Struct http::Extensions

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pub struct Extensions { /* private fields */ }
Expand description

A type map of protocol extensions.

Extensions can be used by Request and Response to store extra data derived from the underlying protocol.

Implementations§

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impl Extensions

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pub fn new() -> Extensions

Create an empty Extensions.

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pub fn insert<T: Clone + Send + Sync + 'static>(&mut self, val: T) -> Option<T>

Insert a type into this Extensions.

If a extension of this type already existed, it will be returned.

§Example
let mut ext = Extensions::new();
assert!(ext.insert(5i32).is_none());
assert!(ext.insert(4u8).is_none());
assert_eq!(ext.insert(9i32), Some(5i32));
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pub fn get<T: Send + Sync + 'static>(&self) -> Option<&T>

Get a reference to a type previously inserted on this Extensions.

§Example
let mut ext = Extensions::new();
assert!(ext.get::<i32>().is_none());
ext.insert(5i32);

assert_eq!(ext.get::<i32>(), Some(&5i32));
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pub fn get_mut<T: Send + Sync + 'static>(&mut self) -> Option<&mut T>

Get a mutable reference to a type previously inserted on this Extensions.

§Example
let mut ext = Extensions::new();
ext.insert(String::from("Hello"));
ext.get_mut::<String>().unwrap().push_str(" World");

assert_eq!(ext.get::<String>().unwrap(), "Hello World");
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pub fn get_or_insert<T: Clone + Send + Sync + 'static>( &mut self, value: T, ) -> &mut T

Get a mutable reference to a type, inserting value if not already present on this Extensions.

§Example
let mut ext = Extensions::new();
*ext.get_or_insert(1i32) += 2;

assert_eq!(*ext.get::<i32>().unwrap(), 3);
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pub fn get_or_insert_with<T: Clone + Send + Sync + 'static, F: FnOnce() -> T>( &mut self, f: F, ) -> &mut T

Get a mutable reference to a type, inserting the value created by f if not already present on this Extensions.

§Example
let mut ext = Extensions::new();
*ext.get_or_insert_with(|| 1i32) += 2;

assert_eq!(*ext.get::<i32>().unwrap(), 3);
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pub fn get_or_insert_default<T: Default + Clone + Send + Sync + 'static>( &mut self, ) -> &mut T

Get a mutable reference to a type, inserting the type’s default value if not already present on this Extensions.

§Example
let mut ext = Extensions::new();
*ext.get_or_insert_default::<i32>() += 2;

assert_eq!(*ext.get::<i32>().unwrap(), 2);
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pub fn remove<T: Send + Sync + 'static>(&mut self) -> Option<T>

Remove a type from this Extensions.

If a extension of this type existed, it will be returned.

§Example
let mut ext = Extensions::new();
ext.insert(5i32);
assert_eq!(ext.remove::<i32>(), Some(5i32));
assert!(ext.get::<i32>().is_none());
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pub fn clear(&mut self)

Clear the Extensions of all inserted extensions.

§Example
let mut ext = Extensions::new();
ext.insert(5i32);
ext.clear();

assert!(ext.get::<i32>().is_none());
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pub fn is_empty(&self) -> bool

Check whether the extension set is empty or not.

§Example
let mut ext = Extensions::new();
assert!(ext.is_empty());
ext.insert(5i32);
assert!(!ext.is_empty());
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pub fn len(&self) -> usize

Get the numer of extensions available.

§Example
let mut ext = Extensions::new();
assert_eq!(ext.len(), 0);
ext.insert(5i32);
assert_eq!(ext.len(), 1);
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pub fn extend(&mut self, other: Self)

Extends self with another Extensions.

If an instance of a specific type exists in both, the one in self is overwritten with the one from other.

§Example
let mut ext_a = Extensions::new();
ext_a.insert(8u8);
ext_a.insert(16u16);

let mut ext_b = Extensions::new();
ext_b.insert(4u8);
ext_b.insert("hello");

ext_a.extend(ext_b);
assert_eq!(ext_a.len(), 3);
assert_eq!(ext_a.get::<u8>(), Some(&4u8));
assert_eq!(ext_a.get::<u16>(), Some(&16u16));
assert_eq!(ext_a.get::<&'static str>().copied(), Some("hello"));

Trait Implementations§

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impl Clone for Extensions

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fn clone(&self) -> Extensions

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Extensions

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Default for Extensions

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fn default() -> Extensions

Returns the “default value” for a type. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.