Add Object Mappings APIs

[hishamco]

Related to #14920

@jtkech I think it's good to map the objects automatically, to avoid such missing. I remember we can apply this pattern in places in the code-base

[sebastienros]

Do we need an abstraction? Maybe just use the mapper directly when necessary. We could think that one day we want to change it but I don't think that would be an issue, just replace with new calls. Or maybe a static helper to wrap the implementation (not suggesting it).

[sebastienros]

Do you have arguments for/against Mapster?

[hishamco]

Or maybe a static helper to wrap the implementation (not suggesting it).

I thought to introduce a static helper at the beginning, but later I thought about the extensibility which is not an issue as you mentioned

Do you have arguments for/against Mapster?

I just looked for some top implementations, of course AutoMapper is one of the popular object mappings libraries but it requires configuration. In the end, I decided to put simplicity & efficiency on top of my head

If you prefer something else in terms of performance, please suggest it, you're our PERF guru :)

[hishamco]

If we agree about the principal I might need to add several unit tests

[MikeAlhayek]

I used AutoMapper in a large project in the past. It made things easy in terms of mapping 1:1 objects. But when properties don't match up, you'll have to configure it so it understands how to map. I think I had a MapFrom and MapTo properties that would allow me to define any custom properties.

What happens when you want to define mappers? Do we have to register all these mappers to the IoC? Could this be an over kill at a framework level?

I don't mind auto mapping from coding perspective. I am just concern about performance issues that we could end up with. Like could we end up with 100s of mapper implementations that needs to be evaluated and added to the IoC container?

We just think about the pros and cons of bringing this to a framework.

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[hishamco]

@sebastienros while I'm cleaning up my PRs, is it fine to introduce an object Mappings APIs such other frameworks or shall I use a static class / method to handle the case I faced in SMTP settings

[Piedone]

Having used AutoMapper before as well, it's awesome when everything is simple, 1-1 mapping with similar properties. When not, you have to juggle around and end up with less than beautiful code.

I think using some auto-mapper is good if you write such mapping code a lot, but not if you write it infrequently but run it all the time (because then there's a performance penalty).

In OC, all the viewmodel-model mappings might be a good candidate too (but there can be security implications, so maybe again we end up ith something more complex).

However, I think this only makes sense if we use source generators: then, there's no practical runtime impact, just build time, but that we can live with if we can delete a lot of code. Could you try something like https://github.com/riok/mapperly?

[hishamco]

I will try to use mapperly or build something custom for OC, let me start on it then properly demo it next week to get the feedback

[hishamco]

I'm still struggling to use a generic version instead of creating a mapper per type. I'm not sure if the generic works well with mapperly I did a quick example but the unit tests fails

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It seems that this pull request didn't really move for quite a while. Is this something you'd like to revisit any time soon or should we close? Please comment if you'd like to pick it up and remove the "stale" label.

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[hishamco]

@Piedone is this something I should continue with?

[Piedone]

I don't think this matter is too important because I don't think having some kind of auto-mapping would bring much value, but I'm open to being convinced. If you're interested in the topic for personal reasons then I'd recommend you do a small PoC with a source generator and then we can discuss.

[hyzx86]

I also use AutoMapper in my OC projects, and it's really handy when I need to convert from a ContentPart to an object type, using the following configuration

    public class ContentFieldsMappings : Profile
    {
        public ContentFieldsMappings()
        {
            #region OC fileds maping

            CreateMap<MultiTextField, string[]>().ConvertUsing(s => s.Values);
            CreateMap<LinkField, string>().ConvertUsing(s => s == null ? default : s.Text);
            CreateMap<HtmlField, string>().ConvertUsing(s => s == null ? default : s.Html);
            CreateMap<TextField, string>().ConvertUsing(s => s == null ? default : s.Text);
            CreateMap<BooleanField, bool?>().ConvertUsing(s => s == null ? default : s.Value);
            CreateMap<BooleanField, bool>().ConvertUsing(s => s == null ? false : s.Value);

            CreateMap<NumericField, decimal?>().ConvertUsing(s => s == null ? default : s.Value);
            CreateMap<NumericField, decimal>().ConvertUsing(s => s == null ? 0 : Convert.ToInt64(s.Value));

            CreateMap<NumericField, int?>().ConvertUsing(s => s == null ? default : Convert.ToInt32(s.Value));
            CreateMap<NumericField, int>().ConvertUsing(s => s == null ? 0 : Convert.ToInt32(s.Value));

            CreateMap<NumericField, long?>().ConvertUsing(s => s == null ? default : Convert.ToInt64(s.Value));
            CreateMap<NumericField, long>().ConvertUsing(s => s == null ? 0 : Convert.ToInt64(s.Value));

            CreateMap<UserPickerField, string[]>().ConvertUsing(s => s == null ? default : s.UserIds);
            CreateMap<UserPickerField, string>().ConvertUsing(s =>
             s != null && s.UserIds != null && s.UserIds.Length > 0 ?
                            s.UserIds.FirstOrDefault() : string.Empty);

            CreateMap<ContentPickerField, string[]>().ConvertUsing(s => s.ContentItemIds ?? Array.Empty<string>());
            CreateMap<ContentPickerField, string>().ConvertUsing(s =>
                                s != null && s.ContentItemIds != null && s.ContentItemIds.Length > 0 ?
                            s.ContentItemIds.FirstOrDefault() : string.Empty);

            CreateMap<DateField, DateTime?>().ConvertUsing(s => s == null ? default : s.Value);
            CreateMap<DateField, DateTime>().ConvertUsing(s => s == null ? default : s.Value.GetValueOrDefault());

            CreateMap<DateTimeField, DateTime?>().ConvertUsing(s => s == null ? default : s.Value);
            CreateMap<DateTimeField, DateTime>().ConvertUsing(s => s == null ? default : s.Value.GetValueOrDefault());

            CreateMap<TimeField, TimeSpan?>().ConvertUsing(s => s == null ? default : s.Value);
            CreateMap<TimeField, TimeSpan>().ConvertUsing(s => s == null ? default : s.Value.GetValueOrDefault());

            CreateMap<JObject, object>().ConvertUsing(s => s == null ? default : s.ToObject<object>());
            CreateMap<JValue, object>().ConvertUsing(s => s == null ? default : s.Value);

            CreateMap<ContentTypeDefinition, ContentTypeDefinitionDto>().ConvertUsing((s, t) => s == null ? default : s.ToDto());
            CreateMap<ContentPartDefinition, ContentPartDefinitionDto>().ConvertUsing((s, t) => s == null ? default : s.ToDto());
            #endregion

            CreateMap<ContentItem, ContentItemIndex>();

        }
    }

[MikeAlhayek]

for instructions on how to resolve the merge conflicts due to #16572 please follow the step listed in this comment.