Neo4j driver compatible with neo4j 4.x versions

An implementation of the bolt protocol to interact with Neo4j server
async/await apis using tokio
Supports bolt 4.2 specification
tested with Neo4j versions: 4.0, 4.1, 4.2

Examples

use neo4rs::*;
use std::sync::Arc;
use std::sync::atomic::{AtomicU32, Ordering};
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let id = Uuid::new_v4().to_string();

let graph = Arc::new(Graph::new(&uri, user, pass).await.unwrap());
let mut result = graph.run(
query("CREATE (p:Person {id: $id})").param("id", id.clone())
).await.unwrap();

let mut handles = Vec::new();
let mut count = Arc::new(AtomicU32::new(0));
for _ in 1..=42 {
let graph = graph.clone();
let id = id.clone();
let count = count.clone();
let handle = tokio::spawn(async move {
let mut result = graph.execute(
query("MATCH (p:Person {id: $id}) RETURN p").param("id", id)
).await.unwrap();
while let Ok(Some(row)) = result.next().await {
count.fetch_add(1, Ordering::Relaxed);
}
});
handles.push(handle);
}

futures::future::join_all(handles).await;
assert_eq!(count.load(Ordering::Relaxed), 42);
}

Nodes

A simple example to create a node and consume the created node from the row stream.

[Graph::run] just returns [errors::Result]<()>, usually used for write only queries.
[Graph::execute] returns [errors::Result]<[RowStream]>

use neo4rs::*;
use futures::stream::*;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

assert!(graph.run(query("RETURN 1")).await.is_ok());

let mut result = graph.execute(
query( "CREATE (friend:Person {name: $name}) RETURN friend")
.param("name", "Mr Mark")
).await.unwrap();

while let Ok(Some(row)) = result.next().await {
let node: Node = row.get("friend").unwrap();
let id = node.id();
let labels = node.labels();
let name: String = node.get("name").unwrap();
assert_eq!(name, "Mr Mark");
assert_eq!(labels, vec!["Person"]);
assert!(id > 0);
}
}

Configurations

Use the config builder to override the default configurations like

fetch_size - number of rows to fetch in batches (default is 200)
max_connections - maximum size of the connection pool (default is 16)
db - the database to connect to (default is neo4j)

use neo4rs::*;
use futures::stream::*;

#[tokio::main]
async fn main() {
let config = config()
.uri("127.0.0.1:7687")
.user("neo4j")
.password("neo")
.db("neo4j")
.fetch_size(500)
.max_connections(10)
.build()
.unwrap();
let graph = Graph::connect(config).await.unwrap();
let mut result = graph.execute(query("RETURN 1")).await.unwrap();
let row = result.next().await.unwrap().unwrap();
let value: i64 = row.get("1").unwrap();
assert_eq!(1, value);
assert!(result.next().await.unwrap().is_none());
}

Transactions

Start a new transaction using [Graph::start_txn], which will return a handle [Txn] that can be used to [Txn::commit] or [Txn::rollback] the transaction.

Note that the handle takes a connection from the connection pool, which will be released once the Txn is dropped

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let txn = graph.start_txn().await.unwrap();
let id = Uuid::new_v4().to_string();
let result = txn.run_queries(vec![
query("CREATE (p:Person {id: $id})").param("id", id.clone()),
query("CREATE (p:Person {id: $id})").param("id", id.clone())
]).await;

assert!(result.is_ok());
txn.commit().await.unwrap();
let mut result = graph
.execute(query("MATCH (p:Person) WHERE p.id = $id RETURN p.id").param("id", id.clone()))
.await
.unwrap();
# assert!(result.next().await.unwrap().is_some());
# assert!(result.next().await.unwrap().is_some());
# assert!(result.next().await.unwrap().is_none());
}

Streams within a transaction

Each [RowStream] returned by various execute within the same transaction are well isolated, so you can consume the stream anytime within the transaction using [RowStream::next]

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let config = config()
.uri("127.0.0.1:7687")
.user("neo4j")
.password("neo")
.fetch_size(1)
.build()
.unwrap();
let graph = Graph::connect(config).await.unwrap();
let name = Uuid::new_v4().to_string();
let txn = graph.start_txn().await.unwrap();

txn.run_queries(vec![
query("CREATE (p { name: $name })").param("name", name.clone()),
query("CREATE (p { name: $name })").param("name", name.clone()),
])
.await
.unwrap();


