+     def parse_chroot_path(self, path):

+         """

+         Take a `path` in an `owner/project/chroot` format and return a tuple of

+         the corresponding values, i.e. `(owner, project, chroot)`

+         """

+         m = re.match(r"(([^/]+)/)?([^/]+)/(.*)", path)

+         if m:

+             owner = m.group(2) or self.config["username"]

+             return owner, m.group(3), m.group(4)

+         raise CoprException("Unexpected chroot path format")

+ 

+         owner, copr, chroot = self.parse_chroot_path(args.coprchroot)

+         owner, copr, chroot = self.parse_chroot_path(args.coprchroot)

+ from coprs.error_handlers import get_error_handler

+ @app.errorhandler(Exception)

+ """

+ A place for exception-handling logic

+ """

+ 

+ import flask

+ from werkzeug.exceptions import HTTPException, NotFound, GatewayTimeout

+ from coprs.exceptions import CoprHttpException

+ from coprs.views.misc import (

+     generic_error,

+     access_restricted,

+     bad_request_handler,

+     conflict_request_handler,

+     page_not_found,

+ )

+ 

+ 

+ def get_error_handler():

+     """

+     Determine what error handler should be used for this request

+     See http://flask.pocoo.org/docs/1.0/blueprints/#error-handlers

+     """

+     if flask.request.path.startswith('/api_3/'):

+         return APIErrorHandler()

+     return UIErrorHandler()

+ 

+ 

+ class BaseErrorHandler:

+     """

+     Do not use this class for handling errors. It is only a parent class for

+     the actual error-handler classes.

+     """

+ 

+     def handle_error(self, error):

+         """

+         Return a flask response suitable for the current situation (e.g. reder

+         HTML page for UI failures, send JSON back to API client, etc).

+ 

+         This method is expected to be implemented in descendants of this class.

+         """

+         raise NotImplementedError

+ 

+     def code(self, error):  # pylint: disable=no-self-use

+         """

+         Return status code for a given exception

+         """

+         return getattr(error, "code", 500)

+ 

+     def message(self, error):  # pylint: disable=no-self-use

+         """

+         Return an error message for a given exception. We want to obtain messages

+         differently for `CoprHttpException`, `HTTPException`, or others.

+         """

+         if isinstance(error, HTTPException):

+             return error.description

+         return str(error)

+ 

+ 

+ class UIErrorHandler(BaseErrorHandler):

+     """

+     Handle exceptions raised from the web user interface

+     """

+ 

+     def handle_error(self, error):

+         code = self.code(error)

+         message = self.message(error)

+ 

+         # The most common error has their own custom error pages. When catching

+         # a new exception, try to keep it simple and just the the generic one.

+         # Create it's own view only if necessary.

+         error_views = {

+             400: bad_request_handler,

+             403: access_restricted,

+             404: page_not_found,

+             409: conflict_request_handler,

+         }

+         if code in error_views:

+             return error_views[code](message)

+         return generic_error(message, code)

+ 

+ 

+ class APIErrorHandler(BaseErrorHandler):

+     """

+     Handle exceptions raised from API (v3)

+     """

+ 

+     def handle_error(self, error):

+         code = self.code(error)

+         message = self.message(error)

+ 

+         # In the majority of cases, we want to return the message that was

+         # passed through an exception, but occasionally we want to redefine the

+         # message to some API-related one. Please try to keep it simple and

+         # do this only if necessary.

+         errors = {

+             NotFound: "Such API endpoint doesn't exist",

+             GatewayTimeout: "The API request timeouted",

+         }

+         if error.__class__ in errors:

+             message = errors[error.__class__]

+ 

+         # Every `CoprHttpException` and `HTTPException` failure has valuable

+         # message for the end user. It holds information that e.g. some value is

+         # missing or incorrect, something cannot be done, something doesn't

+         # exist. Eveything else should really be an uncaught exception caused by

+         # either not properly running all frontend requirements (PostgreSQL,

+         # Redis), or having a bug in the code.

+         if not any([isinstance(error, CoprHttpException),

+                     isinstance(error, HTTPException)]):

+             message = ("Request wasn't successful, "

+                        "there is probably a bug in the API code.")

+         return self.respond(message, code)

+ 

+     def respond(self, message, code):  # pylint: disable=no-self-use

+         """

+         Return JSON response suitable for API clients

+         """

+         response = flask.jsonify(error=message)

+         response.status_code = code

+         return response

+ from werkzeug.exceptions import HTTPException, NotFound, GatewayTimeout

+         r1 = self.tc.get("/api_3/", follow_redirects=True)

+         r1 = self.tc.get("/api_3/", follow_redirects=True)

+         assert r1.status_code == 500

+         data = json.loads(r1.data)

+         assert "Whatever unspecified error" in data["error"]

+ 

+     @new_app_context

+     def test_api_500_default_message(self):

+         def raise_exception():

+             raise CoprHttpException

+         app.view_functions["apiv3_ns.home"] = raise_exception

+         r1 = self.tc.get("/api_3/", follow_redirects=True)

+         assert r1.status_code == 500

+         data = json.loads(r1.data)

+         assert "Generic copr exception" in data["error"]

+ 

+     @new_app_context

+     def test_api_500_runtime_error(self):

+         def raise_exception():

+             raise RuntimeError("Whatever unspecified error")

+         app.view_functions["apiv3_ns.home"] = raise_exception

+         r1 = self.tc.get("/api_3/", follow_redirects=True)

+         r1 = self.tc.get("/api_3/", follow_redirects=True)

+         r1 = self.tc.get("/api_3/", follow_redirects=True)