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"""A simple number and datetime addition JSON API.
Run the app:
$ python examples/tornado_example.py
Try the following with httpie (a cURL-like utility, http://httpie.org):
$ pip install httpie
$ http GET :5001/
$ http GET :5001/ name==Ada
$ http POST :5001/add x=40 y=2
$ http POST :5001/dateadd value=1973-04-10 addend=63
$ http POST :5001/dateadd value=2014-10-23 addend=525600 unit=minutes
"""
import datetime as dt
import tornado.ioloop
from tornado.web import RequestHandler
from webargs import fields, validate
from webargs.tornadoparser import use_args, use_kwargs
class BaseRequestHandler(RequestHandler):
def write_error(self, status_code, **kwargs):
"""Write errors as JSON."""
self.set_header("Content-Type", "application/json")
if "exc_info" in kwargs:
etype, exc, traceback = kwargs["exc_info"]
if hasattr(exc, "messages"):
self.write({"errors": exc.messages})
if getattr(exc, "headers", None):
for name, val in exc.headers.items():
self.set_header(name, val)
self.finish()
class HelloHandler(BaseRequestHandler):
"""A welcome page."""
hello_args = {"name": fields.Str(load_default="Friend")}
@use_args(hello_args)
def get(self, args):
response = {"message": "Welcome, {}!".format(args["name"])}
self.write(response)
class AdderHandler(BaseRequestHandler):
"""An addition endpoint."""
add_args = {"x": fields.Float(required=True), "y": fields.Float(required=True)}
@use_kwargs(add_args)
def post(self, x, y):
self.write({"result": x + y})
class DateAddHandler(BaseRequestHandler):
"""A date adder endpoint."""
dateadd_args = {
"value": fields.Date(required=False),
"addend": fields.Int(required=True, validate=validate.Range(min=1)),
"unit": fields.Str(
load_default="days", validate=validate.OneOf(["minutes", "days"])
),
}
@use_kwargs(dateadd_args)
def post(self, value, addend, unit):
"""A date adder endpoint."""
value = value or dt.datetime.utcnow()
if unit == "minutes":
delta = dt.timedelta(minutes=addend)
else:
delta = dt.timedelta(days=addend)
result = value + delta
self.write({"result": result.isoformat()})
if __name__ == "__main__":
app = tornado.web.Application(
[(r"/", HelloHandler), (r"/add", AdderHandler), (r"/dateadd", DateAddHandler)],
debug=True,
)
port = 5001
app.listen(port)
print(f"Serving on port {port}")
tornado.ioloop.IOLoop.instance().start()
|
