Neo4j Persistor

This module allows data to be saved, retrieved, searched for, and deleted in a Neo4j instance.

####To use this module you can have a Neo4j instance running on your network or you can use Neo4j embedded with this module.

Dependencies

This module can be used with a Neo4j server to be available on the network.

Name

The module name is neo4j-persistor.

Configuration

Mode server

The neo4j-persistor module takes the following configuration:

{
    "address": <address>,
    "server-uri": "http://localhost:7474/db/data/",
    "poolsize": <pool_size>
}

For example:

{
    "address": "neo4j.persistor",
    "server-uri": "http://localhost:7474/db/data/",
    "poolsize": 32
}

Let's take a look at each field in turn:

• address The main address for the module. Every module has a main address. Defaults to neo4j.persistor.
• server-uri uri of the Neo4j instance.
• pool_size The number of socket connections the module instance should maintain to the Neo4j server. Default is 32.

HA

If you want to use the rest mode with Neo4j cluster. You can specify all server address. The persistor manage the check and change of master or slave. For example : "server-uris": ["http://10.13.2.244:7474/db/data/","http://10.13.2.245:7474/db/data/","http://10.13.2.246:7474/db/data/"]

Mode embedded

The neo4j-persistor module takes the following configuration:

{
    "address": <address>,
    "datastore-path": <datastore>,
    "neo4j" : {
        "allow_store_upgrade" : <allow_store_upgrade>,
        "node_auto_indexing" :  <node_auto_indexing>,
        "node_keys_indexable" : <node_keys_indexable>
    }
}

For example:

{
    "address": "wse.neo4j.persistor",
    "datastore-path": "./data/tests/neo4j",
    "neo4j" : {
        "allow_store_upgrade" : "true",
        "node_auto_indexing" : "true",
        "node_keys_indexable" : "externalId"
    }
}

Let's take a look at each field in turn:

• address The main address for the module. Every module has a main address. Defaults to neo4j.persistor.
• datastore-path path in filesystem to store neo4j data.
• allow_store_upgrade allow neo4j to migrate data when upgrade version.
• node_auto_indexing allow neo4j to auto index properties with lucene.
• node_keys_indexable specify properties to index with lucene.

Operations

The module can execute Cypher queries in some modes

####Transactions are only availables in server mode. In embedded mode, queries are execute without transaction.

Execute simple query

To execute a single query in the database.

{
    "action" : "execute",
    "query" : <query>,
    "params" : <params>
}

Where:

• query is the cypher query. This field is mandatory.
• params is the JSON object with query params.

An example would be:

{
    "action" : "execute",
    "query" : "MATCH (u:User {name : {name}}) RETURN u",
    "params" : {
        "name" : "Dalek"
    }
}

When the query complete successfully, a reply message is sent back to the sender with the following data:

{
    "status": "ok",
    "result" : <result>
}

Where

• result is an JsonArray of JsonObject.

If an error occurs in saving the document a reply is returned:

{
    "status": "error",
    "message": <message>
}

Where

• message is an error message.

Execute batch queries

To execute a batch queries in the database.

{
    "action" : "executeBatch",
    "queries" : <queries>,
}

Where:

• queries is a JsonArray. This field is mandatory.

An example would be:

{
    "action" : "executeBatch",
    "queries" : [
        {
            "query" : "MATCH (u:User {name : {name}}) RETURN u",
            "params" : {
                "name" : "Dalek"
            }
        },
        {
            "query" : "MATCH (u:User {name : 'toto'}) RETURN u"
        }
    ]
}

When the save complete successfully, a reply message is sent back to the sender with the following data:

{
    "status": "ok",
    "results" : <result>
}

Where

• result is an JsonArray of JsonObject.

If an error occurs in saving the document a reply is returned:

{
    "status": "error",
    "message": <message>
}

Where

• message is an error message.

Execute transactions

To execute queries with transactions in the database.

{
    "action" : "executeTransaction",
    "statements" : <statements>,
    "commit" : <commit>,
    "transactionId" : <transactionId>
}

Where:

• statements is a JsonArray. This field is mandatory.
• commit is a boolean. If is true the transaction be commit. Else, return transactionId without commit.
• transactionId is a Integer to retrieve transaction.

An example would be:

{
    "action" : "executeTransaction",
    "statements" : [
        {
            "statement" : "MATCH (u:User {name : {name}}) RETURN u",
            "parameters" : {
                "name" : "Dalek"
            }
        },
        {
            "statement" : "MATCH (u:User {name : 'toto'}) RETURN u"
        }
    ],
    "commit" : true
}

When the save complete successfully, a reply message is sent back to the sender with the following data:

{
    "status": "ok",
    "results" : <result>,
    "transactionId" : <transactionId>
}

Where

• result is an JsonArray of JsonObject.
• transactionId is an integer. Is returned only if transaction are not committed.

If an error occurs in saving the document a reply is returned:

{
    "status": "error",
    "message": <message>
}

Where

• message is an error message.

Reset Transaction Timeout

All transaction are a timeout value. You can use this method to reset timeout without commit transaction.

{
    "action" : "resetTransactionTimeout",
    "transactionId" : <transactionId>
}

Where:

• transactionId is a Integer to retrieve transaction.

An example would be:

{
    "action" : "resetTransactionTimeout",
    "transactionId" : 42
}

When the save complete successfully, a reply message is sent back to the sender with the following data:

{
    "status": "ok",
    "results" : <result>,
    "transactionId" : <transactionId>
}

Where

• result is an JsonArray of JsonObject.
• transactionId is an integer. Is returned only if transaction are not committed.

If an error occurs in saving the document a reply is returned:

{
    "status": "error",
    "message": <message>
}

Where

• message is an error message.

Rollback Transaction

You can use this method to rollback transaction.

{
    "action" : "rollbackTransaction",
    "transactionId" : <transactionId>
}

Where:

• transactionId is a Integer to retrieve transaction.

An example would be:

{
    "action" : "rollbackTransaction",
    "transactionId" : 42
}

When the save complete successfully, a reply message is sent back to the sender with the following data:

{
    "status": "ok",
}

If an error occurs in saving the document a reply is returned:

{
    "status": "error",
    "message": <message>
}

Where

• message is an error message.