCredential("ODBC", "myDSN");
} catch (MbException e) {
throw new RuntimeException("Something went wrong during credential lookup", e);
}
if (myCred == null) {
throw new RuntimeException("Credential cannot be found");
}
try {
Map<String, char[]> credentialProperties = myCred.reloadAndRetrieveProperties();

if (credentialProperties.containsKey(MbCredential.USERNAME))
username = new String(credentialProperties.get(MbCredential.USERNAME));

if (credentialProperties.containsKey(MbCredential.PASSWORD))
password = credentialProperties.get(MbCredential.PASSWORD);

break outerLoop;

} catch (MbCredentialDeletedException cde) {
    // oh dear, sad times our original credential has been deleted
username = null;
password = null;
// We can try a new lookup to see if it exists somewhere else in the system in a different provider
myCred = null;
}
}
}
// End of user code
// ----------------------------------------------------------
    • Use and adapt the following pattern if you require full control over updates by using easy access to properties. You need to deal with exception handling to complete this pattern: 
      
// ----------------------------------------------------------
// Add user code below

// Declare in outer scope
MbCredential myCred = null;
String username = null;
char[] password = null;


// Then on each message
boolean reloadCredentialProperties = false;
if (myCred != null) {
try {
reloadCredentialProperties = myCred.hasBeenUpdated();
} catch (MbCredentialDeletedException cde) {
myCred = null; // Force a new lookup
}
}
if (myCred == null) {
// First time through or after delete, we perform a lookup
try {
myCred = MbCredential.getCredential("ODBC", "myDSN");
} catch (MbException e) {
throw new RuntimeException("Something went wrong during credential lookup", e);
}
if (myCred == null) {
throw new RuntimeException("Credential cannot be found");
}
reloadCredentialProperties = true;
}

if (reloadCredentialProperties) {
boolean success = false;
do {
try {
myCred.reload();
Map<String, char[]> credentialProperties = myCred.retrieveProperties();

if (credentialProperties.containsKey(MbCredential.USERNAME))
username = new String(credentialProperties.get(MbCredential.USERNAME));

if (credentialProperties.containsKey(MbCredential.PASSWORD))
password = credentialProperties.get(MbCredential.PASSWORD);

// etc....

success = true;
} catch (MbCredentialUpdatedException cue) {
    // oh dear, have another go
username = null;
password = null;
} catch (MbCredentialDeletedException cde) {
    // oh dear, sad times our original credential has been deleted
username = null;
password = null;
// We can try a new lookup to see if it exists somewhere else in the system in a different provider
try {
myCred = MbCredential.lookupCredential("ODBC", "myDSN");
} catch (MbException e) {
throw new RuntimeException("Something went wrong during credential lookup", e);
}
if (myCred == null) {
throw new RuntimeException("Credential has been deleted");
}
}
} while(!success);
}
}
// End of user code
// ----------------------------------------------------------
    • Use and adapt the following pattern if you require full control over updates by using access methods. You need to deal with exception handling to complete this pattern: 
      
// ----------------------------------------------------------
// Add user code below
{
// Lookup pattern 3. Full control over updates using access methods,
// Need to deal with exception handling to be complete

// Declare in outer scope
MbCredential myCred = null;
String username = null;
char[] password = null;


// Then on each message
boolean reloadCredentialProperties = false;
if (myCred != null) {
try {
reloadCredentialProperties = myCred.hasBeenUpdated();
} catch (MbCredentialDeletedException cde) {
myCred = null; // Force a new lookup
}
}
if (myCred == null) {
// First time through or after delete, we perform a lookup
try {
myCred = MbCredential.getCredential("ODBC", "myDSN");
} catch (MbException e) {
throw new RuntimeException("Something went wrong during credential lookup", e);
}
if (myCred == null) {
throw new RuntimeException("Credential cannot be found");
}
reloadCredentialProperties = true;
}

if (reloadCredentialProperties) {
boolean success = false;
do {
try {
myCred.reload();
if (myCred.hasUsername())
username = new String(myCred.username());
if (myCred.hasPassword())
password = myCred.password();
// etc....
success = true;
} catch (MbCredentialUpdatedException cue) {
    // oh dear, have another go
username = null;
password = null;
} catch (MbCredentialDeletedException cde) {
    // oh dear, sad times our original credential has been deleted
username = null;
password = null;
// We can try a new lookup to see if it exists somewhere else in the system in a different provider
try {
myCred = MbCredential.lookupCredential("ODBC", "myDSN");
} catch (MbException e) {
throw new RuntimeException("Something went wrong during credential lookup", e);
}
if (myCred == null) {
throw new RuntimeException("Credential has been deleted");
}
}
} while(!success);
}
}
// End of user code
// ----------------------------------------------------------
  3. Update the server.conf.yaml file as follows:
    1. In the Credentials section, enable userRetrievableCredentialTypes and set the value to 'userdefined', '', or 'ALL' as required.
    2. 
Credentials:
userRetrievableCredentialTypes: 'userdefined' # Sets the comma-separated list of credential types that user code is allowed to reference.
                                              # Default is 'userdefined'.
                                              # The list can be empty to disallow credential lookups from user code.
                                              # Set the value to 'ALL' to allow access to credentials of any type from user code.