Turn gremlin query result with elementMap into JSON [gremlinpython 3.6.1]

Question

Continuing discussion from here.

I've a query that provides list of paths along-with elementMap(). How do I convert this data to JSON to be consumed by rest of the code.

I did look here that talks about using GraphSONMapper. However, I am using gremlinpython (v 3.6.1) and I couldn't find GraphSONMapper with the library. There is graphsonV2d0.py and graphsonV3d0.py , but not clear on using that.

Sample Graph:

g.addV('color-group').property(id,1).property(single, 'Color', 'primary').next()
g.addV('primary-color').property(id,2).property(single, 'Color', 'red').next()
g.addV('primary-color').property(id,3).property(single, 'Color', 'blue').next()
g.addV('primary-color').property(id,4).property(single, 'Color', 'yellow').next()
g.addV('secondary-color').property(id,5).property(single, 'Color', 'red-10').next()
g.V(1).addE('links').to(V(2)).property(single, 'Key', 'value').next()
g.V(1).addE('links').to(V(3)).property(single, 'Key', 'value').next()
g.V(1).addE('links').to(V(4)).property(single, 'Key', 'value').next()
g.V(4).addE('links').to(V(5)).property(single, 'Key', 'value').next()

Query:

 g.V().hasLabel('color-group').has('Color', 'primary').outE().inV().optional(outE().inV()).path().by(elementMap()).store('data').cap('data').next()

Current Result:

 [path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 7, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 2, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 2, <T.label: 4>: 'primary-color', 'Color': 'red'}], path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 8, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 3, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 3, <T.label: 4>: 'primary-color', 'Color': 'blue'}], path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 9, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 4, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 4, <T.label: 4>: 'primary-color', 'Color': 'yellow'}, {<T.id: 1>: 10, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 5, <T.label: 4>: 'secondary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 4, <T.label: 4>: 'primary-color'}, 'Key': 'value'}, {<T.id: 1>: 5, <T.label: 4>: 'secondary-color', 'Color': 'red-10'}]]

How to convert above to get following Output in JSON?
Truncated rest as patter is same.

[[{
    "< T.id: 1 >": 1,
    "< T.label: 4 >": "color-group",
    "Color": "primary"
}, {
    "< T.id: 1 >": 7,
    "< T.label: 4 >": "links",
    "< Direction.IN: 2 >": {
        "< T.id: 1 >": 2,
        "< T.label: 4 >": "primary-color"
    },
    "< Direction.OUT: 3 >": {
        "< T.id: 1 >": 1,
        "< T.label: 4 >": "color-group"
    },
    "Key": "value"
}, {
    "< T.id: 1 >": 2,
    "< T.label: 4 >": "primary-color",
    "Color": "red"
}], ..... ]

EDIT 1.

I was able to make some progress using graphsonV3d0

from gremlin_python.structure.io import graphsonV3d0
obj = graphsonV3d0.GraphSONWriter()
query = g.V().hasLabel('color-group').has('Color', 'primary').outE().inV().optional(outE().inV()).path().by(elementMap()).store('data').cap('data').next()
obj.to_dict(query)

Result:

{'@type': 'g:List', '@value': [path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 7, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 2, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 2, <T.label: 4>: 'primary-color', 'Color': 'red'}], path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 8, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 3, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 3, <T.label: 4>: 'primary-color', 'Color': 'blue'}], path[{<T.id: 1>: 1, <T.label: 4>: 'color-group', 'Color': 'primary'}, {<T.id: 1>: 9, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 4, <T.label: 4>: 'primary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 1, <T.label: 4>: 'color-group'}, 'Key': 'value'}, {<T.id: 1>: 4, <T.label: 4>: 'primary-color', 'Color': 'yellow'}, {<T.id: 1>: 10, <T.label: 4>: 'links', <Direction.IN: 2>: {<T.id: 1>: 5, <T.label: 4>: 'secondary-color'}, <Direction.OUT: 3>: {<T.id: 1>: 4, <T.label: 4>: 'primary-color'}, 'Key': 'value'}, {<T.id: 1>: 5, <T.label: 4>: 'secondary-color', 'Color': 'red-10'}]]}

This is little better, but yet not entirely in JSON format.

