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
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
//! The HTTP request method
//!
//! This module contains HTTP-method related structs and errors and such. The
//! main type of this module, `Method`, is also reexported at the root of the
//! crate as `http::Method` and is intended for import through that location
//! primarily.
//!
//! # Examples
//!
//! ```
//! use http::Method;
//!
//! assert_eq!(Method::GET, Method::from_bytes(b"GET").unwrap());
//! assert!(Method::GET.is_idempotent());
//! assert_eq!(Method::POST.as_str(), "POST");
//! ```

use self::Inner::*;

use std::convert::AsRef;
use std::error::Error;
use std::str::FromStr;
use std::convert::TryFrom;
use std::{fmt, str};

/// The Request Method (VERB)
///
/// This type also contains constants for a number of common HTTP methods such
/// as GET, POST, etc.
///
/// Currently includes 8 variants representing the 8 methods defined in
/// [RFC 7230](https://tools.ietf.org/html/rfc7231#section-4.1), plus PATCH,
/// and an Extension variant for all extensions.
///
/// # Examples
///
/// ```
/// use http::Method;
///
/// assert_eq!(Method::GET, Method::from_bytes(b"GET").unwrap());
/// assert!(Method::GET.is_idempotent());
/// assert_eq!(Method::POST.as_str(), "POST");
/// ```
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct Method(Inner);

/// A possible error value when converting `Method` from bytes.
pub struct InvalidMethod {
    _priv: (),
}

#[derive(Clone, PartialEq, Eq, Hash)]
enum Inner {
    Options,
    Get,
    Post,
    Put,
    Delete,
    Head,
    Trace,
    Connect,
    Patch,
    // If the extension is short enough, store it inline
    ExtensionInline([u8; MAX_INLINE], u8),
    // Otherwise, allocate it
    ExtensionAllocated(Box<[u8]>),
}

const MAX_INLINE: usize = 15;

// From the HTTP spec section 5.1.1, the HTTP method is case-sensitive and can
// contain the following characters:
//
// ```
// method = token
// token = 1*tchar
// tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
//     "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA
// ```
//
// https://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01#Method
//
const METHOD_CHARS: [u8; 256] = [
    //  0      1      2      3      4      5      6      7      8      9
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', //   x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', //  1x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', //  2x
    b'\0', b'\0', b'\0',  b'!', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', //  3x
    b'\0', b'\0',  b'*',  b'+', b'\0',  b'-',  b'.', b'\0',  b'0',  b'1', //  4x
     b'2',  b'3',  b'4',  b'5',  b'6',  b'7',  b'8',  b'9', b'\0', b'\0', //  5x
    b'\0', b'\0', b'\0', b'\0', b'\0',  b'A',  b'B',  b'C',  b'D',  b'E', //  6x
     b'F',  b'G',  b'H',  b'I',  b'J',  b'K',  b'L',  b'M',  b'N',  b'O', //  7x
     b'P',  b'Q',  b'R',  b'S',  b'T',  b'U',  b'V',  b'W',  b'X',  b'Y', //  8x
     b'Z', b'\0', b'\0', b'\0',  b'^',  b'_',  b'`',  b'a',  b'b',  b'c', //  9x
     b'd',  b'e',  b'f',  b'g',  b'h',  b'i',  b'j',  b'k',  b'l',  b'm', // 10x
     b'n',  b'o',  b'p',  b'q',  b'r',  b's',  b't',  b'u',  b'v',  b'w', // 11x
     b'x',  b'y',  b'z', b'\0',  b'|', b'\0',  b'~', b'\0', b'\0', b'\0', // 12x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 13x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 14x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 15x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 16x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 17x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 18x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 19x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 20x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 21x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 22x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 23x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', b'\0', // 24x
    b'\0', b'\0', b'\0', b'\0', b'\0', b'\0'                              // 25x
];

impl Method {
    /// GET
    pub const GET: Method = Method(Get);

    /// POST
    pub const POST: Method = Method(Post);

    /// PUT
    pub const PUT: Method = Method(Put);

    /// DELETE
    pub const DELETE: Method = Method(Delete);

    /// HEAD
    pub const HEAD: Method = Method(Head);

    /// OPTIONS
    pub const OPTIONS: Method = Method(Options);

    /// CONNECT
    pub const CONNECT: Method = Method(Connect);

    /// PATCH
    pub const PATCH: Method = Method(Patch);

    /// TRACE
    pub const TRACE: Method = Method(Trace);

    /// Converts a slice of bytes to an HTTP method.
    pub fn from_bytes(src: &[u8]) -> Result<Method, InvalidMethod> {
        match src.len() {
            0 => Err(InvalidMethod::new()),
            3 => match src {
                b"GET" => Ok(Method(Get)),
                b"PUT" => Ok(Method(Put)),
                _ => Method::extension_inline(src),
            },
            4 => match src {
                b"POST" => Ok(Method(Post)),
                b"HEAD" => Ok(Method(Head)),
                _ => Method::extension_inline(src),
            },
            5 => match src {
                b"PATCH" => Ok(Method(Patch)),
                b"TRACE" => Ok(Method(Trace)),
                _ => Method::extension_inline(src),
            },
            6 => match src {
                b"DELETE" => Ok(Method(Delete)),
                _ => Method::extension_inline(src),
            },
            7 => match src {
                b"OPTIONS" => Ok(Method(Options)),
                b"CONNECT" => Ok(Method(Connect)),
                _ => Method::extension_inline(src),
            },
            _ => {
                if src.len() < MAX_INLINE {
                    Method::extension_inline(src)
                } else {
                    let mut data: Vec<u8> = vec![0; src.len()];

                    write_checked(src, &mut data)?;

