aliri_tower 0.6.1

Tower middleware for interacting with `aliri` authorities
Documentation 
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
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238

//! Utilities for generating HTTP responses on authorization falures

use aliri_oauth2::{Scope, ScopePolicy};
use http::{header, HeaderValue, Response, StatusCode};

/// Build a `401 Unauthorized` response with the appropriate `www-authenticate`
/// header
///
/// The description provided will be automatically escaped to make sure it
/// is header-friendly.
///
/// The prepared response will have the form:
///
/// ```http
/// HTTP/1.1 401 Unauthorized
/// www-authenticate: Bearer error="invalid_token" error_description="{description}"
/// ```
///
/// `error_description` is omitted if `description` is empty.
pub fn unauthorized<Body: Default>(description: &str) -> Response<Body> {
    let mut resp = Response::new(Body::default());
    *resp.status_mut() = StatusCode::UNAUTHORIZED;
    resp.headers_mut()
        .insert(header::WWW_AUTHENTICATE, invalid_token(description));
    resp
}

/// Build a `403 Forbidden` response with the appropriate `www-authenticate` header(s)
///
/// The description provided will be automatically escaped to make sure it
/// is header-friendly.
///
/// When no policy is given, the prepared response will have the form:
///
/// ```http
/// HTTP/1.1 403 Forbidden
/// www-authenticate: Bearer error="insufficient_scopes" error_description="{description}"
/// ```
///
/// If a `policy` is given, then a `www-authenticate` header will be added for each
/// scope alternative allowed by the policy.
///
/// ```http
/// HTTP/1.1 403 Forbidden
/// www-authenticate: Bearer error="insufficient_scopes" error_description="{description}" scope="get_user"
/// www-authenticate: Bearer error="insufficient_scopes" error_description="{description}" scope="admin"
/// ```
///
/// `error_description` is omitted if `description` is empty.
pub fn forbidden<Body: Default>(description: &str, policy: Option<&ScopePolicy>) -> Response<Body> {
    let mut resp = Response::new(Body::default());
    *resp.status_mut() = StatusCode::FORBIDDEN;

    match policy {
        Some(policy) if policy != &ScopePolicy::deny_all() => {
            for scope in policy {
                resp.headers_mut().append(
                    header::WWW_AUTHENTICATE,
                    insufficient_scope(description, scope),
                );
            }
        }
        _ => {
            resp.headers_mut().insert(
                header::WWW_AUTHENTICATE,
                insufficient_scope_no_policy(description),
            );
        }
    }

    resp
}

fn invalid_token(description: &str) -> HeaderValue {
    if description.is_empty() {
        HeaderValue::from_static(r#"Bearer error="invalid_token""#)
    } else {
        HeaderValue::try_from(format!(
            r#"Bearer error="invalid_token" error_description="{}""#,
            description.escape_default()
        ))
        .expect("escaped description is a valid header value")
    }
}

// Because of the definition of a `Scope`, this never needs to escape `scope`,
// as `Scope` can only be printable ASCII characters and won't include `\` or `"`.
// Thus `scope` is always usable as a valid `HeaderValue`.
fn insufficient_scope(description: &str, scope: &Scope) -> HeaderValue {
    if description.is_empty() {
        HeaderValue::try_from(format!(
            r#"Bearer error="insufficient_scope" scope="{scope}""#
        ))
        .expect("scope is always a valid header value")
    } else {
        HeaderValue::try_from(format!(
            r#"Bearer error="insufficient_scope" error_description="{}" scope="{scope}""#,
            description.escape_default()
        ))
        .expect("escaped description is a valid header value")
    }
}

fn insufficient_scope_no_policy(description: &str) -> HeaderValue {
    if description.is_empty() {
        HeaderValue::from_static(r#"Bearer error="insufficient_scope""#)
    } else {
        HeaderValue::try_from(format!(
            r#"Bearer error="insufficient_scope" error_description="{}""#,
            description.escape_default()
        ))
        .expect("escaped description is a valid header value")
    }
}

#[cfg(test)]
mod tests {
    use std::collections::BTreeSet;

    use aliri_oauth2::{policy, scope};

    use super::*;

    #[test]
    fn in_unauthorized_description_unicode_and_non_printing_description_does_not_panic() {
        let resp = unauthorized::<()>(
            "\0\n\ttest™: \"Ĉu oni povas bone ŝanĝi ĉi tiu mesaĝon en respondon?\"",
        );

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([
            r#"Bearer error="invalid_token" error_description="\u{0}\n\ttest\u{2122}: \"\u{108}u oni povas bone \u{15d}an\u{11d}i \u{109}i tiu mesa\u{11d}on en respondon?\"""#,
        ]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_unauthorized_with_empty_description_doesnt_include_description() {
        let resp = unauthorized::<()>("");

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([r#"Bearer error="invalid_token""#]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_description_unicode_and_non_printing_description_does_not_panic() {
        let resp = forbidden::<()>(
            "\0\n\ttest™: \"Ĉu oni povas bone ŝanĝi ĉi tiu mesaĝon en respondon?\"",
            Some(&ScopePolicy::allow_one_from_static("test1 test2")),
        );

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([
            r#"Bearer error="insufficient_scope" error_description="\u{0}\n\ttest\u{2122}: \"\u{108}u oni povas bone \u{15d}an\u{11d}i \u{109}i tiu mesa\u{11d}on en respondon?\"" scope="test1 test2""#,
        ]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_with_multiple_alternatives_returns_multiple_headers() {
        let resp = forbidden::<()>(
            "descriptive error",
            Some(&policy![scope!["test1", "test2"], scope!["admin"]]),
        );

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([
            r#"Bearer error="insufficient_scope" error_description="descriptive error" scope="test1 test2""#,
            r#"Bearer error="insufficient_scope" error_description="descriptive error" scope="admin""#,
        ]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_with_deny_all_returns_one_header_without_scope() {
        let resp = forbidden::<()>("descriptive error", Some(&policy![]));

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([
            r#"Bearer error="insufficient_scope" error_description="descriptive error""#,
        ]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_with_empty_description_doesnt_include_description() {
        let resp = forbidden::<()>("", Some(&policy![]));

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([r#"Bearer error="insufficient_scope""#]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_with_no_policy_returns_one_header_without_scope() {
        let resp = forbidden::<()>("descriptive error", None);

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([
            r#"Bearer error="insufficient_scope" error_description="descriptive error""#,
        ]);

        assert_eq!(headers, expected);
    }

    #[test]
    fn in_forbidden_with_no_policy_and_empty_description_doesnt_include_description() {
        let resp = forbidden::<()>("", None);

        let headers = extract_www_authenticate_headers(&resp);

        let expected = BTreeSet::from([r#"Bearer error="insufficient_scope""#]);

        assert_eq!(headers, expected);
    }

    fn extract_www_authenticate_headers<B>(resp: &Response<B>) -> BTreeSet<&str> {
        resp.headers()
            .get_all(header::WWW_AUTHENTICATE)
            .iter()
            .map(|v| v.to_str().unwrap())
            .collect::<BTreeSet<_>>()
    }
}