Files
poem/src/route_recognizer/mod.rs
2021-08-13 11:35:10 +08:00

434 lines
13 KiB
Rust

mod nfa;
use std::cmp::Ordering;
use std::collections::BTreeMap;
use std::ops::Index;
use nfa::{CharacterClass, NFA};
#[derive(Clone, Eq, Debug)]
struct Metadata {
statics: u32,
dynamics: u32,
wildcards: u32,
param_names: Vec<String>,
}
impl Metadata {
pub(crate) fn new() -> Self {
Self {
statics: 0,
dynamics: 0,
wildcards: 0,
param_names: Vec::new(),
}
}
}
impl Ord for Metadata {
fn cmp(&self, other: &Self) -> Ordering {
if self.statics > other.statics {
Ordering::Greater
} else if self.statics < other.statics {
Ordering::Less
} else if self.dynamics > other.dynamics {
Ordering::Greater
} else if self.dynamics < other.dynamics {
Ordering::Less
} else if self.wildcards > other.wildcards {
Ordering::Greater
} else if self.wildcards < other.wildcards {
Ordering::Less
} else {
Ordering::Equal
}
}
}
impl PartialOrd for Metadata {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for Metadata {
fn eq(&self, other: &Self) -> bool {
self.statics == other.statics
&& self.dynamics == other.dynamics
&& self.wildcards == other.wildcards
}
}
/// Router parameters.
#[derive(PartialEq, Clone, Debug, Default)]
pub(crate) struct Params(pub(crate) Vec<(String, String)>);
impl Index<&str> for Params {
type Output = str;
fn index(&self, name: &str) -> &Self::Output {
self.0
.iter()
.find(|(n, _)| n == name)
.map(|(_, value)| value.as_str())
.unwrap()
}
}
/// The result of a successful match returned by `Router::recognize`.
#[derive(Debug)]
pub(crate) struct Match<T> {
/// Return the endpoint handler.
pub(crate) handler: T,
/// Return the params.
pub(crate) params: Params,
}
/// Recognizes URL patterns with support for dynamic and wildcard segments.
#[derive(Clone, Debug)]
pub(crate) struct Router<T> {
nfa: NFA<Metadata>,
handlers: BTreeMap<usize, T>,
}
fn segments(route: &str) -> Vec<(Option<char>, &str)> {
let predicate = |c| c == '.' || c == '/';
let mut segments = vec![];
let mut segment_start = 0;
while segment_start < route.len() {
let segment_end = route[segment_start + 1..]
.find(predicate)
.map(|i| i + segment_start + 1)
.unwrap_or_else(|| route.len());
let potential_sep = route.chars().nth(segment_start);
let sep_and_segment = match potential_sep {
Some(sep) if predicate(sep) => (Some(sep), &route[segment_start + 1..segment_end]),
_ => (None, &route[segment_start..segment_end]),
};
segments.push(sep_and_segment);
segment_start = segment_end;
}
segments
}
impl<T> Router<T> {
/// Create a new instance of `Router`.
pub(crate) fn new() -> Self {
Self {
nfa: NFA::new(),
handlers: BTreeMap::new(),
}
}
/// Add a route to the router.
pub(crate) fn add(&mut self, mut route: &str, dest: T) {
if !route.is_empty() && route.as_bytes()[0] == b'/' {
route = &route[1..];
}
let nfa = &mut self.nfa;
let mut state = 0;
let mut metadata = Metadata::new();
for (separator, segment) in segments(route) {
if let Some(separator) = separator {
state = nfa.put(state, CharacterClass::valid_char(separator));
}
if !segment.is_empty() && segment.as_bytes()[0] == b':' {
state = process_dynamic_segment(nfa, state);
metadata.dynamics += 1;
metadata.param_names.push(segment[1..].to_string());
} else if !segment.is_empty() && segment.as_bytes()[0] == b'*' {
state = process_star_state(nfa, state);
metadata.wildcards += 1;
metadata.param_names.push(segment[1..].to_string());
} else {
state = process_static_segment(segment, nfa, state);
metadata.statics += 1;
}
}
nfa.acceptance(state);
nfa.metadata(state, metadata);
self.handlers.insert(state, dest);
}
/// Match a route on the router.
