1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257
//! An implementation of the [chain (tree) of responsibility] pattern.
//!
//! [[`examples/web_server.rs`](https://github.com/teloxide/dptree/blob/master/examples/web_server.rs)]
//! ```
//! use dptree::prelude::*;
//!
//! type WebHandler = Endpoint<'static, DependencyMap, String>;
//!
//! #[rustfmt::skip]
//! #[tokio::main]
//! async fn main() {
//! let web_server = dptree::entry()
//! .branch(smiles_handler())
//! .branch(sqrt_handler())
//! .branch(not_found_handler());
//!
//! assert_eq!(
//! web_server.dispatch(dptree::deps!["/smile"]).await,
//! ControlFlow::Break("🙃".to_owned())
//! );
//! assert_eq!(
//! web_server.dispatch(dptree::deps!["/sqrt 16"]).await,
//! ControlFlow::Break("4".to_owned())
//! );
//! assert_eq!(
//! web_server.dispatch(dptree::deps!["/lol"]).await,
//! ControlFlow::Break("404 Not Found".to_owned())
//! );
//! }
//!
//! fn smiles_handler() -> WebHandler {
//! dptree::filter(|req: &'static str| req.starts_with("/smile"))
//! .endpoint(|| async { "🙃".to_owned() })
//! }
//!
//! fn sqrt_handler() -> WebHandler {
//! dptree::filter_map(|req: &'static str| {
//! if req.starts_with("/sqrt") {
//! let (_, n) = req.split_once(' ')?;
//! n.parse::<f64>().ok()
//! } else {
//! None
//! }
//! })
//! .endpoint(|n: f64| async move { format!("{}", n.sqrt()) })
//! }
//!
//! fn not_found_handler() -> WebHandler {
//! dptree::endpoint(|| async { "404 Not Found".to_owned() })
//! }
//! ```
//!
//! For a high-level overview, please see [`README.md`](https://github.com/p0lunin/dptree).
//!
//! [chain (tree) of responsibility]: https://en.wikipedia.org/wiki/Chain-of-responsibility_pattern
mod handler;
pub mod di;
pub mod prelude;
pub use handler::*;
/// Filters an enumeration, passing its payload forwards.
///
/// This macro expands to a [`crate::Handler`] that acts on your enumeration
/// type: if the enumeration is of a certain variant, the execution continues;
/// otherwise, `dptree` will try the next branch. This is very useful for
/// dialogue FSM transitions and incoming command filtering; for a real-world
/// example, please see teloxide's [`examples/purchase.rs`].
///
/// Variants can take the following forms:
///
/// - `Enum::MyVariant` for empty variants;
/// - `Enum::MyVariant(param1, ..., paramN)` for function-like variants;
/// - `Enum::MyVariant { param1, ..., paramN }` for `struct`-like variants.
///
/// In the first case, this macro results in a simple [`crate::filter`]; in the
/// second and third cases, this macro results in [`crate::filter_map`] that
/// passes the payload of `MyVariant` to the next handler if the match occurs.
/// (This next handler can be an endpoint or a more complex one.) The payload
/// format depend on the form of `MyVariant`:
///
/// - For `Enum::MyVariant(param)` and `Enum::MyVariant { param }`, the payload
/// is `param`.
/// - For `Enum::MyVariant(param,)` and `Enum::MyVariant { param, }`, the
/// payload is `(param,)`.
/// - For `Enum::MyVariant(param1, ..., paramN)` and `Enum::MyVariant { param1,
/// ..., paramN }`, the payload is `(param1, ..., paramN)` (where `N`>1).
///
/// ## Dependency requirements
///
/// - Your enumeration `Enum`.
