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<ol class="chapter"><li class="chapter-item expanded "><a href="index.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item expanded "><a href="installation_features.html"><strong aria-hidden="true">2.</strong> Installation and Features</a></li><li class="chapter-item expanded "><a href="connecting.html" class="active"><strong aria-hidden="true">3.</strong> Connecting to the Database</a></li><li class="chapter-item expanded "><a href="reading.html"><strong aria-hidden="true">4.</strong> Reading From the Database</a></li><li class="chapter-item expanded "><div><strong aria-hidden="true">5.</strong> Writing To the Database</div></li><li class="chapter-item expanded "><a href="performance.html"><strong aria-hidden="true">6.</strong> Performance</a></li><li class="chapter-item expanded "><div><strong aria-hidden="true">7.</strong> Serde Integration</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">8.</strong> Sessions and Transactions</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">9.</strong> Change Streams</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">10.</strong> Monitoring</div></li><li class="chapter-item expanded "><a href="tracing.html"><strong aria-hidden="true">11.</strong> Tracing and Logging</a></li><li class="chapter-item expanded "><a href="web_framework_examples.html"><strong aria-hidden="true">12.</strong> Web Framework Examples</a></li><li class="chapter-item expanded "><a href="encryption.html"><strong aria-hidden="true">13.</strong> Encryption</a></li><li class="chapter-item expanded affix "><li class="part-title">Development</li><li class="chapter-item expanded "><div><strong aria-hidden="true">14.</strong> Writing Tests</div></li></ol>
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<h1 class="menu-title">MongoDB Rust Driver</h1>
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<h1 id="connecting-to-the-database"><a class="header" href="#connecting-to-the-database">Connecting to the Database</a></h1>
<h2 id="connection-string"><a class="header" href="#connection-string">Connection String</a></h2>
<p>Connecting to a MongoDB database requires using a <a href="https://www.mongodb.com/docs/manual/reference/connection-string/#connection-string-formats">connection string</a>, a URI of the form:</p>
<pre><code class="language-uri">mongodb://[username:password@]host1[:port1][,...hostN[:portN]][/[defaultauthdb][?options]]
</code></pre>
<p>At its simplest this can just specify the host and port, e.g.</p>
<pre><code class="language-uri">mongodb://mongodb0.example.com:27017
</code></pre>
<p>For the full range of options supported by the Rust driver, see the documentation for the <a href="https://docs.rs/mongodb/latest/mongodb/options/struct.ClientOptions.html#method.parse"><code>ClientOptions::parse</code></a> method. That method will return a <a href="https://docs.rs/mongodb/latest/mongodb/options/struct.ClientOptions.html"><code>ClientOptions</code></a> struct, allowing for directly querying or setting any of the options supported by the Rust driver:</p>
<pre><pre class="playground"><code class="language-rust no_run edition2021"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">extern crate mongodb;
</span><span class="boring">use mongodb::options::ClientOptions;
</span><span class="boring">async fn run() -> mongodb::error::Result<()> {
</span>let mut options = ClientOptions::parse("mongodb://mongodb0.example.com:27017").await?;
options.app_name = Some("My App".to_string());
<span class="boring">Ok(())
</span><span class="boring">}
</span><span class="boring">}</span></code></pre></pre>
<h2 id="creating-a-client"><a class="header" href="#creating-a-client">Creating a <code>Client</code></a></h2>
<p>The <a href="https://docs.rs/mongodb/latest/mongodb/struct.Client.html"><code>Client</code></a> struct is the main entry point for the driver. You can create one from a <code>ClientOptions</code> struct:</p>
<pre><pre class="playground"><code class="language-rust no_run edition2021"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">extern crate mongodb;
</span><span class="boring">use mongodb::{Client, options::ClientOptions};
</span><span class="boring">async fn run() -> mongodb::error::Result<()> {
</span><span class="boring">let options = ClientOptions::parse("mongodb://mongodb0.example.com:27017").await?;
</span>let client = Client::with_options(options)?;
<span class="boring">Ok(())
</span><span class="boring">}
</span><span class="boring">}</span></code></pre></pre>
<p>As a convenience, if you don't need to modify the <code>ClientOptions</code> before creating the <code>Client</code>, you can directly create one from the connection string:</p>
<pre><pre class="playground"><code class="language-rust no_run edition2021"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">extern crate mongodb;
</span><span class="boring">use mongodb::Client;
</span><span class="boring">async fn run() -> mongodb::error::Result<()> {
</span>let client = Client::with_uri_str("mongodb://mongodb0.example.com:27017").await?;
<span class="boring">Ok(())
</span><span class="boring">}
</span><span class="boring">}</span></code></pre></pre>
<p><code>Client</code> uses <a href="https://doc.rust-lang.org/std/sync/struct.Arc.html"><code>std::sync::Arc</code></a> internally, so it can safely be shared across threads or async tasks. For example:</p>
<pre><pre class="playground"><code class="language-rust no_run edition2021"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">extern crate mongodb;
</span><span class="boring">extern crate tokio;
</span><span class="boring">use mongodb::{bson::Document, Client, error::Result};
</span><span class="boring">use tokio::task;
</span><span class="boring">
</span><span class="boring">async fn start_workers() -> Result<()> {
</span>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
});
}
<span class="boring">
</span><span class="boring">Ok(())
</span><span class="boring">}
</span><span class="boring">}</span></code></pre></pre>
<h2 id="client-performance"><a class="header" href="#client-performance">Client Performance</a></h2>
<p>While cloning a <code>Client</code> is very lightweight, creating a new one is an expensive operation. For most use cases, it is highly recommended to create a single <code>Client</code> and persist it for the lifetime of your application. For more information, see the <a href="performance.html">Performance</a> chapter.</p>
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