pub(crate) fn recognize(&self, mut path: &str) -> Result<Match<&T>, String> {
if !path.is_empty() && path.as_bytes()[0] == b'/' {
path = &path[1..];
}
let nfa = &self.nfa;
let result = nfa.process(path, |index| nfa.get(index).metadata.as_ref().unwrap());
match result {
Ok(nfa_match) => {
let mut params = Params::default();
let state = &nfa.get(nfa_match.state);
let metadata = state.metadata.as_ref().unwrap();
let param_names = metadata.param_names.clone();
for (i, capture) in nfa_match.captures.iter().enumerate() {
if !param_names[i].is_empty() {
params
.0
.push((param_names[i].to_string(), capture.to_string()));
}
}
let handler = self.handlers.get(&nfa_match.state).unwrap();
Ok(Match { handler, params })
}
Err(str) => Err(str),
}
}
}
impl<T> Default for Router<T> {
fn default() -> Self {
Self::new()
}
}
fn process_static_segment<T>(segment: &str, nfa: &mut NFA<T>, mut state: usize) -> usize {
for char in segment.chars() {
state = nfa.put(state, CharacterClass::valid_char(char));
}
state
}
fn process_dynamic_segment<T>(nfa: &mut NFA<T>, mut state: usize) -> usize {
state = nfa.put(state, CharacterClass::invalid_char('/'));
nfa.put_state(state, state);
nfa.start_capture(state);
nfa.end_capture(state);
state
}
fn process_star_state<T>(nfa: &mut NFA<T>, mut state: usize) -> usize {
state = nfa.put(state, CharacterClass::any());
nfa.put_state(state, state);
nfa.start_capture(state);
nfa.end_capture(state);
state
}
#[cfg(test)]
mod tests {
use super::{Params, Router};
#[test]
fn basic_router() {
let mut router = Router::new();
router.add("/thomas", "Thomas".to_string());
router.add("/tom", "Tom".to_string());
router.add("/wycats", "Yehuda".to_string());
let m = router.recognize("/thomas").unwrap();
assert_eq!(*m.handler, "Thomas".to_string());
assert_eq!(m.params, Params::default());
}
#[test]
fn root_router() {
let mut router = Router::new();
router.add("/", 10);
assert_eq!(*router.recognize("/").unwrap().handler, 10)
}
#[test]
fn empty_path() {
let mut router = Router::new();
router.add("/", 12);
assert_eq!(*router.recognize("").unwrap().handler, 12)
}
#[test]
fn empty_route() {
let mut router = Router::new();
router.add("", 12);
assert_eq!(*router.recognize("/").unwrap().handler, 12)
}
#[test]
fn ambiguous_router() {
let mut router = Router::new();
router.add("/posts/new", "new".to_string());
router.add("/posts/:id", "id".to_string());
let id = router.recognize("/posts/1").unwrap();
assert_eq!(*id.handler, "id".to_string());
assert_eq!(id.params, params("id", "1"));
let new = router.recognize("/posts/new").unwrap();
assert_eq!(*new.handler, "new".to_string());
assert_eq!(new.params, Params::default());
}
#[test]
fn ambiguous_router_b() {
let mut router = Router::new();
router.add("/posts/:id", "id".to_string());
router.add("/posts/new", "new".to_string());
let id = router.recognize("/posts/1").unwrap();
assert_eq!(*id.handler, "id".to_string());
assert_eq!(id.params, params("id", "1"));
let new = router.recognize("/posts/new").unwrap();
assert_eq!(*new.handler, "new".to_string());
assert_eq!(new.params, Params::default());
}
#[test]
fn multiple_params() {
let mut router = Router::new();
router.add("/posts/:post_id/comments/:id", "comment".to_string());
router.add("/posts/:post_id/comments", "comments".to_string());
let com = router.recognize("/posts/12/comments/100").unwrap();
let coms = router.recognize("/posts/12/comments").unwrap();
assert_eq!(*com.handler, "comment".to_string());
assert_eq!(com.params, two_params("post_id", "12", "id", "100"));
assert_eq!(*coms.handler, "comments".to_string());
