Technical Q&A QA1462

Programmatically Performing an Open Directory Search

Q: How do I programmatically search for specific records by matching attributes via the Open Directory API?

A: How do I programmatically search for specific records by matching attributes via the Open Directory API?

You'll need to use the Directory Services Framework, more specifically, the dsDoAttributeValueSearchWithData function found within it.

Listing 1 below gives an example:

Listing 1 Executing a trivial Open Directory Search.

//  Begin variable declaration. 
tDirReference                 dirRef;
long                          status = eDSNoErr;
unsigned long                 numResults = 0;
tDataListPtr                  nodePath = NULL;
tDirNodeReference             nodeRef;
tDataList                     recordTypesToSearchFor;
tDataNodePtr                  patternToMatch = NULL;
tDataNodePtr                  matchType;
tDataListPtr                  requestedAttributes = NULL;
tDataBufferPtr                dataBuff = NULL;
tContextData                  context = NULL;

//  Initiate the Open Directory Service. 
status = dsOpenDirService(&dirRef);

//  Allocate a buffer. 
dataBuff = dsDataBufferAllocate(dirRef, 2*1024);

//  Find the default search node.
status = dsFindDirNodes(dirRef, dataBuff, NULL, eDSSearchNodeName, &numResults, &context);

//  Acquire a reference to the default search node.
status = dsGetDirNodeName(dirRef, dataBuff, 1, &nodePath);

//  Do some cleaning up.
dsDataBufferDeAllocate(dirRef, dataBuff);
dataBuff = NULL;
dataBuff = dsDataBufferAllocate(dirRef, 2*1024);

//  Open root level node for search. 
status = dsOpenDirNode(dirRef, nodePath, &nodeRef);

//  Build the tDataList containing the record type that you are searching for; 
//  in this case, the record type is "Users". 
status = dsBuildListFromStringsAlloc (dirRef, &recordTypesToSearchFor, kDSStdRecordTypeUsers, NULL); 
//  Return Records of Users. 

//  tDataNodePtr containing the string value to search for within all records. 
patternToMatch = dsDataNodeAllocateString(dirRef, "Michael");

//  tDataNodePtr containing the constant value that pertains to the scope of the search. 
matchType = dsDataNodeAllocateString(dirRef, kDSAttributesAll);

//  Build a list to contain the requested attributes of the records returned from your search. 
requestedAttributes = dsBuildListFromStrings(dirRef, kDS1AttrDistinguishedName, NULL);

//  The actual query. 
status = dsDoAttributeValueSearchWithData(nodeRef, dataBuff, &recordTypesToSearchFor, matchType, eDSContains,
                    patternToMatch, requestedAttributes, FALSE, &numResults, &context);

You will also have to check the return status and context variables from the dsFindDirNodes and dsDoAttributeValueSearchWithData calls since:

If status is eDSBufferTooSmall then the buffer size needs to be increased. For other return values please refer to the documentation.
If context is not NULL then there are more items needing to be returned, in which case, you'll need to make subsequent calls to dsDoAttributeValueSearchWithData passing in the context variable. When you no longer need context, call dsReleaseContinueData to release the memory associated with it.

It would be wise to check that numResults is larger than 0 after the dsFindDirNodes call since it is possible that no search node could be returned. Once the above code is executed you'll need to pass dataBuff and the appropriate parameters to dsGetRecordEntry, dsGetAttributeEntry, and dsGetAttributeValue in order to acquire the information that you need.

Document Revision History

Date	Notes
2006-09-11	New document that a short guide on how to programmatically search Open Directory for matching attribute values within records.