From: Brian Warner Date: Sat, 7 Mar 2009 11:54:08 +0000 (-0700) Subject: web/common: split out exception-to-explanation+code mapping to a separate humanize_fa... X-Git-Tag: allmydata-tahoe-1.4.0~84 X-Git-Url: https://git.rkrishnan.org/%5B/frontends/%22news.html//%22%22.?a=commitdiff_plain;h=badd79671c55f263427ace41161b6261f93bae46;p=tahoe-lafs%2Ftahoe-lafs.git web/common: split out exception-to-explanation+code mapping to a separate humanize_failure() function, so it can be used by other code. Add explanation for mutable UnrecoverableFileError. --- diff --git a/src/allmydata/web/common.py b/src/allmydata/web/common.py index c47eabeb..5c337581 100644 --- a/src/allmydata/web/common.py +++ b/src/allmydata/web/common.py @@ -6,6 +6,7 @@ from nevow.inevow import IRequest from nevow.util import resource_filename from allmydata.interfaces import ExistingChildError, NoSuchChildError, \ FileTooLargeError, NotEnoughSharesError +from allmydata.mutable.common import UnrecoverableFileError from allmydata.util import abbreviate # TODO: consolidate class IOpHandleTable(Interface): @@ -114,6 +115,45 @@ def should_create_intermediate_directories(req): return bool(req.method in ("PUT", "POST") and t not in ("delete", "rename", "rename-form", "check")) +def humanize_failure(f): + # return text, responsecode + if f.check(ExistingChildError): + return ("There was already a child by that name, and you asked me " + "to not replace it.", http.CONFLICT) + if f.check(NoSuchChildError): + name = f.value.args[0] + return ("No such child: %s" % name.encode("utf-8"), http.NOT_FOUND) + if f.check(NotEnoughSharesError): + got = f.value.got + needed = f.value.needed + if got == 0: + t = ("NotEnoughSharesError: no shares could be found. " + "Zero shares usually indicates a corrupt URI, or that " + "no servers were connected, but it might also indicate " + "severe corruption. You should perform a filecheck on " + "this object to learn more.") + else: + t = ("NotEnoughSharesError: %d share%s found, but we need " + "%d to recover the file. This indicates that some " + "servers were unavailable, or that shares have been " + "lost to server departure, hard drive failure, or disk " + "corruption. You should perform a filecheck on " + "this object to learn more.") % (got, plural(got), needed) + return (t, http.GONE) + if f.check(UnrecoverableFileError): + t = ("UnrecoverableFileError: the directory (or mutable file) could " + "not be retrieved, because there were insufficient good shares. " + "This might indicate that no servers were connected, " + "insufficient servers were connected, the URI was corrupt, or " + "that shares have been lost due to server departure, hard drive " + "failure, or disk corruption. You should perform a filecheck on " + "this object to learn more.") + return (t, http.GONE) + if f.check(WebError): + return (f.value.text, f.value.code) + if f.check(FileTooLargeError): + return (f.getTraceback(), http.REQUEST_ENTITY_TOO_LARGE) + return (str(f), None) class MyExceptionHandler(appserver.DefaultExceptionHandler): def simple(self, ctx, text, code=http.BAD_REQUEST): @@ -130,40 +170,10 @@ class MyExceptionHandler(appserver.DefaultExceptionHandler): req.finishRequest(False) def renderHTTP_exception(self, ctx, f): - traceback = f.getTraceback() - if f.check(ExistingChildError): - return self.simple(ctx, - "There was already a child by that " - "name, and you asked me to not " - "replace it.", - http.CONFLICT) - elif f.check(NoSuchChildError): - name = f.value.args[0] - return self.simple(ctx, - "No such child: %s" % name.encode("utf-8"), - http.NOT_FOUND) - elif f.check(NotEnoughSharesError): - got = f.value.got - needed = f.value.needed - if got == 0: - t = ("NotEnoughSharesError: no shares could be found. " - "Zero shares usually indicates a corrupt URI, or that " - "no servers were connected, but it might also indicate " - "severe corruption. You should perform a filecheck on " - "this object to learn more.") - else: - t = ("NotEnoughSharesError: %d share%s found, but we need " - "%d to recover the file. This indicates that some " - "servers were unavailable, or that shares have been " - "lost to server departure, hard drive failure, or disk " - "corruption. You should perform a filecheck on " - "this object to learn more.") % (got, plural(got), needed) - return self.simple(ctx, t, http.GONE) - elif f.check(WebError): - return self.simple(ctx, f.value.text, f.value.code) - elif f.check(FileTooLargeError): - return self.simple(ctx, str(f.value), http.REQUEST_ENTITY_TOO_LARGE) - elif f.check(server.UnsupportedMethod): + text, code = humanize_failure(f) + if code is not None: + return self.simple(ctx, text, code) + if f.check(server.UnsupportedMethod): # twisted.web.server.Request.render() has support for transforming # this into an appropriate 501 NOT_IMPLEMENTED or 405 NOT_ALLOWED # return code, but nevow does not. @@ -180,6 +190,7 @@ class MyExceptionHandler(appserver.DefaultExceptionHandler): super = appserver.DefaultExceptionHandler return super.renderHTTP_exception(self, ctx, f) # use plain text + traceback = f.getTraceback() return self.simple(ctx, traceback, http.INTERNAL_SERVER_ERROR) class NeedOperationHandleError(WebError):