assert_eq!(coms.params, params("post_id", "12"));
assert_eq!(coms.params["post_id"], "12".to_string());
}
#[test]
fn wildcard() {
let mut router = Router::new();
router.add("*foo", "test".to_string());
router.add("/bar/*foo", "test2".to_string());
let m = router.recognize("/test").unwrap();
assert_eq!(*m.handler, "test".to_string());
assert_eq!(m.params, params("foo", "test"));
let m = router.recognize("/foo/bar").unwrap();
assert_eq!(*m.handler, "test".to_string());
assert_eq!(m.params, params("foo", "foo/bar"));
let m = router.recognize("/bar/foo").unwrap();
assert_eq!(*m.handler, "test2".to_string());
assert_eq!(m.params, params("foo", "foo"));
}
#[test]
fn wildcard_colon() {
let mut router = Router::new();
router.add("/a/*b", "ab".to_string());
router.add("/a/*b/c", "abc".to_string());
router.add("/a/*b/c/:d", "abcd".to_string());
let m = router.recognize("/a/foo").unwrap();
assert_eq!(*m.handler, "ab".to_string());
assert_eq!(m.params, params("b", "foo"));
let m = router.recognize("/a/foo/bar").unwrap();
assert_eq!(*m.handler, "ab".to_string());
assert_eq!(m.params, params("b", "foo/bar"));
let m = router.recognize("/a/foo/c").unwrap();
assert_eq!(*m.handler, "abc".to_string());
assert_eq!(m.params, params("b", "foo"));
let m = router.recognize("/a/foo/bar/c").unwrap();
assert_eq!(*m.handler, "abc".to_string());
assert_eq!(m.params, params("b", "foo/bar"));
let m = router.recognize("/a/foo/c/baz").unwrap();
assert_eq!(*m.handler, "abcd".to_string());
assert_eq!(m.params, two_params("b", "foo", "d", "baz"));
let m = router.recognize("/a/foo/bar/c/baz").unwrap();
assert_eq!(*m.handler, "abcd".to_string());
assert_eq!(m.params, two_params("b", "foo/bar", "d", "baz"));
let m = router.recognize("/a/foo/bar/c/baz/bay").unwrap();
assert_eq!(*m.handler, "ab".to_string());
assert_eq!(m.params, params("b", "foo/bar/c/baz/bay"));
}
#[test]
fn unnamed_parameters() {
let mut router = Router::new();
router.add("/foo/:/bar", "test".to_string());
router.add("/foo/:bar/*", "test2".to_string());
let m = router.recognize("/foo/test/bar").unwrap();
assert_eq!(*m.handler, "test");
assert_eq!(m.params, Params::default());
let m = router.recognize("/foo/test/blah").unwrap();
assert_eq!(*m.handler, "test2");
assert_eq!(m.params, params("bar", "test"));
}
fn params(key: &str, val: &str) -> Params {
let mut params = Params::default();
params.0.push((key.to_string(), val.to_string()));
params
}
fn two_params(k1: &str, v1: &str, k2: &str, v2: &str) -> Params {
let mut params = Params::default();
params.0.push((k1.to_string(), v1.to_string()));
params.0.push((k2.to_string(), v2.to_string()));
params
}
#[test]
fn dot() {
let mut router = Router::new();
router.add("/1/baz.:wibble", ());
router.add("/2/:bar.baz", ());
router.add("/3/:dynamic.:extension", ());
router.add("/4/static.static", ());
let m = router.recognize("/1/baz.jpg").unwrap();
assert_eq!(m.params, params("wibble", "jpg"));
let m = router.recognize("/2/test.baz").unwrap();
assert_eq!(m.params, params("bar", "test"));
let m = router.recognize("/3/any.thing").unwrap();
assert_eq!(m.params, two_params("dynamic", "any", "extension", "thing"));
let m = router.recognize("/3/this.performs.a.greedy.match").unwrap();
assert_eq!(
m.params,
two_params("dynamic", "this.performs.a.greedy", "extension", "match")
);
let m = router.recognize("/4/static.static").unwrap();
assert_eq!(m.params, Params::default());
let m = router.recognize("/4/static/static");
assert!(m.is_err());
let m = router.recognize("/4.static.static");
assert!(m.is_err());
}
}