Parse url query array style like ids=[1,2,3] (#947)

* Parse url query array like `ids=[1,2,3]`

* Format Rust code using rustfmt

* fix

* fix

* Format Rust code using rustfmt

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

crates/core/src/extract/metadata.rs

@@ -49,6 +49,8 @@ pub enum SourceParser {
     MultiMap,
     /// Json parser.
     Json,
+    /// Url or Header parser.
+    Flat,
     /// Smart parser.
     Smart,
 }

crates/core/src/serde/cow_value.rs

@@ -0,0 +1,111 @@
+use std::borrow::Cow;
+
+use serde::de::value::Error as ValError;
+use serde::de::{Deserializer, Error as DeError, IntoDeserializer, Visitor};
+use serde::forward_to_deserialize_any;
+
+use super::ValueEnumAccess;
+
+macro_rules! forward_cow_parsed_value {
+    ($($ty:ident => $method:ident,)*) => {
+        $(
+            fn $method<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+                where V: Visitor<'de>
+            {
+                match self.0.parse::<$ty>() {
+                    Ok(val) => val.into_deserializer().$method(visitor),
+                    Err(e) => Err(DeError::custom(e))
+                }
+            }
+        )*
+    }
+}
+
+#[derive(Debug)]
+pub(super) struct CowValue<'de>(pub(super) Cow<'de, str>);
+impl<'de> IntoDeserializer<'de> for CowValue<'de> {
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self::Deserializer {
+        self
+    }
+}
+
+impl<'de> Deserializer<'de> for CowValue<'de> {
+    type Error = ValError;
+
+    #[inline]
+    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.0 {
+            Cow::Borrowed(value) => visitor.visit_borrowed_str(value),
+            Cow::Owned(value) => visitor.visit_string(value),
+        }
+    }
+
+    #[inline]
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_some(self)
+    }
+
+    #[inline]
+    fn deserialize_enum<V>(
+        self,
+        _name: &'static str,
+        _variants: &'static [&'static str],
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_enum(ValueEnumAccess(self.0))
+    }
+
+    #[inline]
+    fn deserialize_newtype_struct<V>(
+        self,
+        _name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_newtype_struct(self)
+    }
+
+    forward_to_deserialize_any! {
+        char
+        str
+        string
+        unit
+        bytes
+        byte_buf
+        unit_struct
+        tuple_struct
+        struct
+        identifier
+        tuple
+        ignored_any
+        seq
+        map
+    }
+
+    forward_cow_parsed_value! {
+        bool => deserialize_bool,
+        u8 => deserialize_u8,
+        u16 => deserialize_u16,
+        u32 => deserialize_u32,
+        u64 => deserialize_u64,
+        i8 => deserialize_i8,
+        i16 => deserialize_i16,
+        i32 => deserialize_i32,
+        i64 => deserialize_i64,
+        f32 => deserialize_f32,
+        f64 => deserialize_f64,
+    }
+}

