Accessing Dataclass Catalog

Overview

The $catalog endpoint provides metadata about the dataclasses and attributes available in your Qodly application's datastore. This metadata facilitates the discovery of data structures and access points essential for client applications interacting with the API.

The $catalog endpoint also provides shared singletons available in the application.

$catalog Endpoint Variants

The $catalog endpoint offers several variants to retrieve different levels of information based on your requirements:

Endpoint	Description
$catalog	Lists shared singletons (if any) and all dataclasses with basic access URIs.
$catalog/$all	Lists shared singletons (if any) and provides detailed information about all dataclasses and their attributes.
$catalog/{{dataClass}}	Delivers detailed information about a specific dataclass.
$catalog/{{dataStoreClassFunction}}	Executes a specific datastore class function if available.

Properties Returned

Common Properties

Each response from the $catalog endpoint variants includes some common properties:

Key	Type	Description
__UNIQID	String	A unique identifier for the API response session.
__BASEID	null/String	Base identifier, typically null, indicating no base is used.
__NAME	String	The name of the Qodly application to identify the session context.
properties	Object	Contains additional settings or flags relevant to the response.
↪ supportJSONEntityKey	Boolean	Indicates if JSON entity keys are supported, here it is true.
methods	Array of Objects	Lists methods available for execution through the data store. For more details, please refer to the Methods Array Details section.
dataClasses	Array of Objects	Lists dataclasses exposed through the API.

Methods Array

The methods array provides details about specific functionalities that can be executed through the REST API. Each method object includes the following attributes:

Property	Type	Description
name	String	Name of the method.
applyTo	String	Indicates the target of the method (e.g., "dataStore").
scope	String	Scope of accessibility (e.g., "public").
from	String	Origin of the method execution capability, such as "remoteServer".
allowedOnHTTPGET	Boolean	Specifies whether the method can be called via HTTP GET requests.
exposed	Boolean	Indicates if the method is exposed to the API.

$catalog

Purpose

Fetches a list of all dataclasses within the project, providing essential URIs for accessing more detailed metadata.

Properties Returned

Each dataclass listed by the $catalog endpoint returns the following properties:

Key	Type	Description
name	String	The name of the dataclass, here it is "Users".
uri	String	URI to obtain detailed metadata about the dataclass.
dataURI	String	URI to access the actual data directly from the dataclass.

tip

Only the exposed dataclasses are shown in this list for your project's datastore. For more information, please refer to Configuring Data Access section.

Sample Usage Example in Postman

How to Use:

• Method: GET
• URL: {{APIEndpoint}}/rest/$catalog

The response structure for the $catalog endpoint looks something like this in practice:

{
    "__UNIQID": "F182BFDB899C45A587EFA25AE271891D",
    "__BASEID": null,
    "__NAME": "plum-rap",
    "properties": {
        "supportJSONEntityKey": true
    },
    "methods": [
        {
            "name": "checkAvailability",
            "applyTo": "dataStore",
            "scope": "public",
            "from": "remoteServer",
            "allowedOnHTTPGET": false,
            "exposed": true
        }
    ],
    "dataClasses": [
        {
            "name": "Users",
            "uri": "/rest/$catalog/Users",
            "dataURI": "/rest/Users"
        }
    ]
}

$catalog/$all

Purpose

Provides exhaustive details on each dataclass and their attributes, enhancing understanding of data structure and types.

Properties Returned

This endpoint enriches the response with detailed attributes of each dataclass:

Key	Type	Description
dataClasses	Array	Lists all data classes exposed through the API, detailing each class and its associated data and metadata.

info

For a detailed breakdown of individual dataclasses and their specific attributes, please refer to the detailed documentation in the $catalog/{{dataClass}} section.

Sample Usage Example in Postman

How to Use:

• Method: GET
• URL: {{APIEndpoint}}/rest/$catalog/$all

The response structure for the $catalog/$all endpoint looks something like this in practice:

{
    "__UNIQID": "F182BFDB899C45A587EFA25AE271891D",
    "__BASEID": null,
    "__NAME": "plum-rap",
    "properties": {
        "supportJSONEntityKey": true
    },
    "methods": [
        {
            "name": "checkAvailability",
            "applyTo": "dataStore",
            "scope": "public",
            "from": "remoteServer",
            "allowedOnHTTPGET": false,
            "exposed": true
        }
    ],
    "dataClasses": [
        {
            "name": "Users",
            "className": "Users",
            "collectionName": "UsersSelection",
            "exposed": true,
            "tableNumber": 4,
            "scope": "public",
            "uuid": "FA61573F7FB84A8D83CD04215B757F34",
            "dataURI": "/rest/Users",
            "extraProperties": {
                "panelColor": "rgb(68,68,68)",
                "position": {
                    "x": -169.20168158481,
                    "y": 246.41374517022
                }
            },
            "attributes": [
                {
                    "name": "ID",
                    "kind": "storage",
                    "fieldPos": 1,
                    "scope": "public",
                    "exposed": true,
                    "uuid": "94A7339AE34D4C4C8B0F870D975717EC",
                    "indexed": true,
                    "unique": true,
                    "not_null": true,
                    "autosequence": true,
                    "type": "long",
                    "identifying": true
                },
                {
                    "name": "Name",
                    "kind": "storage",
                    "fieldPos": 2,
                    "scope": "public",
                    "exposed": true,
                    "uuid": "40ED3EBC298147FBA23CA0C03107A2C6",
                    "type": "string"
                }
            ],
            "key": [
                {
                    "name": "ID"
                }
            ]
        }
    ]
}

$catalog/{{dataClass}}

Purpose

Fetches comprehensive information about a specific dataclass, including its attributes and their properties.

