feat(headers): add Range header

src/header/common/range.rs

@@ -0,0 +1,231 @@
+use std::fmt::{self, Display};
+use std::str::FromStr;
+
+use header::{Header, HeaderFormat, RangeUnit};
+use header::parsing::{from_one_raw_str, from_one_comma_delimited};
+
+/// `Range` header, defined in [RFC7233](https://tools.ietf.org/html/rfc7233#section-3.1)
+///
+/// The "Range" header field on a GET request modifies the method
+/// semantics to request transfer of only one or more subranges of the
+/// selected representation data, rather than the entire selected
+/// representation data.
+///
+/// # ABNF
+/// ```plain
+/// Range =	byte-ranges-specifier / other-ranges-specifier
+/// other-ranges-specifier = other-range-unit "=" other-range-set
+/// other-range-set = 1*VCHAR
+/// ```
+///
+/// # Example values
+/// * `bytes=1000-`
+/// * `bytes=-2000`
+/// * `bytes=0-1,30-40`
+/// * `custom_unit=0-123,-200`
+///
+/// # Examples
+/// ```
+/// use hyper::header::{Headers, Range, RangeSpec, RangeUnit};
+///
+/// let mut headers = Headers::new();
+///
+/// headers.set(Range {
+///     unit: RangeUnit::Bytes,
+///     ranges: vec![RangeSpec::FromTo(1, 100), RangeSpec::AllFrom(200)]
+/// });
+/// ```
+/// ```
+/// use hyper::header::{Headers, Range};
+///
+/// let mut headers = Headers::new();
+/// headers.set(Range::bytes(1, 100));
+/// ```
+#[derive(PartialEq, Clone, Debug)]
+pub struct Range {
+    /// Unit of the Range i.e. bytes
+    pub unit: RangeUnit,
+    /// Set of ranges as defined in the HTTP spec
+    pub ranges: Vec<RangeSpec>,
+}
+
+/// Each 'Range' header can contain one or more RangeSpecs.
+/// Each RangeSpec defines a range of units to fetch
+#[derive(PartialEq, Clone, Debug)]
+pub enum RangeSpec {
+    /// Get all bytes between x and y ("x-y")
+    FromTo(u64, u64),
+    /// Get all bytes starting from x ("x-")
+    AllFrom(u64),
+    /// Get last x bytes ("-x")
+    Last(u64)
+}
+
+impl Range {
+    /// Get the most common byte range header ("bytes=from-to")
+    pub fn bytes(from: u64, to: u64) -> Range {
+        Range {
+            unit: RangeUnit::Bytes,
+            ranges: vec![RangeSpec::FromTo(from, to)],
+        }
+    }
+}
+
+
+impl fmt::Display for RangeSpec {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            RangeSpec::FromTo(from, to) => write!(f, "{}-{}", from, to),
+            RangeSpec::Last(pos) => write!(f, "-{}", pos),
+            RangeSpec::AllFrom(pos) => write!(f, "{}-", pos),
+        }
+    }
+}
+
+
+impl fmt::Display for Range {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        try!(write!(f, "{}=", self.unit));
+
+        for (i, range) in self.ranges.iter().enumerate() {
+            if i != 0 {
+                try!(f.write_str(","));
+            }
+            try!(Display::fmt(range, f));
+        }
+        Ok(())
+    }
+}
+
+impl FromStr for Range {
+    type Err = ::Error;
+
+    fn from_str(s: &str) -> ::Result<Range> {
+        let mut iter = s.splitn(2, "=");
+
+        match (iter.next(), iter.next()) {
+            (Some(unit), Some(ranges)) => {
+                match (RangeUnit::from_str(unit), from_one_comma_delimited(ranges.as_bytes())) {
+                    (Ok(unit), Ok(ranges)) => {
+                        if ranges.is_empty() {
+                            return Err(::Error::Header);
+                        }
+                        Ok(Range{unit: unit, ranges: ranges})
+                    },
+                    _ => Err(::Error::Header)
+                }
+            }