Answer 1

I edited the creation steps slightly, to work with the database I am using to test this (Amazon Neptune) and ran queries using a graph-notebook.

g.addV('color-group').property(id,'I1').property(single, 'Color', 'primary').as('i1').
  addV('primary-color').property(id,'I2').property(single, 'Color', 'red').as('i2').
  addV('primary-color').property(id,'I3').property(single, 'Color', 'blue').as('i3').
  addV('primary-color').property(id,'I4').property(single, 'Color', 'yellow').as('i4').
  addV('secondary-color').property(id,'I5').property(single, 'Color', 'red-10').as('i5').
  addE('links').from('i1').to('i2').
  addE('links').from('i1').to('i3').
  addE('links').from('i1').to('i4').
  addE('links').from('i4').to('i5')

You can get a lot closer to the form you are looking for if we change the by modulation of the path to use a project step. For example:

g.V().hasLabel('color-group').
      has('Color', 'primary').
      outE().inV().
      optional(outE().inV()).
      path().
        by(project('id','label','properties').
             by(id).
             by(label).
             by(valueMap().by(unfold()))).
      toList()

Which yields

1   path[{'id': 'I1', 'label': 'color-group', 'properties': {'Color': 'primary'}}, {'id': 'aec3ae0e-c3d3-5c55-1ee1-fb3996158e1e', 'label': 'links', 'properties': {}}, {'id': 'I2', 'label': 'primary-color', 'properties': {'Color': 'red'}}]
2   path[{'id': 'I1', 'label': 'color-group', 'properties': {'Color': 'primary'}}, {'id': '12c3ae0e-c3d6-c04c-b386-5273adc8b640', 'label': 'links', 'properties': {}}, {'id': 'I3', 'label': 'primary-color', 'properties': {'Color': 'blue'}}]
3   path[{'id': 'I1', 'label': 'color-group', 'properties': {'Color': 'primary'}}, {'id': 'bec3ae0e-c3d7-5cb5-1616-e53d4bba45fd', 'label': 'links', 'properties': {}}, {'id': 'I4', 'label': 'primary-color', 'properties': {'Color': 'yellow'}}, {'id': '06c3ae0e-c3da-604a-d98d-65c93547209a', 'label': 'links', 'properties': {}}, {'id': 'I5', 'label': 'secondary-color', 'properties': {'Color': 'red-10'}}]

If we now go one step further, using Python, and the query result is in the variable called res - you can do:

for r in res[0]:
    print(r,'\n')

Which gives us

{'id': 'I1', 'label': 'color-group', 'properties': {'Color': 'primary'}} 

{'id': 'aec3ae0e-c3d3-5c55-1ee1-fb3996158e1e', 'label': 'links', 'properties': {}} 

{'id': 'I2', 'label': 'primary-color', 'properties': {'Color': 'red'}} 

Using those building blocks, I think you can stich together whatever JSON-like result you may need.

Once the result has been captured, we can turn one of the "rows" into JSON as follows:

import json
s = '['
for r in res[0]:
    s += str(r)[:-1] + '},'
j = s.replace("'","\"")[:-1] + ']'

print(j)
print(json.loads(j))

Which gives us (now valid JSON):

[{"id": "I1", "label": "color-group", "properties": {"Color": "primary"}},{"id": "aec3ae0e-c3d3-5c55-1ee1-fb3996158e1e", "label": "links", "properties": {}},{"id": "I2", "label": "primary-color", "properties": {"Color": "red"}}]


[{'id': 'I1', 'label': 'color-group', 'properties': {'Color': 'primary'}}, {'id': 'aec3ae0e-c3d3-5c55-1ee1-fb3996158e1e', 'label': 'links', 'properties': {}}, {'id': 'I2', 'label': 'primary-color', 'properties': {'Color': 'red'}}]