json

//[doc-seo]
{
    "Description": "Add custom business logic to dynamic entity CRUD operations using Interceptors in the ABP Low-Code System. Validate, transform, and react to data changes with JavaScript."
}

Interceptors

Interceptors allow you to run custom JavaScript code before, after, or instead of Create, Update, and Delete operations on dynamic entities.

Interceptor Types

Command	Type	When Executed
`Create`	`Pre`	Before entity creation — validation, default values
`Create`	`Post`	After entity creation — notifications, related data
`Create`	`Replace`	Instead of entity creation — must return the new entity's Id (see below)
`Update`	`Pre`	Before entity update — validation, authorization
`Update`	`Post`	After entity update — sync, notifications
`Update`	`Replace`	Instead of entity update — no return value needed
`Delete`	`Pre`	Before entity deletion — dependency checks
`Delete`	`Post`	After entity deletion — cleanup
`Delete`	`Replace`	Instead of entity deletion — no return value needed

Defining Interceptors with Attributes

Use the [DynamicEntityCommandInterceptor] attribute on a C# class:

csharp

[DynamicEntity]
[DynamicEntityCommandInterceptor(
    "Create",
    InterceptorType.Pre,
    "if(!context.commandArgs.data['Name']) { globalError = 'Name is required!'; }"
)]
[DynamicEntityCommandInterceptor(
    "Create",
    InterceptorType.Post,
    "context.log('Entity created: ' + context.commandArgs.entityId);"
)]
public class Organization
{
    public string Name { get; set; }
}

The Name parameter must be one of: "Create", "Update", or "Delete". The InterceptorType can be Pre, Post, or Replace. When Replace is used, the default database operation is completely skipped and only your JavaScript handler executes. Multiple interceptors can be added to the same class (AllowMultiple = true).

Defining Interceptors with Fluent API

Use the Interceptors list on an EntityDescriptor to add interceptors programmatically in your Low-Code Initializer:

csharp

AbpDynamicEntityConfig.EntityConfigurations.Configure(
    "MyApp.Organizations.Organization",
    entity =>
    {
        entity.Interceptors.Add(new CommandInterceptorDescriptor("Create")
        {
            Type = InterceptorType.Pre,
            Javascript = "if(!context.commandArgs.data['Name']) { globalError = 'Name is required!'; }"
        });

        entity.Interceptors.Add(new CommandInterceptorDescriptor("Delete")
        {
            Type = InterceptorType.Post,
            Javascript = "context.log('Deleted: ' + context.commandArgs.entityId);"
        });
    }
);

See Attributes & Fluent API for more details on Fluent API configuration.

Defining Interceptors in model.json

Add interceptors to the interceptors array of an entity:

json

{
  "name": "LowCodeDemo.Customers.Customer",
  "interceptors": [
    {
      "commandName": "Create",
      "type": "Pre",
      "javascript": "if(context.commandArgs.data['Name'] == 'Invalid') {\n  globalError = 'Invalid Customer Name!';\n}"
    }
  ]
}

Interceptor Descriptor

Field	Type	Description
`commandName`	string	`"Create"`, `"Update"`, or `"Delete"`
`type`	string	`"Pre"`, `"Post"`, or `"Replace"`
`javascript`	string	JavaScript code to execute

JavaScript Context

Inside interceptor scripts, you have access to:

`context.commandArgs`

Property / Method	Type	Description
`data`	object	Entity data dictionary (for Create/Update)
`entityId`	string	Entity ID (for Update/Delete)
`commandName`	string	Command name (`"Create"`, `"Update"`, or `"Delete"`)
`entityName`	string	Full entity name
`getValue(name)`	function	Get a property value
`setValue(name, value)`	function	Set a property value (Pre-interceptors only)
`hasValue(name)`	function	Check if a property exists in the data
`removeValue(name)`	function	Remove a property from the data

