Change URL preview setting from bool to a mode, and add support for an allowlist

src/api/client_server/media.rs

@@ -11,9 +11,11 @@ use ruma::api::client::{
 
 #[cfg(feature = "url_preview")]
 use {
+    crate::config::UrlPreviewMode,
     crate::service::media::UrlPreviewData,
     webpage::HTML,
-    std::{io::Cursor, net::IpAddr, sync::Arc, time::Duration},
+    reqwest::Url,
+    std::{io::Cursor, net::IpAddr, sync::Arc},
     tokio::sync::Notify,
     image::io::Reader as ImgReader,
 };
@@ -123,9 +125,9 @@ fn url_request_allowed(addr: &IpAddr) -> bool {
 }
 
 #[cfg(feature = "url_preview")]
-async fn request_url_preview(url: String) -> Result<UrlPreviewData> {
+async fn request_url_preview(url: &str) -> Result<UrlPreviewData> {
     let client = services().globals.default_client();
-    let response = client.head(&url).send().await?;
+    let response = client.head(url).send().await?;
 
     if !response
         .remote_addr()
@@ -151,8 +153,8 @@ async fn request_url_preview(url: String) -> Result<UrlPreviewData> {
         }
     };
     let data = match content_type {
-        html if html.starts_with("text/html") => download_html(&client, &url).await?,
-        img if img.starts_with("image/") => download_image(&client, &url).await?,
+        html if html.starts_with("text/html") => download_html(&client, url).await?,
+        img if img.starts_with("image/") => download_image(&client, url).await?,
         _ => {
             return Err(Error::BadRequest(
                 ErrorKind::Unknown,
@@ -161,14 +163,14 @@ async fn request_url_preview(url: String) -> Result<UrlPreviewData> {
         }
     };
 
-    services().media.set_url_preview(&url, &data).await?;
+    services().media.set_url_preview(url, &data).await?;
 
     Ok(data)
 }
 
 #[cfg(feature = "url_preview")]
-async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
-    if let Some(preview) = services().media.get_url_preview(&url).await {
+async fn get_url_preview(url: &str) -> Result<UrlPreviewData> {
+    if let Some(preview) = services().media.get_url_preview(url).await {
         return Ok(preview);
     }
 
@@ -177,7 +179,7 @@ async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
         .url_preview_requests
         .read()
         .unwrap()
-        .get(&url)
+        .get(url)
         .cloned();
 
     match notif_opt {
@@ -188,15 +190,15 @@ async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
                     .url_preview_requests
                     .write()
                     .unwrap()
-                    .insert(url.clone(), notifier.clone());
+                    .insert(url.to_string(), notifier.clone());
             }
 
-            let data = request_url_preview(url.clone()).await;
+            let data = request_url_preview(url).await;
 
             notifier.notify_waiters();
 
             {
-                services().media.url_preview_requests.write().unwrap().remove(&url);
+                services().media.url_preview_requests.write().unwrap().remove(url);
             }
 
             data
@@ -208,7 +210,7 @@ async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
             notifier.await;
 
             services().media
-                .get_url_preview(&url)
+                .get_url_preview(url)
                 .await
                 .ok_or(Error::BadRequest(
                     ErrorKind::Unknown,
@@ -218,6 +220,29 @@ async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
     }
 }
 
+#[cfg(feature = "url_preview")]
+fn url_preview_allowed(url_str: &str) -> bool {
+    let url = match Url::parse(url_str) {
+        Ok(u) => u,
+        Err(_) => return false,
+    };
+    if ["http", "https"].iter().all(|&scheme| scheme != url.scheme().to_lowercase()) {
+        return false;
+    }
+    match services().globals.url_preview_mode() {
+        UrlPreviewMode::All => true,
+        UrlPreviewMode::None => false,
+        UrlPreviewMode::Allowlist => {
+            match url.host_str() {
+                None => false,
+                Some(host) => {
+                    services().globals.url_preview_allowlist().contains(&host.to_string())
+                }
+            }
+        }
+    }
+}
+
 /// # `GET /_matrix/media/r0/preview_url`
 ///
 /// Returns URL preview.
@@ -225,14 +250,15 @@ async fn get_url_preview(url: String) -> Result<UrlPreviewData> {
 pub async fn get_media_preview_route(
     body: Ruma<get_media_preview::v3::Request>,
 ) -> Result<get_media_preview::v3::Response> {
-    if !services().globals.allow_url_preview() {
+    let url = &body.url;
+    if !url_preview_allowed(url) {
         return Err(Error::BadRequest(
             ErrorKind::Unknown,
             "Previewing URL not allowed",
         ));
     }
 
-    if let Ok(preview) = get_url_preview(body.url.clone()).await {
+    if let Ok(preview) = get_url_preview(url).await {
         let res = serde_json::value::to_raw_value(&preview).expect("Converting to JSON failed");
         return Ok(get_media_preview::v3::Response::from_raw_value(res));
     }