[Twisted-web] Python and Cors

Sun Aug 27 11:03:03 MDT 2017

Perhaps you just need to set the 'Access-Control-Allow-Origin' header?
Something like this might work:

# Import necessary files

import serial

from twisted.web.resource import Resource

# Setup Arduino at correct speed

try:

    arduino = serial.Serial('/dev/ttyACM0', 9600)

except:

    arduino = serial.Serial('/dev/ttyACM1', 9600)

class MoveServo(Resource):

    isLeaf = True

    permitted_origins = ('http://192.168.1.122:9000',)

    def render_GET(self,request):

        if origin in (self.permitted_origins):

            request.setHeader('Access-Control-Allow-Origin', origin)

        try:

            # Send value over serial to the Arduino

            arduino.write(request.args['value'][0])

            return 'Success'

        except:

            return 'Failure'

resource = MoveServo()

On 27 August 2017 at 17:10, Deve Krehbiel <deve at speedprint.com> wrote:

> First post so forgive me if I am not explaining this right.
>
> I am trying to make a baby cam and then heavily document it for everyone
> to have access to. I am using a Raspberry Pi with Rasbian. I am using
> mjpg-streamer for the streaming with no problems.
>
> The problem is I am also using two servos for pan and tilt. To accomplish
> this I am using an Arduino Uno. This is so I can add IR lighting for night
> vision, etc later. I am not a programmer so this is getting frustrating
> after a few weeks of failure.
>
> How is it failing you might ask..well, its working perfectly with only ONE
> exception:
> Every time I push the button for left/right/up/down I get this:
>
> XMLHttpRequest cannot load http://192.168.1.122:81/servos.rpy?value=100P.
> No 'Access-Control-Allow-Origin' header is present on the requested
> resource. Origin 'http://192.168.1.122:9000' is therefore not allowed
> access.
>
> On the local area network, it still works, but taking it to the internet
> it does not.
>
> Here are the two programs that make this happen. One is servos.rpy and the
> other is the supporting HTML/Get script;
> ****
> servos.rpy
> -----------------------------------
> # Import necessary files
> import serial
> from twisted.web.resource import Resource
> # Setup Arduino at correct speed
> try:
>         arduino = serial.Serial('/dev/ttyACM0', 9600)
> except:
>         arduino = serial.Serial('/dev/ttyACM1', 9600)
>
> class MoveServo(Resource):
>         isLeaf = True
>         def render_GET(self,request):
>                 try:
>                 # Send value over serial to the Arduino
>                         arduino.write(request.args['value'][0])
>                         return 'Success'
>                 except:
>                         return 'Failure'
>
> resource = MoveServo()
> ***
>
> Now for the HTML/Get script:
>
> **
> <!doctype html>
> <html>
> <head>
> <title>Make Use Of DIY Security Camera</title>
> <style type="text/css">
> #container {
> /* center the content */
> margin: 0 auto;
> text-align: center;
> }
> </style>
> </head>
> <body>
> <div id="container">
> <img src="/?action=stream" /><br>
> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/
> jquery.min.js"></script><br />
> <button onclick="servos.move('P', 10)">Left</button>
> <button onclick="servos.move('P', -10)">Right</button>
> <button onclick="servos.move('T', -10)">Down</button>
> <button onclick="servos.move('T', 10)">Up</button>
> </div>
> </body>
> <script>
> var servos;
> $( document ).ready(function() {
> servos = moveServos();
> });
> function moveServos() {
> // Store some settings, adjust to suit
> var panPos = 70,
> tiltPos = 90,
> tiltMax = 170,
> tiltMin = 45,
> panMax = 170,
> panMin = 20;
> return {
> move:function(servo, adjustment) {
> var value;
> if(servo == 'P') {
> if(!((panPos >= panMax && adjustment > 0) || (panPos <= panMin &&
> adjustment < 0))) {
> // Still within allowed range, "schedule" the movement
> panPos += adjustment;
> }
> value = panPos + 'P';
> }
> else if(servo == 'T') {
> if(!((tiltPos >= tiltMax && adjustment > 0) || (tiltPos <= tiltMin &&
> adjustment < 0))) {
> // Still within allowed range, "schedule" the movement
> tiltPos += adjustment;
> }
> value = tiltPos + 'T';
> }
> // Use AJAX to actually move the servo
> $.get('http://192.168.1.122:81/servos.rpy?value=' + value);
> },
> }
> }
> </script>
> </html>
>
> *****
> Twisted is started:  sudo twistd -n web -p 81 --path /usr/local/www/
>
> I would be forever grateful if someone could take a serious look at this
> and tell me where I am going wrong. Once this is fixed, I can start
> documenting the entire system for everyone. Thank you!
>
> Deve
>
> _______________________________________________
> Twisted-web mailing list
> Twisted-web at twistedmatrix.com
> https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web
>
>
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