title: How to get access to a private spreadsheet from the API?
body: <p>Hello I need to get access to a spreadsheet from google spreadsheet API. I have enabled Google Sheets API and added API key, but this doesn't work!!!
  <a href="https://sheets.googleapis.com/v4/spreadsheets/[my_spreadsheet_id]/values/A1?key=[my_api_key]" rel="noreferrer">https://sheets.googleapis.com/v4/spreadsheets/[my_spreadsheet_id]/values/A1?key=[my_api_key]</a></p>
  
  <p>The result is: 
  403 - The caller does not have permission</p>
  
  <p>But if I provide public access for this spreadsheet ---> it works!!!</p>
  
  <p>The result is: 
  200 - [correct requested data .....]</p>
  
  <p>The my question is:
  How to get access to a private spreadsheet from the API?</p>
  
  <p>I need to read and write orders data there from my website using php's functions like file_get_contents()</p>