How to fix 403 error when creating GoogleFit datasource - ios

Question

I am using GoogleFit Rest API to create a nutrition data source so that I can subsequently store nutrition information. I have done this successfully on Android via the GoogleFit SDK, but because no such SDK is available on iOS, I resorted to using the REST APIs via the link above. When trying to create the data source I am returned the following error:
{
"error": {
"code": 403,
"message": "The caller does not have permission",
"errors": [
{
"message": "The caller does not have permission",
"domain": "global",
"reason": "forbidden"
}
],
"status": "PERMISSION_DENIED"
}
}
and the POST request I am using is:
Endpoint: https://www.googleapis.com/fitness/v1/users/me/dataSources
Body:
{
"application": {
"detailsUrl": "https://strongfoundation.dev",
"name": "Strong Foundation",
"packageName": "com.coding.casa.Strong.Foundation",
"version": "1.0.1"
},
"dataStreamId": "raw:com.google.nutrition:com.coding.casa.Strong.Foundation:Apple:iPad Air (3rd generation):****",
"dataType": {
"name": "com.google.nutrition"
},
"device": {
"manufacturer": "Apple",
"model": "iPad Air (3rd generation)",
"type": "phone",
"uid": "*****",
"version": "15.7"
},
"name": "strong-foundation-food",
"type": "raw"
}
Has anyone seen this error and was able to resolve it? I have tried adding the API Key to the request, but that did not change the error, and I do have the Fitness API enabled on my project.
EDIT:
I am also supplying a Bearer token with the following authorized scopes
"https://www.googleapis.com/auth/fitness.activity.read",
"https://www.googleapis.com/auth/fitness.body.write",
"https://www.googleapis.com/auth/fitness.body.read",
"https://www.googleapis.com/auth/fitness.nutrition.read",
"https://www.googleapis.com/auth/fitness.nutrition.write",

Answer 1

You don't include the others details of the REST method call.
Importantly, HTTP 403 is Forbidden suggesting that you didn't include an Authorization header in your request with value Bearer {TOKEN} where {TOKEN} is an access token for an identity that has suitable scopes to access the API. See authorization
Although Swift is not one of Google's officially supported languages, Google has a Swift REST Client Generator for Google APIs and you should be able to use it to generate a Google client library for Swift for Google Fit.

Answer 2

Did some more playing around with the FitnessAPI (specifically creating data sources) and found the issues was with my request payload.
The payload that worked for me is as follows:
{
"application": {
"detailsUrl": "https://strongfoundation.dev",
"name": "Strong Foundation",
"version": "1.0.1"
},
"dataType": {
"name": "com.google.nutrition"
},
"device": {
"manufacturer": "Apple",
"model": "iPad Air (3rd generation)",
"type": "phone",
"uid": "****",
"version": "15.7"
},
"name": "strong-foundation-food",
"type": "raw"
}
The deltas from the original one are removed the following properties:
application.packageName
dataStreamId