//start stream_one
let mut stream_one = txn
.execute(query("MATCH (p {name: $name}) RETURN p").param("name", name.clone()))
.await
.unwrap();
let row = stream_one.next().await.unwrap().unwrap();
assert_eq!(row.get::<Node>("p").unwrap().get::<String>("name").unwrap(), name.clone());

//start stream_two
let mut stream_two = txn.execute(query("RETURN 1")).await.unwrap();
let row = stream_two.next().await.unwrap().unwrap();
assert_eq!(row.get::<i64>("1").unwrap(), 1);

//stream_one is still active here
let row = stream_one.next().await.unwrap().unwrap();
assert_eq!(row.get::<Node>("p").unwrap().get::<String>("name").unwrap(), name.clone());

//stream_one completes
assert!(stream_one.next().await.unwrap().is_none());
//stream_two completes
assert!(stream_two.next().await.unwrap().is_none());
txn.commit().await.unwrap();
}

Rollback a transaction

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

let txn = graph.start_txn().await.unwrap();
let id = Uuid::new_v4().to_string();
// create a node
txn.run(query("CREATE (p:Person {id: $id})").param("id", id.clone()))
.await
.unwrap();
// rollback the changes
txn.rollback().await.unwrap();

// changes not updated in the database
let mut result = graph
.execute(query("MATCH (p:Person) WHERE p.id = $id RETURN p.id").param("id", id.clone()))
.await
.unwrap();
assert!(result.next().await.unwrap().is_none());
}

Txn vs Graph

Everytime you execute a query using [Graph::run] or [Graph::execute], a new connection is taken from the pool and released immediately.

However, when you execute a query on a transaction using [Txn::run] or [Txn::execute] the same connection will be reused, the underlying connection will be released to the pool in a clean state only after you commit/rollback the transaction and the [Txn] handle is dropped.

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let txn = graph.start_txn().await.unwrap();
let id = Uuid::new_v4().to_string();
txn.run(query("CREATE (p:Person {id: $id})").param("id", id.clone()))
.await
.unwrap();
txn.run(query("CREATE (p:Person {id: $id})").param("id", id.clone()))
.await
.unwrap();
// graph.execute(..) will not see the changes done above as the txn is not committed yet
let mut result = graph
.execute(query("MATCH (p:Person) WHERE p.id = $id RETURN p.id").param("id", id.clone()))
.await
.unwrap();
assert!(result.next().await.unwrap().is_none());
txn.commit().await.unwrap();

//changes are now seen as the transaction is committed.
let mut result = graph
.execute(query("MATCH (p:Person) WHERE p.id = $id RETURN p.id").param("id", id.clone()))
.await
.unwrap();
assert!(result.next().await.unwrap().is_some());
assert!(result.next().await.unwrap().is_some());
assert!(result.next().await.unwrap().is_none());
}

Relationships

Bounded Relationship between nodes are created using cypher queries and the same can be parsed from the [RowStream]

use neo4rs::*;
use futures::stream::*;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let mut result = graph.execute(
query("CREATE (p:Person { name: 'Oliver Stone' })-[r:WORKS_AT {as: 'Engineer'}]->(neo) RETURN r")
).await.unwrap();

let row = result.next().await.unwrap().unwrap();
let relation: Relation = row.get("r").unwrap();
assert!(relation.id() > -1);
assert!(relation.start_node_id() > -1);
assert!(relation.end_node_id() > -1);
assert_eq!(relation.typ(), "WORKS_AT");
assert_eq!(relation.get::<String>("as").unwrap(), "Engineer");
}

Similar to bounded relation, an unbounded relation can also be created/parsed.

use neo4rs::*;
use futures::stream::*;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let mut result = graph.execute(
query("MERGE (p1:Person { name: 'Oliver Stone' })-[r:RELATED {as: 'friend'}]-(p2: Person {name: 'Mark'}) RETURN r")
).await.unwrap();
let row = result.next().await.unwrap().unwrap();
let relation: Relation = row.get("r").unwrap();
assert!(relation.id() > -1);
assert!(relation.start_node_id() > -1);
assert!(relation.end_node_id() > -1);
assert_eq!(relation.typ(), "RELATED");
assert_eq!(relation.get::<String>("as").unwrap(), "friend");
}

Points

A 2d or 3d point can be represented with the types [Point2D] and [Point3D]

