git.scottworley.com Git - tattlekey/blob - server/src/main.rs

   1 // tattlekey: A one-key UDP keyboard
   2 // Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16
  17 use serde::Serialize;
  18 use std::collections::HashMap;
  19 use std::net::UdpSocket;
  20 use std::time::{Duration, SystemTime};
  21
  22 const MESSAGE_SIZE: usize = 12;
  23 const LOGFILENAME: &str = "log.csv";
  24
  25 #[derive(Eq, Debug, Hash, PartialEq, Serialize)]
  26 struct MessageKey {
  27     epoch: u32,
  28     device: u16,
  29     seq: u16,
  30 }
  31
  32 #[derive(Debug)]
  33 struct Message {
  34     key: MessageKey,
  35     t: SystemTime,
  36 }
  37
  38 impl From<&[u8; MESSAGE_SIZE]> for Message {
  39     fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
  40         let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
  41         Self {
  42             key: MessageKey {
  43                 epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
  44                 device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
  45                 seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
  46             },
  47             t: SystemTime::now() - Duration::new(ago.into(), 0),
  48         }
  49     }
  50 }
  51 impl TryFrom<&[u8]> for Message {
  52     type Error = std::array::TryFromSliceError;
  53     fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
  54         match <[u8; MESSAGE_SIZE]>::try_from(value) {
  55             Ok(correct_size) => Ok(Message::from(&correct_size)),
  56             Err(e) => Err(e),
  57         }
  58     }
  59 }
  60
  61 #[derive(Debug)]
  62 struct Range {
  63     start: SystemTime,
  64     end: SystemTime,
  65 }
  66 impl Range {
  67     fn new(t: &SystemTime) -> Self {
  68         Self { start: *t, end: *t }
  69     }
  70     fn contains(&self, t: &SystemTime) -> bool {
  71         t > &self.start && t < &self.end
  72     }
  73     fn extend(&mut self, t: &SystemTime) {
  74         if t < &self.start {
  75             self.start = *t;
  76         }
  77         if t > &self.end {
  78             self.end = *t;
  79         }
  80     }
  81 }
  82
  83 fn open_log_for_writing() -> csv::Writer<std::fs::File> {
  84     let log_file_exists = std::path::Path::new(LOGFILENAME).exists();
  85     let logfile = std::fs::OpenOptions::new()
  86         .create_new(!log_file_exists)
  87         .append(true)
  88         .open(LOGFILENAME)
  89         .expect("Coudln't open log file");
  90     csv::WriterBuilder::new()
  91         .has_headers(!log_file_exists)
  92         .from_writer(logfile)
  93 }
  94
  95 fn main() {
  96     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
  97     let mut presses = HashMap::<MessageKey, Range>::new();
  98     let mut log = open_log_for_writing();
  99     loop {
 100         let mut buf = [0; MESSAGE_SIZE];
 101         match socket.recv_from(&mut buf) {
 102             Err(e) => eprintln!("Didn't receive data: {e}"),
 103             Ok((number_of_bytes, src_addr)) => {
 104                 let filled_buf = &buf[..number_of_bytes];
 105                 if number_of_bytes != MESSAGE_SIZE {
 106                     eprintln!("Ignoring short message ({number_of_bytes}) from {src_addr}");
 107                     continue;
 108                 }
 109                 let message = Message::try_from(filled_buf).expect("I can't count");
 110                 log.serialize((&message.key, message.t))
 111                     .expect("Couldn't write log");
 112                 log.flush().expect("Couldn't flush log");
 113                 if let Some(r) = presses.get_mut(&message.key) {
 114                     if !r.contains(&message.t) {
 115                         r.extend(&message.t);
 116                     }
 117                 } else {
 118                     presses.insert(message.key, Range::new(&message.t));
 119                 }
 120             }
 121         }
 122     }
 123 }