How reqwest saves cookies from a certain request and uses them for the next time

help
1

How reqwest saves cookies from a certain request and uses them for the next time?

2

When I try to run example code of reqwest_cookie_store:


#[tokio::test]
async fn test_client() {
    // Load an existing set of cookies, serialized as json
    let cookie_store = {
        let file = std::fs::File::open("tests/cookies.json")
            .map(std::io::BufReader::new)
            .unwrap();
        // use re-exported version of `CookieStore` for crate compatibility
        reqwest_cookie_store::CookieStore::load_json(file).unwrap()  // <<< panic here
    };
    let cookie_store = reqwest_cookie_store::CookieStoreMutex::new(cookie_store);
    let cookie_store = std::sync::Arc::new(cookie_store);
    {
        // Examine initial contents
        println!("initial load");
        let store = cookie_store.lock().unwrap();
        for c in store.iter_any() {
        println!("{:?}", c);
        }
    }
    
    // Build a `reqwest` Client, providing the deserialized store
    let client = reqwest::Client::builder()
        .cookie_provider(std::sync::Arc::clone(&cookie_store))
        .build()
        .unwrap();
    
    // Make another request from another domain
    println!("GET from msn");
    client.get("https://msn.com").send().await.unwrap();
    {
        // Examine the contents of the store.
        println!("after msn.com GET");
        let mut store = cookie_store.lock().unwrap();
        for c in store.iter_any() {
        println!("{:?}", c);
        }
        // Clear the store, and examine again
        store.clear();
        println!("after clear");
        for c in store.iter_any() {
        println!("{:?}", c);
        }
    }
    
    // Get some new cookies
    client.get("http://127.0.0.1:8080").send().await.unwrap();
    {
        // Write store back to disk
        let mut writer = std::fs::File::create("cookies2.json")
            .map(std::io::BufWriter::new)
            .unwrap();
        let store = cookie_store.lock().unwrap();
        store.save_json(&mut writer).unwrap();
    }
}

Got panic:

thread 'test_client' panicked at tests\test_client.rs:10:60:
called `Result::unwrap()` on an `Err` value: Error("EOF while parsing an object", line: 1, column: 1)

tests/cookie.json:

{
    "session_id": "abc123"
}
3

From reqwest_cookie_store::CookieStore::load_json:

NB: this method does not expect true valid JSON; it is designed to load output from the corresponding method CookieStore::save_json. For a more robust/universal JSON format, see crate::serde::json, which produces output incompatible with this method.

Maybe you're running into a case where your Json is not considered compatible?

1 Like
4

You are right.
I tried to run CookieStore::save_json to know what json it creates.
In that case, cookie.json should be something like:

{"raw_cookie":"session_id=abc123; HttpOnly; SameSite=Lax; Path=/; Expires=Thu, 03 Apr 2025 15:57:46 GMT","path":["/",true],"domain":{"HostOnly":"127.0.0.1"},"expires":{"AtUtc":"2025-04-03T15:57:46Z"}}