Data Validation

Ductape lets you define validation rules for Action inputs, ensuring data consistency and integrity before requests are sent.

Overview

When you import Actions, Ductape automatically detects input parameters from the request body, query strings, headers, and route parameters. You can then configure validation rules to:

• Enforce required fields
• Set minimum and maximum lengths
• Define data types
• Provide default values
• Add decorators for display formatting

Prerequisites

Before configuring validation, ensure you have:

1. The Ductape SDK installed and initialized
2. An App with imported Actions

TypeScript

import Ductape from '@ductape/sdk';

const ductape = new Ductape({
  accessKey: 'your-access-key',
});

Validation Properties

Field	Type	Description
description	string	Explanation of the field's purpose
required	boolean	Whether the field is mandatory
maxLength	number	Maximum allowed length for strings
minLength	number	Minimum allowed length for strings
decorator	string	Text or symbol displayed alongside the value
decoratorPosition	DecoratorPositions	Position of the decorator (PREPEND, APPEND, or UNSET)
type	DataTypes	The expected data type
defaultValue	string | number | boolean	Default value if none is provided
sampleValue	string | number | object	Example demonstrating expected format

Selector Format

To update validation, you need to specify which field you're targeting using a selector string:

Selector	Target
$Body{action_tag}{...}{key}	Request body fields
$Query{action_tag}{...}{key}	URL query parameters
$Params{action_tag}{...}{key}	Route parameters
$Header{action_tag}{...}{key}	HTTP headers

Nested Fields

For nested objects, chain the keys:

$Body{createUser}{user}{profile}{firstName}

This targets body.user.profile.firstName in the createUser Action.

Updating Validation Rules

Use ductape.apps.validation() to set validation rules:

TypeScript

await ductape.apps.validation(selector, validationRules);

Example: Username Validation

TypeScript

await ductape.apps.validation('$Body{createUser}{user}{username}', {
  description: 'Username for the new account',
  required: true,
  type: 'nospaces_string',
  maxLength: 30,
  minLength: 3,
  defaultValue: '',
});

Example: Price Field with Decorator

TypeScript

import { DecoratorPositions } from '@ductape/sdk/types';

await ductape.apps.validation('$Body{createProduct}{product}{price}', {
  description: 'Price of the product in USD',
  required: true,
  type: 'float',
  decorator: '$',
  decoratorPosition: DecoratorPositions.PREPEND,
  defaultValue: 0.0,
});

Example: Array of Tags

TypeScript

await ductape.apps.validation('$Body{createBlogPost}{post}{tags}', {
  description: 'Tags associated with the blog post',
  type: 'array-string',
  defaultValue: [],
});

Example: Required UUID Parameter

TypeScript

await ductape.apps.validation('$Params{getUser}{id}', {
  type: 'uuid',
  required: true,
  description: 'Unique identifier for the user',
});

Data Types

Type	Value	Description	Example
STRING	"string"	General string	"Hello World"
NOSPACES_STRING	"nospaces_string"	String without spaces	"NoSpaces"
EMAIL_STRING	"email_string"	Valid email format	"user@example.com"
NUMBER_STRING	"numberstring"	Number in string format	"12345"
INTEGER	"number"	Whole number	42
FLOAT	"float"	Floating-point number	3.14
DOUBLE	"double"	Double-precision number	123.456789
UUID	"uuid"	UUID format	"550e8400-e29b-41d4..."
ARRAY	"array"	General array	[1, "text", true]
OBJECT	"object"	Object structure	{ key: "value" }
BOOLEAN	"boolean"	Boolean value	true
STRING_ARRAY	"array-string"	Array of strings	["apple", "banana"]
INTEGER_ARRAY	"array-number"	Array of integers	[1, 2, 3]
FLOAT_ARRAY	"array-float"	Array of floats	[1.1, 2.2, 3.3]
DOUBLE_ARRAY	"array-double"	Array of doubles	[1.123456, 2.654321]
UUID_ARRAY	"array-uuid"	Array of UUIDs	["550e8400-..."]
BOOLEAN_ARRAY	"array-boolean"	Array of booleans	[true, false]

Decorator Positions

Position	Value	Description	Example
PREPEND	"BEFORE"	Decorator appears before value	$100
APPEND	"AFTER"	Decorator appears after value	100$
UNSET	""	No decorator	100

Complete Example

Here's a complete example setting up validation for a user registration Action:

TypeScript

import Ductape from '@ductape/sdk';
import { DecoratorPositions } from '@ductape/sdk/types';

async function setupValidation() {
  const ductape = new Ductape({
    accessKey: 'your-access-key',
  });

  // Username validation
  await ductape.apps.validation('$Body{registerUser}{username}', {
    description: 'Unique username for the account',
    required: true,
    type: 'nospaces_string',
    minLength: 3,
    maxLength: 20,
  });

  // Email validation
  await ductape.apps.validation('$Body{registerUser}{email}', {
    description: 'Email address for account verification',
    required: true,
    type: 'email_string',
  });

  // Age validation
  await ductape.apps.validation('$Body{registerUser}{age}', {
    description: 'User age (must be 18 or older)',
    required: false,
    type: 'number',
    defaultValue: 18,
  });

  // Roles validation
  await ductape.apps.validation('$Body{registerUser}{roles}', {
    description: 'User roles for access control',
    required: false,
    type: 'array-string',
    defaultValue: ['user'],
  });

  console.log('Validation rules configured successfully');
}

setupValidation().catch(console.error);

Best Practices

Use Meaningful Descriptions

TypeScript

// Good
await ductape.apps.validation('$Body{createOrder}{total}', {
  description: 'Total order amount including tax and shipping',
});

// Avoid
await ductape.apps.validation('$Body{createOrder}{total}', {
  description: 'Total', // Too vague
});

Set Appropriate Constraints

TypeScript

// Prevent data overflow
await ductape.apps.validation('$Body{createPost}{title}', {
  maxLength: 200,
  minLength: 1,
  required: true,
});

Use Default Values for Optional Fields

TypeScript

await ductape.apps.validation('$Body{createUser}{status}', {
  required: false,
  defaultValue: 'pending',
});

Choose the Correct Data Type

TypeScript

// Use specific types for better validation
await ductape.apps.validation('$Body{sendEmail}{to}', {
  type: 'email_string', // Not just 'string'
  required: true,
});

Next Steps

• Running Actions - Execute Actions with validated inputs
• Managing Actions - Update Action configuration
• Actions Overview - Return to Actions overview

See Also

• Getting Started with Apps - Create and configure Apps
• Constants & Variables - Dynamic configuration values