jsonnavigator

Need a tool to jump around JSON-generated data strucutres relatively easily. The structures are a mix of dicts and lists in Python.

pain points

• cumbersome to write a series of square bracket addresses
• since the dicts are not defaultdicts, reaching for a missing key causes an exception. need to use get(), BUT using get gets clunky if we are reaching deeper: json_response['result'].get('person',{}).get('name','N/A'); what if we need an element of a dict from a list, but the list is empty (i.e. is there a get()-like method for lists)?
  • would want to return None or some default value when there is a missing key/element along the navigation path
• it would be useful to be able to fetch dicts that contain particular key-value pairs. e.g. from a list of dicts get those dicts where message_type:image, it's difficult to succinctly get to such a pair and then to go back to the other dict entries associated with it. (!!! need to make this a stable filter, to allow later slicing consistent with source order in the list, shouldn't be too hard - just start at the beginning)
  • FOR NOW pass a a two-element tuple with the key and the value.
  • LATER, for this we could pass a dict like this json.navigate('messages',{'message_type':'image'})
    • if we are looking for several possible values of a key, pass dict with list/tuple/set like this json.navigate('messages','{'message_type':['image','text']})
    • and if more key-value pairs should be examined in the filter, just make so in the dict json.navigate('messages',{'message_type':'image', 'sender':'John'}) TBD

the following converges on just passing slices

• would be nice to be able to fetch all elements with a particular key from a list

• would be nice to have wildcards json.navigate('result', '*', 'name'). This is pretty much the same as the point above

  • seems smart to define some constants like ALL to be able to pass that instead of the string asterisk. or use the ellipsis (...) to denote ALL
  • then we can have a switch to turn string wildcards on or off when initializing, or in context manager (as soon as I can wrap my head around those).

• Nice to be able to get a slice of a list when declaring the navigation path json.navigate('result','[2:7]'); It seems like a good idea to accept python slice objects for this.

• would be nice to have control of the depth json.navigate('result','*2'); Do we preserve some nesting in returned result? or maybe add some metadata on depth of an element found? TBD

• Related to the above: do we allow wildcards to reach across levels? What would be path symbol for that? TBD