feat(layouts): allow consuming a layout from a url (#3351)

* feat(cli): allow loading layouts directly from a url

* feat(plugins): allow loading layouts directly from a url

* style(fmt): rustfmt

src/commands.rs

@@ -444,6 +444,7 @@ pub(crate) fn start_client(opts: CliArgs) {
                         layout_dir.clone(),
                         config_without_layout.clone(),
                     ),
+                    LayoutInfo::Url(url) => Layout::from_url(&url, config_without_layout.clone()),
                 };
                 match new_session_layout {
                     Ok(new_session_layout) => {

zellij-utils/src/data.rs

@@ -797,19 +797,22 @@ pub struct SessionInfo {
 pub enum LayoutInfo {
     BuiltIn(String),
     File(String),
+    Url(String),
 }
 
 impl LayoutInfo {
     pub fn name(&self) -> &str {
         match self {
             LayoutInfo::BuiltIn(name) => &name,
             LayoutInfo::File(name) => &name,
+            LayoutInfo::Url(url) => &url,
         }
     }
     pub fn is_builtin(&self) -> bool {
         match self {
             LayoutInfo::BuiltIn(_name) => true,
             LayoutInfo::File(_name) => false,
+            LayoutInfo::Url(_url) => false,
         }
     }
 }

zellij-utils/src/downloader.rs

@@ -16,6 +16,8 @@ pub enum DownloaderError {
     Io(#[source] std::io::Error),
     #[error("File name cannot be found in URL: {0}")]
     NotFoundFileName(String),
+    #[error("Failed to parse URL body: {0}")]
+    InvalidUrlBody(String),
 }
 
 #[derive(Debug)]
@@ -110,6 +112,29 @@ impl Downloader {
 
         Ok(())
     }
+    pub async fn download_without_cache(url: &str) -> Result<String, DownloaderError> {
+        // result is the stringified body
+        let client = surf::client().with(surf::middleware::Redirect::default());
+
+        let res = client
+            .get(url)
+            .header("Content-Type", "application/octet-stream")
+            .await
+            .map_err(|e| DownloaderError::Request(e))?;
+
+        let mut downloaded_bytes: Vec<u8> = vec![];
+        let mut stream = res.bytes();
+        while let Some(byte) = stream.next().await {
+            let byte = byte.map_err(|e| DownloaderError::Io(e))?;
+            downloaded_bytes.push(byte);
+        }
+
+        log::debug!("Download complete");
+        let stringified = String::from_utf8(downloaded_bytes)
+            .map_err(|e| DownloaderError::InvalidUrlBody(format!("{}", e)))?;
+
+        Ok(stringified)
+    }
 
     fn parse_name(&self, url: &str) -> Result<String, DownloaderError> {
         Url::parse(url)

zellij-utils/src/input/actions.rs

@@ -529,9 +529,25 @@ impl Action {
                     let layout_dir = layout_dir
                         .or_else(|| config.and_then(|c| c.options.layout_dir))
                         .or_else(|| get_layout_dir(find_default_config_dir()));
-                    let (path_to_raw_layout, raw_layout, swap_layouts) =
+
+                    let (path_to_raw_layout, raw_layout, swap_layouts) = if let Some(layout_url) =
+                        layout_path.to_str().and_then(|l| {
+                            if l.starts_with("http://") || l.starts_with("https://") {
+                                Some(l)
+                            } else {
+                                None
+                            }
+                        }) {
+                        (
+                            layout_url.to_owned(),
+                            Layout::stringified_from_url(layout_url)
+                                .map_err(|e| format!("Failed to load layout: {}", e))?,
+                            None,
+                        )
+                    } else {
                         Layout::stringified_from_path_or_default(Some(&layout_path), layout_dir)
-                            .map_err(|e| format!("Failed to load layout: {}", e))?;
+                            .map_err(|e| format!("Failed to load layout: {}", e))?
+                    };
                     let layout = Layout::from_str(&raw_layout, path_to_raw_layout, swap_layouts.as_ref().map(|(f, p)| (f.as_str(), p.as_str())), cwd).map_err(|e| {
                         let stringified_error = match e {
                             ConfigError::KdlError(kdl_error) => {

zellij-utils/src/input/config.rs

@@ -96,6 +96,8 @@ pub enum ConfigError {
     PluginsError(#[from] PluginsConfigError),
     #[error("{0}")]
     ConversionError(#[from] ConversionError),
+    #[error("{0}")]
+    DownloadError(String),
 }
 
 impl ConfigError {

zellij-utils/src/input/layout.rs

@@ -8,6 +8,8 @@
 //  place.
 //  If plugins should be able to depend on the layout system
 //  then [`zellij-utils`] could be a proper place.
+#[cfg(not(target_family = "wasm"))]
+use crate::downloader::Downloader;
 use crate::{
     data::{Direction, LayoutInfo},
     home::{default_layout_dir, find_default_config_dir},
@@ -18,6 +20,8 @@ use crate::{
     pane_size::{Constraint, Dimension, PaneGeom},
     setup::{self},
 };
+#[cfg(not(target_family = "wasm"))]
+use async_std::task;
 
