How to automatically authenticate Google Drive through Docusign API - google-apps-script

Question

I am creating an app with Google apps script to send Docusign envelopes to customers when I receive a google form from them (with the responses going into a google sheet with an onFormSubmit trigger). I'm using the Docusign REST API envelopes method to create an envelope, and send directly to the customer.
Once a customer submits their form, my google apps script function will automatically create a pdf document and put it in a google drive folder. I'm using the Docusign Envelopes method with "remoteUrl" parameter (reference in the document section here: https://docs.docusign.com/esign/restapi/Envelopes/Envelopes/create/) to specifiy the google drive document ID (the pdf) from which Docusign will create the envelope from.
Obviously, these pdf files are in my google drive, and mine only, so there's no reason for me to login to my google account every day, and that's the issue I'm having. When I try to run the script without signing into google, the Docusign API throws this error message:
"errorCode": "EXTERNAL_DOC_SERVICE_ERROR", "message": "An error occurred in the external doc service. NotAuthenticated"
Is there a way I can possibly use refresh tokens with one of Google's APIs to stay logged in? In layman's terms, a method of "auto-authentication". It would have to somehow communicate with my script using the Docusign API.
Here is my current Google Apps Script:
function Docusign() {
var ss = SpreadsheetApp.openById('MYSPREADSHEETID');
var sheet = ss.getSheetByName("SHEET");
var quotesheet = ss.getSheetByName("SHEET2");
var Avals = sheet.getRange("A1:A").getValues();
var Alast = Avals.filter(String).length;
var basicinfo = sheet.getRange(Alast, 1, 1, 35).getValues()[0];
var quotelinks = quotesheet.getRange(Alast, 1, 1, 10).getValues()[0];
var name = (basicinfo[2]);
var email = (basicinfo[1]);
//This is where the full links of the pdfs are stored
var doc = (quotelinks[0]);
//"DIGITS" is six digits followed by a colon, it might be private so I put "DIGITS" instead
var sub = "DIGITS" + doc.substring(32,65);
Logger.log(sub);
var url = "https://demo.docusign.net/restApi/v2/accounts/MYACCOUNTID/envelopes";
var payload =
{
"documents": [
{
"documentId": "1",
"fileExtension": "pdf",
"name": "NAMEOFDOC",
"remoteUrl": sub
}
],
"emailSubject": "SUBJECT",
"recipients": {
"signers": [
{
"email": email,
"name": name,
"recipientId": "1",
"tabs": {
"signHereTabs": [
{
"documentId": "1",
"pageNumber": "1",
"tabLabel": "Signature",
"xPosition": "140",
"yPosition": "650"
}
],
"dateTabs": [
{
"documentId": "1",
"pageNumber": "1",
"tabLabel": "date",
"xPosition": "420",
"yPosition": "680"
}
]
}
}
]
},
"status": "sent"
};
var options =
{
"contentType": "application/json",
"method" : "post",
"headers":
{
"X-DocuSign-Authentication": "{\"Username\":\"MYUSERNAME\",\"Password\":\"MYPASSWORD\",\"IntegratorKey\":\"MYINTEGRATORKEY\"}",
},
"payload" : JSON.stringify(payload)
};
UrlFetchApp.fetch(url, options);
}
Any help would be greatly appreciated.

Answer 1

You can try one thing, go to DocuSign webApp and do OAUTH to Google Drive once (by adding document from G Drive at the time of sending an envelope), this way you are giving permission to DocuSign to fetch documents from Google Drive on your behalf.
Once you Google OAUTH is done, then you can use DocuSign API to fetch documents from Google drive using Remote URL. For instance, in below call "112805:0B1-EnSmMAIOmc3RhcnRlcl9maWx" is the id of the document in the Google Drive. So using DS API, I am able to fetch the document and add it to my envelope creation API call.
"documents": [
{
"remoteUrl":"112806:0B1-EnSmMAIOmc3RhcnRlcl9maWx",
"documentId": "1",
"name": "Getting started"
}
]