How can C# override LDAP server limit, but not Jav

2019-08-14 18:42发布

I'm rewriting my C# program to Java and became very curios about the fact that C# application can extract tens of thousands of users with this trick:

DirectorySearcher search = new DirectorySearcher(entry);
search.SizeLimit = 99000;
search.PageSize = 98000;

but my Java programs firmly say

LDAPSearchException(resultCode=4 (size limit exceeded), numEntries=1000, numReferences=0, errorMessage='size limit exceeded')

I tried both unboundid and standard libraries. Found million discussions about this problem and everywhere is said - the limitation is on server, you can do nothing.

But my C# application does work! How can this happen? Secret techniques from Microsoft, that cannot be repeated by other vendors?

Just in case, my code is:

SearchRequest searchRequest = new SearchRequest(path, SearchScope.SUB, filter, "SamAccountName");
searchRequest.setSizeLimit(99000);
searchRequest.setTimeLimitSeconds(999);

SearchResult result = connection.search(searchRequest);

for (SearchResultEntry sre : result.getSearchEntries()) {
System.out.println(count++ + ": " + sre.toString());
}

for unboundid

p.s. I do not want to use workaround with searching for a*, b*, c* et c. Especially, considering that usernames might be not only in English.

标签: java c# ldap
1条回答
我想做一个坏孩纸
2楼-- · 2019-08-14 19:37

Further reading showed, that unboundid does support paged mode, so problem is solved.

 public static void main(String[] args) {

    try {
        int count = 0;
        LDAPConnection connection = new LDAPConnection("hostname", 389, "user@domain", "password");

        final String path = "OU=Users,DC=org,DC=com";
        String[] attributes = {"SamAccountName","name"};

        SearchRequest searchRequest = new SearchRequest(path, SearchScope.SUB, Filter.createEqualityFilter("objectClass", "person"), attributes);

        ASN1OctetString resumeCookie = null;
        while (true)
        {
            searchRequest.setControls(
                    new SimplePagedResultsControl(100, resumeCookie));
            SearchResult searchResult = connection.search(searchRequest);
            for (SearchResultEntry e : searchResult.getSearchEntries())
            {
                if (e.hasAttribute("SamAccountName"))
                    System.out.print(count++ + ": " + e.getAttributeValue("SamAccountName"));

                if (e.hasAttribute("name"))
                    System.out.println("->" + e.getAttributeValue("name"));
            }

            LDAPTestUtils.assertHasControl(searchResult,
                    SimplePagedResultsControl.PAGED_RESULTS_OID);
            SimplePagedResultsControl responseControl =
                    SimplePagedResultsControl.get(searchResult);
            if (responseControl.moreResultsToReturn())
            {
                resumeCookie = responseControl.getCookie();
            }
            else
            {
                break;
            }
        }


    }
    catch (Exception e)
    {
        System.out.println(e.toString());
    }
}
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