 use std::cmp::Ordering;
 use std::fmt::{Display, Formatter};
@@ -1145,6 +1149,7 @@ impl Layout {
             LayoutInfo::BuiltIn(layout_name) => {
                 Self::stringified_from_default_assets(&PathBuf::from(layout_name))?
             },
+            LayoutInfo::Url(url) => (url.clone(), Self::stringified_from_url(&url)?, None),
         };
         Layout::from_kdl(
             &raw_layout,
@@ -1179,6 +1184,20 @@ impl Layout {
             ),
         }
     }
+    pub fn stringified_from_url(url: &str) -> Result<String, ConfigError> {
+        #[cfg(not(target_family = "wasm"))]
+        let raw_layout = task::block_on(async move {
+            let download = Downloader::download_without_cache(url).await;
+            match download {
+                Ok(stringified) => Ok(stringified),
+                Err(e) => Err(ConfigError::DownloadError(format!("{}", e))),
+            }
+        })?;
+        // silently fail - this should not happen in plugins and legacy architecture is hard
+        #[cfg(target_family = "wasm")]
+        let raw_layout = String::new();
+        Ok(raw_layout)
+    }
     pub fn from_path_or_default(
         layout_path: Option<&PathBuf>,
         layout_dir: Option<PathBuf>,
@@ -1197,6 +1216,25 @@ impl Layout {
         let config = Config::from_kdl(&raw_layout, Some(config))?; // this merges the two config, with
         Ok((layout, config))
     }
+    #[cfg(not(target_family = "wasm"))]
+    pub fn from_url(url: &str, config: Config) -> Result<(Layout, Config), ConfigError> {
+        let raw_layout = task::block_on(async move {
+            let download = Downloader::download_without_cache(url).await;
+            match download {
+                Ok(stringified) => Ok(stringified),
+                Err(e) => Err(ConfigError::DownloadError(format!("{}", e))),
+            }
+        })?;
+        let layout = Layout::from_kdl(&raw_layout, url.into(), None, None)?;
+        let config = Config::from_kdl(&raw_layout, Some(config))?; // this merges the two config, with
+        Ok((layout, config))
+    }
+    #[cfg(target_family = "wasm")]
+    pub fn from_url(url: &str, config: Config) -> Result<(Layout, Config), ConfigError> {
+        Err(ConfigError::DownloadError(format!(
+            "Unsupported platform, cannot download layout from the web"
+        )))
+    }
     pub fn from_path_or_default_without_config(
         layout_path: Option<&PathBuf>,
         layout_dir: Option<PathBuf>,

zellij-utils/src/kdl/mod.rs

@@ -2166,6 +2166,7 @@ impl SessionInfo {
             let (layout_name, layout_source) = match layout_info {
                 LayoutInfo::File(name) => (name.clone(), "file"),
                 LayoutInfo::BuiltIn(name) => (name.clone(), "built-in"),
+                LayoutInfo::Url(url) => (url.clone(), "url"),
             };
             let mut layout_node = KdlNode::new(format!("{}", layout_name));
             let layout_source = KdlEntry::new_prop("source", layout_source);

zellij-utils/src/plugin_api/event.rs

@@ -545,6 +545,10 @@ impl TryFrom<LayoutInfo> for ProtobufLayoutInfo {
                 source: "built-in".to_owned(),
                 name,
             }),
+            LayoutInfo::Url(name) => Ok(ProtobufLayoutInfo {
+                source: "url".to_owned(),
+                name,
+            }),
         }
     }
 }
@@ -555,6 +559,7 @@ impl TryFrom<ProtobufLayoutInfo> for LayoutInfo {
         match protobuf_layout_info.source.as_str() {
             "file" => Ok(LayoutInfo::File(protobuf_layout_info.name)),
             "built-in" => Ok(LayoutInfo::BuiltIn(protobuf_layout_info.name)),
+            "url" => Ok(LayoutInfo::Url(protobuf_layout_info.name)),
             _ => Err("Unknown source for layout"),
         }
     }

zellij-utils/src/setup.rs

@@ -671,9 +671,23 @@ impl Setup {
                     .and_then(|cli_options| cli_options.default_layout.clone())
             })
             .or_else(|| config.options.default_layout.clone());
-        // we merge-override the config here because the layout might contain configuration
-        // that needs to take precedence
-        Layout::from_path_or_default(chosen_layout.as_ref(), layout_dir.clone(), config)
+        if let Some(layout_url) = chosen_layout
+            .as_ref()
+            .and_then(|l| l.to_str())
+            .and_then(|l| {
+                if l.starts_with("http://") || l.starts_with("https://") {
+                    Some(l)
+                } else {
+                    None
+                }
+            })
+        {
+            Layout::from_url(layout_url, config)
+        } else {
+            // we merge-override the config here because the layout might contain configuration
+            // that needs to take precedence
+            Layout::from_path_or_default(chosen_layout.as_ref(), layout_dir.clone(), config)
+        }
     }
     fn handle_setup_commands(cli_args: &CliArgs) {
         if let Some(Command::Setup(ref setup)) = &cli_args.command {