[tahoe-lafs-trac-stream] [tahoe-lafs] #1799: Document how to distinguish exceptions from JSON, or encode exceptions as JSON

[tahoe-lafs]

#1799: Document how to distinguish exceptions from JSON, or encode exceptions as
JSON
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 Reporter:  davidsarah           |          Owner:
     Type:  defect               |         Status:  new
 Priority:  normal               |      Milestone:  undecided
Component:  code-frontend-web    |        Version:  1.9.2
 Keywords:  json usability docs  |  Launchpad Bug:
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 darrob: hello again. i have a python program that runs tahoe repair
 operations using urllib and parses tahoe's json responses. this works very
 well except for one thing: if a file is gone and i attempt a repair, the
 resulting NotEnoughSharesError is not presented as json data but plaintext
 (a check without repair responds in json, however).

 darrob: am i missing something on tahoe's side that i can do about it? if
 not, are there other error messages like this that i should be aware of
 before i adapt the program?

 We need to document how to distinguish exceptions (I *think* valid JSON
 always starts with a "{" or "[" character).

 An alternative would be to encode the exception as JSON (i.e. something
 like {"exception": "..."}), although that would make it more difficult to
 read. Since these APIs are mainly for programmatic use, that might be
 acceptible.

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1799>
tahoe-lafs <https://tahoe-lafs.org>
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