hyper_sync/header/common/
range.rs

1use std::fmt::{self, Display};
2use std::str::FromStr;
3
4use header::{Header, Raw};
5use header::parsing::from_one_raw_str;
6
7/// `Range` header, defined in [RFC7233](https://tools.ietf.org/html/rfc7233#section-3.1)
8///
9/// The "Range" header field on a GET request modifies the method
10/// semantics to request transfer of only one or more subranges of the
11/// selected representation data, rather than the entire selected
12/// representation data.
13///
14/// # ABNF
15///
16/// ```text
17/// Range =	byte-ranges-specifier / other-ranges-specifier
18/// other-ranges-specifier = other-range-unit "=" other-range-set
19/// other-range-set = 1*VCHAR
20///
21/// bytes-unit = "bytes"
22///
23/// byte-ranges-specifier = bytes-unit "=" byte-range-set
24/// byte-range-set = 1#(byte-range-spec / suffix-byte-range-spec)
25/// byte-range-spec = first-byte-pos "-" [last-byte-pos]
26/// first-byte-pos = 1*DIGIT
27/// last-byte-pos = 1*DIGIT
28/// ```
29///
30/// # Example values
31///
32/// * `bytes=1000-`
33/// * `bytes=-2000`
34/// * `bytes=0-1,30-40`
35/// * `bytes=0-10,20-90,-100`
36/// * `custom_unit=0-123`
37/// * `custom_unit=xxx-yyy`
38///
39/// # Examples
40///
41/// ```
42/// use hyper_sync::header::{Headers, Range, ByteRangeSpec};
43///
44/// let mut headers = Headers::new();
45/// headers.set(Range::Bytes(
46///     vec![ByteRangeSpec::FromTo(1, 100), ByteRangeSpec::AllFrom(200)]
47/// ));
48///
49/// headers.clear();
50/// headers.set(Range::Unregistered("letters".to_owned(), "a-f".to_owned()));
51/// ```
52///
53/// ```
54/// use hyper_sync::header::{Headers, Range};
55///
56/// let mut headers = Headers::new();
57/// headers.set(Range::bytes(1, 100));
58///
59/// headers.clear();
60/// headers.set(Range::bytes_multi(vec![(1, 100), (200, 300)]));
61/// ```
62#[derive(PartialEq, Clone, Debug)]
63pub enum Range {
64    /// Byte range
65    Bytes(Vec<ByteRangeSpec>),
66    /// Custom range, with unit not registered at IANA
67    /// (`other-range-unit`: String , `other-range-set`: String)
68    Unregistered(String, String)
69}
70
71/// Each `Range::Bytes` header can contain one or more `ByteRangeSpecs`.
72/// Each `ByteRangeSpec` defines a range of bytes to fetch
73#[derive(PartialEq, Clone, Debug)]
74pub enum ByteRangeSpec {
75    /// Get all bytes between x and y ("x-y")
76    FromTo(u64, u64),
77    /// Get all bytes starting from x ("x-")
78    AllFrom(u64),
79    /// Get last x bytes ("-x")
80    Last(u64)
81}
82
83impl ByteRangeSpec {
84    /// Given the full length of the entity, attempt to normalize the byte range
85    /// into an satisfiable end-inclusive (from, to) range.
86    ///
87    /// The resulting range is guaranteed to be a satisfiable range within the bounds
88    /// of `0 <= from <= to < full_length`.
89    ///
90    /// If the byte range is deemed unsatisfiable, `None` is returned.
91    /// An unsatisfiable range is generally cause for a server to either reject
92    /// the client request with a `416 Range Not Satisfiable` status code, or to
93    /// simply ignore the range header and serve the full entity using a `200 OK`
94    /// status code.
95    ///
96    /// This function closely follows [RFC 7233][1] section 2.1.
97    /// As such, it considers ranges to be satisfiable if they meet the following
98    /// conditions:
99    ///
100    /// > If a valid byte-range-set includes at least one byte-range-spec with
101    /// a first-byte-pos that is less than the current length of the
102    /// representation, or at least one suffix-byte-range-spec with a
103    /// non-zero suffix-length, then the byte-range-set is satisfiable.
