Postman Collection Bearer Token Pre-Request Script

azure-rest-apis-with-postman-pre-request-script.js

if (!pm.collectionVariables.get("bearerToken") || Date.now() > new Date(pm.collectionVariables.get("bearerTokenExpiresOn") * 1000)) {
    pm.sendRequest({
        url: 'https://login.microsoftonline.com/' + pm.collectionVariables.get("tenantId") + '/oauth2/token',
        method: 'POST',
        header: 'Content-Type: application/x-www-form-urlencoded',
        body: {
            mode: 'urlencoded',
            urlencoded: [
                { key: "grant_type", value: "client_credentials", disabled: false },
                { key: "client_id", value: pm.collectionVariables.get("clientId"), disabled: false },
                { key: "client_secret", value: pm.collectionVariables.get("clientSecret"), disabled: false },
                { key: "resource", value: pm.collectionVariables.get("resource") || "https://management.azure.com/", disabled: false }
            ]
        }
    }, function (err, res) {
        if (err) {
            console.log(err);
        } else {
            let resJson = res.json();
            pm.collectionVariables.set("bearerTokenExpiresOn", resJson.expires_on);
            pm.collectionVariables.set("bearerToken", resJson.access_token);
        }
    });
}