第一种方法：
x = "some data you want to return"
return x, 200, {'Content-Type': 'text/css; charset=utf-8'}
第二种方法：
from flask import Response
r = Response(response="TEST OK", status=200, mimetype="application/xml")
r.headers["Content-Type"] = "text/xml; charset=utf-8"
return r
不建议使用。原因如
If you use Response directly, you lose the chance to customize the responses by setting app.response_class. The make_response method uses the app.responses_class to make the response object
第三种方法：
from flask import Flask, make_response
app = Flask(__name__)
@app.route('/')
def index():
bar = '<body>foo</body>'
response = make_response(bar)
response.headers['Content-Type'] = 'text/xml; charset=utf-8'
return response
