Struct gotham::state::State

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pub struct State { /* private fields */ }

Expand description

Provides storage for request state, and stores one item of each type. The types used for storage must implement the StateData trait to allow its storage, which is usually done by adding #[derive(StateData)] on the type in question.

§Examples

use gotham::state::{State, StateData};

#[derive(StateData)]
struct MyStruct {
    value: i32,
}
state.put(MyStruct { value: 1 });
assert_eq!(state.borrow::<MyStruct>().value, 1);

Implementations§

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impl State

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pub fn from_request(req: Request<Body>, client_addr: SocketAddr) -> Self

Instantiate a new State for a given Request. This is primarily useful if you’re calling Gotham from your own Hyper service.

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pub fn put<T>(&mut self, t: T)
where T: StateData,

Puts a value into the State storage. One value of each type is retained. Successive calls to put will overwrite the existing value of the same type.

§Examples

state.put(MyStruct { value: 1 });
assert_eq!(state.borrow::<MyStruct>().value, 1);

state.put(AnotherStruct { value: "a string" });
state.put(MyStruct { value: 100 });

assert_eq!(state.borrow::<AnotherStruct>().value, "a string");
assert_eq!(state.borrow::<MyStruct>().value, 100);

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pub fn has<T>(&self) -> bool
where T: StateData,

Determines if the current value exists in State storage.

§Examples

state.put(MyStruct { value: 1 });
assert!(state.has::<MyStruct>());
assert_eq!(state.borrow::<MyStruct>().value, 1);

assert!(!state.has::<AnotherStruct>());

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pub fn try_borrow<T>(&self) -> Option<&T>
where T: StateData,

Tries to borrow a value from the State storage.

§Examples

state.put(MyStruct { value: 1 });
assert!(state.try_borrow::<MyStruct>().is_some());
assert_eq!(state.try_borrow::<MyStruct>().unwrap().value, 1);

assert!(state.try_borrow::<AnotherStruct>().is_none());

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pub fn borrow<T>(&self) -> &T
where T: StateData,

Borrows a value from the State storage.

§Panics

If a value of type T is not present in State.

§Examples

state.put(MyStruct { value: 1 });
assert_eq!(state.borrow::<MyStruct>().value, 1);

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pub fn try_borrow_mut<T>(&mut self) -> Option<&mut T>
where T: StateData,

Tries to mutably borrow a value from the State storage.

§Examples

state.put(MyStruct { value: 100 });

if let Some(a) = state.try_borrow_mut::<MyStruct>() {
    a.value += 10;
}

assert_eq!(state.borrow::<MyStruct>().value, 110);

assert!(state.try_borrow_mut::<AnotherStruct>().is_none());

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pub fn borrow_mut<T>(&mut self) -> &mut T
where T: StateData,

Mutably borrows a value from the State storage.

§Panics

If a value of type T is not present in State.

§Examples

state.put(MyStruct { value: 100 });

{
    let a = state.borrow_mut::<MyStruct>();
    a.value += 10;
}

assert_eq!(state.borrow::<MyStruct>().value, 110);

assert!(state.try_borrow_mut::<AnotherStruct>().is_none());

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pub fn try_take<T>(&mut self) -> Option<T>
where T: StateData,

Tries to move a value out of the State storage and return ownership.

§Examples

state.put(MyStruct { value: 110 });

assert_eq!(state.try_take::<MyStruct>().unwrap().value, 110);

assert!(state.try_take::<MyStruct>().is_none());
assert!(state.try_borrow_mut::<MyStruct>().is_none());
assert!(state.try_borrow::<MyStruct>().is_none());

assert!(state.try_take::<AnotherStruct>().is_none());

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pub fn take<T>(&mut self) -> T
where T: StateData,

Moves a value out of the State storage and returns ownership.

§Panics

If a value of type T is not present in State.

§Examples

state.put(MyStruct { value: 110 });

assert_eq!(state.take::<MyStruct>().value, 110);

assert!(state.try_take::<MyStruct>().is_none());
assert!(state.try_borrow_mut::<MyStruct>().is_none());
assert!(state.try_borrow::<MyStruct>().is_none());