Dereferences Twitter short url (t.co) to the real URLs + add Error handling (not used at the moment)

src/lib.rs

@@ -1,7 +1,9 @@
 // std
 use std::{
     borrow::Cow,
+    collections::HashMap,
     io,
+    fmt,
     fs::{read_to_string, write},
     error::Error,
 };
@@ -13,6 +15,7 @@ use serde::Deserialize;
 use egg_mode::{
     Token,
     KeyPair,
+    entities::UrlEntity,
     tweet::{
         Tweet,
         user_timeline,
@@ -28,8 +31,6 @@ use mammut::status_builder::StatusBuilder;
 /**********
  * Generic usage functions
 ***********/
-
-
 /*
  * Those functions are related to the Twitter side of things
  */
@@ -85,10 +86,64 @@ fn get_mastodon_token(masto: &MastodonConfig) -> Mastodon {
 
     Mastodon::from_data(data)
 }
+
+/// build toot from tweet
+fn build_status(tweet: &Tweet) -> Result<StatusBuilder, Box<dyn Error>> {
+    let mut toot = String::from(&tweet.text);
+
+    let decoded_urls = decode_urls(&tweet.entities.urls);
+
+    for decoded_url in decoded_urls {
+        toot = toot.replace(&decoded_url.0, &decoded_url.1);
+    }
+
+    Ok(StatusBuilder::new(toot))
+}
+
+fn decode_urls(urls: &Vec<UrlEntity>) -> HashMap<String, String> {
+    let mut decoded_urls = HashMap::new();
+
+    for url in urls {
+        if url.expanded_url.is_some() {
+            // unwrap is safe here as we just verified that there is something inside expanded_url
+            decoded_urls.insert(String::from(&url.url), String::from(url.expanded_url.as_deref().unwrap()));
+        }
+    }
+
+    decoded_urls
+}
+
+/**********
+ * local error handler
+**********/
+#[derive(Debug)]
+struct ScootalooError {
+    details: String,
+}
+
+impl ScootalooError {
+    fn new(msg: &str) -> ScootalooError {
+        ScootalooError {
+            details: String::from(msg),
+        }
+    }
+}
+
+impl fmt::Display for ScootalooError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.details)
+    }
+}
+
+impl std::error::Error for ScootalooError {
+    fn description(&self) -> &str {
+        &self.details
+    }
+}
+
 /**********
  * Config structure
 ***********/
-
 /// General configuration Struct
 #[derive(Debug, Deserialize)]
 pub struct Config {
@@ -118,7 +173,6 @@ struct MastodonConfig {
 /*********
  * Main functions
 *********/
-
 /// Parses the TOML file into a Config Struct
 pub fn parse_toml(toml_file: &str) -> Config {
     let toml_config = read_to_string(toml_file).unwrap_or_else(|e|
@@ -187,8 +241,13 @@ pub fn run(config: Config) {
     feed.reverse();
 
     for tweet in &feed {
-        // build status based upon the original tweet
-        let status = StatusBuilder::new(String::from(&tweet.text));
+        let status = match build_status(tweet) {
+            Ok(t) => t,
+            Err(e) => {
+                println!("Could not create status from tweet {}: {}", tweet.id ,e);
+                continue;
+            },
+        };
 
         // publish status
         mastodon.new_status(status).unwrap();