Adding Content-Type to Response produced 2 Content-Type headers

[vlads-copart]

curl -v localhost:8000
>GET / HTTP/1.1
>Host: localhost:8000
>User-Agent: curl/7.52.1
>Accept: */*

HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Server: BaseHTTP/0.3 Python/2.7.12
< Date: Thu, 27 Apr 2017 20:30:54 GMT
< Content-Length: 83
< Content-Type: application/xml
< Content-Type: application/xml
<
Curl_http_done: called premature == 0
Closing connection 0
<?xml version="1.0" encoding="UTF-8"?><Response><Say>Hello World</Say>

[jamesls]

Confirmed bug, thanks for reporting.

from chalice import Chalice, Response

app = Chalice(app_name='headerfix')


@app.route('/', content_types=['application/json'])
def index():
    return Response(body='{"foo": "bar"}',
                    status_code=200,
                    headers={'Content-Type': 'application/json'})

$ chalice local &
$ curl -vv localhost:8000
* Rebuilt URL to: localhost:8000/
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> GET / HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.43.0
> Accept: */*
>
127.0.0.1 - - [27/Apr/2017 17:09:26] "GET / HTTP/1.1" 200 -
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Server: BaseHTTP/0.3 Python/2.7.12
< Date: Fri, 28 Apr 2017 00:09:26 GMT
< Content-Length: 14
< Content-Type: application/json
< Content-Type: application/json
<
* Closing connection 0