adding Gstreamer plugin for handling asset:// (linux specific)

asset:// is registered as a custom protocol through WebKit, but when an audio or video is got from that protocol, gstreamer is used in the background and can't play the media because there is no handler for asset://

Author: aaalloc

Cargo.lock

@@ -14,6 +14,8 @@ members = [
   "crates/tauri-bundler",
   "crates/tauri-macos-sign",
   "crates/tauri-driver",
+  "crates/tauri-asset-gst-plugin",
+
 
   # @tauri-apps/cli rust project
   "packages/cli",

Cargo.toml

@@ -0,0 +1 @@
+/target

crates/tauri-asset-gst-plugin/.gitignore

@@ -0,0 +1,20 @@
+[package]
+name = "tauri-asset-gst-plugin"
+version = "0.1.0"
+authors = ["Alexander Yanovskyy <[email protected]>"]
+license = "MIT OR Apache-2.0"
+edition = "2018"
+repository = "https://github.com/tauri-apps/tauri"
+description = "Gstreamer plugin for asset protocol"
+
+[dependencies]
+gstreamer = "0.24"
+gstreamer-base = "0.24"
+
+[lib]
+name = "gsttauriasset"
+crate-type = ["cdylib"]
+path = "src/lib.rs"
+
+[build-dependencies]
+gst-plugin-version-helper = "0.8.3"

crates/tauri-asset-gst-plugin/Cargo.toml

@@ -0,0 +1,3 @@
+fn main() {
+    gst_plugin_version_helper::info();
+}

crates/tauri-asset-gst-plugin/build.rs

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "stable-2025-10-30"

crates/tauri-asset-gst-plugin/rust-toolchain.toml

@@ -0,0 +1,21 @@
+use gst::glib;
+use gstreamer_base::gst;
+
+mod tauri_asset;
+// https://github.com/sdroege/gst-plugin-rs/blob/main/net/aws/src/lib.rs
+
+fn plugin_init(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
+  tauri_asset::register(plugin)
+}
+
+gst::plugin_define!(
+  tauriasset,
+  env!("CARGO_PKG_DESCRIPTION"),
+  plugin_init,
+  concat!(env!("CARGO_PKG_VERSION"), "-", env!("COMMIT_ID")),
+  "The Plugin's License",
+  env!("CARGO_PKG_NAME"),
+  env!("CARGO_PKG_NAME"),
+  env!("CARGO_PKG_REPOSITORY"),
+  env!("BUILD_REL_DATE")
+);

crates/tauri-asset-gst-plugin/src/lib.rs

@@ -0,0 +1,95 @@
+use gst::glib::subclass::types::ObjectSubclassExt;
+use gst::prelude::{ElementExt, GhostPadExt, GstBinExt, PadExt};
+use gst::subclass::prelude::{BinImpl, ElementImpl, ObjectImpl, URIHandlerImpl};
+use gst::subclass::prelude::{GstObjectImpl, ObjectSubclass};
+use gst::{glib, GhostPad, PadDirection};
+use gstreamer_base::gst;
+
+const ASSET_URI_SCHEME: &str = "asset";
+
+#[derive(Default)]
+pub struct TauriAsset {
+  // uri: Option<String>,
+}
+
+impl TauriAsset {
+  pub fn new() -> Self {
+    Self::default()
+  }
+}
+
+#[glib::object_subclass]
+impl ObjectSubclass for TauriAsset {
+  const NAME: &'static str = "GstTauriAsset";
+  type Type = super::TauriAsset;
+  type ParentType = gst::Bin;
+  type Interfaces = (gst::URIHandler,);
+}
+
+impl GstObjectImpl for TauriAsset {}
+impl ObjectImpl for TauriAsset {}
+impl BinImpl for TauriAsset {}
+impl ElementImpl for TauriAsset {}
+
+impl URIHandlerImpl for TauriAsset {
+  const URI_TYPE: gst::URIType = gst::URIType::Src;
+
+  fn protocols() -> &'static [&'static str] {
+    &[ASSET_URI_SCHEME]
+  }
+
+  fn uri(&self) -> Option<String> {
+    None
+  }
+
+  fn set_uri(&self, uri: &str) -> Result<(), glib::Error> {
+    // uri is like: asset://path/to/asset or asset://localhost/path/to/asset
+
+    let sep = format!("{}://", ASSET_URI_SCHEME);
+    let mut split = uri.split(sep.as_str());
+    let location = split
+      .nth(1)
+      .ok_or_else(|| glib::Error::new(gst::URIError::BadUri, "Could not get location from URI"))?;
+
+    // directly having full path after asset:// or having localhost
+    let location = location.strip_prefix("localhost").unwrap_or(location);
+
+    // now location is like: /path/to/asset
+    let internal_src = gst::ElementFactory::make("filesrc")
+      .name("filesrc")
+      .property("location", location)
+      .build()
+      .ok();
+
+    let element = self.obj();
+    element
+      .add(internal_src.as_ref().unwrap())
+      .expect("Failed to add internal source");
+
+    let srcpad = internal_src
+      .as_ref()
+      .and_then(|src| src.static_pad("src"))
+      .ok_or_else(|| {
+        glib::Error::new(
+          gst::URIError::BadUri,
+          "Could not get src pad from internal source",
+        )
+      })?;
+
+    let ghostpad = GhostPad::new(PadDirection::Src);
+    ghostpad
+      .set_target(Some(&srcpad))
+      .ok()
+      .ok_or_else(|| glib::Error::new(gst::URIError::BadUri, "Could not create ghost pad"))?;
+
+    ghostpad
+      .set_active(true)
+      .ok()
+      .ok_or_else(|| glib::Error::new(gst::URIError::BadUri, "Could not activate ghost pad"))?;
+
+    let element = self.obj();
+    element.add_pad(&ghostpad).expect("Failed to add ghost pad");
+    println!("Set URI to location: {}", location);
+    Ok(())
+  }
+}

crates/tauri-asset-gst-plugin/src/tauri_asset/imp.rs

@@ -0,0 +1,20 @@
+use gst::glib;
+use gst::prelude::*;
+use gstreamer_base::gst;
+
+mod imp;
+
+glib::wrapper! {
+    pub struct TauriAsset(ObjectSubclass<imp::TauriAsset>)
+    @extends gst::Bin, gst::Element, gst::Object,
+    @implements gst::URIHandler;
+}
+
+pub fn register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
+  gst::Element::register(
+    Some(plugin),
+    "tauriasset",
+    gst::Rank::PRIMARY,
+    TauriAsset::static_type(),
+  )
+}