Mercurial > p > roundup > code
view roundup/cgi/exceptions.py @ 5630:07abc8d36940
Add etag support to rest interface to prevent multiple users from
overwriting other users changes.
All GET requests for an object (issue, user, keyword etc.) or a
property of an object (e.g the title of an issue) return the etag for
the object in the ETag header as well as the @etag field in the
returned object.
All requests that change existing objects (DELETE, PUT or PATCH)
require:
1 A request include an ETag header with the etag value retrieved
for the object.
2 A submits a form that includes the field @etag that must have
the value retrieved for the object.
If an etag is not supplied by one of these methods, or any supplied
etag does not match the etag calculated at the time the DELETE, PUT or
PATCH request is made, HTTP error 412 (Precondition Failed) is
returned and no change is made. At that time the client code should
retrieve the object again, reconcile the changes and can try to send a
new update.
The etag is the md5 hash of the representation (repr()) of the object
retrieved from the database.
| author | John Rouillard <rouilj@ieee.org> |
|---|---|
| date | Fri, 01 Mar 2019 22:57:07 -0500 |
| parents | 32f95ec6bd8e |
| children | 1a835db41674 |
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"""Exceptions for use in Roundup's web interface. """ __docformat__ = 'restructuredtext' from roundup.exceptions import LoginError, Unauthorised import cgi class HTTPException(BaseException): pass class Redirect(HTTPException): pass class NotFound(HTTPException): pass class NotModified(HTTPException): pass class PreconditionFailed(HTTPException): pass class DetectorError(BaseException): """Raised when a detector throws an exception. Contains details of the exception.""" def __init__(self, subject, html, txt): self.subject = subject self.html = html self.txt = txt class FormError(ValueError): """An 'expected' exception occurred during form parsing. That is, something we know can go wrong, and don't want to alarm the user with. We trap this at the user interface level and feed back a nice error to the user. """ pass class SendFile(BaseException): """Send a file from the database.""" class SendStaticFile(BaseException): """Send a static file from the instance html directory.""" class SeriousError(BaseException): """Raised when we can't reasonably display an error message on a templated page. The exception value will be displayed in the error page, HTML escaped. """ def __str__(self): return """ <html><head><title>Roundup issue tracker: An error has occurred</title> <link rel="stylesheet" type="text/css" href="@@file/style.css"> </head> <body class="body" marginwidth="0" marginheight="0"> <p class="error-message">%s</p> </body></html> """%cgi.escape(self.args[0]) # vim: set filetype=python sts=4 sw=4 et si :