Properties Returned (dataClasses Array)

The properties of the dataclasses returned by the API are:

Key	Type	Description
name	String	The name of the dataclass.
className	String	The class name as defined in the datastore.
collectionName	String	The name used for entity collections derived from this dataclass.
exposed	Boolean	Indicates if the dataclass is exposed to the API.
tableNumber	Integer	Numerical identifier for the table in the database.
scope	String	Visibility scope of the dataclass (e.g., 'public').
uuid	String	A unique identifier for the dataclass.
dataURI	String	API endpoint URI for accessing the dataclass's data.
extraProperties	Object	Contains additional, non-standard properties of the dataclass.
↪ panelColor	String	Color configuration for UI elements, if applicable.
↪ position	Object	Position settings for UI elements, defined by coordinates x and y.
attributes	Array of Objects	Defines the attributes (fields) available within the dataclass.

info

Each dataclass includes various attributes, the details of which are described in the subsequent section on attributes properties.

attributes Array Details

Each attribute within a dataclass has properties that describe its configuration and purpose within the datastore:

Key	Type	Description
name	String	The name of the attribute.
kind	String	The type of attribute (e.g., 'storage', 'relatedEntities').
fieldPos	Integer	Position of the attribute in the database table.
scope	String	Visibility scope of the attribute (e.g., 'public').
exposed	Boolean	Indicates if the attribute is exposed to the API.
uuid	String	A unique identifier for the attribute.
indexed	Boolean	Indicates if the attribute is indexed.
unique	Boolean	Indicates if the attribute must be unique.
not_null	Boolean	Indicates if the attribute must not be null.
autosequence	Boolean	Indicates if the attribute uses auto-incrementing.
type	String	Data type of the attribute (e.g., 'long', 'string').
identifying	Boolean	Indicates if the attribute is a primary key.
reversePath	Boolean	For related entities, indicates if the relationship is inverse.
path	String	Path to the related dataclass for relationship definitions.
key	Array	Defines the primary key attributes for the dataclass.

Sample Usage Example in Postman

How to Use:

• Method: GET
• URL: {{APIEndpoint}}/rest/$catalog/{{dataClass}}, e.g., {{APIEndpoint}}/rest/$catalog/Users

The response structure for the $catalog/{{dataClass}} endpoint looks something like this in practice:

{
    "__UNIQID": "F182BFDB899C45A587EFA25AE271891D",
    "__BASEID": null,
    "__NAME": "plum-rap",
    "properties": {
        "supportJSONEntityKey": true
    },
    "methods": [
        {
            "name": "checkAvailability",
            "applyTo": "dataStore",
            "scope": "public",
            "from": "remoteServer",
            "allowedOnHTTPGET": false,
            "exposed": true
        }
    ],
    "dataClasses": [
        {
            "name": "Users",
            "className": "Users",
            "collectionName": "UsersSelection",
            "exposed": true,
            "tableNumber": 4,
            "scope": "public",
            "uuid": "FA61573F7FB84A8D83CD04215B757F34",
            "dataURI": "/rest/Users",
            "extraProperties": {
                "panelColor": "rgb(68,68,68)",
                "position": {
                    "x": -169.20168158481,
                    "y": 246.41374517022
                }
            },
            "attributes": [
                {
                    "name": "ID",
                    "kind": "storage",
                    "fieldPos": 1,
                    "scope": "public",
                    "exposed": true,
                    "uuid": "94A7339AE34D4C4C8B0F870D975717EC",
                    "indexed": true,
                    "unique": true,
                    "not_null": true,
                    "autosequence": true,
                    "type": "long",
                    "identifying": true
                },
                {
                    "name": "Name",
                    "kind": "storage",
                    "fieldPos": 2,
                    "scope": "public",
                    "exposed": true,
                    "uuid": "40ED3EBC298147FBA23CA0C03107A2C6",
                    "type": "string"
                }
            ],
            "key": [
                {
                    "name": "ID"
                }
            ]
        }
    ]
}

singletons

If you have defined shared singletons containing at least one exposed function, a singletons section is added to the returned json for both the /$catalog and /$catalog/$all syntaxes. It contains the collection of singleton classes as objects with their name and methods (i.e., exposed functions).

Singleton functions can be called by REST requests using the $singleton command.

Example

GET /rest/$catalog/$all

Result:

{...
	singletons": [
    {
      "name": "VehicleFactory",
      "methods": [
        {
          "name": "buildVehicle",
          "allowedOnHTTPGET": false,
          "exposed": true
        }
      ]
    }
  ],

	dataClasses: [...]
}