What is JSON Schema?

Any valid JSON document has a specific structure of JSON fields and/or JSON arrays.

In case to make sure that a JSON document complies with an expected structure, you can define rules for such a JSON. Such rules can define for example:

• The name of fields

• The datatype of values

• The nesting structure

• The number of child items

• … and more.

The combination of such rules is called a JSON Schema. It is a formalized, worldwide defactor-standard to describe such rules. It is similar to XML Schema, DTD or Database Schemas.

See here for details about the official JSON schema specification: https://json-schema.org/

For example, let's define a simple JSON document that contains person data:

And now let's define a JSON Schema in order to formalize the rules for this person JSON document:

You can see, the JSON Schema defines four fields of different types: The firstName, lastName, age and gender of a person. So whenever a person JSON document is validated using this JSON Schema now, it must comply with exactly these rules. For example: In case such a person JSON document contains the attribute value age as string instead of a number, JSON Schema validation will fail.

Usage inside PIPEFORCE

In PIPEFORCE, a JSON Schema can be used mainly for these purposes:

• To define the widgets of a form in a Form Schema → Any Form Schema is a valid JSON Schema.

• To define the schema for list columns in a List Schema → Any List Schema is a valid JSON Schema.

• To define the schema of custom JSON documents and validate them whenever required using the command json.validate.

In order to get a full documentation of the JSON Schema specification, you should go to the official website at: https://json-schema.org.

Form Schema

A Form Schema is a JSON Schema which defines the validation, type and structure rules of widgets inside a PIPEFORCE Form. For more details see: Form Schema & Widgets (Model).

List Schema

A List Schema is a JSON Schema which defines the columns of a table (list) of a PIPEFORCE List. For more details see: Lists.

Define and validate a JSON object

You can also use a JSON Schema in order to specify the structure of a given JSON document (object). PIPEFORCE provides built-in toolings for storage, resolving and validation using JSON Schemas.

For more details see: Validating Properties.

Schema attribute type​

The type attribute inside a JSON schema defines the required data type of a JSON attribute. Possible values are:

• string

• number

• integer

• object

• array

• boolean

• null

Using these types you can specify the required data type of a field value inside a JSON document. For details, see the official documentation of these types: https://json-schema.org/understanding-json-schema/reference/type.html

Example:

Schema attribute format

The format attribute can be used for more precise semantic specification of string types. For example you can define whether a string must be a valid email address or URL for example.

Here is an example which uses the format attribute in order to define an email field:

There are several built-in formats available in the JSON Schema specification. Some example:

• date-time, time, date, duration

• email

• hostname

• ipv4, ipv6

• uuid

• uri

For a full list of built-in format types, see: https://json-schema.org/understanding-json-schema/reference/string.html#format

Schema Validation Rules

Below you can find some common validation rules in JSON Schema.​

Length​

Valid: hi

Regular expression​

Valid: 555-1212

Date and Time​

Valid: 2018-11-13T20:20:39+00:00

Time ​

Valid: 20:20:39+00:00

Date ​

Valid: 2018-11-13

Email​

Valid: my@email.de

Hostname​

Valid: google.com

Uri​

Valid: https://google.com

Required fields​