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</pre><pre class="rust"><code><span class="kw">use </span>std::collections::HashMap;
<span class="kw">use </span>actix_web::cookie::time::Duration;
<span class="kw">use </span>derive_more::Display;
<span class="kw">use </span><span class="kw">super</span>::SessionKey;
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">type </span>SessionState = HashMap<String, String>;
<span class="doccomment">/// The interface to retrieve and save the current session data from/to the chosen storage backend.
///
/// You can provide your own custom session store backend by implementing this trait.
///
/// [`async-trait`](https://docs.rs/async-trait) is used for this trait's definition. Therefore, it
/// is required for implementations, too. In particular, we use the send-optional variant:
/// `#[async_trait(?Send)]`.
</span><span class="attribute">#[async_trait::async_trait(<span class="question-mark">?</span>Send)]
</span><span class="kw">pub trait </span>SessionStore {
<span class="doccomment">/// Loads the session state associated to a session key.
</span><span class="kw">async fn </span>load(<span class="kw-2">&</span><span class="self">self</span>, session_key: <span class="kw-2">&</span>SessionKey) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><SessionState>, LoadError>;
<span class="doccomment">/// Persist the session state for a newly created session.
///
/// Returns the corresponding session key.
</span><span class="kw">async fn </span>save(
<span class="kw-2">&</span><span class="self">self</span>,
session_state: SessionState,
ttl: <span class="kw-2">&</span>Duration,
) -> <span class="prelude-ty">Result</span><SessionKey, SaveError>;
<span class="doccomment">/// Updates the session state associated to a pre-existing session key.
</span><span class="kw">async fn </span>update(
<span class="kw-2">&</span><span class="self">self</span>,
session_key: SessionKey,
session_state: SessionState,
ttl: <span class="kw-2">&</span>Duration,
) -> <span class="prelude-ty">Result</span><SessionKey, UpdateError>;
<span class="doccomment">/// Updates the TTL of the session state associated to a pre-existing session key.
</span><span class="kw">async fn </span>update_ttl(
<span class="kw-2">&</span><span class="self">self</span>,
session_key: <span class="kw-2">&</span>SessionKey,
ttl: <span class="kw-2">&</span>Duration,
) -> <span class="prelude-ty">Result</span><(), anyhow::Error>;
<span class="doccomment">/// Deletes a session from the store.
</span><span class="kw">async fn </span>delete(<span class="kw-2">&</span><span class="self">self</span>, session_key: <span class="kw-2">&</span>SessionKey) -> <span class="prelude-ty">Result</span><(), anyhow::Error>;
}
<span class="comment">// We cannot derive the `Error` implementation using `derive_more` for our custom errors:
// `derive_more`'s `#[error(source)]` attribute requires the source implement the `Error` trait,
// while it's actually enough for it to be able to produce a reference to a dyn Error.
</span><span class="doccomment">/// Possible failures modes for [`SessionStore::load`].
</span><span class="attribute">#[derive(Debug, Display)]
</span><span class="kw">pub enum </span>LoadError {
<span class="doccomment">/// Failed to deserialize session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Failed to deserialize session state"</span>)]
</span>Deserialization(anyhow::Error),
<span class="doccomment">/// Something went wrong when retrieving the session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Something went wrong when retrieving the session state"</span>)]
</span>Other(anyhow::Error),
}
<span class="kw">impl </span>std::error::Error <span class="kw">for </span>LoadError {
<span class="kw">fn </span>source(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>(<span class="kw">dyn </span>std::error::Error + <span class="lifetime">'static</span>)> {
<span class="kw">match </span><span class="self">self </span>{
<span class="self">Self</span>::Deserialization(err) => <span class="prelude-val">Some</span>(err.as_ref()),
<span class="self">Self</span>::Other(err) => <span class="prelude-val">Some</span>(err.as_ref()),
}
}
}
<span class="doccomment">/// Possible failures modes for [`SessionStore::save`].
</span><span class="attribute">#[derive(Debug, Display)]
</span><span class="kw">pub enum </span>SaveError {
<span class="doccomment">/// Failed to serialize session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Failed to serialize session state"</span>)]
</span>Serialization(anyhow::Error),
<span class="doccomment">/// Something went wrong when persisting the session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Something went wrong when persisting the session state"</span>)]
</span>Other(anyhow::Error),
}
<span class="kw">impl </span>std::error::Error <span class="kw">for </span>SaveError {
<span class="kw">fn </span>source(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>(<span class="kw">dyn </span>std::error::Error + <span class="lifetime">'static</span>)> {
<span class="kw">match </span><span class="self">self </span>{
<span class="self">Self</span>::Serialization(err) => <span class="prelude-val">Some</span>(err.as_ref()),
<span class="self">Self</span>::Other(err) => <span class="prelude-val">Some</span>(err.as_ref()),
}
}
}
<span class="attribute">#[derive(Debug, Display)]
</span><span class="doccomment">/// Possible failures modes for [`SessionStore::update`].
</span><span class="kw">pub enum </span>UpdateError {
<span class="doccomment">/// Failed to serialize session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Failed to serialize session state"</span>)]
</span>Serialization(anyhow::Error),
<span class="doccomment">/// Something went wrong when updating the session state.
</span><span class="attribute">#[display(fmt = <span class="string">"Something went wrong when updating the session state."</span>)]
</span>Other(anyhow::Error),
}
<span class="kw">impl </span>std::error::Error <span class="kw">for </span>UpdateError {
<span class="kw">fn </span>source(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>(<span class="kw">dyn </span>std::error::Error + <span class="lifetime">'static</span>)> {
<span class="kw">match </span><span class="self">self </span>{
<span class="self">Self</span>::Serialization(err) => <span class="prelude-val">Some</span>(err.as_ref()),
<span class="self">Self</span>::Other(err) => <span class="prelude-val">Some</span>(err.as_ref()),
}
}
}
</code></pre></div>
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