Not receiving Google OAuth refresh token

I want to get the access token from Google. The Google API says that to get the access token, send the code and other parameters to token generating page, and the response will be a JSON Object like :

{
"access_token" : "ya29.AHES6ZTtm7SuokEB-RGtbBty9IIlNiP9-eNMMQKtXdMP3sfjL1Fc",
"token_type" : "Bearer",
"expires_in" : 3600,
"refresh_token" : "1/HKSmLFXzqP0leUihZp2xUt3-5wkU7Gmu2Os_eBnzw74"
}

However, I'm not receiving the refresh token. The response in my case is:

{
 "access_token" : "ya29.sddsdsdsdsds_h9v_nF0IR7XcwDK8XFB2EbvtxmgvB-4oZ8oU",
"token_type" : "Bearer",
"expires_in" : 3600
}

The refresh_token is only provided on the first authorization from the user. Subsequent authorizations, such as the kind you make while testing an OAuth2 integration, will not return the refresh_token again. :)

1. Go to the page showing Apps with access to your account: https://myaccount.google.com/u/0/permissions.
2. Under the Third-party apps menu, choose your app.
3. Click Remove access and then click Ok to confirm
4. The next OAuth2 request you make will return a refresh_token (providing that it also includes the 'access_type=offline' query parameter.

Alternatively, you can add the query parameters prompt=consent&access_type=offline to the OAuth redirect (see Google's OAuth 2.0 for Web Server Applications page).

This will prompt the user to authorize the application again and will always return a refresh_token.