Content Providers 101 – Part II: From read-only to writable

// will contain all draft versions of attendee content

private List<Attendee> _attendees = new List<Attendee>();

public override ContentReference Save(IContent content, SaveAction action)

{

    // we have a new version. Either the attendee has been autosaved, or it has been published or a new one has been created

    var newVersion = content as Attendee;

    // new content - someone want to create a new attendee from the UI

    if (newVersion.ContentLink == ContentReference.EmptyReference)

    {

        var person = new Person()

        {

            Name = newVersion.Name,

            Company = newVersion.Company,

            Email = newVersion.Email,

            Title = newVersion.Title

        };

        PersonService.CreatePerson(person);

        newVersion = ConvertToAttendee(person);

        return newVersion.ContentLink;

    }

    // if the current version has the WorkID set to 0, the save event has fired for the first time since a publish.

    if (newVersion.ContentLink.WorkID == 0)

    {

        // indicate that this is not the published version

        newVersion.Status = VersionStatus.CheckedOut;

        newVersion.ContentLink.WorkID = 1;

        // adding the version to the in-memory list

        _attendees.Add(newVersion);

    }

    else

    {

        // save has been triggered with a draft and the publish button has been hit by the editor

        if (action == SaveAction.Publish)

        {

            // check if the email has been changed. This is important as the email serves as the unique identifier in the IdentityMappingService

            var identifier = IdentityMappingService.Service.Get(newVersion.ContentLink).ExternalIdentifier;

            if (IdentityMappingService.Service.Get(MappedIdentity.ConstructExternalIdentifier(ProviderKey,newVersion.Email)) == null)

            {

                // email has been changed as no mapping was found with the identifier

                // First, delete the identifier with the old email, and then map the content with the new email

                // if we had not done this, all previous references to the content would have become invalid

                IdentityMappingService.Service.Delete(identifier);

                IdentityMappingService.Service.MapContent(MappedIdentity.ConstructExternalIdentifier(ProviderKey, newVersion.Email), newVersion);

            }

            // update the data using the PersonService. The text file will now be updated!

            PersonService.UpdatePerson(identifier.Segments[1], newVersion.Email, newVersion.Title, newVersion.Name, newVersion.Company);

            // WorkId and status are being reverted, and the working copies in _attendees are removed.

            newVersion.ContentLink.WorkID = 0;

            newVersion.Status = VersionStatus.Published;

            _attendees.RemoveAll(x => x.ContentLink.ID.Equals(newVersion.ContentLink.ID));

        }

    }

    return newVersion.ContentLink;

}

protected override IContent LoadContent(ContentReference contentLink, ILanguageSelector languageSelector)

{

    // check for a matching working copy

    var attendee = _attendees.FirstOrDefault(p => p.ContentLink.Equals(contentLink));

    if (attendee == null)

    {

        // In order to return the attendee, the contentLink must be mapped to an e-mail so that the person object can be found using the PersonService

        MappedIdentity mappedIdentity = IdentityMappingService.Service.Get(contentLink);

        // the email is found in the ExternalIdentifier that was created earlier. Not that Segments[1] is used due to the fat that the ExternalIdentifier is an Uri.

        // It contains two segments. Segments[0] contains the content provider key, and Segments[1] contains the unique path, which is the e-mail in this case.

        string email = mappedIdentity.ExternalIdentifier.Segments[1];

        attendee = ConvertToAttendee(PersonService.GetPersonByEmail(email));

    }

    return attendee;

}

public override void Delete(ContentReference contentLink, bool forceDelete)

{

    var mappedIdentity = IdentityMappingService.Service.Get(contentLink);

    string email = mappedIdentity.ExternalIdentifier.Segments[1];

    PersonService.Delete(email);

    IdentityMappingService.Service.Delete(mappedIdentity.ExternalIdentifier);

}