added neo4j push and pull functions

README.md

@@ -17,9 +17,9 @@ The library is built specifically for converting data into a [neo4j](https://neo
 
 
 ## Installation
-If you have setup a private ssh key for your github, copy-paste the command below to install the latest version ([v1.1.0][latest_tag]):
+If you have setup a private ssh key for your github, copy-paste the command below to install the latest version ([v1.2.0][latest_tag]):
 ```
-pip install git+ssh://[email protected]/sg-dev/rel2graph@v1.1.0
+pip install git+ssh://[email protected]/sg-dev/rel2graph@v1.2.0
 ```
 
 If you don't have ssh set up, download the latest wheel [here][latest_wheel] and install the wheel with:
@@ -93,7 +93,7 @@ converter()
 # Known issues
 If you encounter a bug or an unexplainable behavior, please check the [known issues](https://github.com/sg-dev/rel2graph/labels/bug) list. If your issue is not found, submit a new one.
 
-[latest_version]: v1.1.0
-[latest_tag]: https://github.com/sg-dev/rel2graph/releases/tag/v1.1.0
-[latest_wheel]: https://github.com/sg-dev/rel2graph/releases/download/v1.1.0/rel2graph-1.0.1-py3-none-any.whl
+[latest_version]: v1.2.0
+[latest_tag]: https://github.com/sg-dev/rel2graph/releases/tag/v1.2.0
+[latest_wheel]: https://github.com/sg-dev/rel2graph/releases/download/v1.2.0/rel2graph-1.0.1-py3-none-any.whl
 [wiki]: https://rel2graph.jkminder.ch/index.html

docs/source/api/neo4j.rst

@@ -8,6 +8,10 @@ These functions abstract complexity of interacting with Neo4j. Instead of writin
 
 .. autofunction:: rel2graph.neo4j.merge
 
+.. autofunction:: rel2graph.neo4j.push
+
+.. autofunction:: rel2graph.neo4j.pull
+
 .. autofunction:: rel2graph.neo4j.match_nodes
 
 .. autofunction:: rel2graph.neo4j.match_relationships

docs/source/neo4j.rst

@@ -3,8 +3,8 @@ Neo4j Integration
 
 The rel2graph library comes with a set of abstract classes that simplify the interaction with neo4j in python. They are derived from the now EOL library py2neo.
 This includes python objects to represent |Node| and |Relationship| objects as well as a |Subgraph| object that can be used to represent a set of nodes and relationships.
-|Node| and |Relationship| objects are themself a |Subgraph|. The two functions :py:func:`create <rel2graph.neo4j.create>` and :py:func:`merge <rel2graph.neo4j.create>` can be used to create or merge a |Subgraph| into a neo4j database given a neo4j session.
-Further use the functions :py:func:`match_nodes <rel2graph.neo4j.match_nodes>` and :py:func:`match_relationships <rel2graph.neo4j.match_relationships>` to match elements in the graph and return a list of |Node| or |Relationship|.
+|Node| and |Relationship| objects are themself a |Subgraph|. The functions :py:func:`create <rel2graph.neo4j.create>` and :py:func:`merge <rel2graph.neo4j.merge>` can be used to create or merge a |Subgraph| into a neo4j database given a neo4j session. To sync local
+|Subgraph| objects with the database, use the :py:func:`push <rel2graph.neo4j.push>` and :py:func:`pull <rel2graph.neo4j.pull>` functions.Further use the functions :py:func:`match_nodes <rel2graph.neo4j.match_nodes>` and :py:func:`match_relationships <rel2graph.neo4j.match_relationships>` to match elements in the graph and return a list of |Node| or |Relationship|.
 We refer to the :doc:`neo4j documentation <api/neo4j>` for more information.
 