                    Ok(Method(ExtensionAllocated(data.into_boxed_slice())))
                }
            }
        }
    }

    fn extension_inline(src: &[u8]) -> Result<Method, InvalidMethod> {
        let mut data: [u8; MAX_INLINE] = Default::default();

        write_checked(src, &mut data)?;

        Ok(Method(ExtensionInline(data, src.len() as u8)))
    }

    /// Whether a method is considered "safe", meaning the request is
    /// essentially read-only.
    ///
    /// See [the spec](https://tools.ietf.org/html/rfc7231#section-4.2.1)
    /// for more words.
    pub fn is_safe(&self) -> bool {
        match self.0 {
            Get | Head | Options | Trace => true,
            _ => false,
        }
    }

    /// Whether a method is considered "idempotent", meaning the request has
    /// the same result if executed multiple times.
    ///
    /// See [the spec](https://tools.ietf.org/html/rfc7231#section-4.2.2) for
    /// more words.
    pub fn is_idempotent(&self) -> bool {
        match self.0 {
            Put | Delete => true,
            _ => self.is_safe(),
        }
    }

    /// Return a &str representation of the HTTP method
    #[inline]
    pub fn as_str(&self) -> &str {
        match self.0 {
            Options => "OPTIONS",
            Get => "GET",
            Post => "POST",
            Put => "PUT",
            Delete => "DELETE",
            Head => "HEAD",
            Trace => "TRACE",
            Connect => "CONNECT",
            Patch => "PATCH",
            ExtensionInline(ref data, len) => unsafe {
                str::from_utf8_unchecked(&data[..len as usize])
            },
            ExtensionAllocated(ref data) => unsafe { str::from_utf8_unchecked(data) },
        }
    }
}

fn write_checked(src: &[u8], dst: &mut [u8]) -> Result<(), InvalidMethod> {
    for (i, &b) in src.iter().enumerate() {
        let b = METHOD_CHARS[b as usize];

        if b == 0 {
            return Err(InvalidMethod::new());
        }

        dst[i] = b;
    }

    Ok(())
}

impl AsRef<str> for Method {
    #[inline]
    fn as_ref(&self) -> &str {
        self.as_str()
    }
}

impl<'a> PartialEq<&'a Method> for Method {
    #[inline]
    fn eq(&self, other: &&'a Method) -> bool {
        self == *other
    }
}

impl<'a> PartialEq<Method> for &'a Method {
    #[inline]
    fn eq(&self, other: &Method) -> bool {
        *self == other
    }
}

impl PartialEq<str> for Method {
    #[inline]
    fn eq(&self, other: &str) -> bool {
        self.as_ref() == other
    }
}

impl PartialEq<Method> for str {
    #[inline]
    fn eq(&self, other: &Method) -> bool {
        self == other.as_ref()
    }
}

impl<'a> PartialEq<&'a str> for Method {
    #[inline]
    fn eq(&self, other: &&'a str) -> bool {
        self.as_ref() == *other
    }
}

impl<'a> PartialEq<Method> for &'a str {
    #[inline]
    fn eq(&self, other: &Method) -> bool {
        *self == other.as_ref()
    }
}

impl fmt::Debug for Method {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(self.as_ref())
    }
}

impl fmt::Display for Method {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.write_str(self.as_ref())
    }
}

impl Default for Method {
    #[inline]
    fn default() -> Method {
        Method::GET
    }
}

impl<'a> From<&'a Method> for Method {
    #[inline]
    fn from(t: &'a Method) -> Self {
        t.clone()
    }
}

impl<'a> TryFrom<&'a [u8]> for Method {
    type Error = InvalidMethod;

    #[inline]
    fn try_from(t: &'a [u8]) -> Result<Self, Self::Error> {
        Method::from_bytes(t)
    }
}

impl<'a> TryFrom<&'a str> for Method {
    type Error = InvalidMethod;

    #[inline]
    fn try_from(t: &'a str) -> Result<Self, Self::Error> {
        TryFrom::try_from(t.as_bytes())
    }
}

impl FromStr for Method {
    type Err = InvalidMethod;

    #[inline]
    fn from_str(t: &str) -> Result<Self, Self::Err> {
        TryFrom::try_from(t)
    }
}

impl InvalidMethod {
    fn new() -> InvalidMethod {
        InvalidMethod { _priv: () }
    }
}

impl fmt::Debug for InvalidMethod {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.debug_struct("InvalidMethod")
            // skip _priv noise
            .finish()
    }
}

impl fmt::Display for InvalidMethod {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.description())
    }
}

impl Error for InvalidMethod {
    fn description(&self) -> &str {
        "invalid HTTP method"
    }
}

#[test]
fn test_method_eq() {
    assert_eq!(Method::GET, Method::GET);
    assert_eq!(Method::GET, "GET");
    assert_eq!(&Method::GET, "GET");

    assert_eq!("GET", Method::GET);
    assert_eq!("GET", &Method::GET);

    assert_eq!(&Method::GET, Method::GET);
    assert_eq!(Method::GET, &Method::GET);
}

#[test]
fn test_invalid_method() {
    assert!(Method::from_str("").is_err());
    assert!(Method::from_bytes(b"").is_err());
}

#[test]
fn test_is_idempotent() {
    assert!(Method::OPTIONS.is_idempotent());
    assert!(Method::GET.is_idempotent());
    assert!(Method::PUT.is_idempotent());
    assert!(Method::DELETE.is_idempotent());
    assert!(Method::HEAD.is_idempotent());
    assert!(Method::TRACE.is_idempotent());

    assert!(!Method::POST.is_idempotent());
    assert!(!Method::CONNECT.is_idempotent());
    assert!(!Method::PATCH.is_idempotent());
}