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use std::{collections::BTreeMap, fs, io};
pub type HostMap = BTreeMap<String, String>;
/// For now just load the hostnames and their labels.
pub fn load_ssh_config(path: &str) -> Result<HostMap, io::Error> {
parse_ssh_config(&fs::read_to_string(path.replace('~', env!("HOME")))?)
}
/// Parse .ssh/config to a (sorted) BTree.
pub fn parse_ssh_config<S: AsRef<str>>(config: S) -> Result<HostMap, io::Error> {
let config = config.as_ref();
let mut map = BTreeMap::new();
let mut token = String::new(); // the token we're parsing
let mut line = vec![]; // current line
let mut skip_line = false; // skip until EOL for comments
let mut stanza = String::new(); // ssh config is broken into stanzas
let mut key = true; // parsing the key or the value?
for c in config.chars() {
if skip_line {
if c == '\n' {
skip_line = false;
}
continue;
}
if c == '#' {
// skip comments
skip_line = true;
if !token.is_empty() {
line.push(token);
token = String::new();
}
} else if key && (c == ' ' || c == '=') {
// "key = value" OR "key value" separator
if !token.is_empty() {
line.push(token);
token = String::new();
key = false;
}
} else if c == '\n' {
if !token.is_empty() {
line.push(token);
token = String::new();
key = true;
}
if line.is_empty() {
continue;
} else if line.len() != 2 {
return Err(io::Error::new(
io::ErrorKind::Other,
format!("can't parse line: {:?}", line),
));
} else {
match line[0].to_lowercase().as_ref() {
"host" => {
let parsed = &line[1];
// skip any Host patterns
if parsed.contains('*')
|| parsed.contains('!')
|| parsed.contains(',')
|| parsed.contains(' ')
{
stanza.clear();
} else {
stanza = parsed.clone();
// by default we assume host patterns are
// actual hostnames
map.insert(stanza.clone(), stanza.clone());
}
}
"hostname" => {
if !stanza.is_empty() {
map.insert(stanza.clone(), line[1].clone());
stanza.clear();
}
}
_ => {}
}
line.clear();
}
} else if (c == ' ' || c == '=') && token.is_empty() {
// skip = and whitespace at start of value, key = value format
continue;
} else {
// regular char
token.push(c);
}
}
Ok(map)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_config() {
let config = load_ssh_config("./tests/test_config").expect("failed to parse config");
assert_eq!(11, config.len());
assert_eq!(
config.keys().cloned().collect::<Vec<_>>(),
vec![
"devserver",
"docker1",
"docker2",
"docker3",
"ec2-some-long-name.amazon.probably.com",
"ec2-some-long-namer.amazon.probably.com",
"homework-server",
"midi-files.com",
"nas01",
"nixcraft",
"torrentz-server",
]
);
assert_eq!("torrentz-r-us.com", config.get("torrentz-server").unwrap());
assert_eq!("docker3", config.get("docker3").unwrap());
assert_eq!("192.168.1.100", config.get("nas01").unwrap());
assert_eq!("midi-files.com", config.get("midi-files.com").unwrap());
}
}