Connecting to the Database
+Connection String
+Connecting to a MongoDB database requires using a connection string, a URI of the form:
+mongodb://[username:password@]host1[:port1][,...hostN[:portN]][/[defaultauthdb][?options]]
+At its simplest this can just specify the host and port, e.g.
+mongodb://mongodb0.example.com:27017
+For the full range of options supported by the Rust driver, see the documentation for the ClientOptions::parse method. That method will return a ClientOptions struct, allowing for directly querying or setting any of the options supported by the Rust driver:
++#![allow(unused)] +fn main() { +extern crate mongodb; +use mongodb::options::ClientOptions; +async fn run() -> mongodb::error::Result<()> { +let mut options = ClientOptions::parse("mongodb://mongodb0.example.com:27017").await?; +options.app_name = Some("My App".to_string()); +Ok(()) +} +} +
Creating a Client
+The Client struct is the main entry point for the driver. You can create one from a ClientOptions struct:
++#![allow(unused)] +fn main() { +extern crate mongodb; +use mongodb::{Client, options::ClientOptions}; +async fn run() -> mongodb::error::Result<()> { +let options = ClientOptions::parse("mongodb://mongodb0.example.com:27017").await?; +let client = Client::with_options(options)?; +Ok(()) +} +} +
As a convenience, if you don't need to modify the ClientOptions before creating the Client, you can directly create one from the connection string:
++#![allow(unused)] +fn main() { +extern crate mongodb; +use mongodb::Client; +async fn run() -> mongodb::error::Result<()> { +let client = Client::with_uri_str("mongodb://mongodb0.example.com:27017").await?; +Ok(()) +} +} +
Client uses std::sync::Arc internally, so it can safely be shared across threads or async tasks. For example:
++#![allow(unused)] +fn main() { +extern crate mongodb; +extern crate tokio; +use mongodb::{bson::Document, Client, error::Result}; +use tokio::task; + +async fn start_workers() -> Result<()> { +let client = Client::with_uri_str("mongodb://example.com").await?; + +for i in 0..5 { + let client_ref = client.clone(); + + task::spawn(async move { + let collection = client_ref.database("items").collection::<Document>(&format!("coll{}", i)); + + // Do something with the collection + }); +} + +Ok(()) +} +} +
For more information on the client and parallel operation, see the Performance chapter.
+ +