crates/core/src/serde/flat_value.rs

@@ -0,0 +1,242 @@
+use std::borrow::Cow;
+
+use serde::de::value::{Error as ValError, SeqDeserializer};
+use serde::de::{Deserializer, Error as DeError, IntoDeserializer, Visitor};
+use serde::forward_to_deserialize_any;
+
+use super::{CowValue, ValueEnumAccess};
+
+macro_rules! forward_url_query_parsed_value {
+    ($($ty:ident => $method:ident,)*) => {
+        $(
+            fn $method<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+                where V: Visitor<'de>
+            {
+                if let Some(item) = self.0.into_iter().next() {
+                    match item.0.parse::<$ty>() {
+                        Ok(val) => val.into_deserializer().$method(visitor),
+                        Err(e) => Err(DeError::custom(e))
+                    }
+                } else {
+                    Err(DeError::custom("expected vec not empty"))
+                }
+            }
+        )*
+    }
+}
+
+pub(super) struct FlatValue<'de>(pub(super) Vec<CowValue<'de>>);
+impl<'de> IntoDeserializer<'de> for FlatValue<'de> {
+    type Deserializer = Self;
+
+    #[inline]
+    fn into_deserializer(self) -> Self::Deserializer {
+        self
+    }
+}
+
+impl<'de> Deserializer<'de> for FlatValue<'de> {
+    type Error = ValError;
+
+    #[inline]
+    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        if let Some(item) = self.0.into_iter().next() {
+            item.deserialize_any(visitor)
+        } else {
+            Err(DeError::custom("expected url query not empty"))
+        }
+    }
+
+    #[inline]
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_some(self)
+    }
+
+    #[inline]
+    fn deserialize_enum<V>(
+        self,
+        _name: &'static str,
+        _variants: &'static [&'static str],
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        if let Some(item) = self.0.into_iter().next() {
+            visitor.visit_enum(ValueEnumAccess(item.0))
+        } else {
+            Err(DeError::custom("expected vec not empty"))
+        }
+    }
+
+    #[inline]
+    fn deserialize_newtype_struct<V>(
+        self,
+        _name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_newtype_struct(self)
+    }
+
+    #[inline]
+    fn deserialize_tuple_struct<V>(
+        self,
+        _name: &'static str,
+        _len: usize,
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_seq(visitor)
+    }
+    #[inline]
+    fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_seq(visitor)
+    }
+    #[inline]
+    fn deserialize_seq<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        let mut items = std::mem::take(&mut self.0);
+        let single_mode = if items.len() == 1 {
+            if let Some(item) = items.get(0) {
+                item.0.starts_with('[') && item.0.ends_with(']')
+            } else {
+                false
+            }
+        } else {
+            false
+        };
+        if single_mode {
+            let parser = FlatParser::new(items.remove(0).0);
+            visitor.visit_seq(SeqDeserializer::new(parser.into_iter()))
+        } else {
+            visitor.visit_seq(SeqDeserializer::new(items.into_iter()))
+        }
+    }
+
+    forward_to_deserialize_any! {
+        char
+        str
+        string
+        unit
+        bytes
+        byte_buf
+        unit_struct
+        struct
+        identifier
+        ignored_any
+        map
+    }
+
+    forward_url_query_parsed_value! {
+        bool => deserialize_bool,
+        u8 => deserialize_u8,
+        u16 => deserialize_u16,
+        u32 => deserialize_u32,
+        u64 => deserialize_u64,
+        i8 => deserialize_i8,
+        i16 => deserialize_i16,
+        i32 => deserialize_i32,
+        i64 => deserialize_i64,
+        f32 => deserialize_f32,
+        f64 => deserialize_f64,
+    }
+}
+
+struct FlatParser<'de> {
+    input: Cow<'de, str>,
+    start: usize,
+}
+impl<'de> FlatParser<'de> {
+    fn new(input: Cow<'de, str>) -> Self {
+        Self { input, start: 1 }
+    }
+}
+impl<'de> Iterator for FlatParser<'de> {
+    type Item = CowValue<'de>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let mut quote = None;
+        let mut in_escape = false;
+        let mut end = self.start;
+        let mut in_next = false;
+        for c in self.input[self.start..].chars() {
+            if in_escape {
+                in_escape = false;
+                continue;
+            }
+            match c {
+                '\\' => {
+                    in_escape = true;
+                    in_next = true;
+                }
+                ' ' => {
+                    if quote.is_none() {
+                        self.start += 1;
+                    }
+                }
+                '"' | '\'' => {
+                    in_next = true;
+                    if quote == Some(c) {
+                        let item = Cow::Owned(self.input[self.start..end].to_string());
+                        self.start = end + 2;
+                        return Some(CowValue(item));
+                    } else {
+                        quote = Some(c);
+                        self.start += 1;
+                    }
+                }
+                ',' | ']' => {
+                    if quote.is_none() && in_next {
+                        let item = Cow::Owned(self.input[self.start..end].to_string());
+                        self.start = end + 1;
+                        return Some(CowValue(item));
+                    }
+                }
+                _ => {
+                    in_next = true;
+                }
+            }
+            end += 1;
+        }
+        None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_flat_parser_1() {
+        let parser = super::FlatParser::new("[1,2, 3]".into());
+        let mut iter = parser.into_iter();
+        assert_eq!(iter.next().unwrap().0, "1");
+        assert_eq!(iter.next().unwrap().0, "2");
+        assert_eq!(iter.next().unwrap().0, "3");
+        assert!(iter.next().is_none());
+    }
+    #[test]
+    fn test_flat_parser_2() {
+        let parser = super::FlatParser::new(r#"['3',  '2',"11","1,2"]"#.into());
+        let mut iter = parser.into_iter();
+        assert_eq!(iter.next().unwrap().0, "3");
+        assert_eq!(iter.next().unwrap().0, "2");
+        assert_eq!(iter.next().unwrap().0, "11");
+        assert_eq!(iter.next().unwrap().0, "1,2");
+        assert!(iter.next().is_none());
+    }
+}