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

let mut result = graph
.execute(query(
"WITH point({ x: 2.3, y: 4.5, crs: 'cartesian' }) AS p1,
point({ x: 1.1, y: 5.4, crs: 'cartesian' }) AS p2 RETURN distance(p1,p2) AS dist, p1, p2",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let dist: f64 = row.get("dist").unwrap();
let p1: Point2D = row.get("p1").unwrap();
let p2: Point2D = row.get("p2").unwrap();
assert_eq!(1.5, dist);
assert_eq!(p1.sr_id(), 7203);
assert_eq!(p1.x(), 2.3);
assert_eq!(p1.y(), 4.5);
assert_eq!(p2.sr_id(), 7203);
assert_eq!(p2.x(), 1.1);
assert_eq!(p2.y(), 5.4);
assert!(result.next().await.unwrap().is_none());

let mut result = graph
.execute(query(
"RETURN point({ longitude: 56.7, latitude: 12.78, height: 8 }) AS point",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let point: Point3D = row.get("point").unwrap();
assert_eq!(point.sr_id(), 4979);
assert_eq!(point.x(), 56.7);
assert_eq!(point.y(), 12.78);
assert_eq!(point.z(), 8.0);
assert!(result.next().await.unwrap().is_none());

}

Raw bytes

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let mut result = graph
.execute(query("RETURN $b as output").param("b", vec![11, 12]))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let b: Vec<u8> = row.get("output").unwrap();
assert_eq!(b, &[11, 12]);
assert!(result.next().await.unwrap().is_none());
}

Durations

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let duration = std::time::Duration::new(5259600, 7);
let mut result = graph
.execute(query("RETURN $d as output").param("d", duration))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let d: std::time::Duration = row.get("output").unwrap();
assert_eq!(d.as_secs(), 5259600);
assert_eq!(d.subsec_nanos(), 7);
assert!(result.next().await.unwrap().is_none());
}

Date

See NaiveDate for date abstraction, it captures the date without time component.

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let date = chrono::NaiveDate::from_ymd(1985, 2, 5);
let mut result = graph
.execute(query("RETURN $d as output").param("d", date))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let d: chrono::NaiveDate = row.get("output").unwrap();
assert_eq!(d.to_string(), "1985-02-05");
assert!(result.next().await.unwrap().is_none());
}

Time

NaiveTime captures only the time of the day
tuple(NaiveTime, Option<FixedOffset>) captures the time of the day along with the offset

Time as param

Pass a time as a parameter to the query:

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

//send time without offset as param
let time = chrono::NaiveTime::from_hms_nano(11, 15, 30, 200);
let mut result = graph.execute(query("RETURN $d as output").param("d", time)).await.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: (chrono::NaiveTime, Option<chrono::FixedOffset>) = row.get("output").unwrap();
assert_eq!(t.0.to_string(), "11:15:30.000000200");
assert_eq!(t.1, None);
assert!(result.next().await.unwrap().is_none());


//send time with offset as param
let time = chrono::NaiveTime::from_hms_nano(11, 15, 30, 200);
let offset = chrono::FixedOffset::east(3 * 3600);
let mut result = graph
.execute(query("RETURN $d as output").param("d", (time, offset)))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: (chrono::NaiveTime, Option<chrono::FixedOffset>) = row.get("output").unwrap();
assert_eq!(t.0.to_string(), "11:15:30.000000200");
assert_eq!(t.1, Some(offset));
assert!(result.next().await.unwrap().is_none());
}

Parsing time from result

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

//Parse time without offset
let mut result = graph
.execute(query(
" WITH time({hour:10, minute:15, second:30, nanosecond: 200}) AS t RETURN t",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: (chrono::NaiveTime, Option<chrono::FixedOffset>) = row.get("t").unwrap();
assert_eq!(t.0.to_string(), "10:15:30.000000200");
assert_eq!(t.1, None);
assert!(result.next().await.unwrap().is_none());

//Parse time with timezone information
let mut result = graph
.execute(query(
" WITH time({hour:10, minute:15, second:33, nanosecond: 200, timezone: '+01:00'}) AS t RETURN t",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: (chrono::NaiveTime, Option<chrono::FixedOffset>) = row.get("t").unwrap();
assert_eq!(t.0.to_string(), "10:15:33.000000200");
assert_eq!(t.1, Some(chrono::FixedOffset::east(1 * 3600)));
assert!(result.next().await.unwrap().is_none());
}

