Add EntryCrawler that uses readability lib

Actors delegating to actors baybeeee

src/actors/entry_crawler.rs

@@ -0,0 +1,180 @@
+use std::fmt::{self, Display, Formatter};
+use std::fs;
+use std::path::Path;
+use std::sync::Arc;
+
+use bytes::Buf;
+use feed_rs::parser;
+use readability::extractor;
+use reqwest::Client;
+use sqlx::PgPool;
+use tokio::sync::{broadcast, mpsc, Mutex};
+use tracing::{info, instrument};
+use url::Url;
+
+use crate::config::Config;
+use crate::models::entry::{update_entry, CreateEntry, Entry};
+use crate::models::feed::{upsert_feed, CreateFeed, Feed};
+
+/// The `EntryCrawler` actor fetches an entry url, extracts the content, and saves the content to
+/// the file system and any associated metadata to the database.
+///
+/// It receives `EntryCrawlerMessage` messages via the `receiver` channel. It communicates back to
+/// the sender of those messages via the `respond_to` channel on the `EntryCrawlerMessage`.
+///
+/// `EntryCrawler` should not be instantiated directly. Instead, use the `EntryCrawlerHandle`.
+struct EntryCrawler {
+    receiver: mpsc::Receiver<EntryCrawlerMessage>,
+    pool: PgPool,
+    client: Client,
+    content_dir: String,
+}
+
+#[derive(Debug)]
+enum EntryCrawlerMessage {
+    Crawl {
+        entry: Entry,
+        respond_to: broadcast::Sender<EntryCrawlerHandleMessage>,
+    },
+}
+
+impl Display for EntryCrawlerMessage {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        match self {
+            EntryCrawlerMessage::Crawl { entry, .. } => write!(f, "Crawl({})", entry.url),
+        }
+    }
+}
+
+/// An error type that enumerates possible failures during a crawl and is cloneable and can be sent
+/// across threads (does not reference the originating Errors which are usually not cloneable).
+#[derive(thiserror::Error, Debug, Clone)]
+pub enum EntryCrawlerError {
+    #[error("invalid entry url: {0}")]
+    InvalidUrl(String),
+    #[error("failed to fetch entry: {0}")]
+    FetchError(String),
+    #[error("failed to extract content for entry: {0}")]
+    ExtractError(String),
+    #[error("failed to create entry: {0}")]
+    CreateEntryError(String),
+    #[error("failed to save entry content: {0}")]
+    SaveContentError(String),
+}
+pub type EntryCrawlerResult<T, E = EntryCrawlerError> = ::std::result::Result<T, E>;
+
+impl EntryCrawler {
+    fn new(
+        receiver: mpsc::Receiver<EntryCrawlerMessage>,
+        pool: PgPool,
+        client: Client,
+        content_dir: String,
+    ) -> Self {
+        EntryCrawler {
+            receiver,
+            pool,
+            client,
+            content_dir,
+        }
+    }
+
+    #[instrument(skip_all, fields(entry = %entry.url))]
+    async fn crawl_entry(&self, entry: Entry) -> EntryCrawlerResult<Entry> {
+        info!("Fetching and parsing entry");
+        let content_dir = Path::new(&self.content_dir);
+        let url =
+            Url::parse(&entry.url).map_err(|_| EntryCrawlerError::InvalidUrl(entry.url.clone()))?;
+        let bytes = self
+            .client
+            .get(url.clone())
+            .send()
+            .await
+            .map_err(|_| EntryCrawlerError::FetchError(entry.url.clone()))?
+            .bytes()
+            .await
+            .map_err(|_| EntryCrawlerError::FetchError(entry.url.clone()))?;
+        let article = extractor::extract(&mut bytes.reader(), &url)
+            .map_err(|_| EntryCrawlerError::ExtractError(entry.url.clone()))?;
+        let id = entry.entry_id;
+        // TODO: update entry with scraped data
+        // if let Some(date) = article.date {
+        //     // prefer scraped date over rss feed date
+        //     let mut updated_entry = entry.clone();
+        //     updated_entry.published_at = date;
+        //     entry = update_entry(&self.pool, updated_entry)
+        //         .await
+        //         .map_err(|_| EntryCrawlerError::CreateEntryError(entry.url.clone()))?;
+        // };
+        fs::write(content_dir.join(format!("{}.html", id)), article.content)
+            .map_err(|_| EntryCrawlerError::SaveContentError(entry.url.clone()))?;
+        fs::write(content_dir.join(format!("{}.txt", id)), article.text)
+            .map_err(|_| EntryCrawlerError::SaveContentError(entry.url.clone()))?;
+        Ok(entry)
+    }
+
+    #[instrument(skip_all, fields(msg = %msg))]
+    async fn handle_message(&mut self, msg: EntryCrawlerMessage) {
+        match msg {
+            EntryCrawlerMessage::Crawl { entry, respond_to } => {
+                let result = self.crawl_entry(entry).await;
+                // ignore the result since the initiator may have cancelled waiting for the
+                // response, and that is ok
+                let _ = respond_to.send(EntryCrawlerHandleMessage::Entry(result));
+            }
+        }
+    }
+
+    #[instrument(skip_all)]
+    async fn run(&mut self) {
+        info!("starting entry crawler");
+        while let Some(msg) = self.receiver.recv().await {
+            self.handle_message(msg).await;
+        }
+    }
+}
+
+/// The `EntryCrawlerHandle` is used to initialize and communicate with a `EntryCrawler` actor.
+///
+/// The `EntryCrawler` actor fetches a feed url, parses it, and saves it to the database. It runs
+/// as a separate asynchronous task from the main web server and communicates via channels.
+#[derive(Clone)]
+pub struct EntryCrawlerHandle {
+    sender: mpsc::Sender<EntryCrawlerMessage>,
+}
+
+/// The `EntryCrawlerHandleMessage` is the response to a `EntryCrawlerMessage` sent to the
+/// `EntryCrawlerHandle`.
+///
+/// `EntryCrawlerHandleMessage::Entry` contains the result of crawling an entry url.
+#[derive(Clone)]
+pub enum EntryCrawlerHandleMessage {
+    Entry(EntryCrawlerResult<Entry>),
+}
+
+impl EntryCrawlerHandle {
+    /// Creates an async actor task that will listen for messages on the `sender` channel.
+    pub fn new(pool: PgPool, client: Client, content_dir: String) -> Self {
+        let (sender, receiver) = mpsc::channel(8);
+        let mut crawler = EntryCrawler::new(receiver, pool, client, content_dir);
+        tokio::spawn(async move { crawler.run().await });
+
+        Self { sender }
+    }
+
+    /// Sends a `EntryCrawlerMessage::Crawl` message to the running `EntryCrawler` actor.
+    ///
+    /// Listen to the result of the crawl via the returned `broadcast::Receiver`.
+    pub async fn crawl(&self, entry: Entry) -> broadcast::Receiver<EntryCrawlerHandleMessage> {
+        let (sender, receiver) = broadcast::channel(8);
+        let msg = EntryCrawlerMessage::Crawl {
+            entry,
+            respond_to: sender,
+        };
+
+        self.sender
+            .send(msg)
+            .await
+            .expect("entry crawler task has died");
+        receiver
+    }
+}

