Creating Data extension field through SSJS (through API calling)

Question

I'm now testing a new method to create a data extension field automatically through REST API calling,referring to this developer DOC It's operated by POST method, and I think I wrote all of the elements(token access body, payload and endpoint etc) properly but still the code doesn't work. Would there be problem with 'Script.Util.HttpRequest' function? The request worked properly as I tried on the postman, so I think there's nothing wrong with the payload or request body itself. Here's the code, and it would be greatly helpful it you guys can give me some feedback on this. I filled out the variable properly when I tried out on my own account.

<script runat="server">
Platform.Load("Core", "1.1.1");

try {
    // TOKEN ACCESS
    var authEndpoint = 'HERE'S THE authEndpoint  ';
    var url = authEndpoint + '/v2/token';
    var payload = {
        "grant_type": "client_credentials",
        "client_id": {{client_id}},
        "client_secret": {{client_secret}},
        "account_id": {{account_id}}
    };
    var contentType = 'application/json';
    var accessTokenRequest = HTTP.Post(url, contentType, Stringify(payload));
    var accessToken;

    if (accessTokenRequest.StatusCode == 200) {
        var tokenResponse = Platform.Function.ParseJSON(accessTokenRequest.Response);
        accessToken = tokenResponse.access_token;
        var rows = Platform.Function.InsertData("API_createfields",["TOKEN"],[accessToken]);
    } else {
        Write("Failed to obtain access token. Status code: " + accessTokenRequest.StatusCode);
        throw new Error("Failed to obtain access token.");
    }

    // Define fields payload
    var payload2 = {
        "fields": [
            {
                "description": "Unique Contact Identifier",
                "isActive": true,
                "isHidden": false,
                "isInheritable": false,
                "isNullable": false,
                "isOverridable": false,
                "isPrimaryKey": false,
                "isReadOnly": false,
                "ordinal": 5,
                "isTemplateField": false,
                "length": 50,
                "maskType": "None",
                "mustOverride": false,
                "name": "ContactKey",
                "storageType": "Plain",
                "type": "Text"
            }
        ]
    };

    // API calling
    var deurl = 'https://{{restendpoint}}.rest.marketingcloudapis.com/data/v1/customobjectsasync/b979adcc-094f-ef11-b860-48df37d082c9/fields';
    var req = new Script.Util.HttpRequest(deurl);
    req.emptyContentHandling = 0;
    req.retries = 2;
    req.continueOnError = true;
    req.contentType = "application/json";
    req.setHeader("Authorization", "Bearer " + accessToken);
    req.method = "POST";
    req.postData = Stringify(payload2);
    var response = req.send();

    if (response.StatusCode < 200 || response.StatusCode >= 300) {
        Write("Error");
    } else {
        Write("Successful");
    }

} catch (e) {
    Write("error");
}

Answer 1

There are a couple mistakes here:

The response from your authenticate call should be a string so it can be parsed

var tokenResponse = Platform.Function.ParseJSON(String(accessTokenRequest.Response));

The status code for the 2nd call should be statusCode not StatusCode since you are using Script.Util.HttpRequest.

Also the status code = 202 means you successfully issued the HTTP request, it doesn't mean the request applied successfully on the DE.

You put the field attribute with "isNullable": false it may have the conflict if the DE already has some records there.

Here is my version:

<script runat="server">
Platform.Load("Core", "1.1.1");
// TOKEN ACCESS

var url = 'https://SubDomain.auth.marketingcloudapis.com/v2/token';
var payload = {
    "grant_type": "client_credentials",
    "client_id": 'Client ID',
    "client_secret": 'Client Secret'
};
var contentType = 'application/json';
var accessToken;

var accessTokenRequest = HTTP.Post(url, contentType, Stringify(payload));

if (accessTokenRequest.StatusCode == 200) {
    var tokenResponse = Platform.Function.ParseJSON(String(accessTokenRequest.Response));
    accessToken = tokenResponse.access_token;
} else {
    Write("Failed to obtain access token. Status code: " + accessTokenRequest.StatusCode);
}


// Define fields payload
var payload2 = {
    "fields": [
        {
            "description": "Unique Contact Identifier",
            "isActive": true,
            "isHidden": false,
            "isInheritable": false,
            "isNullable": true,
            "isOverridable": false,
            "isPrimaryKey": false,
            "isReadOnly": false,
            "ordinal": 5,
            "isTemplateField": false,
            "length": 50,
            "maskType": "None",
            "mustOverride": false,
            "name": "ContactKey",
            "storageType": "Plain",
            "type": "Text"
        }
    ]
};

// API calling
var deurl = 'https://SubDomain.rest.marketingcloudapis.com/data/v1/customobjectsasync/Data Extension ID/fields';
var req = new Script.Util.HttpRequest(deurl);
req.emptyContentHandling = 0;
req.retries = 2;
req.continueOnError = true;
req.contentType = "application/json";
req.setHeader("Authorization", "Bearer " + accessToken);
req.method = "POST";
req.postData = Stringify(payload2);
var response = req.send();

if (response.statusCode == 202){
    Write("Call API Successful");
} else {
    Write("Error");
}
</script>