serde_html_form/
de.rs

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
//! Deserialization support for the `application/x-www-form-urlencoded` format.

use std::io::Read;

use form_urlencoded::{parse, Parse as UrlEncodedParse};
use indexmap::map::{self, IndexMap};
use serde::{
    de::{self, value::MapDeserializer},
    forward_to_deserialize_any,
};

#[doc(inline)]
pub use serde::de::value::Error;

mod part;
mod val_or_vec;

use self::{part::Part, val_or_vec::ValOrVec};

/// Deserializes a `application/x-www-form-urlencoded` value from a `&[u8]`.
///
/// ```
/// let meal = vec![
///     ("bread".to_owned(), "baguette".to_owned()),
///     ("cheese".to_owned(), "comté".to_owned()),
///     ("meat".to_owned(), "ham".to_owned()),
///     ("fat".to_owned(), "butter".to_owned()),
/// ];
///
/// assert_eq!(
///     serde_html_form::from_bytes::<Vec<(String, String)>>(
///         b"bread=baguette&cheese=comt%C3%A9&meat=ham&fat=butter"
///     ),
///     Ok(meal)
/// );
/// ```
pub fn from_bytes<'de, T>(input: &'de [u8]) -> Result<T, Error>
where
    T: de::Deserialize<'de>,
{
    T::deserialize(Deserializer::new(parse(input)))
}

/// Deserializes a `application/x-www-form-urlencoded` value from a `&str`.
///
/// ```
/// let meal = vec![
///     ("bread".to_owned(), "baguette".to_owned()),
///     ("cheese".to_owned(), "comté".to_owned()),
///     ("meat".to_owned(), "ham".to_owned()),
///     ("fat".to_owned(), "butter".to_owned()),
/// ];
///
/// assert_eq!(
///     serde_html_form::from_str::<Vec<(String, String)>>(
///         "bread=baguette&cheese=comt%C3%A9&meat=ham&fat=butter"
///     ),
///     Ok(meal)
/// );
/// ```
pub fn from_str<'de, T>(input: &'de str) -> Result<T, Error>
where
    T: de::Deserialize<'de>,
{
    from_bytes(input.as_bytes())
}

/// Convenience function that reads all bytes from `reader` and deserializes
/// them with `from_bytes`.
pub fn from_reader<T, R>(mut reader: R) -> Result<T, Error>
where
    T: de::DeserializeOwned,
    R: Read,
{
    let mut buf = vec![];
    reader
        .read_to_end(&mut buf)
        .map_err(|e| de::Error::custom(format_args!("could not read input: {}", e)))?;
    from_bytes(&buf)
}

/// A deserializer for the `application/x-www-form-urlencoded` format.
///
/// * Supported top-level outputs are structs, maps and sequences of pairs,
///   with or without a given length.
///
/// * Main `deserialize` methods defers to `deserialize_map`.
///
/// * Everything else but `deserialize_seq` and `deserialize_seq_fixed_size`
///   defers to `deserialize`.
pub struct Deserializer<'de> {
    inner: UrlEncodedParse<'de>,
}

impl<'de> Deserializer<'de> {
    /// Returns a new `Deserializer`.
    pub fn new(parse: UrlEncodedParse<'de>) -> Self {
        Deserializer { inner: parse }
    }
}

impl<'de> de::Deserializer<'de> for Deserializer<'de> {
    type Error = Error;

    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_seq(visitor)
    }

    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_map(MapDeserializer::new(group_entries(self.inner).into_iter()))
    }

    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_seq(MapDeserializer::new(PartIterator(self.inner)))
    }

    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        let deserializer = MapDeserializer::new(PartIterator(self.inner));
        deserializer.end()?;
        visitor.visit_unit()
    }

    fn deserialize_newtype_struct<V>(self, _name: &str, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_newtype_struct(self)
    }

    fn deserialize_struct<V>(
        self,
        _name: &'static str,
        _fields: &'static [&'static str],
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_map(visitor)
    }

    forward_to_deserialize_any! {
        bool
        u8
        u16
        u32
        u64
        i8
        i16
        i32
        i64
        f32
        f64
        char
        str
        string
        option
        bytes
        byte_buf
        unit_struct
        tuple_struct
        identifier
        tuple
        enum
        ignored_any
    }
}

struct PartIterator<'de>(UrlEncodedParse<'de>);

impl<'de> Iterator for PartIterator<'de> {
    type Item = (Part<'de>, Part<'de>);

    fn next(&mut self) -> Option<Self::Item> {
        self.0.next().map(|(k, v)| (Part(k), Part(v)))
    }
}

fn group_entries(parse: UrlEncodedParse<'_>) -> IndexMap<Part<'_>, ValOrVec<Part<'_>>> {
    use map::Entry::*;

    let mut res = IndexMap::new();

    for (key, value) in parse {
        match res.entry(Part(key)) {
            Vacant(v) => {
                v.insert(ValOrVec::Val(Part(value)));
            }
            Occupied(mut o) => {
                o.get_mut().push(Part(value));
            }
        }
    }

    res
}

#[cfg(test)]
mod tests;