[tahoe-dev] [tahoe-lafs] #646: CLI should report webapi errors better

[tahoe-lafs]

#646: CLI should report webapi errors better
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 Reporter:  warner             |           Owner:           
     Type:  defect             |          Status:  new      
 Priority:  major              |       Milestone:  undecided
Component:  code-frontend-cli  |         Version:  1.3.0    
 Keywords:  web                |   Launchpad_bug:           
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 Most of the filesystem-manipulating CLI tools display some frustratingly
 useless error messages when something goes wrong. They all use the webapi
 to contact the node, and the default webapi/Nevow exception-handling
 response is to return an HTML representation of the exception traceback
 (for use in a browser), as well as a 500 Internal Server Error. The CLI
 tools, when they see 500, just dump the HTTP response body to stderr.

 One tool that might help fix this is to identify the most likely sorts of
 exceptions (!NotEnoughSharesError, !UnrecoverableFileError) and map them
 into HTTP error codes. There is already some code to do this, in
 web/common.py, but we could add more error types, and add tests to make
 sure that we actually catch the errors in the right places.

 Another tool that might help would be an extra flag (perhaps a request
 header, like Accepts:) that tells the webapi server that we (a CLI client,
 not a browser) want plain text tracebacks instead of HTML. This would at
 least reduce the pages of impenetrable HTML on stderr to a dozen lines of
 python stack trace.

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Ticket URL: <http://allmydata.org/trac/tahoe/ticket/646>
tahoe-lafs <http://allmydata.org>
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