Bitbucket API - Unable to Generate Access Token from JWT - jwt

Question

I'm using Bitbucket Connect App and getting JWT token from webhook event.
When I am using the latest JWT to get access token, the access token API returning blank in response.
API:
curl -X POST -H "Authorization: JWT {jwt_token}" \ https://bitbucket.org/site/oauth2/access_token \ -d grant_type=urn:bitbucket:oauth2:jwt
Example:
curl -X POST -H "Authorization: JWT ey*****XVCJ9.eyJpc3MiOi****asdfQ.**BBD**" \
https://bitbucket.org/site/oauth2/access_token \
-d grant_type=urn:bitbucket:oauth2:jwt
Response
{blank}
API Reference:
https://developer.atlassian.com/cloud/bitbucket/oauth-2/
Thanks

Answer 1

I had the same problem until I added the sub key to the payload. Set the value to the value received in clientKey during the app installation lifeycle event.

Answer 2

I followed this documentation to generate Access Token and it worked.
https://pawelniewiadomski.com/2016/06/06/building-bitbucket-add-on-in-rails-part-7/
Most of the Part for generating access token using Bitbucket Cloud API
def get_access_token
unless current_jwt_auth
raise 'Missing Authentication context'
end
# Expiry for the JWT token is 3 minutes from now
issued_at = Time.now.utc.to_i
expires_at = issued_at + 180
jwt = JWT.encode({
iat: issued_at,
exp: expires_at,
iss: current_jwt_auth.addon_key,
sub: current_jwt_auth.client_key
}, current_jwt_auth.shared_secret)
response = HTTParty.post("#{current_jwt_auth.base_url}/site/oauth2/access_token", {
body: {grant_type: 'urn:bitbucket:oauth2:jwt'},
headers: {
'Content-Type' => 'application/x-www-form-urlencoded',
'Authorization' => 'JWT ' + jwt
}
})
if response.code == 200
Response.new(200, response.parsed_response)
else
Response.new(response.code)
end
end