use std::{
fs::{self, File, ReadDir},
io::{Read, Write},
path::{Path, PathBuf},
time::Duration,
};
use anyhow::{Result, bail};
use log::{debug, error};
use crate::http::{Agent, Connection, Url};
pub struct Cache {
path: PathBuf,
}
impl Cache {
const MAGIC: &str = concat!(env!("CARGO_PKG_NAME"), "\n");
const EXPIRATION_TIME: Duration = Duration::from_secs(48 * 60 * 60);
pub fn new(dir: &Option<String>, channel: &str, quality: &Option<String>) -> Option<Self> {
let (dir, quality) = (dir.as_ref()?, quality.as_ref()?);
match Self::read_dir(dir) {
Ok(iter) => {
for entry in iter {
let Ok(entry) = entry else {
continue;
};
Self::remove_if_stale(&entry.path());
}
}
Err(e) => {
error!("Failed to read playlist cache directory: {e}");
return None;
}
}
Some(Self {
path: format!("{dir}/{channel}-{quality}").into(),
})
}
pub fn get(&self, agent: &Agent) -> Option<Connection> {
debug!("Trying playlist cache: {}", self.path.display());
let mut file = Self::check_magic(&self.path)?;
let mut string = String::new();
file.read_to_string(&mut string).ok()?;
let url = string.into();
let Some(request) = agent.exists(&url) else {
Self::remove_cache(&self.path);
return None;
};
Some(Connection::new(url, request))
}
pub fn create(&self, url: &Url) {
debug!("Creating playlist cache: {}", self.path.display());
let file = File::create_new(&self.path);
if let Err(e) = file.and_then(|mut f| write!(f, "{}{url}", Self::MAGIC)) {
error!("Failed to create playlist cache: {e}");
}
}
fn read_dir(dir: &str) -> Result<ReadDir> {
let metadata = fs::metadata(dir)?;
if !metadata.is_dir() || metadata.permissions().readonly() {
bail!("Playlist cache path isn't a directory or is read only");
}
Ok(fs::read_dir(dir)?)
}
fn check_magic(path: &Path) -> Option<File> {
let mut file = File::open(path).ok()?;
let mut buf = [0u8; Self::MAGIC.len()];
file.read_exact(&mut buf).ok()?;
if buf != Self::MAGIC.as_bytes() {
return None;
}
Some(file)
}
fn remove_cache(path: &Path) {
debug!("Removing playlist cache: {}", path.display());
if let Err(e) = fs::remove_file(path) {
error!("Failed to remove playlist cache: {e}");
}
}
fn remove_if_stale(path: &Path) -> Option<()> {
Self::check_magic(path)?;
let metadata = fs::metadata(path).ok()?;
let modified = metadata.modified().ok().and_then(|t| t.elapsed().ok())?;
if metadata.is_file() && modified >= Self::EXPIRATION_TIME {
Self::remove_cache(path);
}
Some(())
}
}