4 ms·

I built an online RSS reader with Rust and WebAssembly

8 points by huydotnet 7y ago

huydotnet 7y ago
I built this as an experiment with Cloudflare's Worker Script. Here's a bit behind this app. - Frontend: Just few lines of code using Svelte - Backend: a Worker Script using Rust, here's how I do the RSS to JSON stuff: #[wasm_bindgen] pub fn parse(content: &str) -> String { let feed: Option<rss::Channel> = match content.parse::<Feed>().unwrap() { Feed::RSS(rss_feed) => Some(rss_feed), _ => None }; if feed.is_some() { let rss_feed = feed.unwrap(); let items: Vec<serde_json::Value> = rss_feed.items.iter().map(|item: &rss::Item| { return json!({ "title": item.title.as_ref(), "link": item.link.as_ref(), "date": item.pub_date.as_ref(), }); }).collect(); return json!({ "feed": items }).to_string(); } return "".to_string(); } The only overhead, I think, is the part that I have to actually write the code to fetch RSS content in JavaScript (worker.js), as fool as you can imagine: const url = request.url.match(/url=(.*)/); if (url && url.length > 1) { const feeds = url[1].split(','); let promises = feeds.map(async url => { const res = await fetch(url); const text = await res.text(); const json = JSON.parse(parse(text)); return json && json.feed || []; }); let result = await Promise.all(promises); let combined = result.reduce((arr, feed) => { arr = arr.concat(feed); return arr; }, []); return new Response(JSON.stringify({ "items": combined }), {status: 200, headers: { 'Content-Type': 'application/json' }}); } If network libraries such as `reqwest`, and some date parser libraries like `chrono` already supported WASM, I'd be able to skip this JS step for good. Deployed on Cloudflare using Wrangler CLI, I'm still on my free plan, and I hope I won't hit a 100k requests/day limit anytime soon.
rahuldottech 7y ago
This is neat! I'm definitely going to be making use of this :)
- huydotnet 7y ago
  thank you :D
- dplgk 7y ago
  Do you have a current rss reader you use? Will you be moving all your feeds to this reader?
lostmsu 7y ago
It is cool, but it is not really an application in the expected sense. It is just a 2 stage RSS to HTML converter (e.g. RSS->JSON server, JSON->HTML client). Not sure why not make just do RSS->HTML directly on the server. Obviously, does not track read state or sync, or anything else basically.

8 points by huydotnet 7y ago

I built this as an experiment with Cloudflare's Worker Script. Here's a bit behind this app. - Frontend: Just few lines of code using Svelte - Backend: a Worker Script using Rust, here's how I do the RSS to JSON stuff: #[wasm_bindgen] pub fn parse(content: &str) -> String { let feed: Option<rss::Channel> = match content.parse::<Feed>().unwrap() { Feed::RSS(rss_feed) => Some(rss_feed), _ => None }; if feed.is_some() { let rss_feed = feed.unwrap(); let items: Vec<serde_json::Value> = rss_feed.items.iter().map(|item: &rss::Item| { return json!({ "title": item.title.as_ref(), "link": item.link.as_ref(), "date": item.pub_date.as_ref(), }); }).collect(); return json!({ "feed": items }).to_string(); } return "".to_string(); } The only overhead, I think, is the part that I have to actually write the code to fetch RSS content in JavaScript (worker.js), as fool as you can imagine: const url = request.url.match(/url=(.*)/); if (url && url.length > 1) { const feeds = url[1].split(','); let promises = feeds.map(async url => { const res = await fetch(url); const text = await res.text(); const json = JSON.parse(parse(text)); return json && json.feed || []; }); let result = await Promise.all(promises); let combined = result.reduce((arr, feed) => { arr = arr.concat(feed); return arr; }, []); return new Response(JSON.stringify({ "items": combined }), {status: 200, headers: { 'Content-Type': 'application/json' }}); } If network libraries such as `reqwest`, and some date parser libraries like `chrono` already supported WASM, I'd be able to skip this JS step for good. Deployed on Cloudflare using Wrangler CLI, I'm still on my free plan, and I hope I won't hit a 100k requests/day limit anytime soon.

rahuldottech 7y ago

This is neat! I'm definitely going to be making use of this :)

huydotnet 7y ago
thank you :D
dplgk 7y ago
Do you have a current rss reader you use? Will you be moving all your feeds to this reader?

lostmsu 7y ago

It is cool, but it is not really an application in the expected sense. It is just a 2 stage RSS to HTML converter (e.g. RSS->JSON server, JSON->HTML client). Not sure why not make just do RSS->HTML directly on the server. Obviously, does not track read state or sync, or anything else basically.