<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="Describes how long a session should last."><metaname="keywords"content="rust, rustlang, rust-lang, SessionLength"><title>SessionLength in actix_session - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../SourceSerif4-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../FiraSans-Regular.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../FiraSans-Medium.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../SourceCodePro-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../SourceSerif4-Bold.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../SourceCodePro-Semibold.ttf.woff2"><linkrel="stylesheet"type="text/css"href="../normalize.css"><linkrel="stylesheet"type="text/css"href="../rustdoc.css"id="mainThemeStyle"><linkrel="stylesheet"type="text/css"href="../ayu.css"disabled><linkrel="stylesheet"type="text/css"href="../dark.css"disabled><linkrel="stylesheet"type="text/css"href="../light.css"id="themeStyle"><scriptid="default-settings"></script><scriptsrc="../storage.js"></script><scriptsrc="../crates.js"></script><scriptdefersrc="../main.js"></script>
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}</code></pre></div><detailsclass="rustdoc-toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Describes how long a session should last.</p>
<p>Used by <ahref="struct.SessionMiddlewareBuilder.html#method.session_length"title="SessionMiddlewareBuilder::session_length"><code>SessionMiddlewareBuilder::session_length</code></a>.</p>
</div></details><h2id="variants"class="variants small-section-header">Variants<ahref="#variants"class="anchor"></a></h2><h3id="variant.BrowserSession"class="variant small-section-header"><ahref="#variant.BrowserSession"class="anchor field"></a><code>BrowserSession</code></h3><divclass="sub-variant"id="variant.BrowserSession.fields"><h4>Fields</h4><divclass="sub-variant-field"><spanid="variant.BrowserSession.field.state_ttl"class="variant small-section-header"><ahref="#variant.BrowserSession.field.state_ttl"class="anchor field"></a><code>state_ttl: <aclass="enum"href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html"title="enum core::option::Option">Option</a><Duration></code></span><divclass="docblock"><p>We must provide a time-to-live (TTL) when storing the session state in the storage
backend—we do not want to store session states indefinitely, otherwise we will
inevitably run out of storage by holding on to the state of countless abandoned or
expired sessions!</p>
<p>We are dealing with the lifecycle of two uncorrelated object here: the session cookie
and the session state. It is not a big issue if the session state outlives the cookie—
we are wasting some space in the backend storage, but it will be cleaned up eventually.
What happens, instead, if the cookie outlives the session state? A new session starts—
e.g. if sessions are being used for authentication, the user is de-facto logged out.</p>
<p>It is not possible to predict with certainty how long a browser session is going to
last—you need to provide a reasonable upper bound. You do so via <code>state_ttl</code>—it dictates
what TTL should be used for session state when the lifecycle of the session cookie is
tied to the browser session length. <ahref="struct.SessionMiddleware.html"title="SessionMiddleware"><code>SessionMiddleware</code></a> will default to 1 day if
<code>state_ttl</code> is left unspecified.</p>
</div></div></div><divclass="docblock"><p>The session cookie will expire when the current browser session ends.</p>
<p>When does a browser session end? It depends on the browser! Chrome, for example, will often
continue running in the background when the browser is closed—session cookies are not
deleted and they will still be available when the browser is opened again. Check the
</div><h3id="variant.Predetermined"class="variant small-section-header"><ahref="#variant.Predetermined"class="anchor field"></a><code>Predetermined</code></h3><divclass="sub-variant"id="variant.Predetermined.fields"><h4>Fields</h4><divclass="sub-variant-field"><spanid="variant.Predetermined.field.max_session_length"class="variant small-section-header"><ahref="#variant.Predetermined.field.max_session_length"class="anchor field"></a><code>max_session_length: <aclass="enum"href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html"title="enum core::option::Option">Option</a><Duration></code></span><divclass="docblock"><p>Set <code>max_session_length</code> to specify how long the session cookie should live.