104    /// Otherwise, the byte-range-set is unsatisfiable.
105    ///
106    /// The function also computes remainder ranges based on the RFC:
107    ///
108    /// > If the last-byte-pos value is
109    /// absent, or if the value is greater than or equal to the current
110    /// length of the representation data, the byte range is interpreted as
111    /// the remainder of the representation (i.e., the server replaces the
112    /// value of last-byte-pos with a value that is one less than the current
113    /// length of the selected representation).
114    ///
115    /// [1]: https://tools.ietf.org/html/rfc7233
116    pub fn to_satisfiable_range(&self, full_length: u64) -> Option<(u64, u64)> {
117        // If the full length is zero, there is no satisfiable end-inclusive range.
118        if full_length == 0 {
119            return None;
120        }
121        match self {
122            &ByteRangeSpec::FromTo(from, to) => {
123                if from < full_length && from <= to {
124                    Some((from, ::std::cmp::min(to, full_length - 1)))
125                } else {
126                    None
127                }
128            },
129            &ByteRangeSpec::AllFrom(from) => {
130                if from < full_length {
131                    Some((from, full_length - 1))
132                } else {
133                    None
134                }
135            },
136            &ByteRangeSpec::Last(last) => {
137                if last > 0 {
138                    // From the RFC: If the selected representation is shorter
139                    // than the specified suffix-length,
140                    // the entire representation is used.
141                    if last > full_length {
142                        Some((0, full_length - 1))
143                    } else {
144                        Some((full_length - last, full_length - 1))
145                    }
146                } else {
147                    None
148                }
149            }
150        }
151    }
152}
153
154impl Range {
155    /// Get the most common byte range header ("bytes=from-to")
156    pub fn bytes(from: u64, to: u64) -> Range {
157        Range::Bytes(vec![ByteRangeSpec::FromTo(from, to)])
158    }
159
160    /// Get byte range header with multiple subranges
161    /// ("bytes=from1-to1,from2-to2,fromX-toX")
162    pub fn bytes_multi(ranges: Vec<(u64, u64)>) -> Range {
163        Range::Bytes(ranges.iter().map(|r| ByteRangeSpec::FromTo(r.0, r.1)).collect())
164    }
165}
166
167
168impl fmt::Display for ByteRangeSpec {
169    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
170        match *self {
171            ByteRangeSpec::FromTo(from, to) => write!(f, "{}-{}", from, to),
172            ByteRangeSpec::Last(pos) => write!(f, "-{}", pos),
173            ByteRangeSpec::AllFrom(pos) => write!(f, "{}-", pos),
174        }
175    }
176}
177
178
179impl fmt::Display for Range {
180    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
181        match *self {
182            Range::Bytes(ref ranges) => {
183                try!(write!(f, "bytes="));
184
185                for (i, range) in ranges.iter().enumerate() {
186                    if i != 0 {
187                        try!(f.write_str(","));
188                    }
189                    try!(Display::fmt(range, f));
190                }
191                Ok(())
192            },
193            Range::Unregistered(ref unit, ref range_str) => {
194                write!(f, "{}={}", unit, range_str)
195            },
196        }
