cypher query to generate special path - neo4j

Question

I have a graph like this
O
|
A
|
B
/ \
C E
/ \
D F
I want to find the path from O to F. node F can contain an attribute call "non-direct". If this attribute is set false, then the path is
O-A-B-E-F
However, if it is set to true, the path is
O-A-B-C-D-C-B-E-F
I.e., the path first has to reach B which is a terminal node and then go back to the common parent between D and F, then walk to F.
How can I create a query to return these two path based on the attribute value?

Answer 1

Since Neo4j will not traverse back over the same relationship, you may need to create relationships in both direction on the branches. So something like this:
In addition, I would add some properties that indicate the toplogy, so for instance add a property on-branch for the nodes C and D.
Then you can run queries like this:
MATCH (f:Thing {name:'F'}), (o:Thing {name:'O'}), (d:Thing {name:'D'})
MATCH p = (o)-[:NEXT*]->(f)
WHERE ANY(node IN nodes(p) WHERE node.`on-branch`) = f.`non-direct`
AND (d IN nodes(p)) = f.`non-direct`
RETURN REDUCE(s='', node IN nodes(p) | s+ ' '+ node.name) AS nodes
The graph I tried this on can be created from this json:
{
"nodes": [
{
"id": 0,
"labels": [
"Thing"
],
"properties": {
"name": "O",
"on-branch": false
}
},
{
"id": 1,
"labels": [
"Thing"
],
"properties": {
"name": "A",
"on-branch": false
}
},
{
"id": 2,
"labels": [
"Thing"
],
"properties": {
"name": "B",
"on-branch": false
}
},
{
"id": 3,
"labels": [
"Thing"
],
"properties": {
"name": "C",
"on-branch": true
}
},
{
"id": 4,
"labels": [
"Thing"
],
"properties": {
"name": "D",
"on-branch": true
}
},
{
"id": 5,
"labels": [
"Thing"
],
"properties": {
"name": "E",
"on-branch": false
}
},
{
"id": 6,
"labels": [
"Thing"
],
"properties": {
"name": "F",
"non-direct": false,
"on-branch": false
}
}
],
"relations": [
{
"id": 0,
"source": 0,
"target": 1,
"type": "NEXT",
"properties": {}
},
{
"id": 1,
"source": 1,
"target": 2,
"type": "NEXT",
"properties": {}
},
{
"id": 2,
"source": 3,
"target": 2,
"type": "NEXT",
"properties": {}
},
{
"id": 3,
"source": 2,
"target": 3,
"type": "NEXT",
"properties": {}
},
{
"id": 4,
"source": 4,
"target": 3,
"type": "NEXT",
"properties": {}
},
{
"id": 5,
"source": 3,
"target": 4,
"type": "NEXT",
"properties": {}
},
{
"id": 6,
"source": 2,
"target": 5,
"type": "NEXT",
"properties": {}
},
{
"id": 7,
"source": 5,
"target": 6,
"type": "NEXT",
"properties": {}
}
]
}
The json above can be loaded with this cypher (in Neo4j with apoc):
CALL apoc.load.json([ url to the json]) YIELD value AS v
UNWIND v.nodes AS node
CALL apoc.merge.node(
node.labels,
{ _tempID : node.id},
node.properties,
{}
) YIELD node AS n
WITH DISTINCT v
UNWIND v.relations AS rel
MATCH (from {_tempID: rel.source})
MATCH (to {_tempID: rel.target})
CALL apoc.merge.relationship(
from,
rel.type,
{},
rel.properties,
to,
{}
) YIELD rel AS r
WITH DISTINCT v
MATCH (n) WHERE EXISTS(n._tempID)
REMOVE n._tempID