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/// An extended header parameter value (i.e., tagged with a character set and optionally,
#[derive(Clone, Debug, PartialEq)]
pub struct ExtendedValue {
/// The character set that is used to encode the `value` to a string.
pub charset: Charset,
/// The human language details of the `value`, if available.
pub language_tag: Option<LanguageTag>,
/// The parameter value, as expressed in octets.
pub value: Vec<u8>,
}
/// Parses extended header parameter values (`ext-value`), as defined in
///
/// Extended values are denoted by parameter names that end with `*`.
///
/// ## ABNF
///
/// ```text
/// ext-value = charset "'" [ language ] "'" value-chars
/// ; like RFC 2231's <extended-initial-value>
/// ; (see [RFC2231], Section 7)
///
/// charset = "UTF-8" / "ISO-8859-1" / mime-charset
///
/// mime-charset = 1*mime-charsetc
/// mime-charsetc = ALPHA / DIGIT
/// / "!" / "#" / "$" / "%" / "&"
/// / "+" / "-" / "^" / "_" / "`"
/// / "{" / "}" / "~"
/// ; as <mime-charset> in Section 2.3 of [RFC2978]
/// ; except that the single quote is not included
/// ; SHOULD be registered in the IANA charset registry
///
/// language = <Language-Tag, defined in [RFC5646], Section 2.1>
///
/// value-chars = *( pct-encoded / attr-char )
///
/// pct-encoded = "%" HEXDIG HEXDIG
/// ; see [RFC3986], Section 2.1
///
/// attr-char = ALPHA / DIGIT
/// / "!" / "#" / "$" / "&" / "+" / "-" / "."
/// / "^" / "_" / "`" / "|" / "~"
/// ; token except ( "*" / "'" / "%" )
/// ```
pub fn parse_extended_value(val: &str) -> ::Result<ExtendedValue> {
// Break into three pieces separated by the single-quote character
let mut parts = val.splitn(3,'\'');
// Interpret the first piece as a Charset
let charset: Charset = match parts.next() {
None => return Err(::Error::Header),
Some(n) => try!(FromStr::from_str(n)),
};
// Interpret the second piece as a language tag
let lang: Option<LanguageTag> = match parts.next() {
None => return Err(::Error::Header),
Some("") => None,
Some(s) => match s.parse() {
Ok(lt) => Some(lt),
Err(_) => return Err(::Error::Header),
}
};
// Interpret the third piece as a sequence of value characters
let value: Vec<u8> = match parts.next() {
None => return Err(::Error::Header),
Some(v) => percent_encoding::percent_decode(v.as_bytes()).collect(),
};
Ok(ExtendedValue {
charset: charset,
language_tag: lang,
value: value,
})
}
impl Display for ExtendedValue {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let encoded_value =
percent_encoding::percent_encode(&self.value[..], self::percent_encoding_http::HTTP_VALUE);
if let Some(ref lang) = self.language_tag {
write!(f, "{}'{}'{}", self.charset, lang, encoded_value)
} else {
write!(f, "{}''{}", self.charset, encoded_value)
}
}
}
/// Percent encode a sequence of bytes with a character set defined in
///
pub fn http_percent_encode(f: &mut fmt::Formatter, bytes: &[u8]) -> fmt::Result {
let encoded = percent_encoding::percent_encode(bytes, self::percent_encoding_http::HTTP_VALUE);
fmt::Display::fmt(&encoded, f)
}
mod percent_encoding_http {
use percent_encoding;
// internal module because macro is hard-coded to make a public item
// but we don't want to public export this item
define_encode_set! {
// This encode set is used for HTTP header values and is defined at
pub HTTP_VALUE = [percent_encoding::SIMPLE_ENCODE_SET] | {
' ', '"', '%', '\'', '(', ')', '*', ',', '/', ':', ';', '<', '-', '>', '?',
'[', '\\', ']', '{', '}'
}
}
}
#[cfg(test)]
mod tests {
use shared::Charset;
use super::{ExtendedValue, parse_extended_value};
use language_tags::LanguageTag;
#[test]
fn test_parse_extended_value_with_encoding_and_language_tag() {
let expected_language_tag = "en".parse::<LanguageTag>().unwrap();
// RFC 5987, Section 3.2.2
// Extended notation, using the Unicode character U+00A3 (POUND SIGN)
let result = parse_extended_value("iso-8859-1'en'%A3%20rates");
assert!(result.is_ok());
let extended_value = result.unwrap();
assert_eq!(Charset::Iso_8859_1, extended_value.charset);
assert!(extended_value.language_tag.is_some());
assert_eq!(expected_language_tag, extended_value.language_tag.unwrap());
assert_eq!(vec![163, b' ', b'r', b'a', b't', b'e', b's'], extended_value.value);
}
#[test]
fn test_parse_extended_value_with_encoding() {
// RFC 5987, Section 3.2.2
// Extended notation, using the Unicode characters U+00A3 (POUND SIGN)
// and U+20AC (EURO SIGN)
let result = parse_extended_value("UTF-8''%c2%a3%20and%20%e2%82%ac%20rates");
assert!(result.is_ok());
let extended_value = result.unwrap();
assert_eq!(Charset::Ext("UTF-8".to_string()), extended_value.charset);
assert!(extended_value.language_tag.is_none());
assert_eq!(vec![194, 163, b' ', b'a', b'n', b'd', b' ', 226, 130, 172, b' ', b'r', b'a', b't', b'e', b's'], extended_value.value);
}
#[test]
fn test_parse_extended_value_missing_language_tag_and_encoding() {
let result = parse_extended_value("foo%20bar.html");
assert!(result.is_err());
}
#[test]
fn test_parse_extended_value_partially_formatted() {
let result = parse_extended_value("UTF-8'missing third part");
assert!(result.is_err());
}
#[test]
fn test_parse_extended_value_partially_formatted_blank() {
let result = parse_extended_value("blank second part'");
assert!(result.is_err());
}
#[test]
fn test_fmt_extended_value_with_encoding_and_language_tag() {
let extended_value = ExtendedValue {
charset: Charset::Iso_8859_1,
language_tag: Some("en".parse().expect("Could not parse language tag")),
value: vec![163, b' ', b'r', b'a', b't', b'e', b's'],
};
assert_eq!("ISO-8859-1'en'%A3%20rates", format!("{}", extended_value));
}
#[test]
fn test_fmt_extended_value_with_encoding() {
let extended_value = ExtendedValue {
charset: Charset::Ext("UTF-8".to_string()),
language_tag: None,
value: vec![194, 163, b' ', b'a', b'n', b'd', b' ', 226, 130, 172, b' ', b'r', b'a',
b't', b'e', b's'],
};
assert_eq!("UTF-8''%C2%A3%20and%20%E2%82%AC%20rates",
format!("{}", extended_value));
}
}