python - Catch exception and output them to django's messages system -

so noticed django has nice message framework. has 5 different levels (info, error, debug, warning, , success).

it nice propagate exception way views level, , report of these exceptions.

lib.py

def read_file(user, filename, **kwargs):    try:      open(...):         return f.read()    except exception, e:      raise e 

utli.py

def wrapper_read_file(user, filename, **kwargs):    try:       if user.is_authenticated , user.belongs('admin'):           lib.read_file(...)       else:           raise exception("unauthenticated user!!!")    except exception, e:       raise e 

views.py

def my_view(request):    [..] here    try:      result = wrapper_read_file(...)      return render(request, 'hello.html', {'result': result})    except exception, e:      if isinstance(e, ioerror):          if e.errno==errno.enoent:          messages.add_message(request, message.error, 'file not exist.')      elif isinstance(e, oserror):          messages.add_message(request, message.error, 'you don't have sufficient permission open file.')      return render(request, 'hello.html', {'hello_world': 'hello_world'} 

django knows how render messages , have facility that. display messages.

do think exception handling looks reasonable? alternative suggestions? pretty new python error exception handling.

you don't want catch every exception. may mask other errors, , things prevent ctrl-c working. instead, catch exceptions want handle.

try:     # action may throw exception except ioerror, e: # catch ioerrors     if e.errno == errno.enoent:         messages.add_message(request, messages.error, "file not found")     else:         raise e    # re-raise other ioerrors except oserror, e: # catch oserrors     messages.add_message(request, messages.error, "insufficient permissions")  return render(request, 'hello.html', {}) 

update: added second except clause handle other exception type. note still insufficient, makes (big) assumption all oserrors permissions related.