src/actors/feed_crawler.rs

@@ -1,18 +1,21 @@
 use std::fmt::{self, Display, Formatter};
 
+use chrono::Utc;
 use feed_rs::parser;
 use reqwest::Client;
 use sqlx::PgPool;
 use tokio::sync::{broadcast, mpsc};
-use tracing::{info, instrument};
+use tracing::log::warn;
+use tracing::{info, info_span, instrument};
 use url::Url;
 
-use crate::models::entry::Entry;
+use crate::actors::entry_crawler::EntryCrawlerHandle;
+use crate::models::entry::{upsert_entries, CreateEntry, Entry};
 use crate::models::feed::{upsert_feed, CreateFeed, Feed};
 
 /// The `FeedCrawler` actor fetches a feed url, parses it, and saves it to the database.
 ///
-/// It receives `FeedCrawlerMessage` messages via the `receiver` channel. It communicates back to 
+/// It receives `FeedCrawlerMessage` messages via the `receiver` channel. It communicates back to
 /// the sender of those messages via the `respond_to` channel on the `FeedCrawlerMessage`.
 ///
 /// `FeedCrawler` should not be instantiated directly. Instead, use the `FeedCrawlerHandle`.
@@ -20,6 +23,7 @@ struct FeedCrawler {
     receiver: mpsc::Receiver<FeedCrawlerMessage>,
     pool: PgPool,
     client: Client,
+    content_dir: String,
 }
 
