Still a WIP: need to use async reqwest to respect the global context of usage (reqwest::blocking is using async inside so it does not really sync whatever)

src/lib.rs

@@ -1,18 +1,14 @@
 // std
 use std::{
-    path::Path,
     borrow::Cow,
     collections::HashMap,
-    io::{stdin, copy},
+    io::stdin,
     fmt,
-    fs::{read_to_string, write, create_dir_all, File, remove_file},
+    fs::{read_to_string, write},
     error::Error,
+    sync::{Arc, Mutex},
 };
 
-//tokio
-use tokio::runtime::Runtime;
-use tokio_compat_02::FutureExt;
-
 // toml
 use serde::Deserialize;
 
@@ -37,34 +33,45 @@ use elefren::{
 };
 
 // reqwest
-use reqwest::blocking::Client;
+use reqwest::Url;
+
+// tokio
+use tokio::{
+    io::copy,
+    fs::{File, create_dir_all, remove_file},
+    sync::mpsc,
+};
 
 // htmlescape
 use htmlescape::decode_html;
 
+// log
+use log::{info, warn, error, debug};
+
 /**********
  * Generic usage functions
 ***********/
 /*
  * Those functions are related to the Twitter side of things
  */
-/// Read last tweet id from a file
+/// Reads last tweet id from a file
 fn read_state(s: &str) -> Option<u64> {
     let state = read_to_string(s);
 
     if let Ok(s) = state {
+        debug!("Last Tweet ID (from file): {}", &s);
         return s.parse::<u64>().ok();
     }
 
     None
 }
 
-/// Write last treated tweet id to a file
+/// Writes last treated tweet id to a file
 fn write_state(f: &str, s: u64) -> Result<(), std::io::Error> {
     write(f, format!("{}", s))
 }
 
-/// Get twitter oauth2 token
+/// Gets Twitter oauth2 token
 fn get_oauth2_token(config: &Config) -> Token {
     let con_token = KeyPair::new(String::from(&config.twitter.consumer_key), String::from(&config.twitter.consumer_secret));
     let access_token = KeyPair::new(String::from(&config.twitter.access_key), String::from(&config.twitter.access_secret));
@@ -75,19 +82,18 @@ fn get_oauth2_token(config: &Config) -> Token {
     }
 }
 
-/// Get twitter user timeline
-fn get_user_timeline(config: &Config, token: Token, lid: Option<u64>) -> Result<Vec<Tweet>, Box<dyn Error>> {
+/// Gets Twitter user timeline
+async fn get_user_timeline(config: &Config, token: Token, lid: Option<u64>) -> Result<Vec<Tweet>, Box<dyn Error>> {
     // fix the page size to 200 as it is the maximum Twitter authorizes
-    let rt = Runtime::new()?;
-    let (_timeline, feed) = rt.block_on(user_timeline(UserID::from(String::from(&config.twitter.username)), true, false, &token)
+    let (_, feed) = user_timeline(UserID::from(String::from(&config.twitter.username)), true, false, &token)
                 .with_page_size(200)
                 .older(lid)
-                .compat())?;
+                .await?;
 
     Ok(feed.to_vec())
 }
 
-/// decode urls from UrlEntities
+/// Decodes urls from UrlEntities
 fn decode_urls(urls: &Vec<UrlEntity>) -> HashMap<String, String> {
     let mut decoded_urls = HashMap::new();
 
@@ -101,6 +107,8 @@ fn decode_urls(urls: &Vec<UrlEntity>) -> HashMap<String, String> {
     decoded_urls
 }
 
+/// Decodes the Twitter mention to something that will make sense once Twitter has joined the
+/// Fediverse
 fn twitter_mentions(ums: &Vec<MentionEntity>) -> HashMap<String, String> {
     let mut decoded_mentions = HashMap::new();
 
@@ -111,18 +119,18 @@ fn twitter_mentions(ums: &Vec<MentionEntity>) -> HashMap<String, String> {
     decoded_mentions
 }
 
-/// Retrieve a single media from a tweet and store it in a temporary file
-fn get_tweet_media(m: &MediaEntity, t: &str) -> Result<String, Box<dyn Error>> {
+/// Retrieves a single media from a tweet and store it in a temporary file
+async fn get_tweet_media(m: &MediaEntity, t: &str) -> Result<String, Box<dyn Error>> {
     match m.media_type {
         MediaType::Photo => {
-            return cache_media(&m.media_url_https, t);
+            return cache_media(&m.media_url_https, t).await;
         },
         _ => {
             match &m.video_info {
                 Some(v) => {
                     for variant in &v.variants {
                         if variant.content_type == "video/mp4" {
-                            return cache_media(&variant.url, t);
+                            return cache_media(&variant.url, t).await;
                         }
                     }
                     return Err(Box::new(ScootalooError::new(format!("Media Type for {} is video but no mp4 file URL is available", &m.url).as_str())));
@@ -138,7 +146,7 @@ fn get_tweet_media(m: &MediaEntity, t: &str) -> Result<String, Box<dyn Error>> {
 /*
  * Those functions are related to the Mastodon side of things
  */
-/// Get Mastodon Data
+/// Gets Mastodon Data
 fn get_mastodon_token(masto: &MastodonConfig) -> Mastodon {
     let data = Data {
         base: Cow::from(String::from(&masto.base)),
@@ -151,7 +159,7 @@ fn get_mastodon_token(masto: &MastodonConfig) -> Mastodon {
     Mastodon::from(data)
 }
 
