Validating Input

In some cases it is important to validate the state of the flow. This can be done as the first state in the flow to protect the flow from rogue data or within the flow to check the state data before proceeding. Direktiv is using JSON schema to validate the state data.

Check Attribute

direktiv_api: workflow/v1
states:
- id: data
  type: noop
  transform: 
    name: Michael
  transition: check
- id: check
  type: validate
  schema:
    type: object
    required: 
    - name
    properties:
      name:
        type: string

The above example will succedd because the attribute name is set and it is a string, in this case Michael. If the the value would be an integer the flow would fail.

Failed Attribute

direktiv_api: workflow/v1
states:
- id: start
  type: validate
  schema:
    type: object
    required: 
    - name
    properties:
      name:
        type: string

JSON schema is used to validate JSON structures and not contents. It can not validate if the value of name has a certain content. If that is a requirement Direktiv's switch statement has to be used.

First State

Direktiv can generate a form if the validate state is the first state in the flow.

Validate Form

direktiv_api: workflow/v1
states:
- id: start
  type: validate
  schema:
    type: object
    required: 
    - name
    properties:
      name:
        type: string
        title: Name
        description: Please enter your name
        default: My Name

In this example the default attribute is used and it is shown in the form. Direktiv can not set defaults via API or in a running flow. It is for form generation only. If defaults are required jq can be used like jq(.name // "Michael"). The following validate would ask for the name but set it to Michael if it is empty.

Setting Defaults

direktiv_api: workflow/v1
states:
- id: start
  type: validate
  schema:
    type: object
    properties:
      name:
        type: string
        title: Name
        description: Please enter your name
  transition: next-state
- id: next-state
  type: noop
  transform: 'jq(. + { name: (.name // "Michael") })'