 .. |Subgraph| replace:: :py:class:`Subgraph <rel2graph.neo4j.Subgraph>`

rel2graph/neo4j/__init__.py

@@ -27,6 +27,26 @@ def merge(graph: Subgraph, session: Session, primary_label=None, primary_key=Non
     session.execute_write(graph.__db_merge__, primary_label=primary_label, primary_key=primary_key)
 
 
+def push(graph: Subgraph, session: Session):
+    """
+    Updates local graph elements with the database. The graph needs to be already in the database.
+
+    Args:
+        graph (Subgraph): The graph to create.
+        session (Session): The `session <https://neo4j.com/docs/api/python-driver/current/api.html#session>`_ to use.
+    """
+    session.execute_write(graph.__db_push__)
+
+def pull(graph: Subgraph, session: Session):
+    """
+    Pulls remote changes to the graph to the local copy. The graph needs to be already in the database.
+
+    Args:
+        graph (Subgraph): The graph to create.
+        session (Session): The `session <https://neo4j.com/docs/api/python-driver/current/api.html#session>`_ to use.
+    """
+    session.execute_write(graph.__db_pull__)
+
 
 def match_nodes(session: Session, *labels: List[str], **properties: dict):
     """

rel2graph/neo4j/graph_elements.py

@@ -42,7 +42,7 @@
                     unwind_merge_nodes_query, \
                     unwind_create_relationships_query, \
                     unwind_merge_relationships_query, \
-                    cypher_join
+                    cypher_join, cypher_escape
 from .encoder import encode_value, xstr, is_safe_key
 from collections import OrderedDict
 
@@ -191,6 +191,7 @@ def __db_create__(self, tx):
             for i, record in enumerate(records):
                 node = nodes[i]
                 node.identity = record[0]
+                node._remote_labels = frozenset(labels)
         for r_type, relationships in rel_dict.items():
             data = map(lambda r: [r.start_node.identity, dict(r), r.end_node.identity],
                        relationships)
@@ -260,6 +261,7 @@ def __db_merge__(self, tx, primary_label=None, primary_key=None):
             for i, identity in enumerate(identities):
                 node = nodes[i]
                 node.identity = identity
+                node._remote_labels = frozenset(labels)
         for (pk, r_type), relationships in rel_dict.items():
             if pk is None:
                 raise ValueError("Primary key are required for relationship MERGE operation")
@@ -279,6 +281,60 @@ def __db_merge__(self, tx, primary_label=None, primary_key=None):
             for i, identity in enumerate(identities):
                 relationship = relationships[i]
                 relationship.identity = identity
+
+    def __db_pull__(self, tx):
+        """ Copy data from a remote :class:`.Graph` into this
+        :class:`.Subgraph`.
+
+        :param tx:
+        """
+        # Pull nodes
+        nodes = {}
+        for node in self.nodes:
+            if node.identity is not None:
+                nodes[node.identity] = node
+        query = tx.run("MATCH (_) WHERE id(_) in $x "
+                       "RETURN id(_), labels(_), properties(_)", x=list(nodes.keys()))
+        for identity, new_labels, new_properties in query:
+            node = nodes[identity]
+            node.labels = set(new_labels)
+            node.properties = new_properties
+
+        # Pull relationships
+        relationships = {}
+        for relationship in self.relationships:
+            if relationship.identity is not None:
+                relationships[relationship.identity] = relationship
+        query = tx.run("MATCH ()-[_]->() WHERE id(_) in $x "
+                       "RETURN id(_), properties(_)", x=list(relationships.keys()))
+        for identity, new_properties in query:
+            relationship = relationships[identity]
+            relationship.properties = new_properties
+
+    def __db_push__(self, tx):
+        """ Copy data into a remote :class:`.Graph` from this
+        :class:`.Subgraph`.
+
+        :param tx:
+        """
+        for node in self.nodes:
+            if node.identity is not None:
+                clauses = ["MATCH (_) WHERE id(_) = $x", "SET _ = $y"]
+                parameters = {"x": node.identity, "y": dict(node)}
+                old_labels = node._remote_labels - node.labels
+                if old_labels:
+                    clauses.append("REMOVE _:%s" % ":".join(map(cypher_escape, old_labels)))
+                new_labels = node.labels - node._remote_labels
+                if new_labels:
+                    clauses.append("SET _:%s" % ":".join(map(cypher_escape, new_labels)))
+                tx.run("\n".join(clauses), parameters)
+                node._remote_labels = node.labels
+        for relationship in self.relationships:
+            if relationship.identity is not None:
+                clauses = ["MATCH ()-[_]->() WHERE id(_) = $x", "SET _ = $y"]
+                parameters = {"x": relationship.identity, "y": dict(relationship)}
+                tx.run("\n".join(clauses), parameters)
+
     @property
     def nodes(self):
         """ The set of all nodes in this subgraph.
@@ -437,6 +493,7 @@ def __init__(self, *labels: str, **attributes: str) -> None:
             attributes: Key value pairs of attributes for the Node
         """
         self.labels = set(labels)
+        self._remote_labels = frozenset()
         self.__primarylabel__ = labels[0]
 
