Agent::cookie_store to persist cookies

src/agent.rs

@@ -7,7 +7,10 @@ use crate::resolve::{ArcResolver, StdResolver};
 use std::time::Duration;
 
 #[cfg(feature = "cookies")]
-use {crate::cookies::CookieTin, cookie_store::CookieStore};
+use {
+    crate::cookies::{CookieStoreGuard, CookieTin},
+    cookie_store::CookieStore,
+};
 
 #[derive(Debug)]
 pub struct AgentBuilder {
@@ -131,6 +134,29 @@ impl Agent {
     pub fn delete(&self, path: &str) -> Request {
         self.request("DELETE", path)
     }
+
+    /// Read access to the cookie store.
+    ///
+    /// Used to persist the cookies to an external writer.
+    ///
+    /// ```no_run
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// let mut file = File::create("cookies.json").unwrap();
+    ///
+    /// let agent = ureq::agent();
+    ///
+    /// // Cookies set by www.google.com are stored in agent.
+    /// agent.get("https://www.google.com/").call().unwrap();
+    ///
+    /// // Saves (persistent) cookies
+    /// agent.cookie_store().save_json(&mut file).unwrap();
+    /// ```
+    #[cfg(feature = "cookies")]
+    pub fn cookie_store(&self) -> CookieStoreGuard<'_> {
+        self.state.cookie_tin.read_lock()
+    }
 }
 
 const DEFAULT_MAX_IDLE_CONNECTIONS: usize = 100;

src/cookies.rs

@@ -1,5 +1,8 @@
 #[cfg(feature = "cookies")]
-use std::sync::RwLock;
+use {
+    std::ops::Deref,
+    std::sync::{RwLock, RwLockReadGuard},
+};
 
 #[cfg(feature = "cookies")]
 use cookie_store::CookieStore;
@@ -12,6 +15,16 @@ pub(crate) struct CookieTin {
     inner: RwLock<CookieStore>,
 }
 
+/// RAII guard for read access to the CookieStore.
+pub struct CookieStoreGuard<'a>(RwLockReadGuard<'a, CookieStore>);
+
+impl<'a> Deref for CookieStoreGuard<'a> {
+    type Target = CookieStore;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 #[cfg(feature = "cookies")]
 impl CookieTin {
     pub(crate) fn new(store: CookieStore) -> Self {
@@ -19,6 +32,12 @@ impl CookieTin {
             inner: RwLock::new(store),
         }
     }
+
+    pub(crate) fn read_lock(&self) -> CookieStoreGuard<'_> {
+        let lock = self.inner.read().unwrap();
+        CookieStoreGuard(lock)
+    }
+
     pub(crate) fn get_request_cookies(&self, url: &Url) -> Vec<cookie::Cookie> {
         let store = self.inner.read().unwrap();
         store