How to dynamically add a content part in a Orchard content handler? - orchardcms

Question

I have an Orchard content handler that calls
Filters.Add(new Orchard.ContentManagement.Handlers.ActivatingFilter<MyPart>("User"));
in its constructor to weld MyPart to a user content item.
How can i weld MyPart based on the content item id?
The issue here is that the content item is not yet created when the constructor is called. I tried hooking into the life cycle with overriding Activating() but that doesn't work either as the content item is also not created yet.

Answer 1

Okay, this task is really difficult. Here's my solution.
1) Create an extension method that welds a content part to a content item (sadly, we cannot use ContentItemBuild.Weld() as there's no chance to pass the content item)
// adopted from ContentItemBuilder.Weld<>()
public static TPart Weld<TPart>(this Orchard.ContentManagement.ContentItem aContentItem)
where TPart: Orchard.ContentManagement.ContentPart, new()
{
var partName = typeof(TPart).Name;
// obtain the type definition for the part
var typePartDefinition = aContentItem.TypeDefinition.Parts.FirstOrDefault(p => p.PartDefinition.Name == partName);
if (typePartDefinition == null) {
// If the content item's type definition does not define the part; use an empty type definition.
typePartDefinition = new Orchard.ContentManagement.MetaData.Models.ContentTypePartDefinition(
new Orchard.ContentManagement.MetaData.Models.ContentPartDefinition(partName),
new Orchard.ContentManagement.MetaData.Models.SettingsDictionary());
}
// build and weld the part
var part = new TPart { TypePartDefinition = typePartDefinition };
aContentItem.Weld(part);
return part;
}
2) Define a StorageFilter for dynamically welding the content part to the content item
public class BaseWeldBeforeStorageFilter<TPart, TRecord> : Orchard.ContentManagement.Handlers.IContentStorageFilter
where TPart: Orchard.ContentManagement.ContentPart, new()
where TRecord: Orchard.ContentManagement.Records.ContentPartRecord
{
// public
public BaseWeldBeforeStorageFilter(Orchard.Data.IRepository<TRecord> aPartRecords)
{
mPartRecords = aPartRecords;
}
...
public void Loading(Orchard.ContentManagement.Handlers.LoadContentContext aContext)
{
// dynamically weld TPart to content item when condition is met (is a user, does record exist)
if (aContext.ContentItem.Is<Orchard.Users.Models.UserPart>())
{
if (!aContext.ContentItem.Is<TPart>())
{
if (mPartRecords.Count(r => r.Id == aContext.ContentItem.Id) > 0)
aContext.ContentItem.Weld<TPart>();
}
}
}
...
// private
Orchard.Data.IRepository<TRecord> mPartRecords;
}
3) Define the content handler for the dynamic content part
public abstract class BasePartHandler<TPart, TRecord> : Orchard.ContentManagement.Handlers.ContentHandler
where TPart: Orchard.ContentManagement.ContentPart<TRecord>, new()
where TRecord: Orchard.ContentManagement.Records.ContentPartRecord, new()
{
// public
// the constructor of a content handler is called when a content item (e.g. user) is created
public BasePartHandler(Orchard.Data.IRepository<TRecord> aPartRecords)
{
...
// add storage filter for dynamically welding TPart to content item
Filters.Add(new BaseWeldBeforeStorageFilter<TPart, TRecord>(aPartRecords));
// enable storing TPart to associated table
Filters.Add(Orchard.ContentManagement.Handlers.StorageFilter.For<TRecord>(aPartRecords));
...
// listen to user creation, update, removal...
OnCreated<Orchard.Users.Models.UserPart>(UserCreated);
...
}
...
// private
private void UserCreated(Orchard.ContentManagement.Handlers.CreateContentContext aContext, Orchard.Users.Models.UserPart aUserPart)
{
if (...) // condition for checking whether user
CreatePartRecordWhenNeededAndWeldPart(aContext.ContentItem, ...);
}
private void CreatePartRecordWhenNeededAndWeldPart(Orchard.ContentManagement.ContentItem aContentItem)
{
TPart lPart = aContentItem.Weld<TPart>();
// assign record, adopted from StorageFilter.cs
// todo: find a way to do it the "Orchard way" as this feels like hack
lPart._record.Loader(r =>
new TRecord {
Id = aContentItem.Id,
ContentItemRecord = new Orchard.ContentManagement.Records.ContentItemRecord {Id = aContentItem.Id}
});
// there are situations where part record already exists in DB but part is not welded at this point, thus check for existing record to avoid
// - creating record multiple times
// - NHibernate exception
if (!mPartRecords.Table.Contains(lPart.Record))
mPartRecords.Create(lPart.Record);
}
private Orchard.Data.IRepository<TRecord> mPartRecords;
}
As for now, the dynamic content part handling is working but I'm still unsure how to create a content part record in Orchard properly (see todo hint in source code of step 3).