         PropertyDict.__init__(self, **attributes)

setup.py

@@ -9,7 +9,7 @@
 setup(
     name = "rel2graph", 
     packages = find_packages(),
-    version = "1.1.0",
+    version = "1.2.0",
     description = "Library for converting relational data into graph data (neo4j)",
     author = "Julian Minder",
     author_email = "[email protected]",   

tests/unit/neo4j/test_create_merge.py → tests/unit/neo4j/test_basic_ops.py

@@ -11,7 +11,7 @@
 import datetime
 from neo4j import GraphDatabase, time
 
-from rel2graph.neo4j import Node, Relationship, Subgraph, create, merge
+from rel2graph.neo4j import Node, Relationship, Subgraph, create, merge, push, pull
 from rel2graph.common_modules import MERGE_RELATIONSHIPS
 
 @pytest.fixture
@@ -32,8 +32,9 @@ def session():
             session.close()
             driver.close()
             return
+
 def get_nodes(session):
-    return session.run("MATCH (c:test) RETURN c").data()
+    return session.run("MATCH (c:test) RETURN c, labels(c)").data()
 
 def get_relationships(session):
     return session.run("MATCH p=()-[d]->() RETURN p, properties(d) AS props").data()
@@ -315,3 +316,65 @@ def test_create_node_with_date(session):
     assert(nodes[0]["c"]["id"] == 1)
     assert(nodes[0]["c"]["date"] == time.Date(2020,1,1))
 
+def test_push_node(session):
+    n1 = Node("test", id=1)
+    create(n1, session)
+    n1["id"] = 2
+    push(n1, session)
+    nodes = get_nodes(session)
+    assert(len(nodes) == 1)
+    assert(nodes[0]["c"]["id"] == 2)
+
+    # labels
+    n1.labels = set(["test", "another"])
+    push(n1, session)
+    nodes = get_nodes(session)
+    assert(len(nodes) == 1)
+    assert(nodes[0]["labels(c)"] == ["test", "another"])
+
+    # remove label
+    n1.labels = set(["test"])
+    push(n1, session)
+    nodes = get_nodes(session)
+    assert(len(nodes) == 1)
+    assert(nodes[0]["labels(c)"] == ["test"])
+
+def test_pull_node(session):
+    n1 = Node("test", id=1)
+    create(n1, session)
+    n1["id"] = 2
+    pull(n1, session)
+    assert(n1["id"] == 1)
+
+    # remove label
+    n1.labels = set(["test", "another"])
+    pull(n1, session)
+    assert(n1.labels == {"test"})
+
+    # add label
+    n1.labels = set(["test", "another"])
+    push(n1, session)
+    n1.labels = set(["test"])
+    pull(n1, session)
+    assert(n1.labels == {"test", "another"})
+
+
+def test_push_relationship(session):
+    n1 = Node("test", id=1)
+    n2 = Node("test", id=2)
+    r1 = Relationship(n1, "to", n2)
+    create(r1, session)
+    r1["id"] = 2
+    push(r1, session)
+    rels = get_relationships(session)
+    assert(len(rels) == 1)
+    assert(rels[0]["props"]["id"] == 2)
+
+def test_pull_relationship(session):
+    n1 = Node("test", id=1)
+    n2 = Node("test", id=2)
+    r1 = Relationship(n1, "to", n2, id=1)
+    create(r1, session)
+    r1["id"] = 2
+    pull(r1, session)
+    assert(r1["id"] == 1)