Check and/or Create a ContentDistribution with a ContentDownloadURL (allows for public links of 'Files' in Salesforce)

content-distribution.cls

String linkedEntityId = 'a05B000000ACLmYIAX';

List<ContentDocumentLink> cdl = [
    SELECT
        ContentDocument.Id, ContentDocument.Title, ContentDocument.FileType, ContentDocumentId
    FROM ContentDocumentLink
    WHERE LinkedEntityId =: linkedEntityId
];
ContentDocumentLink cdl1 = cdl[0];

Id contentDocId = cdl1.ContentDocumentId;

ContentDistribution contentDist = [
    SELECT
        Id, ContentDownloadUrl
    FROM ContentDistribution
    WHERE ContentDocumentId =: contentDocId
];
System.debug('contentDist.Id ' + contentDist.Id);
System.debug('contentDist.ContentDownloadUrl ' + contentDist.ContentDownloadUrl);


ContentVersion cv = [SELECT Id, Title FROM ContentVersion WHERE ContentDocumentId =: contentDocId];
List<ContentDistribution> contentDistList = [
    SELECT
        Id, ContentDownloadUrl, ContentVersionId
    FROM ContentDistribution
    WHERE ContentDocumentId =: contentDocId
];

System.debug('Found ' + contentDistList.size() + ' ContentDistribution objects.');

if (contentDistList.size() == 0) {
    System.debug('No ContentDistribution found for ContentDoc with Id ' + contentDocId);

    // Create a new ContentDistribution
    ContentDistribution cd = new ContentDistribution();
    cd.Name = cv.Title;
    cd.ContentVersionId = cv.Id;
    cd.PreferencesAllowViewInBrowser = true;
    cd.PreferencesLinkLatestVersion = true;
    cd.PreferencesNotifyOnVisit = false;
    cd.PreferencesPasswordRequired = false;
    cd.PreferencesAllowOriginalDownload = true;
    insert cd;

    System.debug('cd ' + cd.Id);
    
    // Have to re-query to get the 
    ContentDistribution cdAfter = [ SELECT ContentDownloadUrl FROM ContentDistribution WHERE Id =: cd.Id];
    System.debug('cdAfter ' + cdAfter.ContentDownloadUrl);
} else {
    System.debug('We already have a public link');
    System.debug('Existing URL: ' + contentDistList[0].ContentDownloadUrl);

    for (ContentDistribution cDist : contentDistList) {
        System.debug('cDist ' + cDist);
    }
}