解决javascript调用本地sanic接口报跨域错误的问题

在py代码中利用middleware()方法修饰request/response即可，无需别的操作。 

app=Sanic('Sanic_Server')

@app.middleware("request")
def cors_middle_req(request: Request):
    """路由需要启用OPTIONS方法"""
    if request.method.lower() == 'options':
        allow_headers = [
            'Authorization',
            'content-type'
        ]
        headers = {
            'Access-Control-Allow-Methods':
                ','.join(['GET','POST','OPTIONS']),
            'Access-Control-Max-Age': '86400',
            'Access-Control-Allow-Headers': ', '.join(allow_headers),
        }
        return HTTPResponse('', headers=headers)

@app.middleware("response")
def cors_middle_res(request: Request, response: HTTPResponse):
    """跨域处理"""
    allow_origin = '*'
    response.headers.update(
        {
            'Access-Control-Allow-Origin': allow_origin,
        }
    )