harn_vm/http/
framing.rs

1#[cfg(test)]
2use std::collections::BTreeMap;
3use std::error::Error;
4use std::fmt;
5
6/// Shared cap for lightweight HTTP readers used by in-process test servers.
7pub const TEST_HTTP_MAX_BODY_BYTES: usize = 16 * 1024 * 1024;
8
9#[derive(Clone, Copy, Debug, Eq, PartialEq)]
10pub struct HttpContentLengthLimitError {
11    pub content_length: usize,
12    pub max_bytes: usize,
13}
14
15impl fmt::Display for HttpContentLengthLimitError {
16    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
17        write!(
18            f,
19            "HTTP Content-Length {} exceeds limit {} bytes",
20            self.content_length, self.max_bytes
21        )
22    }
23}
24
25impl Error for HttpContentLengthLimitError {}
26
27pub fn enforce_http_content_length_limit(
28    content_length: usize,
29    max_bytes: usize,
30) -> Result<usize, HttpContentLengthLimitError> {
31    if content_length > max_bytes {
32        Err(HttpContentLengthLimitError {
33            content_length,
34            max_bytes,
35        })
36    } else {
37        Ok(content_length)
38    }
39}
40
41pub fn parse_http_content_length(
42    value: Option<&str>,
43    max_bytes: usize,
44) -> Result<usize, HttpContentLengthLimitError> {
45    let Some(value) = value else {
46        return Ok(0);
47    };
48    let Ok(content_length) = value.trim().parse::<usize>() else {
49        return Ok(0);
50    };
51    enforce_http_content_length_limit(content_length, max_bytes)
52}
53
54#[cfg(test)]
55pub fn http_content_length_from_headers(
56    headers: &BTreeMap<String, String>,
57    max_bytes: usize,
58) -> Result<usize, HttpContentLengthLimitError> {
59    parse_http_content_length(headers.get("content-length").map(String::as_str), max_bytes)
60}
61
62pub fn http_content_length_from_header_lines<'a>(
63    lines: impl IntoIterator<Item = &'a str>,
64    max_bytes: usize,
65) -> Result<usize, HttpContentLengthLimitError> {
66    let value = lines.into_iter().find_map(|line| {
67        let (name, value) = line.split_once(':')?;
68        name.eq_ignore_ascii_case("content-length")
69            .then_some(value.trim())
70    });
71    parse_http_content_length(value, max_bytes)
72}
73
74#[cfg(test)]
75mod tests {
76    use super::*;
77
78    #[test]
79    fn missing_or_invalid_content_length_defaults_to_zero() {
80        assert_eq!(
81            parse_http_content_length(None, TEST_HTTP_MAX_BODY_BYTES).expect("missing length"),
82            0
83        );
84        assert_eq!(
85            parse_http_content_length(Some("not-a-number"), TEST_HTTP_MAX_BODY_BYTES)
86                .expect("invalid length"),
87            0
88        );
89    }
90
91    #[test]
92    fn header_line_lookup_is_case_insensitive() {
93        let headers = ["Host: example.test", "Content-Length: 12"];
94        assert_eq!(
95            http_content_length_from_header_lines(headers, TEST_HTTP_MAX_BODY_BYTES)
96                .expect("content length"),
97            12
98        );
99    }
100
101    #[test]
102    fn oversized_content_length_is_rejected() {
103        let error = parse_http_content_length(
104            Some(&(TEST_HTTP_MAX_BODY_BYTES + 1).to_string()),
105            TEST_HTTP_MAX_BODY_BYTES,
106        )
107        .expect_err("oversized content length");
108        assert_eq!(error.content_length, TEST_HTTP_MAX_BODY_BYTES + 1);
109        assert_eq!(error.max_bytes, TEST_HTTP_MAX_BODY_BYTES);
110    }
111}
harn_vm/http/framing.rs

harn_vm/http/
framing.rs