-/// build toot text from tweet
+/// Builds toot text from tweet
 fn build_basic_status(tweet: &Tweet) -> Result<String, Box<dyn Error>> {
     let mut toot = String::from(&tweet.text);
 
@@ -177,35 +185,40 @@ fn build_basic_status(tweet: &Tweet) -> Result<String, Box<dyn Error>> {
 /*
  * Generic private functions
  */
-fn cache_media(u: &str, t: &str) -> Result<String, Box<dyn Error>> {
+
+/// Gets and caches Twitter Media inside the determined temp dir
+async fn cache_media(u: &str, t: &str) -> Result<String, Box<dyn Error>> {
     // create dir
-    if !Path::new(t).is_dir() {
-        create_dir_all(t)?;
-    }
+    create_dir_all(t).await?;
 
     // get file
-    let client = Client::new();
-    let mut response = client.get(u).send()?;
+    let mut response = reqwest::get(u).await?;
 
     // create local file
-    let dest_filename = match response.url()
-                    .path_segments()
-                    .and_then(|segments| segments.last()) {
-                        Some(r) => r,
-                        None => {
-                            return Err(Box::new(ScootalooError::new(format!("Cannot determine the destination filename for {}", u).as_str())));
-                        },
-                    };
+    let url = Url::parse(u)?;
+    let dest_filename = url.path_segments().ok_or_else(|| Box::new(ScootalooError::new(format!("Cannot determine the destination filename for {}", u).as_str())))?
+                    .last().ok_or_else(|| Box::new(ScootalooError::new(format!("Cannot determine the destination filename for {}", u).as_str())))?;
 
     let dest_filepath = format!("{}/{}", t, dest_filename);
 
-    let mut dest_file = File::create(&dest_filepath)?;
+    let mut dest_file = File::create(&dest_filepath).await?;
 
-    copy(&mut response, &mut dest_file)?;
+    while let Some(chunk) = response.chunk().await? {
+        copy(&mut &*chunk, &mut dest_file).await?;
+    }
 
     Ok(dest_filepath)
 }
 
+/**********
+ * This is the struct that holds the Mastodon Media ID and the Twitter Media URL at the same Time
+**********/
+#[derive(Debug)]
+struct ScootalooSpawnResponse {
+    mastodon_media_id: String,
+    twitter_media_url: String,
+}
+
 /**********
  * local error handler
 **********/
@@ -287,7 +300,7 @@ pub fn parse_toml(toml_file: &str) -> Config {
 
 /// Generic register function
 /// As this function is supposed to be run only once, it will panic for every error it encounters
-/// Most of this function is a direct copy/paste of the official `mammut` crate
+/// Most of this function is a direct copy/paste of the official `elefren` crate
 pub fn register(host: &str) {
     let mut builder = App::builder();
     builder.client_name(Cow::from(String::from(env!("CARGO_PKG_NAME"))))
@@ -315,7 +328,8 @@ pub fn register(host: &str) {
 }
 
 /// This is where the magic happens
-pub fn run(config: Config) {
+#[tokio::main]
+pub async fn run(config: Config) {
     // retrieve the last tweet ID for the username
     let last_tweet_id = read_state(&config.scootaloo.last_tweet_path);
 
@@ -323,16 +337,18 @@ pub fn run(config: Config) {
     let token = get_oauth2_token(&config);
 
     // get Mastodon instance
-    let mastodon = get_mastodon_token(&config.mastodon);
+    let mastodon = Arc::new(Mutex::new(get_mastodon_token(&config.mastodon)));
 
     // get user timeline feed (Vec<tweet>)
-    let mut feed = get_user_timeline(&config, token, last_tweet_id).unwrap_or_else(|e|
+    let mut feed = get_user_timeline(&config, token, last_tweet_id)
+        .await
+        .unwrap_or_else(|e|
         panic!("Something went wrong when trying to retrieve {}’s timeline: {}", &config.twitter.username, e)
     );
 
     // empty feed -> exiting
     if feed.is_empty() {
-        println!("Nothing to retrieve since last time, exiting…");
+        info!("Nothing to retrieve since last time, exiting…");
         return;
     }
 
