title: Python, Flask: How to set response header for all responses
body: <p>I want to set all of my http headers responses to something like this:</p>
  
  <pre><code>response.headers["X-Frame-Options"] = "SAMEORIGIN"
  </code></pre>
  
  <p>I checked <a href="https://stackoverflow.com/questions/25860304/how-do-i-set-response-headers-in-flask">this question</a>, but it only changes the header for one specific controller. I want to change all of my headers maybe in "before_request" function similar to the following logic. How can I do that?</p>
  
  <pre><code>@app.before_request
  def before_request():
      # response.headers["X-Frame-Options"] = "SAMEORIGIN"
  </code></pre>