197    }
198}
199
200impl FromStr for Range {
201    type Err = ::Error;
202
203    fn from_str(s: &str) -> ::Result<Range> {
204        let mut iter = s.splitn(2, '=');
205
206        match (iter.next(), iter.next()) {
207            (Some("bytes"), Some(ranges)) => {
208                let ranges = from_comma_delimited(ranges);
209                if ranges.is_empty() {
210                    return Err(::Error::Header);
211                }
212                Ok(Range::Bytes(ranges))
213            }
214            (Some(unit), Some(range_str)) if unit != "" && range_str != "" => {
215                Ok(Range::Unregistered(unit.to_owned(), range_str.to_owned()))
216
217            },
218            _ => Err(::Error::Header)
219        }
220    }
221}
222
223impl FromStr for ByteRangeSpec {
224    type Err = ::Error;
225
226    fn from_str(s: &str) -> ::Result<ByteRangeSpec> {
227        let mut parts = s.splitn(2, '-');
228
229        match (parts.next(), parts.next()) {
230            (Some(""), Some(end)) => {
231                end.parse().or(Err(::Error::Header)).map(ByteRangeSpec::Last)
232            },
233            (Some(start), Some("")) => {
234                start.parse().or(Err(::Error::Header)).map(ByteRangeSpec::AllFrom)
235            },
236            (Some(start), Some(end)) => {
237                match (start.parse(), end.parse()) {
238                    (Ok(start), Ok(end)) if start <= end => Ok(ByteRangeSpec::FromTo(start, end)),
239                    _ => Err(::Error::Header)
240                }
241            },
242            _ => Err(::Error::Header)
243        }
244    }
245}
246
247fn from_comma_delimited<T: FromStr>(s: &str) -> Vec<T> {
248    s.split(',')
249        .filter_map(|x| match x.trim() {
250            "" => None,
251            y => Some(y)
252        })
253        .filter_map(|x| x.parse().ok())
254        .collect()
255}
256
257impl Header for Range {
258
259    fn header_name() -> &'static str {
260        static NAME: &'static str = "Range";
261        NAME
262    }
263
264    fn parse_header(raw: &Raw) -> ::Result<Range> {
265        from_one_raw_str(raw)
266    }
267
268    fn fmt_header(&self, f: &mut ::header::Formatter) -> fmt::Result {
269        f.fmt_line(self)
270    }
271
272}
273
274#[test]
275fn test_parse_bytes_range_valid() {
276    let r: Range = Header::parse_header(&"bytes=1-100".into()).unwrap();
277    let r2: Range = Header::parse_header(&"bytes=1-100,-".into()).unwrap();
278    let r3 =  Range::bytes(1, 100);
279    assert_eq!(r, r2);
280    assert_eq!(r2, r3);
281
282    let r: Range = Header::parse_header(&"bytes=1-100,200-".into()).unwrap();
283    let r2: Range = Header::parse_header(&"bytes= 1-100 , 101-xxx,  200- ".into()).unwrap();
284    let r3 =  Range::Bytes(
285        vec![ByteRangeSpec::FromTo(1, 100), ByteRangeSpec::AllFrom(200)]
286    );
287    assert_eq!(r, r2);
288    assert_eq!(r2, r3);
289
290    let r: Range = Header::parse_header(&"bytes=1-100,-100".into()).unwrap();
291    let r2: Range = Header::parse_header(&"bytes=1-100, ,,-100".into()).unwrap();
292    let r3 =  Range::Bytes(
293        vec![ByteRangeSpec::FromTo(1, 100), ByteRangeSpec::Last(100)]
294    );
295    assert_eq!(r, r2);
296    assert_eq!(r2, r3);
297
298    let r: Range = Header::parse_header(&"custom=1-100,-100".into()).unwrap();
299    let r2 =  Range::Unregistered("custom".to_owned(), "1-100,-100".to_owned());
300    assert_eq!(r, r2);
301
302}
303
304#[test]
305fn test_parse_unregistered_range_valid() {
306    let r: Range = Header::parse_header(&"custom=1-100,-100".into()).unwrap();