///
/// ## Examples
///
/// ```
/// use dptree::prelude::*;
///
/// # #[tokio::main]
/// # async fn main() {
/// #[derive(Clone)]
/// enum Command {
/// Meow,
/// Add(i32, i32),
/// }
///
/// let h: crate::Handler<_, _> = dptree::entry()
/// .branch(dptree::case![Command::Meow].endpoint(|| async move { format!("Meow!") }))
/// .branch(
/// dptree::case![Command::Add(x, y)]
/// .endpoint(|(x, y): (i32, i32)| async move { format!("{}", x + y) }),
/// );
///
/// assert_eq!(
/// h.dispatch(dptree::deps![Command::Meow]).await,
/// ControlFlow::Break("Meow!".to_owned())
/// );
/// assert_eq!(
/// h.dispatch(dptree::deps![Command::Add(1, 2)]).await,
/// ControlFlow::Break("3".to_owned())
/// );
/// # }
/// ```
///
/// [`examples/purchase.rs`]: https://github.com/teloxide/teloxide/blob/master/examples/purchase.rs
#[macro_export]
macro_rules! case {
($($variant:ident)::+) => {
$crate::filter(|x| matches!(x, $($variant)::+))
};
($($variant:ident)::+ ($param:ident)) => {
$crate::filter_map(|x| match x {
$($variant)::+($param) => Some($param),
_ => None,
})
};
($($variant:ident)::+ ($($param:ident),+ $(,)?)) => {
$crate::filter_map(|x| match x {
$($variant)::+($($param),+) => Some(($($param),+ ,)),
_ => None,
})
};
($($variant:ident)::+ {$param:ident}) => {
$crate::filter_map(|x| match x {
$($variant)::+{$param} => Some($param),
_ => None,
})
};
($($variant:ident)::+ {$($param:ident),+ $(,)?}) => {
$crate::filter_map(|x| match x {
$($variant)::+ { $($param),+ } => Some(($($param),+ ,)),
_ => None,
})
};
}
#[cfg(test)]
mod tests {
use std::ops::ControlFlow;
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
enum State {
A,
B(i32),
C(i32, &'static str),
D { foo: i32 },
E { foo: i32, bar: &'static str },
Other,
}
#[tokio::test]
async fn handler_empty_variant() {
let input = State::A;
let h: crate::Handler<_, _> = case![State::A].endpoint(|| async move { 123 });
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_single_fn_variant() {
let input = State::B(42);
let h: crate::Handler<_, _> = case![State::B(x)].endpoint(|x: i32| async move {
assert_eq!(x, 42);
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_single_fn_variant_trailing_comma() {
let input = State::B(42);
let h: crate::Handler<_, _> = case![State::B(x,)].endpoint(|(x,): (i32,)| async move {
assert_eq!(x, 42);
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_fn_variant() {
let input = State::C(42, "abc");
let h: crate::Handler<_, _> =
case![State::C(x, y)].endpoint(|(x, str): (i32, &'static str)| async move {
assert_eq!(x, 42);
assert_eq!(str, "abc");
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_single_struct_variant() {
let input = State::D { foo: 42 };
let h: crate::Handler<_, _> = case![State::D { foo }].endpoint(|x: i32| async move {
assert_eq!(x, 42);
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_single_struct_variant_trailing_comma() {
let input = State::D { foo: 42 };
#[rustfmt::skip] // rustfmt removes the trailing comma from `State::D { foo, }`, but it plays a vital role in this test.
let h: crate::Handler<_, _> = case![State::D { foo, }].endpoint(|(x,): (i32,)| async move {
assert_eq!(x, 42);
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
#[tokio::test]
async fn handler_struct_variant() {
let input = State::E { foo: 42, bar: "abc" };
let h: crate::Handler<_, _> =
case![State::E { foo, bar }].endpoint(|(x, str): (i32, &'static str)| async move {
assert_eq!(x, 42);
assert_eq!(str, "abc");
123
});
assert_eq!(h.dispatch(crate::deps![input]).await, ControlFlow::Break(123));
assert!(matches!(h.dispatch(crate::deps![State::Other]).await, ControlFlow::Continue(_)));
}
}