Neo4j Python REST Client
| synopsis: | Allows interact with Neo4j standalone REST server from Python. |
|---|
The first objective of Neo4j Python REST Client is to make transparent for Python programmers the use of a local database through neo4j.py or a remote database thanks to Neo4j REST Server. So, the syntax of this API is fully compatible with neo4j.py. However, a new syntax is introduced in order to reach a more pythonic style.
The main file is named client.py, but you can rename with whatever you want.
Instantiation
The main class is GraphDatabase, exactly how in neo4j.py:
>>> from client import GraphDatabase
>>> gdb = GraphDatabase("http://localhost:9999")
Two global options are available:
client.CACHE = False # Default
If CACHE is 'True', a '.cache' directory is created and the future request to the same URL will be taken from cache And:
client.DEBUG = False # Default
If DEBUG is 'True', 'httplib2' is set to debuglevel = 1.
Node, Relationships and Properties
Due to the syntax is fully compatible with neo4j.py, the next lines only show the commands added and its differences.
Creating a node:
>>> n = graphdb.node() # Equivalent to >>> n = graphdb.nodes.create()
Specify properties for new node:
>>> n = graphdb.node(color="Red", widht=16, height=32) # Or >>> n = graphdb.nodes.create(color="Red", widht=16, height=32)
Accessing node by id:
>>> n = graphdb.node[14] # Using the identifier or the URL is possible too >>> n = graphdb.nodes.get(14)
Accessing properties:
>>> value = n['key'] # Get property value
>>> n['key'] = value # Set property value
>>> del n['key'] # Remove property value
# Or the other way
>>> value = n.get('key', 'default') # Support 'default' values
>>> n.set('key', value)
>>> n.delete('key')
Besides, a Node object has other attributes:
>>> n.properties
{}
>>> n.properties = {'name': 'John'}
{'name': 'John'}
# The URL and the identifier assigned by Neo4j are added too
>>> n.id
14
>>> n.url
'http://localhost:9999/node/14'
Create relationship:
>>> n1.Knows(n2)
# Or
>>> n1.relationships.create("Knows", n2) # Usefull when the name of
# relationship is stored in a variable
Specify properties for new relationships:
>>> n1.Knows(n2, since=123456789, introduced_at="Christmas party")
# It's the same to
>>> n1.relationships.create("Knows", n2, since=123456789,
introduced_at="Christmas party")
The creation returns a Relationship object, which has properties, setter and getters like a node:
>>> rel = n1.relationships.create("Knows", n2, since=123456789)
>>> rel.start
<Neo4j Node: http://localhost:9999/node/14>
>>> rel.end
<Neo4j Node: http://localhost:9999/node/32>
>>> rel.type
'Knows'
>>> rel.properties
{'since': 123456789}
Others functions over 'relationships' attribute are possible. Like get all, incoming or outgoing relationships (typed or not):
>>> rels = n1.relationships.all() [<Neo4j Relationship: http://localhost:9999/relationship/35843>, <Neo4j Relationship: http://localhost:9999/relationship/35840>, <Neo4j Relationship: http://localhost:9999/relationship/35841>, <Neo4j Relationship: http://localhost:9999/relationship/35842>, <Neo4j Relationship: http://localhost:9999/relationship/35847>, <Neo4j Relationship: http://localhost:9999/relationship/35846>, <Neo4j Relationship: http://localhost:9999/relationship/35845>, <Neo4j Relationship: http://localhost:9999/relationship/35844>, <Neo4j Relationship: http://localhost:9999/relationship/11>, <Neo4j Relationship: http://localhost:9999/relationship/10>, <Neo4j Relationship: http://localhost:9999/relationship/9>] >>> rels = n1.relationships.incoming(types=["Knows"]) [<Neo4j Relationship: http://localhost:9999/relationship/35843>, <Neo4j Relationship: http://localhost:9999/relationship/35840>, <Neo4j Relationship: http://localhost:9999/relationship/11>, <Neo4j Relationship: http://localhost:9999/relationship/10>, <Neo4j Relationship: http://localhost:9999/relationship/9>] >>> rels = n1.relationships.outgoing(["Knows", "Loves"]) [<Neo4j Relationship: http://localhost:9999/relationship/35842>, <Neo4j Relationship: http://localhost:9999/relationship/35847>]
Traversals
The traversals framework is supported too with the same syntax of neo4j.py, but with some added issues.
Regular way:
>>> n1.relationships.create("Knows", n2, since=1970)
<Neo4j Relationship: http://localhost:9999/relationship/36009>
>>> class TraversalClass(gdb.Traversal):
...: types = [
...: Undirected.Knows
...: ]
...:
>>> [traversal for traversal in TraversalClass(n1)]
[<Neo4j Node: http://localhost:9999/node/15880>]
Added way (more ''pythonic''):
>>> n1.relationships.create("Knows", n2, since=1970)
<Neo4j Relationship: http://localhost:9999/relationship/36009>
>>> n1.traverse(types=[client.Undirected.Knows])
[<Neo4j Node: http://localhost:9999/node/15880>]
Extensions
The server plugins are supported as extensions of GraphDatabase, Node or Relationship objects:
>>> gdb.extensions
{u'GetAll': <Neo4j ExtensionModule: [u'get_all_nodes', u'getAllRelationships']>}
>>> gdb.extensions.GetAll
<Neo4j ExtensionModule: [u'get_all_nodes', u'getAllRelationships']>
>>> gdb.extensions.GetAll.getAllRelationships()
[<Neo4j Relationship: http://localhost:7474/db/data/relationship/0>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/1>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/2>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/3>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/4>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/5>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/6>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/7>,
<Neo4j Relationship: http://localhost:7474/db/data/relationship/8>]
An example using extensions over nodes:
>>> n1 = gdb.nodes.get(0)
>>> n1.extensions
{u'DepthTwo': <Neo4j ExtensionModule: [u'nodesOnDepthTwo', u'relationshipsOnDepthTwo', u'pathsOnDepthTwo']>, u'ShortestPath': <Neo4j ExtensionModule: [u'shortestPath']>}
>>> n2 = gdb.nodes.get(1)
>>> n1.relationships.create("Kwnos", n2)
<Neo4j Relationship: http://localhost:7474/db/data/relationship/36>
>>> n1.extensions.ShortestPath
<Neo4j ExtensionModule: [u'shortestPath']>
>>> n1.extensions.ShortestPath.shortestPath.parameters
[{u'description': u'The node to find the shortest path to.',
u'name': u'target',
u'optional': False,
u'type': u'node'},
{u'description': u'The relationship types to follow when searching for the shortest path(s). Order is insignificant, if omitted all types are followed.',
u'name': u'types',
u'optional': True,
u'type': u'strings'},
{u'description': u'The maximum path length to search for, default value (if omitted) is 4.',
u'name': u'depth',
u'optional': True,
u'type': u'integer'}]
Transaction
Currently, the transaction support is not implemented in Neo4j REST server, so the Python client is not able to provide it.