Sharing Knowledge Files with Community Users for Knowledge

shareKnowledgeFiles_Test.apxc

@IsTest
public class shareKnowledgeFiles_Test {

    static testmethod void init(){

        Knowledge__kav article = new Knowledge__kav();
        article.Title='Test';
        article.UrlName='Test';
        insert article;
        
        ContentVersion contentVersion = new ContentVersion(
          Title = 'Penguins',
          PathOnClient = 'Penguins.jpg',
          VersionData = Blob.valueOf('Test Content'),
          IsMajorVersion = true
        );
        insert contentVersion;    
        List<ContentDocument> documents = [SELECT Id, Title, LatestPublishedVersionId FROM ContentDocument];
        test.startTest();
        //create ContentDocumentLink  record 
        ContentDocumentLink cdl = New ContentDocumentLink();
        cdl.LinkedEntityId = article.id;
        cdl.ContentDocumentId = documents[0].Id;
        cdl.shareType = 'V';
        insert cdl;
        test.stopTest();
        System.assertEquals(1, documents.size());
    }
}

shareKnowledgeFilesWithCommunityUsers.apxc

trigger shareKnowledgeFilesWithCommunityUsers on ContentDocumentLink (before insert) {
   Schema.DescribeSObjectResult r = Knowledge__kav.sObjectType.getDescribe();
   String keyPrefix = r.getKeyPrefix();

      for(ContentDocumentLink cdl:trigger.new){
        if((String.valueOf(cdl.LinkedEntityId)).startsWith(keyPrefix)){
          cdl.ShareType = 'I';
          cdl.Visibility = 'AllUsers';
          } 
       }
}