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use std::str;
use std::string::FromUtf8Error;
pub fn encode(data: &str) -> String {
let mut escaped = String::new();
for b in data.as_bytes().iter() {
match *b as char {
'A'...'Z' | 'a'...'z' | '0'...'9' | '-' | '_' | '.' | '~' => escaped.push(*b as char),
b => escaped.push_str(format!("%{:02X}", b as u32).as_str()),
};
}
return escaped;
}
pub fn decode(data: &str) -> Result<String, FromUrlEncodingError> {
validate_urlencoded_str(data)?;
let mut unescaped_bytes: Vec<u8> = Vec::new();
let mut bytes = data.bytes();
while let Some(b) = bytes.next() {
match b as char {
'%' => {
let bytes_to_decode = &[bytes.next().unwrap(), bytes.next().unwrap()];
let hex_str = str::from_utf8(bytes_to_decode).unwrap();
unescaped_bytes.push(u8::from_str_radix(hex_str, 16).unwrap());
},
_ => {
unescaped_bytes.push(b);
}
}
}
String::from_utf8(unescaped_bytes).or_else(|e| Err(FromUrlEncodingError::Utf8CharacterError {
error: e,
}))
}
fn validate_urlencoded_str(data: &str) -> Result<(), FromUrlEncodingError> {
let mut iter = data.char_indices();
while let Some((idx, chr)) = iter.next() {
match chr {
'%' => {
validate_percent_encoding(&mut iter, idx)?;
},
_ => continue,
}
}
Ok(())
}
fn validate_percent_encoding(iter: &mut str::CharIndices, current_idx: usize) -> Result<(), FromUrlEncodingError> {
for _ in 0..2 {
match iter.next() {
Some((_, c)) if c.is_digit(16) => {
continue
},
Some((i, c)) => return Err(FromUrlEncodingError::UriCharacterError {
character: c,
index: i,
}),
None => return Err(FromUrlEncodingError::UriCharacterError {
character: '%',
index: current_idx,
}),
}
}
Ok(())
}
#[derive(Debug)]
pub enum FromUrlEncodingError {
UriCharacterError { character: char, index: usize },
Utf8CharacterError { error: FromUtf8Error },
}
#[cfg(test)]
mod tests {
use super::encode;
use super::decode;
use super::FromUrlEncodingError;
#[test]
fn it_encodes_successfully() {
let expected = "this%20that";
assert_eq!(expected, encode("this that"));
}
#[test]
fn it_encodes_successfully_emoji() {
let emoji_string = "👾 Exterminate!";
let expected = "%F0%9F%91%BE%20Exterminate%21";
assert_eq!(expected, encode(emoji_string));
}
#[test]
fn it_decodes_successfully() {
let expected = String::from("this that");
let encoded = "this%20that";
assert_eq!(expected, decode(encoded).unwrap());
}
#[test]
fn it_decodes_successfully_emoji() {
let expected = String::from("👾 Exterminate!");
let encoded = "%F0%9F%91%BE%20Exterminate%21";
assert_eq!(expected, decode(encoded).unwrap());
}
#[test]
fn it_decodes_unsuccessfully_emoji() {
let bad_encoded_string = "👾 Exterminate!";
assert_eq!(bad_encoded_string, decode(bad_encoded_string).unwrap());
}
#[test]
fn it_decodes_unsuccessfuly_bad_percent_01() {
let bad_encoded_string = "this%2that";
let expected_idx = 6;
let expected_char = 't';
match decode(bad_encoded_string).unwrap_err() {
FromUrlEncodingError::UriCharacterError { index: i, character: c } => {
assert_eq!(expected_idx, i);
assert_eq!(expected_char, c)
},
_ => panic!()
}
}
#[test]
fn it_decodes_unsuccessfuly_bad_percent_02() {
let bad_encoded_string = "this%20that%";
let expected_idx = 11;
let expected_char = '%';
match decode(bad_encoded_string).unwrap_err() {
FromUrlEncodingError::UriCharacterError { index: i, character: c } => {
assert_eq!(expected_idx, i);
assert_eq!(expected_char, c)
},
_ => panic!()
}
}
#[test]
fn it_decodes_unsuccessfuly_bad_percent_03() {
let bad_encoded_string = "this%20that%2";
let expected_idx = 11;
let expected_char = '%';
match decode(bad_encoded_string).unwrap_err() {
FromUrlEncodingError::UriCharacterError { index: i, character: c } => {
assert_eq!(expected_idx, i);
assert_eq!(expected_char, c)
},
_ => panic!()
}
}
}