+            _ => Err(::Error::Header)
+        }
+    }
+}
+
+impl FromStr for RangeSpec {
+    type Err = ::Error;
+
+    fn from_str(s: &str) -> ::Result<RangeSpec> {
+        let mut parts = s.splitn(2, "-");
+
+        match (parts.next(), parts.next()) {
+            (Some(""), Some(end)) => {
+                end.parse().or(Err(::Error::Header)).map(|end| RangeSpec::Last(end))
+            },
+            (Some(start), Some("")) => {
+                start.parse().or(Err(::Error::Header)).map(|start| RangeSpec::AllFrom(start))
+            },
+            (Some(start), Some(end)) => {
+                match (start.parse(), end.parse()) {
+                    (Ok(start), Ok(end)) if start <= end => Ok(RangeSpec::FromTo(start, end)),
+                    _ => Err(::Error::Header)
+                }
+            },
+            _ => Err(::Error::Header)
+        }
+    }
+}
+
+impl Header for Range {
+
+    fn header_name() -> &'static str {
+        "Range"
+    }
+
+    fn parse_header(raw: &[Vec<u8>]) -> ::Result<Range> {
+        from_one_raw_str(raw)
+    }
+}
+
+impl HeaderFormat for Range {
+
+    fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        Display::fmt(self, f)
+    }
+
+}
+
+#[test]
+fn test_parse_valid() {
+    let r: Range = Header::parse_header(&[b"bytes=1-100".to_vec()]).unwrap();
+    let r2: Range = Header::parse_header(&[b"bytes=1-100,-".to_vec()]).unwrap();
+    let r3 =  Range::bytes(1, 100);
+    assert_eq!(r, r2);
+    assert_eq!(r2, r3);
+
+    let r: Range = Header::parse_header(&[b"bytes=1-100,200-".to_vec()]).unwrap();
+    let r2: Range = Header::parse_header(&[b"bytes= 1-100 , 101-xxx,  200- ".to_vec()]).unwrap();
+    let r3 =  Range {
+        unit: RangeUnit::Bytes,
+        ranges: vec![RangeSpec::FromTo(1, 100), RangeSpec::AllFrom(200)]
+    };
+    assert_eq!(r, r2);
+    assert_eq!(r2, r3);
+
+    let r: Range = Header::parse_header(&[b"custom=1-100,-100".to_vec()]).unwrap();
+    let r2: Range = Header::parse_header(&[b"custom=1-100, ,,-100".to_vec()]).unwrap();
+    let r3 =  Range {
+        unit: RangeUnit::Unregistered("custom".to_owned()),
+        ranges: vec![RangeSpec::FromTo(1, 100), RangeSpec::Last(100)]
+    };
+    assert_eq!(r, r2);
+    assert_eq!(r2, r3);
+}
+
+#[test]
+fn test_parse_invalid() {
+    let r: ::Result<Range> = Header::parse_header(&[b"bytes=1-a,-".to_vec()]);
+    assert_eq!(r.ok(), None);
+
+    let r: ::Result<Range> = Header::parse_header(&[b"bytes=1-2-3".to_vec()]);
+    assert_eq!(r.ok(), None);
+
+    let r: ::Result<Range> = Header::parse_header(&[b"abc".to_vec()]);
+    assert_eq!(r.ok(), None);
+
+    let r: ::Result<Range> = Header::parse_header(&[b"bytes=1-100=".to_vec()]);
+    assert_eq!(r.ok(), None);
+
+    let r: ::Result<Range> = Header::parse_header(&[b"bytes=".to_vec()]);
+    assert_eq!(r.ok(), None);
+}
+
+#[test]
+fn test_fmt() {
+    use header::Headers;
+
+    let range_header = Range {
+        unit: RangeUnit::Bytes,
+        ranges: vec![RangeSpec::FromTo(0, 1000), RangeSpec::AllFrom(2000)],
+    };
+    let mut headers = Headers::new();
+    headers.set(range_header);
+
+    assert_eq!(&headers.to_string(), "Range: bytes=0-1000,2000-\r\n");
+
+    headers.clear();
+    headers.set(Range {unit: RangeUnit::Bytes, ranges: vec![]});
+
+    assert_eq!(&headers.to_string(), "Range: bytes=\r\n");
+}
+
+bench_header!(bytes_multi, Range, { vec![b"bytes=1-1001,2001-3001,10001-".to_vec()]});
+bench_header!(custom_unit, Range, { vec![b"custom_unit=0-100000".to_vec()]});