<ahref="struct.SessionMiddleware.html"title="SessionMiddleware"><code>SessionMiddleware</code></a> will default to 1 day if <code>max_session_length</code> is set to <code>None</code>.</p>
<p><code>max_session_length</code> is also used as the TTL for the session state in the
storage backend.</p>
</div></div></div><divclass="docblock"><p>The session cookie will be a <ahref="https://www.whitehatsec.com/glossary/content/persistent-session-cookie">persistent cookie</a>.</p>
<p>Persistent cookies have a pre-determined lifetime, specified via the <code>Max-Age</code> or <code>Expires</code>
attribute. They do not disappear when the current browser session ends.</p>
</div><h2id="trait-implementations"class="small-section-header">Trait Implementations<ahref="#trait-implementations"class="anchor"></a></h2><divid="trait-implementations-list"><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-Clone"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="../src/actix_session/middleware.rs.html#144">source</a></span><ahref="#impl-Clone"class="anchor"></a><h3class="code-header in-band">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a> for <aclass="enum"href="enum.SessionLength.html"title="enum actix_session::SessionLength">SessionLength</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.clone"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="../src/actix_session/middleware.rs.html#144">source</a></span><ahref="#method.clone"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone"class="fnname">clone</a>(&self) -><aclass="enum"href="enum.SessionLength.html"title="enum actix_session::SessionLength">SessionLength</a></h4></section></summary><divclass='docblock'><p>Returns a copy of the value. <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.clone_from"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/clone.rs.html#134-136">source</a></span><ahref="#method.clone_from"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from"class="fnname">clone_from</a>(&mut self, source: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Self)</h4></section></summary><divclass='docblock'><p>Performs copy-assignment from <code>source</code>. <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-Debug"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="../src/actix_session/middleware.rs.html#144">source</a></span><ahref="#impl-Debug"class="anchor"></a><h3class="code-header in-band">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html"title="trait core::fmt::Debug">Debug</a> for <aclass="enum"href="enum.SessionLength.html"title="enum actix_session::SessionLength">SessionLength</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.fmt"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="../src/actix_session/middleware.rs.html#144">source</a></span><ahref="#method.fmt"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt"class="fnname">fmt</a>(&self, f: &mut <aclass="struct"href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html"title="struct core::fmt::Formatter">Formatter</a><'_>) -><aclass="type"href="https://doc.rust-lang.org/nightly/core/fmt/type.Result.html"title="type core::fmt::Result">Result</a></h4></section></summary><divclass='docblock'><p>Formats the value using the given formatter. <ahref="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"><summary><sectionid="impl-Instrument"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://docs.rs/tracing/0.1.32/src/tracing/instrument.rs.html#276">source</a></span><ahref="#impl-Instrument"class="anchor"></a><h3class="code-header in-band">impl<T><aclass="trait"href="https://docs.rs/tracing/0.1.32/tracing/instrument/trait.Instrument.html"title="trait tracing::instrument::Instrument">Instrument</a> for T</h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.instrument"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://docs.rs/tracing/0.1.32/src/tracing/instrument.rs.html#82">source</a></span><ahref="#method.instrument"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.32/tracing/instrument/trait.Instrument.html#method.instrument"class="fnname">instrument</a>(self, span: <aclass="struct"href="https://docs.rs/tracing/0.1.32/tracing/span/struct.Span.html"title="struct tracing::span::Span">Span</a>) -><aclass="struct"href="https://docs.rs/tracing/0.1.32/tracing/instrument/struct.Instrumented.html"title="struct tracing::instrument::Instrumented">Instrumented</a><Self></h4></section></summary><divclass='docblock'><p>Instruments this type with the provided <ahref="https://docs.rs/tracing/0.1.32/tracing/span/struct.Span.html"title="Span"><code>Span</code></a>, returning an
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.in_current_span"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://docs.rs/tracing/0.1.32/src/tracing/instrument.rs.html#121">source</a></span><ahref="#method.in_current_span"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.32/tracing/instrument/trait.Instrument.html#method.in_current_span"class="fnname">in_current_span</a>(self) -><aclass="struct"href="https://docs.rs/tracing/0.1.32/tracing/instrument/struct.Instrumented.html"title="struct tracing::instrument::Instrumented">Instrumented</a><Self></h4></section></summary><divclass='docblock'><p>Instruments this type with the <ahref="https://docs.rs/tracing/0.1.32/tracing/span/struct.Span.html#method.current">current</a><ahref="https://docs.rs/tracing/0.1.32/tracing/span/struct.Span.html"><code>Span</code></a>, returning an
