Flask throwing 'working outside of request context' when starting sub thread

Wrap your thread code in a test_request_context so you have access to context locals:

@app.route('/my_endpoint', methods=['POST'])def my_endpoint_handler():    #do tracking in sub-thread so we don't hold up the page    def handle_sub_view(req):        with app.test_request_context():            from flask import request            request = req            # Do Expensive work    thread.start_new_thread(handle_sub_view, (request))    return "Thanks"

Edit: it's worth pointing out that the thread will have a different context than the original request. You need to extract any interesting request data, such as the user ID, before spawning the thread. You can then grab a (different) user object in the sub-thread using the ID.

Since version 0.10 there is a supported way of doing this: http://flask.pocoo.org/docs/api/#flask.copy_current_request_context

If you want the before_request hooks to run you must call current_app.preprocess_request() inside of the decorated function.

As @runfalk pointed out, you'll need to use @copy_current_request_context. Here's a working code snippet:

import threadingfrom flask import request, jsonify, copy_current_request_context@app.route('/foo')def get_foo():    @copy_current_request_context    def foo_main():        # insert your code here        print(request.url)    threading.Thread(target=foo_main).start()    return jsonify({'status': 'started'})