 #[derive(Debug)]
@@ -38,7 +42,7 @@ impl Display for FeedCrawlerMessage {
     }
 }
 
-/// An error type that enumerates possible failures during a crawl and is cloneable and can be sent 
+/// An error type that enumerates possible failures during a crawl and is cloneable and can be sent
 /// across threads (does not reference the originating Errors which are usually not cloneable).
 #[derive(thiserror::Error, Debug, Clone)]
 pub enum FeedCrawlerError {
@@ -48,15 +52,23 @@ pub enum FeedCrawlerError {
     ParseError(Url),
     #[error("failed to create feed: {0}")]
     CreateFeedError(Url),
+    #[error("failed to create feed entries: {0}")]
+    CreateFeedEntriesError(Url),
 }
 pub type FeedCrawlerResult<T, E = FeedCrawlerError> = ::std::result::Result<T, E>;
 
 impl FeedCrawler {
-    fn new(receiver: mpsc::Receiver<FeedCrawlerMessage>, pool: PgPool, client: Client) -> Self {
+    fn new(
+        receiver: mpsc::Receiver<FeedCrawlerMessage>,
+        pool: PgPool,
+        client: Client,
+        content_dir: String,
+    ) -> Self {
         FeedCrawler {
             receiver,
             pool,
             client,
+            content_dir,
         }
     }
 
@@ -87,6 +99,40 @@ impl FeedCrawler {
         .await
         .map_err(|_| FeedCrawlerError::CreateFeedError(url.clone()))?;
         info!(%feed.feed_id, "upserted feed");
+
+        let mut payload = Vec::with_capacity(parsed_feed.entries.len());
+        for entry in parsed_feed.entries {
+            let entry_span = info_span!("entry", id = entry.id);
+            let _entry_span_guard = entry_span.enter();
+            if let Some(link) = entry.links.get(0) {
+                // if no scraped or feed date is available, fallback to the current time
+                let published_at = entry.published.unwrap_or_else(Utc::now);
+                let entry = CreateEntry {
+                    title: entry.title.map(|t| t.content),
+                    url: link.href.clone(),
+                    description: entry.summary.map(|s| s.content),
+                    feed_id: feed.feed_id,
+                    published_at,
+                };
+                payload.push(entry);
+            } else {
+                warn!("Skipping feed entry with no links");
+            }
+        }
+        let entries = upsert_entries(&self.pool, payload)
+            .await
+            .map_err(|_| FeedCrawlerError::CreateFeedEntriesError(url.clone()))?;
+        info!("Created {} entries", entries.len());
+
+        for entry in entries {
+            let entry_crawler = EntryCrawlerHandle::new(
+                self.pool.clone(),
+                self.client.clone(),
+                self.content_dir.clone(),
+            );
+            // TODO: ignoring this receiver for the time being, pipe through events eventually
+            let _ = entry_crawler.crawl(entry).await;
+        }
         Ok(feed)
     }
 
@@ -124,7 +170,7 @@ pub struct FeedCrawlerHandle {
 /// `FeedCrawlerHandle`.
 ///
 /// `FeedCrawlerHandleMessage::Feed` contains the result of crawling a feed url.
-/// `FeedCrawlerHandleMessage::Entry` contains the result of crawling an entry url.
+/// `FeedCrawlerHandleMessage::Entry` contains the result of crawling an entry url within the feed.
 #[derive(Clone)]
 pub enum FeedCrawlerHandleMessage {
     Feed(FeedCrawlerResult<Feed>),
@@ -133,9 +179,9 @@ pub enum FeedCrawlerHandleMessage {
 
 impl FeedCrawlerHandle {
     /// Creates an async actor task that will listen for messages on the `sender` channel.
-    pub fn new(pool: PgPool, client: Client) -> Self {
+    pub fn new(pool: PgPool, client: Client, content_dir: String) -> Self {
         let (sender, receiver) = mpsc::channel(8);
-        let mut crawler = FeedCrawler::new(receiver, pool, client);
+        let mut crawler = FeedCrawler::new(receiver, pool, client, content_dir);
         tokio::spawn(async move { crawler.run().await });
 
         Self { sender }

src/actors/mod.rs

@@ -1 +1,2 @@
+pub mod entry_crawler;
 pub mod feed_crawler;