CORS on App Engine

For Python-based applications in Google App Engine, the self.response.headers.add_header() method can be used, such as:

class CORSEnabledHandler(webapp.RequestHandler):
  def get(self):
    self.response.headers.add_header("Access-Control-Allow-Origin", "*")
    self.response.headers['Content-Type'] = 'text/csv'

For Java-based applications, use resp.addHeader():

public void doGet(HttpServletRequest req, HttpServletResponse resp) {
  resp.addHeader("Access-Control-Allow-Origin", "*");
  resp.addHeader("Content-Type", "text/csv");

And for Go-based applications, use w.Header().Add():

func doGet(w http.ResponseWriter, r *http.Request) {
  w.Header().Add("Access-Control-Allow-Origin", "*")
  w.Header().Add("Content-Type", "text/csv")
  fmt.Fprintf(w, csvData)

Who’s behind this

Monsur Hossain and Michael Hausenblas


The content on this site stays fresh thanks to help from users like you! If you have suggestions or would like to contribute, fork us on GitHub.

Buy the book

Save 39% on CORS in Action with promotional code hossainco at