Support par-encoded character

Cargo.toml

@@ -12,7 +12,7 @@ include = ["src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 readme = "README.md"
 
 [dependencies]
-form_urlencoded = { version = "1.0", default-features = false }
+form_urlencoded = { version = "1.0", default-features = false, features = ["alloc"] }
 serde = { version = "1.0", default-features = false, features = ["alloc", "derive"], optional = true }
 
 [dev-dependencies]

src/core.rs

@@ -258,6 +258,10 @@ impl Core {
     loop {
       match input.peek() {
         Some('/') | Some('?') | Some('#') | None => break,
+        Some('%') => self
+          .parse_pct_enc_char(input)
+          .map(|_| ())
+          .ok_or(Error::InvalidMethodId)?,
         Some(ch) if char_method_id(ch) => {}
         _ => return Err(Error::InvalidMethodId),
       }
@@ -268,6 +272,17 @@ impl Core {
     Ok(())
   }
 
+  fn parse_pct_enc_char(&mut self, input: &mut Input) -> Option<char> {
+    if input.next() != Some('%') {
+      return None;
+    }
+
+    let hex_value = input.take(2)?;
+    u8::from_str_radix(hex_value, 16)
+      .ok()
+      .map(|ascii| ascii as char)
+  }
+
   fn parse_path(&mut self, input: &mut Input) -> Result<()> {
     self.path = input.index();
 

tests/parse.rs

@@ -25,6 +25,7 @@ fn test_parse_valid_method_id() {
   assert!(DID::parse("did:method:identifier").is_ok());
   assert!(DID::parse("did:method:IDENTIFIER").is_ok());
   assert!(DID::parse("did:method:did:__:--:1231093213").is_ok());
+  assert!(DID::parse("did:web:user%40localhost%3A12345").is_ok());
 }
 
 #[test]
@@ -35,6 +36,7 @@ fn test_parse_invalid_method_id() {
   assert!(DID::parse("did:method: - - -").is_err());
   assert!(DID::parse("did:method:*****").is_err());
   assert!(DID::parse("did:method:identifier-|$|").is_err());
+  assert!(DID::parse("did:web:user%localhost%12345").is_err());
 }
 
 #[test]