307    let r2 =  Range::Unregistered("custom".to_owned(), "1-100,-100".to_owned());
308    assert_eq!(r, r2);
309
310    let r: Range = Header::parse_header(&"custom=abcd".into()).unwrap();
311    let r2 =  Range::Unregistered("custom".to_owned(), "abcd".to_owned());
312    assert_eq!(r, r2);
313
314    let r: Range = Header::parse_header(&"custom=xxx-yyy".into()).unwrap();
315    let r2 =  Range::Unregistered("custom".to_owned(), "xxx-yyy".to_owned());
316    assert_eq!(r, r2);
317}
318
319#[test]
320fn test_parse_invalid() {
321    let r: ::Result<Range> = Header::parse_header(&"bytes=1-a,-".into());
322    assert_eq!(r.ok(), None);
323
324    let r: ::Result<Range> = Header::parse_header(&"bytes=1-2-3".into());
325    assert_eq!(r.ok(), None);
326
327    let r: ::Result<Range> = Header::parse_header(&"abc".into());
328    assert_eq!(r.ok(), None);
329
330    let r: ::Result<Range> = Header::parse_header(&"bytes=1-100=".into());
331    assert_eq!(r.ok(), None);
332
333    let r: ::Result<Range> = Header::parse_header(&"bytes=".into());
334    assert_eq!(r.ok(), None);
335
336    let r: ::Result<Range> = Header::parse_header(&"custom=".into());
337    assert_eq!(r.ok(), None);
338
339    let r: ::Result<Range> = Header::parse_header(&"=1-100".into());
340    assert_eq!(r.ok(), None);
341}
342
343#[test]
344fn test_fmt() {
345    use header::Headers;
346
347    let mut headers = Headers::new();
348
349    headers.set(
350        Range::Bytes(
351            vec![ByteRangeSpec::FromTo(0, 1000), ByteRangeSpec::AllFrom(2000)]
352    ));
353    assert_eq!(&headers.to_string(), "Range: bytes=0-1000,2000-\r\n");
354
355    headers.clear();
356    headers.set(Range::Bytes(vec![]));
357
358    assert_eq!(&headers.to_string(), "Range: bytes=\r\n");
359
360    headers.clear();
361    headers.set(Range::Unregistered("custom".to_owned(), "1-xxx".to_owned()));
362
363    assert_eq!(&headers.to_string(), "Range: custom=1-xxx\r\n");
364}
365
366#[test]
367fn test_byte_range_spec_to_satisfiable_range() {
368    assert_eq!(Some((0, 0)), ByteRangeSpec::FromTo(0, 0).to_satisfiable_range(3));
369    assert_eq!(Some((1, 2)), ByteRangeSpec::FromTo(1, 2).to_satisfiable_range(3));
370    assert_eq!(Some((1, 2)), ByteRangeSpec::FromTo(1, 5).to_satisfiable_range(3));
371    assert_eq!(None, ByteRangeSpec::FromTo(3, 3).to_satisfiable_range(3));
372    assert_eq!(None, ByteRangeSpec::FromTo(2, 1).to_satisfiable_range(3));
373    assert_eq!(None, ByteRangeSpec::FromTo(0, 0).to_satisfiable_range(0));
374
375    assert_eq!(Some((0, 2)), ByteRangeSpec::AllFrom(0).to_satisfiable_range(3));
376    assert_eq!(Some((2, 2)), ByteRangeSpec::AllFrom(2).to_satisfiable_range(3));
377    assert_eq!(None, ByteRangeSpec::AllFrom(3).to_satisfiable_range(3));
378    assert_eq!(None, ByteRangeSpec::AllFrom(5).to_satisfiable_range(3));
379    assert_eq!(None, ByteRangeSpec::AllFrom(0).to_satisfiable_range(0));
380
381    assert_eq!(Some((1, 2)), ByteRangeSpec::Last(2).to_satisfiable_range(3));
382    assert_eq!(Some((2, 2)), ByteRangeSpec::Last(1).to_satisfiable_range(3));
383    assert_eq!(Some((0, 2)), ByteRangeSpec::Last(5).to_satisfiable_range(3));
384    assert_eq!(None, ByteRangeSpec::Last(0).to_satisfiable_range(3));
385    assert_eq!(None, ByteRangeSpec::Last(2).to_satisfiable_range(0));
386}
387
388bench_header!(bytes_multi, Range, { vec![b"bytes=1-1001,2001-3001,10001-".to_vec()]});
389bench_header!(custom_unit, Range, { vec![b"other=0-100000".to_vec()]});
hyper_sync/header/common/range.rs

hyper_sync/header/common/
range.rs
