json-inspect 0.1.5

json-inspect
============

|PyPI version| |PyPI license|

A command-line tool for inspecting and working with JSON files. Current
sub-commands supported include

**Table of Contents**

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- `Installation <#installation>`__
- `Sub-Commands <#sub-commands>`__
- `histo <#histo>`__
- `ext <#ext>`__
- `keys <#keys>`__
- `Planned Improvements <#planned-improvements>`__

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Installation
------------

You an simply install with the normal method for Python utils, such as

.. code:: sh

pip install json-inspect

Sub-Commands
------------

Each sub-command has it's own help file and options and serves different
purposes. Please be sure to read the docs for each command as it may not
work like the others. To see the most up-to-date documentation on all
available sub-commands, run the utility with the ``-h`` options without
providing a sub-command.

.. code:: text

$ json-inspect -h
usage: json-inspect [-h] [-v] [-f FILE] {histo,ext,keys,validate,format} ...

Utility for inspecting JSON files/input

positional arguments:
{histo,ext,keys,validate,format}
histo Create histograms from JSON values
ext Extract values from JSON
keys Lists keys in a JSON document
validate Validate text input as JSON (coming soon maybe)
format Nicely format JSON input (coming soon maybe)

optional arguments:
-h, --help show this help message and exit
-v, --version show program's version number and exit
-f FILE, --file FILE JSON file to read in. If not provided STDIN will be
used

Note that there are some global options. The main thing here is that
some sort of JSON input is required for this utility to work. This is
defined with the global ``-f`` option, or by providing input via
``STDIN``.

histo
~~~~~

If you are processing a large number of JSON objects/arrays, then it may
be useful to know what fields are present, what values they contain, and
the frequency of both. Starting off with the help file

.. code:: text

usage: json-inspect histo [-h] [-p PREFIX] [-c] paths [paths ...]

Generate a histogram based on values found using a JSON search expression

positional arguments:
paths search paths to create histograms for, prefixed with
optional value from the --prefix option

optional arguments:
-h, --help show this help message and exit
-p PREFIX, --prefix PREFIX
String to prefix all search-paths with
-c, --conflate Conflate non-empty responses to the same value

- The ``-p`` option will allow you to prefix all of your search paths.
This is useful if you are performing multiple searches that have a
common prefix for deeply nested JSON searches.
- The ``-c`` option will conflate your histogram to two values,
``__none__`` and ``__some__``. The first meaning that no key/value
was found for a given lookup in your search path and the latter
meaning that *a* value was found. This is useful if you only care
about the frequency of presence.

A search path is a dot-delimited expression used for traversing JSON
objects. An example to get us started is

.. code:: text

[].*.user.demographic.regions.[].name

To start, note that search expressions contain 3 types of tokens

- ``[]`` - indicates an array. Each item in the array is collected and
will be processed by the next token
- ``*`` - indicates an object in which all fields should be collected
and will be processed by the next token
- ``TOKEN`` - a field-value of an object. It's value will be collected
and processed by the next token

For our example above, it would be satisfied by the following JSON
document

.. code:: json

[
{
"facebook": {
"user": {
"demographic": {
"regions": [ {"name": "US"}, {"name": "Kentucky"}, {"name": "Louisville"} ]
}
}
},
"google": {
"user": {
"demographic": {
"regions": [ {"name": "US"}, {"name": "Kentucky"}, {"name": "Highland Heights"} ]
}
}
}
},
{
"twitter": {
"user": {
"demographic": {
"regions": [ {"name": "UK"}, {"name": "Wales"} ]
}
}
}
}
]

Running the ``histo`` sub-command, we would get output such as

.. code:: sh

cat test.json | json-inspect histo '[].*.user.demographic.regions.[].name'

[].*.user.demographic.regions.[].name:
Highland Heig | ######################### | (1)
US | ################################################## | (2)
Louisville | ######################### | (1)
Kentucky | ################################################## | (2)
UK | ######################### | (1)
Wales | ######################### | (1)

The bar-chart represents the number found relative to the max found with
a total count of finds per-element in the rightmost column.

ext
~~~

The ``ext``, extraction command, is used for pulling data out of JSON
files. It supports the same prefix and search expressions as ``histo``
along with a few other options for value output.

::

$ json-inspect ext -h
usage: json-inspect ext [-h] [-p PREFIX] [-d DELIM] [-F] paths [paths ...]

Extract values from JSON using a JSON search expression

positional arguments:
paths search paths to return values for

optional arguments:
-h, --help show this help message and exit
-p PREFIX, --prefix PREFIX
String to prefix all search-paths with
-d DELIM, --delimiter DELIM
String to delimit all results by
-F, --flatten Flatten array and object values. For objects, only the
values (not the keys) are retained in the falttened
values

Using the same input test JSON file from the ``histo`` command, we can
see an example of output

::

$ cat test.json | json-inspect ext "[].*.user.demographic.regions.[].*"
Louisville,Kentucky,US,Highland Heights,Kentucky,US,Wales,UK

$ cat test.json | json-inspect ext -d '|' "[].*.user.demographic.regions.[].*"
Louisville|Kentucky|US|Highland Heights|Kentucky|US|Wales|UK

keys
~~~~

The ``keys`` command is used for listing alls keys found within a JSON
document. Flags can be provided to filter which keys are extracted.

::

$ json-inspect keys -h
usage: json-inspect keys [-h] [-n] [-o] [-p] [-e]

List all keys within the JSON document using a period-delimited notation
similar to search-paths

optional arguments:
-h, --help show this help message and exit
-n, --exclude-null Exclude keys that contain a null value
-o, --exclude-empty-objects
Exclude keys that contain an empty object
-p, --exclude-empty-primitives
Exclude keys that contain an empty primitive value
(zero and empty string)
-e, --exclude-empty-array
Exclude keys that contain an empty array value

Adding a new lines to each top-level object in our ``test.json`` with

``"null": null, "empty_object": {}, "empty_array": [], "empty_string": "", "empty_int": 0, "empty_float": 0.0,``

We can make some sample calls such as

``bash $ cat test.json | json-inspect keys facebook.null facebook.empty_object facebook.user.demographic.regions.name facebook.empty_float facebook.empty_array # ...``

``bash # filter all keys with empty values $ cat test.json | json-inspect keys -nope facebook.user.demographic.regions.name google.user.demographic.regions.name twitter.user.demographic.regions.name``

Planned Improvements
--------------------

[ ] Refactor code to be testable (maybe write some test) [ ] Add support
for ``**``

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:target: https://github.com/JohnMurray/json-inspect/blob/master/LICENSE