PublishOptions failing when trying to publish media items programatically

Question

I'm trying to publish a media item programmatically but I am encountering a problem with the PublishOptions object. At runtime, the line of code where the PublishOptions object is being instantiated is breaking when I upload a media item. I get the following message saying:

"Value cannot be null. Parameter Name: item"

And the stacktrace is:

at Sitecore.Diagnostics.Assert.ArgumentNotNull(Object argument, String argumentName)
at Sitecore.Data.Managers.ItemProvider.ApplySecurity(Item item, SecurityCheck securityCheck)
at Sitecore.Data.Managers.ItemProvider.GetRootItem(Language language, Version version, Database database, SecurityCheck securityCheck)
at Sitecore.Data.Managers.ItemManager.GetRootItem(Language language, Version version, Database database)
at Sitecore.Nexus.Data.DataCommands.ResolvePathCommand.(String itemPath, Database database)
at Sitecore.Nexus.Data.DataCommands.ResolvePathCommand.(String itemPath, Database database)
at Sitecore.Nexus.Data.NexusDataApi.ResolvePath(String itemPath, Database database)
at Sitecore.Data.Engines.DataCommands.ResolvePathCommand.DoExecute()
at Sitecore.Data.Engines.EngineCommand`2.Execute()
at Sitecore.Data.Engines.DataEngine.ResolvePath(String itemPath)
at Sitecore.Data.Managers.ItemProvider.ResolvePath(String itemPath, Database database)
at Sitecore.Data.Managers.ItemProvider.GetItem(String itemPath, Language language, Version version, Database database, SecurityCheck 

Here's the code where the PublishOptions object is being instantiated (where it is breaking):

public void OnItemSaved(Object sender, EventArgs args)
    {
        var item = Event.ExtractParameter(args, 0) as Item;

        using (new SecurityDisabler())
        {
            if (item != null)
            {
                if (item.Paths.IsMediaItem)
                {
                    var source = new Database("master");
                    var target = new Database("web");


                    var options = new PublishOptions(source, target, PublishMode.SingleItem, item.Language, DateTime.Now)
                                      {
                                          RootItem = item,
                                          Deep = true,

                                      };

                    var publisher = new Publisher(options);

                    publisher.PublishAsync();
                }
            }
        }
    }

What could be the reason why I'm getting this error?

Answer 1

Try this and see if this works, I am guessing it is to with the database.

public void OnItemSaved(Object sender, EventArgs args)
    {
        var item = Event.ExtractParameter(args, 0) as Item;

        using (new SecurityDisabler())
        {
            if (item != null)
            {
                if (item.Paths.IsMediaItem)
                {
                    var source = Factory.GetDatabase("master");
                    var target = Factory.GetDatabase("web");

                    var options = new PublishOptions(source, target, 
                                                     PublishMode.SingleItem, item.Language, 
                                                     DateTime.Now)
                                      {
                                          RootItem = item,
                                          Deep = true,
                                      };

                    var publisher = new Publisher(options);

                    publisher.PublishAsync();
                }
            }
        }
    }

Answer 2

I think you're being caught in a classic mistake. item:saved will also fire for your items as they're being published.

My initial guess would be, that you should expand your check to be

if ( item != null && item.Database.Name == "master" )

to prevent your code from attempting to publish the item, as the item:saved event fires on "web" during publishing.