snix/web/planet-mars/src/feed_store.rs
2025-01-12 20:13:18 +02:00

185 lines
5.4 KiB
Rust

use anyhow::bail;
use anyhow::Result;
use feed_rs::model::Entry;
use feed_rs::model::Feed;
use ron::ser::{to_string_pretty, PrettyConfig};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::convert::AsRef;
use std::fs;
use std::io::BufReader;
use std::path::PathBuf;
use ureq::http::HeaderMap;
use ureq::http::Response;
use ureq::Body;
use url::Url;
#[derive(Deserialize, Serialize, Default)]
pub struct FetchData {
pub etag: String,
pub last_modified: String,
}
pub struct FeedStore {
pub dir: PathBuf,
}
impl FeedStore {
pub fn new(dir: &str) -> Self {
Self {
dir: super::to_checked_pathbuf(dir),
}
}
fn slugify_url(url: &Url) -> Result<String> {
let Some(domain) = url.domain() else {
bail!("Url has no domain: '{url}'.")
};
let query = url.query().unwrap_or("");
Ok(slug::slugify(format!("{domain}{}{query}", url.path())))
}
fn generic_path(&self, url: &Url, ext: &str) -> Result<String> {
Ok(format!(
"{}/{}{ext}",
self.dir.display(),
Self::slugify_url(url)?
))
}
fn feed_path(&self, url: &Url) -> Result<String> {
self.generic_path(url, "")
}
fn fetchdata_path(&self, url: &Url) -> Result<String> {
self.generic_path(url, ".toml")
}
pub fn load_fetchdata(&self, url: &Url) -> Result<FetchData> {
let path = self.fetchdata_path(url)?;
if !fs::exists(path.clone())? {
return Ok(FetchData::default());
}
Ok(toml::from_str(&fs::read_to_string(path)?)?)
}
fn has_changed(&self, url: &Url, new_feed: &Feed) -> Result<bool> {
let Some(old_feed) = self.load_feed(url, false)? else {
return Ok(true);
};
let mut old_iter = old_feed.entries.iter();
for new in &new_feed.entries {
let Some(old) = old_iter.next() else {
return Ok(true);
};
if old != new {
return Ok(true);
}
}
// ignoring any entries left in old_iter
Ok(false)
}
fn write<P: AsRef<std::path::Path> + std::fmt::Display, C: AsRef<[u8]>>(
path: P,
contents: C,
) -> std::io::Result<()> {
if fs::exists(&path)? {
fs::rename(&path, format!("{path}.backup"))?;
}
fs::write(path, contents)
}
pub fn store(&self, url: &Url, mut response: Response<Body>) -> Result<bool> {
let headers = response.headers();
let fetchdata = FetchData {
etag: hv(headers, "etag"),
last_modified: hv(headers, "last_modified"),
};
let body = response.body_mut().with_config().read_to_vec()?;
let feed = match feed_rs::parser::parse(body.as_slice()) {
Ok(f) => f,
Err(e) => {
warn!("Error when parsing feed for {url}: {e:?}");
return Ok(false);
}
};
if !self.has_changed(url, &feed)? {
return Ok(false);
}
debug!("Storing feed for {url}.");
// todo don't serialize to string but to writer
Self::write(
self.generic_path(url, ".ron")?,
to_string_pretty(&feed, PrettyConfig::default())?,
)?;
Self::write(self.feed_path(url)?, body)?;
Self::write(self.fetchdata_path(url)?, toml::to_string(&fetchdata)?)?;
Ok(true)
}
fn load_feed(&self, url: &Url, sanitize: bool) -> Result<Option<Feed>> {
let parser = feed_rs::parser::Builder::new()
.sanitize_content(sanitize)
.build();
let path = self.feed_path(url)?;
if !fs::exists(path.clone())? {
return Ok(None);
}
let file = fs::File::open(path)?;
Ok(Some(parser.parse(BufReader::new(file))?))
}
pub fn collect(
&self,
feed_configs: &Vec<super::FeedConfig>,
max_entries: usize,
) -> (HashMap<String, Feed>, Vec<Entry>) {
let mut feeds = HashMap::new();
let mut entries = Vec::new();
for feed_config in feed_configs {
let mut feed = match (|| {
let url = Url::parse(&feed_config.url)?;
self.load_feed(&url, true)
})() {
Err(e) => {
warn!(
"Problem parsing feed file for feed {}: {e:?}",
feed_config.url
);
continue;
}
Ok(None) => continue,
Ok(Some(f)) => f,
};
for entry in &mut feed.entries {
entry.source = Some(feed_config.url.clone());
}
entries.append(&mut std::mem::take(&mut feed.entries));
feeds.insert(feed_config.url.clone(), feed);
// optimization to reduce memory usage
if entries.len() > 4 * max_entries {
entries = trim_entries(entries, max_entries);
}
}
(feeds, trim_entries(entries, max_entries))
}
}
fn trim_entries(mut entries: Vec<Entry>, max_entries: usize) -> Vec<Entry> {
entries.sort_by_key(|e| std::cmp::Reverse(e.updated.or(e.published).unwrap_or_default()));
entries.truncate(max_entries);
entries
}
fn hv(headers: &HeaderMap, key: &str) -> String {
match headers.get(key) {
Some(hv) => hv.to_str().unwrap_or_default().to_string(),
_ => "".to_string(),
}
}