Content Migration from one to another property for live site

In one of my projects I recently faced an issue where we have to change all the standard category properties to IList<ContentReference> and the site was live so we just couldn't take the field and get it over with.

So I create new IList<ContentReference> properties and migrate the data and change the logic. Here are the steps that I followed.

Step To follow:-

• • Create new fields -- for all categories while don't remove old ones once
  • Create a scheduled job that migrates data from the old field to the new field
  • Switch the logic from old to new fields as new fields have multiple categories
  • remove old fields (only after running the migration job)

Step-1:-

We create new Ilist<contentreference> properties for every standard category property.

 [Display(
            Name = "Something",
            GroupName = SystemTabNames.Content,
            Order = 10)]
        [Categories]
        public virtual IList<ContentReference> Something { get; set; }

Step-2:-

Here we have to write the code so that content that is already existing on the live site migrates from old to new properties.

Few things that I did while creating a scheduled job:

• • • • Get all the pages where I changed the property, So for that, I created a generic method.

 private IEnumerable<T> GetDataList<T>()
            where T : ContentData
        {
            var objectType = _contentTypeRepository.Load<T>();
            var usages = _contentModelUsage.ListContentOfContentType(objectType)
                .Select(x => x.ContentLink.ToReferenceWithoutVersion())
                .Distinct()
                .Select(x => _contentLoader.Get<IContentData>(x))
                .OfType<T>()
                .ToList();
            return (IEnumerable<T>)usages;
        }

• • • • After this method call loop through all the pages and create a writeable clone so that we change the data
      • invoke the list and then assign the value to it.

 OnStatusChanged($"Migration start for ChapterDetailPage");

            var chapterDetailPages = GetDataList<ChapterDetailPage>();
            if (chapterDetailPages != null)
            {
                foreach (var cdp in chapterDetailPages)
                {
                    //migrate data
                    var page = (ChapterDetailPage)cdp.CreateWritableClone();
                    page.LocationIdNew = new List<ContentReference>();

                    var hit = _getaCatRep.TryGet(new ContentReference(page.LocationID), out stdCat) ? stdCat : null;
                    if (hit != null)
                    {
                        page.LocationIdNew.Add(hit.ContentLink);
                        _contentRepository.Save(page, SaveAction.Publish, AccessLevel.NoAccess);
                    }
                }
            }

            OnStatusChanged($"Migration end for ChapterDetailPage");

• • • • Then Save the page using the Content Repository.

Step-3

Change all the existing logic so that pages don't error.

Step-4

The last step will be to remove all old properties.