Vote!

X-Git-Url: http://git.scottworley.com/voter/blobdiff_plain/c8402f1cb2962db5a2036c9273f62fff4c8c100c..05232d49a6890f9c2c01eb0462d49b5fd6c479bc:/src/main.rs diff --git a/src/main.rs b/src/main.rs index 15a1655..a12f73a 100644 --- a/src/main.rs +++ b/src/main.rs @@ -1,6 +1,11 @@ +use rand::prelude::*; +use std::collections::{HashMap, HashSet}; +use std::io::prelude::*; use std::path::{Path, PathBuf}; const DATA_PATH: &str = "/var/lib/voter"; +const COOKIE_NAME: &[u8] = b"__Secure-id"; +const COOKIE_LENGTH: usize = 12; fn validate_path(path: &str) -> Result { let invalid_path = || cgi::text_response(404, "Invalid path"); @@ -24,19 +29,221 @@ fn validate_path(path: &str) -> Result { Ok(dir) } +fn get_voter(request: &cgi::Request) -> Result<&[u8], cgi::Response> { + // Expect exactly one cookie, exactly as we generate it. + let cookie = request + .headers() + .get(cgi::http::header::COOKIE) + .map(|c| c.as_bytes()) + .and_then(|c| c.strip_prefix(COOKIE_NAME)) + .and_then(|c| c.strip_prefix(b"=")) + .ok_or_else(|| cgi::text_response(400, "Invalid cookie"))?; + if cookie.len() != COOKIE_LENGTH || cookie.contains(&b' ') || cookie.contains(&b';') { + Err(cgi::text_response(400, "Invalid cookie")) + } else { + Ok(cookie) + } +} + +fn tally_votes(dir: PathBuf) -> std::io::Result>> { + let mut tally: HashMap> = HashMap::new(); + let vfile = std::fs::File::open(dir.join("votes"))?; + for liner in std::io::BufReader::new(vfile).lines() { + let line = liner?; + if let Some((voter, datum)) = line.split_once(' ') { + if voter.len() == COOKIE_LENGTH { + if let Some((vote, candidate)) = datum.split_once(' ') { + if vote == "0" { + if let Some(entry) = tally.get_mut(candidate) { + entry.remove(voter); + } + } else if vote == "1" { + tally + .entry(candidate.to_owned()) + .or_default() + .insert(voter.to_owned()); + } + } + } + } + } + Ok(tally) +} + +fn make_random_id() -> [u8; COOKIE_LENGTH] { + let mut id = [0; COOKIE_LENGTH]; + for i in 0..COOKIE_LENGTH { + while !(b'A'..=b'Z').contains(&id[i]) + && !(b'a'..=b'z').contains(&id[i]) + && !(b'0'..=b'9').contains(&id[i]) + { + id[i] = random() + } + } + id +} + +fn set_cookie(mut response: cgi::Response, path: &str) -> Result { + response.headers_mut().append( + cgi::http::header::SET_COOKIE, + cgi::http::header::HeaderValue::from_bytes( + &[ + COOKIE_NAME, + b"=", + &make_random_id(), + b"; Secure HttpOnly SameSite=Strict Max-Age=30000000 Path=", + path.as_bytes(), + ] + .concat(), + ) + .map_err(|_| cgi::text_response(503, "Couldn't make cookie"))?, + ); + Ok(response) +} + +const HTML_HEADER: &str = " + + + + Vote! + + + + + + + + + + "; +const HTML_FOOTER: &str = " +

Count	Vote	Candidate

+ +"; + +fn supports(tally: &HashMap>, me: &str, candidate: &str) -> bool { + tally + .get(candidate) + .map(|supporters| supporters.contains(me)) + .unwrap_or(false) +} + fn prompt_for_vote(dir: PathBuf, request: cgi::Request) -> Result { - Err(cgi::text_response(503, "Not Implemented")) + let voter = get_voter(&request); + let me = if let Ok(id) = voter { + std::str::from_utf8(id).ok() + } else { + None + }; + let tally = + tally_votes(dir.clone()).map_err(|_| cgi::text_response(503, "Couldn't tally votes"))?; + let cfile = std::fs::File::open(dir.join("candidates")) + .map_err(|_| cgi::text_response(503, "No candidates"))?; + let mut response = cgi::html_response( + 200, + std::iter::once(Ok(HTML_HEADER.to_owned())) + .chain(std::io::BufReader::new(cfile).lines().map(|rc| { + rc.map(|c| { + let count = tally + .get(&c) + .map(|supporters| supporters.len()) + .unwrap_or(0); + let checked = if me.map(|me| supports(&tally, me, &c)).unwrap_or(false) { + "checked" + } else { + "" + }; + format!( + " + {count} + + {c} + " + ) + }) + })) + .chain(std::iter::once(Ok(HTML_FOOTER.to_owned()))) + .collect::>() + .map_err(|_| cgi::text_response(503, "Missing candidates"))?, + ); + if voter.is_err() { + response = set_cookie(response, request.uri().path())? + } + Ok(response) +} + +fn write_vote(dir: PathBuf, voter: &[u8], vote: &[u8]) -> std::io::Result<()> { + let datum = [voter, b" ", vote, b"\n"].concat(); + let vpath = dir.join("votes"); + let vfile = std::fs::File::options() + .append(true) + .create(true) + .open(vpath)?; + let mut vlock = fd_lock::RwLock::new(vfile); + vlock.write()?.write(&datum)?; + Ok(()) } fn record_vote(dir: PathBuf, request: cgi::Request) -> Result { - Err(cgi::text_response(503, "Not Implemented")) + let body = request.body(); + // Valid votes look like "0 foo" or "1 bar" + if body.len() < 3 + || (body[0] != b'0' && body[0] != b'1') + || body[1] != b' ' + || body.contains(&b'\n') + { + return Err(cgi::text_response(415, "Invalid vote")); + } + write_vote(dir, &get_voter(&request)?, body) + .map_err(|_| cgi::text_response(503, "Couldn't record vote"))?; + Ok(cgi::text_response(200, "Vote recorded")) +} + +fn strip_body(mut response: cgi::Response) -> cgi::Response { + response.body_mut().clear(); + response } fn respond(request: cgi::Request) -> Result { let dir = validate_path(request.uri().path())?; match request.method() { + &cgi::http::Method::HEAD => prompt_for_vote(dir, request).map(strip_body), &cgi::http::Method::GET => prompt_for_vote(dir, request), - &cgi::http::Method::POST => record_vote(dir, request), + &cgi::http::Method::PUT => record_vote(dir, request), _ => Err(cgi::text_response(405, "Huh?")), } }