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

use hyper::{
    header::HeaderValue,
    http::{
        header,
        uri::{Authority, Scheme},
        Extensions, HeaderMap, HeaderName, Method, Uri, Version,
    },
};
use url::{Host, Url};
use volo::net::Address;

use crate::param::Params;

static X_FORWARDED_HOST: HeaderName = HeaderName::from_static("x-forwarded-host");
static X_FORWARDED_PROTO: HeaderName = HeaderName::from_static("x-forwarded-proto");

#[derive(Debug)]
pub struct HttpContext {
    pub peer: Address,
    pub method: Method,
    pub uri: Uri,
    pub version: Version,
    pub headers: HeaderMap,
    pub extensions: Extensions,

    pub params: Params,
}

#[derive(Debug)]
pub struct ConnectionInfo {
    scheme: Scheme,
    host: Option<Host>,
    port: Option<u16>,
}

impl HttpContext {
    pub(crate) fn get_connection_info(&self) -> ConnectionInfo {
        let mut host = None;
        let mut scheme = None;

        for (name, val) in self
            .headers
            .get_all(&header::FORWARDED)
            .into_iter()
            .filter_map(|hdr| hdr.to_str().ok())
            // "for=1.2.3.4, for=5.6.7.8; scheme=https"
            .flat_map(|val| val.split(';'))
            // ["for=1.2.3.4, for=5.6.7.8", " scheme=https"]
            .flat_map(|vals| vals.split(','))
            // ["for=1.2.3.4", " for=5.6.7.8", " scheme=https"]
            .flat_map(|pair| {
                let mut items = pair.trim().splitn(2, '=');
                Some((items.next()?, items.next()?))
            })
        {
            // [(name , val      ), ...                                    ]
            // [("for", "1.2.3.4"), ("for", "5.6.7.8"), ("scheme", "https")]

            // taking the first value for each property is correct because spec states that first
            // "for" value is client and rest are proxies; multiple values other properties have
            // no defined semantics
            //
            // > In a chain of proxy servers where this is fully utilized, the first
            // > "for" parameter will disclose the client where the request was first
            // > made, followed by any subsequent proxy identifiers.
            // --- https://datatracker.ietf.org/doc/html/rfc7239#section-5.2

            match name.trim().to_lowercase().as_str() {
                "host" => host.get_or_insert_with(|| unquote(val)),
                "proto" => scheme.get_or_insert_with(|| unquote(val)),
                "by" => {
                    // TODO: implement https://datatracker.ietf.org/doc/html/rfc7239#section-5.1
                    continue;
                }
                _ => continue,
            };
        }

        let host = match host {
            // Forwarded
            Some(host) => host,
            None => {
                if let Some(host) = first_header_value(&self.headers, &X_FORWARDED_HOST) {
                    // X-Forwarded-Host
                    host
                } else if let Some(Ok(host)) =
                    self.headers.get(&header::HOST).map(HeaderValue::to_str)
                {
                    // Host
                    host
                } else if let Some(host) = self.uri.authority().map(Authority::as_str) {
                    host
                } else {
                    ""
                }
            }
        };
        let host = host.to_owned();

        let scheme = match scheme {
            // Forwarded
            Some(scheme) => Some(scheme),
            None => {
                // X-Forwarded-Host
                first_header_value(&self.headers, &X_FORWARDED_PROTO)
            }
        };
        // map str to `Scheme`
        let scheme = match scheme {
            Some(scheme) => Scheme::try_from(scheme).ok(),
            None => self.uri.scheme().map(Scheme::to_owned),
        };
        // fallback
        let scheme = match scheme {
            Some(scheme) => scheme,
            None => Scheme::HTTP,
        };

        let (host, port) = match Url::parse(format!("{scheme}://{host}/").as_str()) {
            // SAFETY: calling `unwrap` is safe because the original string is a valid url
            // constructed with the format `scheme://host/`
            Ok(url) => (url.host().map(|s| s.to_owned()), url.port()),
            Err(_) => (None, None),
        };

        ConnectionInfo { host, port, scheme }
    }
}

impl ConnectionInfo {
    /// Hostname and port of the request.
    ///
    /// Hostname is resolved through the following, in order:
    /// - `Forwarded` header
    /// - `X-Forwarded-Host` header
    /// - `Host` header
    /// - request target / URI
    #[inline]
    pub fn hostport(&self) -> (Option<&Host>, Option<u16>) {
        (self.host.as_ref(), self.port)
    }

    /// Scheme of the request.
    ///
    /// Scheme is resolved through the following, in order:
    /// - `Forwarded` header
    /// - `X-Forwarded-Proto` header
    /// - request target / URI
    #[inline]
    pub fn scheme(&self) -> &Scheme {
        &self.scheme
    }
}

fn unquote(val: &str) -> &str {
    val.trim().trim_start_matches('"').trim_end_matches('"')
}

fn first_header_value<'a>(headers: &'a HeaderMap, name: &'_ HeaderName) -> Option<&'a str> {
    let hdr = headers.get(name)?.to_str().ok()?;
    let val = hdr.split(',').next()?.trim();
    Some(val)
}