DateTime

DateTime captures the date and time with offset
NaiveDateTime captures the date time without offset
tuple(NaiveDateTime, String) captures the date/time and the time zone id

DateTime as param

Pass a DateTime as parameter to the query:

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

//send datetime as parameter in the query
let datetime = chrono::DateTime::parse_from_rfc2822("Tue, 01 Jul 2003 10:52:37 +0200").unwrap();

let mut result = graph
.execute(query("RETURN $d as output").param("d", datetime))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: chrono::DateTime<chrono::FixedOffset> = row.get("output").unwrap();
assert_eq!(t.to_string(), "2003-07-01 10:52:37 +02:00");
assert!(result.next().await.unwrap().is_none());

//send NaiveDateTime as parameter in the query
let localdatetime = chrono::NaiveDateTime::parse_from_str("2015-07-01 08:55:59.123", "%Y-%m-%d %H:%M:%S%.f").unwrap();

let mut result = graph
.execute(query("RETURN $d as output").param("d", localdatetime))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: chrono::NaiveDateTime = row.get("output").unwrap();
assert_eq!(t.to_string(), "2015-07-01 08:55:59.123");
assert!(result.next().await.unwrap().is_none());

//send NaiveDateTime with timezone id as parameter in the query
let datetime = chrono::NaiveDateTime::parse_from_str("2015-07-03 08:55:59.555", "%Y-%m-%d %H:%M:%S%.f").unwrap();
let timezone =  "Europe/Paris";

let mut result = graph
.execute(query("RETURN $d as output").param("d", (datetime, timezone)))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let (time, zone): (chrono::NaiveDateTime, String) = row.get("output").unwrap();
assert_eq!(time.to_string(), "2015-07-03 08:55:59.555");
assert_eq!(zone, "Europe/Paris");
assert!(result.next().await.unwrap().is_none());

}

Parsing DateTime from result

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();

//Parse NaiveDateTime from result
let mut result = graph
.execute(query(
"WITH localdatetime('2015-06-24T12:50:35.556') AS t RETURN t",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: chrono::NaiveDateTime = row.get("t").unwrap();
assert_eq!(t.to_string(), "2015-06-24 12:50:35.556");
assert!(result.next().await.unwrap().is_none());

//Parse DateTime from result
let mut result = graph
.execute(query(
"WITH datetime('2015-06-24T12:50:35.777+0100') AS t RETURN t",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let t: chrono::DateTime<chrono::FixedOffset> = row.get("t").unwrap();
assert_eq!(t.to_string(), "2015-06-24 12:50:35.777 +01:00");
assert!(result.next().await.unwrap().is_none());


//Parse NaiveDateTime with zone id from result
let mut result = graph
.execute(query(
"WITH datetime({ year:1984, month:11, day:11, hour:12, minute:31, second:14, nanosecond: 645876123, timezone:'Europe/Stockholm' }) AS d return d",
))
.await
.unwrap();
let row = result.next().await.unwrap().unwrap();
let (datetime, zone_id): (chrono::NaiveDateTime, String) = row.get("d").unwrap();
assert_eq!(datetime.to_string(), "1984-11-11 12:31:14.645876123");
assert_eq!(zone_id, "Europe/Stockholm");
assert!(result.next().await.unwrap().is_none());

}

Path

use neo4rs::*;
use futures::stream::*;
use uuid::Uuid;

#[tokio::main]
async fn main() {
let uri = "127.0.0.1:7687";
let user = "neo4j";
let pass = "neo";
let graph = Graph::new(uri, user, pass).await.unwrap();
let name = Uuid::new_v4().to_string();
graph.run(
query("CREATE (p:Person { name: $name })-[r:WORKS_AT]->(n:Company { name: 'Neo'})").param("name", name.clone()),
).await.unwrap();

let mut result = graph.execute(
query("MATCH p = (person:Person { name: $name })-[r:WORKS_AT]->(c:Company) RETURN p").param("name", name),
).await.unwrap();

let row = result.next().await.unwrap().unwrap();
let path: Path = row.get("p").unwrap();
assert_eq!(path.ids().len(), 2);
assert_eq!(path.nodes().len(), 2);
assert_eq!(path.rels().len(), 1);
assert!(result.next().await.unwrap().is_none());
}

neo4rs 0.5.5