`context.currentUser`

Property / Method	Type	Description
`isAuthenticated`	bool	Whether user is logged in
`id`	string	User ID
`userName`	string	Username
`email`	string	Email address
`name`	string	First name
`surName`	string	Last name
`phoneNumber`	string	Phone number
`phoneNumberVerified`	bool	Whether phone is verified
`emailVerified`	bool	Whether email is verified
`tenantId`	string	Tenant ID (for multi-tenant apps)
`roles`	string[]	User's role names
`isInRole(roleName)`	function	Check if user has a specific role

`context.emailSender`

Property / Method	Description
`isAvailable`	Whether the email sender is configured and available
`sendAsync(to, subject, body)`	Send a plain-text email
`sendHtmlAsync(to, subject, htmlBody)`	Send an HTML email

Logging

Method	Description
`context.log(message)`	Log an informational message
`context.logWarning(message)`	Log a warning message
`context.logError(message)`	Log an error message

Use these methods instead of console.log (which is blocked in the sandbox).

`db` (Database API)

Full access to the Scripting API for querying and mutating data.

`globalError`

Set this variable to a string to abort the operation and return an error:

javascript

globalError = 'Cannot delete this entity!';

Examples

Pre-Create: Validation

json

{
  "commandName": "Create",
  "type": "Pre",
  "javascript": "if(!context.commandArgs.data['Name']) {\n  globalError = 'Organization name is required!';\n}"
}

Post-Create: Email Notification

json

{
  "commandName": "Create",
  "type": "Post",
  "javascript": "if(context.currentUser.isAuthenticated && context.emailSender) {\n  await context.emailSender.sendAsync(\n    context.currentUser.email,\n    'New Order Created',\n    'Order total: $' + context.commandArgs.data['TotalAmount']\n  );\n}"
}

Pre-Update: Role-Based Authorization

json

{
  "commandName": "Update",
  "type": "Pre",
  "javascript": "if(context.commandArgs.data['IsDelivered']) {\n  if(!context.currentUser.roles.includes('admin')) {\n    globalError = 'Only administrators can mark orders as delivered!';\n  }\n}"
}

Pre-Delete: Business Rule Check

json

{
  "commandName": "Delete",
  "type": "Pre",
  "javascript": "var project = await db.get('LowCodeDemo.Projects.Project', context.commandArgs.entityId);\nif(project.Budget > 100000) {\n  globalError = 'Cannot delete high-budget projects!';\n}"
}

Pre-Update: Negative Value Check

json

{
  "commandName": "Update",
  "type": "Pre",
  "javascript": "if(context.commandArgs.data['Quantity'] < 0) {\n  globalError = 'Quantity cannot be negative!';\n}"
}

Replace-Create: Custom Insert Logic

When you need to completely replace the default create operation with custom logic:

json

{
  "commandName": "Create",
  "type": "Replace",
  "javascript": "var data = context.commandArgs.data;\ndata['Code'] = 'PRD-' + Date.now();\nvar result = await db.insert('LowCodeDemo.Products.Product', data);\ncontext.log('Product created with custom code: ' + data['Code']);\nreturn result.Id;"
}

Important: Replace-Create interceptors must return the new entity's Id (Guid). The system uses this value to fetch and return the created entity. Use return result.Id; after db.insert(...).

Replace-Update and Replace-Delete interceptors do not need to return a value.

Pre-Update: Self-Reference Check

json

{
  "commandName": "Update",
  "type": "Pre",
  "javascript": "if(context.commandArgs.data.ParentCategoryId === context.commandArgs.entityId) {\n  globalError = 'A category cannot be its own parent!';\n}"
}

Interceptors

Interceptors

Interceptor Types

Defining Interceptors with Attributes

Defining Interceptors with Fluent API

Defining Interceptors in model.json

Interceptor Descriptor

JavaScript Context

context.commandArgs

context.currentUser

context.emailSender

Logging

db (Database API)

globalError

Examples

Pre-Create: Validation

Post-Create: Email Notification

Pre-Update: Role-Based Authorization

Pre-Delete: Business Rule Check

Pre-Update: Negative Value Check

Replace-Create: Custom Insert Logic

Pre-Update: Self-Reference Check

See Also

`context.commandArgs`

`context.currentUser`

`context.emailSender`

`db` (Database API)

`globalError`