Main: Support downloading thumbnails from events instead of the actual media

src/main.rs

@@ -247,6 +247,10 @@ struct Arguments {
     element_export_path: Option<PathBuf>,
 
     mxc_url: Option<String>,
+
+    /// When used with an event, download the thumbnail instead of the actual media.
+    #[clap(long, env)]
+    thumbnail: bool,
 }
 
 #[tokio::main]
@@ -256,7 +260,8 @@ async fn main() -> Result<()> {
     let Arguments {
         server,
         mxc_url,
-        element_export_path
+        element_export_path,
+        thumbnail,
     } = Arguments::parse();
 
     if let Some(element_export_path) = element_export_path {
@@ -351,8 +356,30 @@ async fn main() -> Result<()> {
     if let Err(error) = match event.content.msgtype {
         MessageType::Audio(content) => process_media(content.source, Some(content.body), &server).await,
         MessageType::File(content) => process_media(content.source, Some(content.body), &server).await,
-        MessageType::Image(content) => process_media(content.source, Some(content.body), &server).await,
+        MessageType::Image(content) => {
-        MessageType::Video(content) => process_media(content.source, Some(content.body), &server).await,
+            let source = if thumbnail {
+                content.info
+                    .ok_or(anyhow::Error::msg("Requested thumbnail but image doesn't have info"))?
+                    .thumbnail_source
+                    .ok_or(anyhow::Error::msg("Requested thumbnail image info doesn't contain one"))?
+            } else {
+                content.source
+            };
+
+            process_media(source, Some(content.body), &server).await
+        },
+        MessageType::Video(content) => {
+            let source = if thumbnail {
+                content.info
+                    .ok_or(anyhow::Error::msg("Requested thumbnail but video doesn't have info"))?
+                    .thumbnail_source
+                    .ok_or(anyhow::Error::msg("Requested thumbnail video info doesn't contain one"))?
+            } else {
+                content.source
+            };
+
+            process_media(source, Some(content.body), &server).await
+        },
         _ => {
             error!("Event content is not known to contain media, exiting");
             exit(1);