twilight_http/request/
multipart.rs

1#[derive(Clone, Debug)]
2#[must_use = "has no effect if not built into a Form"]
3pub struct Form {
4    boundary: [u8; 15],
5    buffer: Vec<u8>,
6}
7
8impl Form {
9    const APPLICATION_JSON: &'static [u8; 16] = b"application/json";
10
11    const BOUNDARY_TERMINATOR: &'static [u8; 2] = b"--";
12    const CONTENT_DISPOSITION_1: &'static [u8; 38] = b"Content-Disposition: form-data; name=\"";
13    const CONTENT_DISPOSITION_2: &'static [u8; 13] = b"\"; filename=\"";
14    const CONTENT_DISPOSITION_3: &'static [u8; 1] = b"\"";
15    const CONTENT_TYPE: &'static [u8; 14] = b"Content-Type: ";
16    const NEWLINE: &'static [u8; 2] = b"\r\n";
17
18    pub fn new() -> Self {
19        Self::default()
20    }
21
22    /// Consume the form, returning the buffer's contents.
23    pub fn build(mut self) -> Vec<u8> {
24        self.buffer.extend(Self::BOUNDARY_TERMINATOR);
25
26        self.buffer
27    }
28
29    /// Get the form's appropriate content type for requests.
30    pub fn content_type(&self) -> Vec<u8> {
31        const NAME: &str = "multipart/form-data; boundary=";
32
33        let mut content_type = Vec::with_capacity(NAME.len() + self.boundary.len());
34        content_type.extend(NAME.as_bytes());
35        content_type.extend(self.boundary);
36
37        content_type
38    }
39
40    pub fn part(mut self, name: &[u8], value: &[u8]) -> Self {
41        // Write the Content-Disposition header.
42        self.buffer.extend(Self::NEWLINE);
43        self.buffer.extend(Self::CONTENT_DISPOSITION_1);
44        self.buffer.extend(name);
45        self.buffer.extend(Self::CONTENT_DISPOSITION_3);
46        self.buffer.extend(Self::NEWLINE);
47
48        // Write a newline between the headers and the value, the value
49        // itself, a newline, and finally the boundary.
50        self.buffer.extend(Self::NEWLINE);
51        self.buffer.extend(value);
52        self.buffer.extend(Self::NEWLINE);
53        self.buffer.extend(Self::BOUNDARY_TERMINATOR);
54        self.buffer.extend(self.boundary);
55
56        self
57    }
58
59    pub fn file_part(mut self, name: &[u8], filename: &[u8], value: &[u8]) -> Self {
60        // Write the Content-Disposition header.
61        self.buffer.extend(Self::NEWLINE);
62        self.buffer.extend(Self::CONTENT_DISPOSITION_1);
63        self.buffer.extend(name);
64        self.buffer.extend(Self::CONTENT_DISPOSITION_2);
65        self.buffer.extend(filename);
66        self.buffer.extend(Self::CONTENT_DISPOSITION_3);
67        self.buffer.extend(Self::NEWLINE);
68
69        // Write a newline between the headers and the value, the value
70        // itself, a newline, and finally the boundary.
71        self.buffer.extend(Self::NEWLINE);
72        self.buffer.extend(value);
73        self.buffer.extend(Self::NEWLINE);
74        self.buffer.extend(Self::BOUNDARY_TERMINATOR);
75        self.buffer.extend(self.boundary);
76
77        self
78    }
79
80    /// Preview the built buffer's length without consuming the form.
81    #[allow(clippy::len_without_is_empty)]
82    pub fn len(&self) -> usize {
83        self.buffer.len() + Self::BOUNDARY_TERMINATOR.len()
84    }
85
86    pub fn json_part(mut self, name: &[u8], value: &[u8]) -> Self {
87        // Write the Content-Disposition header.
88        self.buffer.extend(Self::NEWLINE);
89        self.buffer.extend(Self::CONTENT_DISPOSITION_1);
90        self.buffer.extend(name);
91        self.buffer.extend(Self::CONTENT_DISPOSITION_3);
92        self.buffer.extend(Self::NEWLINE);
93
94        // If there is a Content-Type, write its key, itself, and a newline.
95        self.buffer.extend(Self::CONTENT_TYPE);
96        self.buffer.extend(Self::APPLICATION_JSON);
97        self.buffer.extend(Self::NEWLINE);
98
99        // Write a newline between the headers and the value, the value
100        // itself, a newline, and finally the boundary.
101        self.buffer.extend(Self::NEWLINE);
102        self.buffer.extend(value);
103        self.buffer.extend(Self::NEWLINE);
104        self.buffer.extend(Self::BOUNDARY_TERMINATOR);
105        self.buffer.extend(self.boundary);
106
107        self
108    }
109}
110
111impl Default for Form {
112    fn default() -> Self {
113        let mut form = Self {
114            boundary: random_boundary(),
115            buffer: Vec::new(),
116        };
117
118        // Write the first boundary.
119        form.buffer.extend(Self::BOUNDARY_TERMINATOR);
120        form.buffer.extend(form.boundary);
121
122        form
123    }
124}
125
126/// Generate a random boundary that is 15 characters long.
127pub fn random_boundary() -> [u8; 15] {
128    let mut boundary = [0; 15];
129
130    for value in &mut boundary {
131        *value = fastrand::alphanumeric() as u8;
132    }
133
134    boundary
135}
136
137#[cfg(test)]
138mod tests {
139    use super::*;
140    use std::str;
141
142    #[test]
143    fn form_builder() {
144        let form = Form::new()
145            .json_part(b"payload_json", b"json_value")
146            .file_part(b"files[0]", b"filename.jpg", b"file_value");
147
148        let boundary = str::from_utf8(&form.boundary).unwrap();
149        let expected = format!(
150            "--{boundary}\r\n\
151        Content-Disposition: form-data; name=\"payload_json\"\r\n\
152        Content-Type: application/json\r\n\
153        \r\n\
154        json_value\r\n\
155        --{boundary}\r\n\
156        Content-Disposition: form-data; name=\"files[0]\"; filename=\"filename.jpg\"\r\n\
157        \r\n\
158        file_value\r\n\
159        --{boundary}--",
160        );
161
162        let buffer_len = form.len();
163        let buffer = form.build();
164
165        assert_eq!(expected.as_bytes(), buffer);
166        assert_eq!(buffer_len, buffer.len());
167    }
168}
twilight_http/request/multipart.rs

twilight_http/request/
multipart.rs