@@ -340,10 +356,12 @@ pub fn run(config: Config) {
     feed.reverse();
 
     for tweet in &feed {
+        debug!("Treating Tweet {} inside feed", tweet.id);
         // determine if the tweet is part of a thread (response to self) or a standard response
         if let Some(r) =  &tweet.in_reply_to_screen_name {
                 if &r.to_lowercase() != &config.twitter.username.to_lowercase() {
                     // we are responding not threading
+                    info!("Tweet is a direct response, skipping");
                     continue;
                 }
         };
@@ -352,7 +370,7 @@ pub fn run(config: Config) {
         let mut status_text = match build_basic_status(tweet) {
             Ok(t) => t,
             Err(e) => {
-                println!("Could not create status from tweet {}: {}", tweet.id ,e);
+                error!("Could not create status from tweet {}: {}", tweet.id ,e);
                 continue;
             },
         };
@@ -361,35 +379,64 @@ pub fn run(config: Config) {
 
         // reupload the attachments if any
         if let Some(m) = &tweet.extended_entities {
+            let (tx, mut rx) = mpsc::channel(4);
+
             for media in &m.media {
-                let local_tweet_media_path = match get_tweet_media(&media, &config.scootaloo.cache_path) {
-                    Ok(m) => m,
-                    Err(e) => {
-                        println!("Cannot get tweet media for {}: {}", &media.url, e);
-                        continue;
-                    },
-                };
+                // creating a new tx for this initial loop
+                let tx = tx.clone();
+                // creating a new mastodon from the original mutex
+                let mastodon = mastodon.clone();
+                // unfortunately for this to be thread safe, we need to clone a lot of structures
+                let media = media.clone();
+                let cache_path = config.scootaloo.cache_path.clone();
 
-                let mastodon_media_ids = match mastodon.media(Cow::from(String::from(&local_tweet_media_path))) {
-                    Ok(m) => {
-                        remove_file(&local_tweet_media_path).unwrap_or_else(|e|
-                            println!("Attachment for {} has been upload, but I’m unable to remove the existing file: {}", &local_tweet_media_path, e)
-                        );
-                        m.id
-                    },
-                    Err(e) => {
-                        println!("Cannot attach media {} to Mastodon Instance: {}", &local_tweet_media_path, e);
-                        continue;
+                tokio::spawn(async move {
+                    debug!("Spawing new async thread to treat {}", &media.id);
+                    let local_tweet_media_path = match get_tweet_media(&media, &cache_path).await {
+                        Ok(m) => m,
+                        Err(e) => {
+                            // we could have panicked here, no issue, but I’m not confortable using
+                            // that for now
+                            warn!("Cannot get tweet media for {}: {}", &media.url, e);
+                            return;
+                        }
+                    };
+
+                    // we cannot directly do all the stuff inside here because mastodon lock can
+                    // live outside this
+                    let mas_result = mastodon.lock().unwrap().media(Cow::from(String::from(&local_tweet_media_path)));
+
+                    match mas_result {
+                        Ok(m) => {
+                            remove_file(&local_tweet_media_path).await.unwrap_or_else(|e|
+                                warn!("Attachment {} has been uploaded but I’m unable to remove the existing file: {}", &local_tweet_media_path, e)
+                            );
+                            // we can unwrap here because we’re in a thread
+                            tx.send(ScootalooSpawnResponse {
+                                mastodon_media_id: m.id.clone(),
+                                twitter_media_url: local_tweet_media_path.clone()
+                            }).await.unwrap();
+                        },
+                        Err(e) => {
+                            error!("Attachment {} cannot be uploaded to Mastodon Instance: {}", &local_tweet_media_path, e);
+                        }
                     }
-                };
+                });
+            }
 
-                status_medias.push(mastodon_media_ids);
+            // dropping the last tx otherwise recv() will wait indefinitely
+            drop(tx);
 
-                // last step, removing the reference to the media from with the toot’s text
-                status_text = status_text.replace(&media.url, "");
+            while let Some(i) = rx.recv().await {
+                // pushes the media into the media vec
+                status_medias.push(i.mastodon_media_id);
+                // removes the URL from the original Tweet text
+                status_text = status_text.replace(&i.twitter_media_url, "");
             }
         }
+        // finished reuploading attachments, now let’s do the toot baby!
 
+        debug!("Building corresponding Mastodon status");
         let status = StatusBuilder::new()
             .status(&status_text)
             .media_ids(status_medias)
@@ -397,7 +444,8 @@ pub fn run(config: Config) {
             .expect(format!("Cannot build status with text {}", &status_text).as_str());
 
         // publish status
-        mastodon.new_status(status).unwrap();
+        // again unwrap is safe here as we are in the main thread
+        mastodon.lock().unwrap().new_status(status).unwrap();
         // this will panic if it cannot publish the status, which is a good thing, it allows the
         // last_tweet gathered not to be written