Fetch - Scoped, Global

The Fetch API provides methods for fetching resources using request and response objects.

You can use the Fetch API in a background script and wherever you can make HTTP calls (like a REST endpoint). The Fetch API allows you to make both simple and more complicated fetch requests by setting headers, body options, and so on.

This API is part of a set of Fetch APIs, which provide various actions for fetching resources from external websites. The full Fetch API collection includes:

• Fetch - fetch(String resource, Object options): Starts the process of fetching a resource from the network.
• Fetch Headers - Scoped, Global: Retrieve and modify request and response headers.
• Fetch Request - Scoped, Global: Create a new request object.
• Fetch RequestInit - Scoped, Global: Set options to configure a fetch request.
• Fetch Response - Scoped,Global: Create a new response object.

To support fetch actions, the system property, glide.hosts.allowlist, allows controls over what hosts a fetch method can access. It applies to HTTP APIs like RestMessageV2 and those mentioned above. For more information about glide.hosts.allowlist, see Available system properties.

Fetch - fetch(String resource, Object options)

Starts the process of fetching a resource from the network and returns a promise that is fulfilled once the response is available.

Tableau 1. Parameters

Name	Type	Description
resource	String or Object	Required. The resource to fetch. Accepted values: A string or an object with a stringifier, including a URL object, that provides the URL of the resource you want to fetch. The URL may be relative to the base URL which is the document's baseURI. A Fetch Request - Request() object.
options	Object	Optional. A Fetch RequestInit - Scoped, Global object containing custom settings to apply to the request. Default: The request is passed without any customization settings.

Tableau 2. Returns

Type

Description

Object

A promise that resolves to a response object. A fetch() promise only rejects when the request fails, for example, because of a badly-formed request URL or a network error. Remarque : A fetch() promise is not considered as rejected if the server responds with HTTP status codes that indicate errors like 404 or 504. In this instance, use a then() handler to check the ok and status Fetch Response - Scoped,Globalproperties.

The following example demonstrates how to form a new Request object using Fetch Request - Request() and then fetch() to retrieve its data. Here is a simple explanation of how each part of the code is used:

• request(): Configures the API request with URL, method, and headers.
• fetch(): Makes the fetch request.
• response.json(): Parses the JSON response body into a JavaScript object. (See Fetch Response - json() for more information.)
• console.log(): Outputs the incidents (data.result) using the Console API (See Console - log(Object val1...val2, String msg, String subst1...subst2)).

async function fetchIncidents() {
    const url = 'https://your-instance.service-now.com/api/now/table/incident';
    const username = 'your_username';
    const password = 'your_password';

    // Create a Request object
    const request = new Request(url, {
        method: 'GET',
        headers: {
            'Content-Type': 'application/json',
            Authorization: 'Basic ' + btoa(`${username}:${password}`)
        }
    });

    // Fetch data and use response.json() to process it
    const response = await fetch(request);
    const data = await response.json(); // Parse the response to JSON
    console.log(data.result); // Log the incidents data to system logs
}

fetchIncidents();

Output:

[
    { "number": "INC0001", "short_description": "System outage" },
    { "number": "INC0002", "short_description": "Password reset request" }
]