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
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268

use crate::{api_error::ApiError, json::JsonError, response::StatusCode};
use hyper::{Body, Response};
use std::{
    error::Error as StdError,
    fmt::{Debug, Display, Formatter, Result as FmtResult},
    str,
};

#[derive(Debug)]
pub struct Error {
    pub(super) source: Option<Box<dyn StdError + Send + Sync>>,
    pub(super) kind: ErrorType,
}

impl Error {
    /// Immutable reference to the type of error that occurred.
    #[must_use = "retrieving the type has no effect if left unused"]
    pub const fn kind(&self) -> &ErrorType {
        &self.kind
    }

    /// Consume the error, returning the source error if there is any.
    #[must_use = "consuming the error and retrieving the source has no effect if left unused"]
    pub fn into_source(self) -> Option<Box<dyn StdError + Send + Sync>> {
        self.source
    }

    /// Consume the error, returning the owned error type and the source error.
    #[must_use = "consuming the error into its parts has no effect if left unused"]
    pub fn into_parts(self) -> (ErrorType, Option<Box<dyn StdError + Send + Sync>>) {
        (self.kind, self.source)
    }

    pub(super) fn json(source: JsonError) -> Self {
        Self {
            kind: ErrorType::Json,
            source: Some(Box::new(source)),
        }
    }
}

impl Display for Error {
    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
        match &self.kind {
            ErrorType::BuildingRequest => f.write_str("failed to build the request"),
            ErrorType::ChunkingResponse => f.write_str("Chunking the response failed"),
            ErrorType::CreatingHeader { name, .. } => {
                f.write_str("Parsing the value for header {}")?;
                f.write_str(name)?;

                f.write_str(" failed")
            }
            ErrorType::Json => f.write_str("Given value couldn't be serialized"),
            ErrorType::Parsing { body, .. } => {
                f.write_str("Response body couldn't be deserialized: ")?;

                if let Ok(body) = str::from_utf8(body) {
                    f.write_str(body)
                } else {
                    Debug::fmt(body, f)
                }
            }
            ErrorType::RatelimiterTicket => f.write_str("Failed to get ratelimiter ticket"),
            ErrorType::RequestCanceled => {
                f.write_str("Request was canceled either before or while being sent")
            }
            ErrorType::RequestError => f.write_str("Parsing or sending the response failed"),
            ErrorType::RequestTimedOut => f.write_str("request timed out"),
            ErrorType::Response { body, status, .. } => {
                f.write_str("Response error: status code ")?;
                Display::fmt(status, f)?;
                f.write_str(", error: ")?;

                f.write_str(&String::from_utf8_lossy(body))
            }
            ErrorType::ServiceUnavailable { .. } => {
                f.write_str("api may be temporarily unavailable (received a 503)")
            }
            ErrorType::Unauthorized => {
                f.write_str("token in use is invalid, expired, or is revoked")
            }
        }
    }
}

impl StdError for Error {
    fn source(&self) -> Option<&(dyn StdError + 'static)> {
        self.source
            .as_ref()
            .map(|source| &**source as &(dyn StdError + 'static))
    }
}

/// Type of [`Error`] that occurred.
#[non_exhaustive]
pub enum ErrorType {
    BuildingRequest,
    ChunkingResponse,
    CreatingHeader {
        name: String,
    },
    Json,
    Parsing {
        body: Vec<u8>,
    },
    RatelimiterTicket,
    RequestCanceled,
    RequestError,
    RequestTimedOut,
    Response {
        body: Vec<u8>,
        error: ApiError,
        status: StatusCode,
    },
    /// API service is unavailable. Consider re-sending the request at a
    /// later time.
    ///
    /// This may occur during Discord API stability incidents.
    ServiceUnavailable {
        response: Response<Body>,
    },
    /// Token in use has become revoked or is otherwise invalid.
    ///
    /// This can occur if a bot token is invalidated or an access token expires
    /// or is revoked. Recreate the client to configure a new token.
    Unauthorized,
}

impl Debug for ErrorType {
    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
        match self {
            Self::BuildingRequest => f.write_str("BuildingRequest"),
            Self::ChunkingResponse => f.write_str("ChunkingResponse"),
            Self::CreatingHeader { name } => f
                .debug_struct("CreatingHeader")
                .field("name", name)
                .finish(),
            Self::Json => f.write_str("Json"),
            Self::Parsing { body } => {
                let mut debug = f.debug_struct("Parsing");

                if let Ok(body_string) = str::from_utf8(body) {
                    debug.field("body_string", &body_string);
                }

                debug.field("body", body).finish()
            }
            Self::RatelimiterTicket => f.write_str("RatelimiterTicket"),
            Self::RequestCanceled => f.write_str("RequestCanceled"),
            Self::RequestError => f.write_str("RequestError"),
            Self::RequestTimedOut => f.write_str("RequestTimedOut"),
            Self::Response {
                body,
                error,
                status,
            } => {
                let mut debug = f.debug_struct("Response");

                if let Ok(body_string) = str::from_utf8(body) {
                    debug.field("body_string", &body_string);
                }

                debug
                    .field("body", body)
                    .field("error", error)
                    .field("status", status)
                    .finish()
            }
            Self::ServiceUnavailable { response } => f
                .debug_struct("ServiceUnavailable")
                .field("response", response)
                .finish(),
            Self::Unauthorized => f.write_str("Unauthorized"),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::ErrorType;
    use crate::{
        api_error::{ApiError, GeneralApiError},
        response::StatusCode,
    };

    /// Ensure
    #[test]
    fn parsing_variant_debug() {
        let body = br#"{"message": "aaa"#.to_vec();

        let error = ErrorType::Parsing { body };

        assert_eq!(
            "Parsing {
    body_string: \"{\\\"message\\\": \\\"aaa\",
    body: [
        123,
        34,
        109,
        101,
        115,
        115,
        97,
        103,
        101,
        34,
        58,
        32,
        34,
        97,
        97,
        97,
    ],
}",
            format!("{error:#?}"),
        );
    }

    #[test]
    fn response_variant_debug() {
        let body = br#"{"message": "aaa"}"#.to_vec();

        let error = ErrorType::Response {
            body,
            error: ApiError::General(GeneralApiError {
                code: 0,
                message: "401: Unauthorized".to_owned(),
            }),
            status: StatusCode::new(401),
        };

        assert_eq!(
            "Response {
    body_string: \"{\\\"message\\\": \\\"aaa\\\"}\",
    body: [
        123,
        34,
        109,
        101,
        115,
        115,
        97,
        103,
        101,
        34,
        58,
        32,
        34,
        97,
        97,
        97,
        34,
        125,
    ],
    error: General(
        GeneralApiError {
            code: 0,
            message: \"401: Unauthorized\",
        },
    ),
    status: StatusCode(
        401,
    ),
}",
            format!("{error:#?}"),
        );
    }
}