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.to_owned"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/nightly/src/alloc/borrow.rs.html#89">source</a></span><ahref="#method.to_owned"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#tymethod.to_owned"class="fnname">to_owned</a>(&self) -> T</h4></section></summary><divclass='docblock'><p>Creates owned data from borrowed data, usually by cloning. <ahref="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#tymethod.to_owned">Read more</a></p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.clone_into"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/nightly/src/alloc/borrow.rs.html#93">source</a></span><ahref="#method.clone_into"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#method.clone_into"class="fnname">clone_into</a>(&self, target: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>T)</h4></section></summary><divclass="item-info"><divclass="stab unstable"><spanclass="emoji">🔬</span> This is a nightly-only experimental API. (<code>toowned_clone_into</code>)</div></div><divclass='docblock'><p>Uses borrowed data to replace owned data, usually by cloning. <ahref="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#method.clone_into">Read more</a></p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"><summary><sectionid="impl-TryFrom%3CU%3E"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#598-607">source</a></span><ahref="#impl-TryFrom%3CU%3E"class="anchor"></a><h3class="code-header in-band">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U> for T <spanclass="where fmt-newline">where<br> U: <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><T>, </span></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><sectionid="associatedtype.Error"class="type trait-impl has-srclink"><ahref="#associatedtype.Error"class="anchor"></a><h4class="code-header">type <ahref="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error"class="associatedtype">Error</a> = <aclass="enum"href="https://doc.rust-lang.org/nightly/core/convert/enum.Infallible.html"title="enum core::convert::Infallible">Infallible</a></h4></section></summary><divclass='docblock'><p>The type returned in the event of a conversion error.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.try_from"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="const unstable">const: <ahref="https://github.com/rust-lang/rust/issues/88674"title="Tracking issue for const_convert">unstable</a></span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#604">source</a></span><ahref="#method.try_from"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#tymethod.try_from"class="fnname">try_from</a>(value: U) -><aclass="enum"href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"title="enum core::result::Result">Result</a><T, <T as <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U>>::<aclass="associatedtype"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><divclass='docblock'><p>Performs the conversion.</p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"><summary><sectionid="impl-TryInto%3CU%3E"class="impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#583-592">source</a></span><ahref="#impl-TryInto%3CU%3E"class="anchor"></a><h3class="code-header in-band">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html"title="trait core::convert::TryInto">TryInto</a><U> for T <spanclass="where fmt-newline">where<br> U: <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>, </span></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><sectionid="associatedtype.Error-1"class="type trait-impl has-srclink"><ahref="#associatedtype.Error-1"class="anchor"></a><h4class="code-header">type <ahref="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#associatedtype.Error"class="associatedtype">Error</a> = <U as <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="associatedtype"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a></h4></section></summary><divclass='docblock'><p>The type returned in the event of a conversion error.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.try_into"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="const unstable">const: <ahref="https://github.com/rust-lang/rust/issues/88674"title="Tracking issue for const_convert">unstable</a></span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#589">source</a></span><ahref="#method.try_into"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#tymethod.try_into"class="fnname">try_into</a>(self) -><aclass="enum"href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"title="enum core::result::Result">Result</a><U, <U as <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="associatedtype"href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><divclass='docblock'><p>Performs the conversion.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.with_current_subscriber"class="method trait-impl has-srclink"><spanclass="rightside"><aclass="srclink"href="https://docs.rs/tracing/0.1.32/src/tracing/instrument.rs.html#221">source</a></span><ahref="#method.with_current_subscriber"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.32/tracing/instrument/trait.WithSubscriber.html#method.with_current_subscriber"class="fnname">with_current_subscriber</a>(self) -><aclass="struct"href="https://docs.rs/tracing/0.1.32/tracing/instrument/struct.WithDispatch.html"title="struct tracing::instrument::WithDispatch">WithDispatch</a><Self></h4></section></summary><divclass='docblock'><p>Attaches the current <ahref="https://docs.rs/tracing/0.1.32/tracing/dispatcher/index.html#setting-the-default-subscriber">default</a><ahref="https://docs.rs/tracing-core/0.1.22/tracing_core/subscriber/trait.Subscriber.html"><code>Subscriber</code></a> to this type, returning a
