✅ Pragma-Validators

A set of declarative validators for Pharo accessors, inspired by JSR-380 Java Bean Validation annotations.

🪄 Usage in a nutshell

1. Make a class, declare several inst vars and generate their corresponsing accessors.

Object subclass: #RegistrationRequest
    instanceVariableNames: 'username name password emails'
    classVariableNames: ''
    package: 'MyApplication-DataTransfer'

2. Annotate the accessors with desired validators. ^1),2)

2.1 Simple validation

username
    <validateAs: 'string'> "should be a string"
    <validateAs: 'notBlank'> "notBlank ~ should not be an empty string or whitespace"
    ^ username

2.2 Collection validation (note that ALL collection elements must conform to the declared validation pragmas)

emails
    <validateAs: '#string'>
    <validateAs: '#email'> "the '#' signifies that emails shoule be a collection"
                           "the 'email' signifies that each element of the collection"
                           "should be a string containing a valid email"
    ^ emails

3. Validate the object once filled. If the validations find a problem, PragmaValidationError will be raised.

| r |
r := RegistrationRequest new username: 'john'; emails: {'john@smalltalk.com'. 'jsmith@acme.com'}; validate.

1. Note that annotating a mutator or an accessor with a protocol different than "accessing" will not work.

2)The accessors are called in the process of validation, thus one must add additional code to them with caution.

📑 Supported validations

Validation	Usage Example	Description
notNil	<validateAs: 'notNil'>	Accessor value is not nil
assertTrue	<validateAs: 'assertTrue'>	Accessor value
size:MIN,MAX	<validateAs: 'size:1,3'>	Accessor value has a size between the attributes MIN and MAX; can be applied to any collection
min:VAL	<validateAs: 'min:100'>	Accessor value has a value no smaller than VAL
max:VAL	<validateAs: 'max:1000'>	Accessor value has a value no larger than VAL
email	<validateAs: 'email'>	Accessor value is a valid email address
notEmpty	<validateAs: 'notEmpty'>	Accessor value is not null or empty; can be applied to any collection
notBlank	<validateAs: 'notBlank'>	Accessor value is not null, empty string or string containing solely whitespace
positive	<validateAs: 'positive'>	Accessor value is strictly positive number
positiveOrZero	<validateAs: 'positiveOrZero'>	Accessor value is strictly positive number, or 0
negative	<validateAs: 'negative'>	Accessor value is strictly negative number
negativeOrZero	<validateAs: 'negativeOrZero'>	Accessor value is strictly negative number, or 0
datetimeString	<validateAs: 'datetimeString'>	Accessor value is a string containing date and time
past	<validateAs: 'past'>	Accessor value is a string containing date and time which is in the past
future	<validateAs: 'future'>	Accessor value is a string containing date and time which is in the future

🎁 Installation

Metacello new
    baseline: 'PragmaValidators';
    repository: 'github://radekbusa/Pragma-Validators';
    load.

🔌 Integration example

Let's say that we want to use the pragma validators for validating JSON request bodies in our RESTful API.

1. In a controller or a Teapot filter, write:

| body parsedBody |
body := aRequest entity string.
parsedBody := NeoJSONReader fromString: body as: RegistrationRequest.
parsedBody validate. "will validate each incoming request body"

🧩 Compatibility

Tested in Pharo 7, 8 and 9.

👨‍💻 Author

Radek Busa is the author and maintainer of this project.

• Tech blog: www.medium.com/@radekbusa
• Hire me for your next Smalltalk project: www.radekbusa.eu

"I love building enterprise-grade software products in no time and Pharo greatly contributes to that with its amazing debugger, test-driven environment and other great stuff, such as refactoring tools. My vision is to build libraries for ultra-productive enterprise microservice development with minimalistic and easy-to-grasp APIs for Smalltalk in 2020s."

If you endorse my vision and/or this project helped you, please don't hesitate to donate. Your donations will be welcome!