Adding A Server-Side Notification Handler To Umbraco Forms

using System.Linq;
using Microsoft.AspNetCore.Http;
using Umbraco.Cms.Core.Events;
using Umbraco.Forms.Core.Models;
using Umbraco.Forms.Core.Services.Notifications;

namespace MyFormsExtensions
{
    /// <summary>
    /// Catch form submissions before being saved and perform custom validation.
    /// </summary>
    public class FormValidateNotificationHandler : INotificationHandler<FormValidateNotification>
    {
        public void Handle(FormValidateNotification notification)
        {
            // If needed, be selective about which form submissions you affect.
            if (notification.Form.Name == "Form Name")
            {
                // Check the ModelState
                if (notification.ModelState.IsValid == false)
                {
                    return;
                }

                // A sample validation
                var email = GetPostFieldValue(notification.Form, notification.Context, "email");
                var emailConfirm = GetPostFieldValue(notification.Form, notification.Context, "verifyEmail");

                // If the validation fails, return a ModelError
                if (email.ToLower() != emailConfirm.ToLower())
                {
                    notification.ModelState.AddModelError(GetPostField(notification.Form, "verifyEmail").Id.ToString(), "Email does not match");
                }
            }
        }

        private static string GetPostFieldValue(Form form, HttpContext context, string key)
        {
            Field field = GetPostField(form, key);
            if (field == null)
            {
                return string.Empty;
            }


            return context.Request.HasFormContentType &&  context.Request.Form.Keys.Contains(field.Id.ToString())
                ? context.Request.Form[field.Id.ToString()].ToString().Trim()
                : string.Empty;
        }

        private static Field GetPostField(Form form, string key) => form.AllFields.SingleOrDefault(f => f.Alias == key);
    }
}

public static IUmbracoBuilder AddUmbracoFormsCoreProviders(this IUmbracoBuilder builder)
{
    builder.AddNotificationHandler<FormValidateNotification, FormValidateNotificationHandler>();
}

    public class TestSiteComposer : IComposer
    {
        public void Compose(IUmbracoBuilder builder)
        {
            builder.AddNotificationHandler<FormSavingNotification, FormSavingNotificationHandler>();
        }
    }

    public class FormSavingNotificationHandler : INotificationHandler<FormSavingNotification>
    {
        public void Handle(FormSavingNotification notification)
        {
            foreach (Form form in notification.SavedEntities)
            {
                foreach (Page page in form.Pages)
                {
                    foreach (FieldSet fieldset in page.FieldSets)
                    {
                        foreach (FieldsetContainer fieldsetContainer in fieldset.Containers)
                        {
                            foreach (Field field in fieldsetContainer.Fields)
                            {
                                field.Caption += " (updated)";
                            }
                        }
                    }
                }
            }
        }
    }

    public class TestSiteComposer : IComposer
    {
        public void Compose(IUmbracoBuilder builder)
        {
            builder.AddNotificationHandler<FormSavingNotification, FormSavingNotificationHandler>();
        }
    }

    public class FormSavingNotificationHandler : INotificationHandler<FormSavingNotification>
    {
        private readonly ILogger<FormSavingNotification> _logger;

        public FormSavingNotificationHandler(ILogger<FormSavingNotification> logger) => _logger = logger;

        public void Handle(FormSavingNotification notification)
        {
            foreach (Form savedEntity in notification.SavedEntities)
            {
                _logger.LogInformation($"Form updated. New parent: {savedEntity.FolderId}. Old parent: {notification.State["MovedFromFolderId"]}");
            }
        }
    }

    public class TestSiteComposer : IComposer
    {
        public void Compose(IUmbracoBuilder builder)
        {
            builder.AddNotificationHandler<EntrySearchResultFetchingNotification, EntrySearchResultFetchingNotificationHandler>();
        }
    }

    public class EntrySearchResultFetchingNotificationHandler : INotificationHandler<EntrySearchResultFetchingNotification>
    {
        public void Handle(EntrySearchResultFetchingNotification notification)
        {
            var transformedFields = new List<object>();
            foreach (var field in notification.EntrySearchResult.Fields)
            {
                if (field?.ToString() == "Test")
                {
                    transformedFields.Add("Test (updated)");
                }
                else
                {
                    transformedFields.Add(field);
                }
            }

            notification.EntrySearchResult.Fields = transformedFields;
        }
    }