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

use std::collections::HashMap;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;
use std::ops::Add;

use crate::Result;
use crate::HttpRequest;
use super::HandlerFunc;
use crate::server::error::err;

/// Authentication Config
///
/// Helps wrapping [handler functions](HandlerFunc) behing authentication
///
/// # Example
/// ```
/// use http_srv::request::handler::AuthConfig;
/// use http_srv::request::handler::Handler;
/// use http_srv::HttpRequest;
///
/// let auth = AuthConfig::of_list(&[("user", "passwd")]);
///
/// let mut handler = Handler::default();
/// let func = |req: &mut HttpRequest| {
///     req.respond_str("Super secret message")
/// };
/// handler.get("/secret", auth.apply(func));
/// ```
pub struct AuthConfig {
    users: HashMap<String,String>,
    required_users: Vec<String>,
}

impl AuthConfig {
    pub fn of_file(filename: &str) -> Self {
        let f = File::open(filename).unwrap();
        let f = BufReader::new(f);
        let mut users = HashMap::new();
        let mut lines = f.lines();
        while let Some(Ok(l))  = lines.next() {
            let mut l = l.split_whitespace();
            let u = l.next().unwrap().to_owned();
            let p = l.next().unwrap().to_owned();
            users.insert(u,p);
        }
        users.shrink_to_fit();
        Self {
            users,
            required_users: Vec::new(),
        }
    }
    pub fn of_list(list: & [(& str,& str)]) -> Self {
        let mut users = HashMap::new();
        list.iter().for_each(|e| { users.insert(e.0.to_owned(), e.1.to_owned()); } );
        Self {
            users,
            required_users: Vec::new(),
        }
    }
    pub fn require_user(mut self, user: &str) -> Self {
        self.required_users.push(user.to_owned());
        self
    }
    pub fn apply(&self, f: impl HandlerFunc) -> impl HandlerFunc {
        let users = self.required_users.clone();
        let passwd = self.users.clone();
        move |req: &mut HttpRequest| {
            let Some(auth) = req.header("Authorization") else {
                req.set_header("WWW-Authenticate", "Basic");
                return req.unauthorized();
            };
            let auth = HttpAuth::parse(auth)?;
            if auth.check(&users, &passwd) {
                f(req)
            } else {
                req.unauthorized()
            }
        }
    }
}

impl<F> Add<F> for &AuthConfig
where
    F: HandlerFunc
{
    type Output = Box<dyn HandlerFunc>;

    fn add(self, rhs: F) -> Self::Output {
        Box::new(self.apply(rhs))
    }
}


#[derive(Clone, PartialEq, Debug)]
enum HttpAuth {
    Basic(String,String),
}

impl HttpAuth {
    fn parse(header: &str) -> Result<Self> {
        let mut auth = header.split_whitespace();
        let t = auth.next().ok_or("Malfromatted Authentication header")?;
        let payload = auth.next().ok_or("Malfromatted Authentication header")?;

        match t {
            "Basic" => parse_basic(payload),
            _ => err!("Unknown authentication method {t}")
        }
    }
    fn check(&self, users: &Vec<String>, passwds: &HashMap<String,String>) -> bool {
        match self {
            HttpAuth::Basic(user,pass) => {
                if users.is_empty() || users.contains(&user) {
                    if let Some(p) = passwds.get(user).as_ref() {
                        *p == pass
                    } else {
                        false
                    }
                } else {
                    false
                }
            },
        }
    }
}

fn parse_basic(payload: &str) -> Result<HttpAuth> {
    let decoded = base64::decode(payload)?;
    let decoded = String::from_utf8(decoded)?;
    let mut decoded = decoded.splitn(2, ":");
    let user = decoded.next().unwrap_or("");
    let passwd = decoded.next().unwrap_or("");
    let user = url::decode(user)?.into_owned();
    let passwd = url::decode(passwd)?.into_owned();
    Ok(HttpAuth::Basic(user,passwd))
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test() {
        let auth = HttpAuth::parse("Basic dXNlcjpwYXNzd2Q=").expect("Expected correct parsing");
        match auth {
            HttpAuth::Basic(user,passwd) => {
                assert_eq!(user, "user");
                assert_eq!(passwd, "passwd");
            },
        }
    }
}