H1rono/assimp fetch (#222)

* Support URL with assimp enabled

* Store fetched content in named tempfile

* Update CSpell dictionary

.github/.cspell/rust-dependencies.txt

@@ -5,6 +5,7 @@ assimp
 bindgen
 getrandom
 structopt
+tempfile
 thiserror
 urdf
 ureq

Cargo.toml

@@ -15,7 +15,7 @@ members = ["examples/wasm"]
 
 [features]
 default = ["assimp"]
-assimp = ["assimp-crate", "assimp-sys"]
+assimp = ["assimp-crate", "assimp-sys", "tempfile"]
 
 # Note: k, kiss3d, serde, structopt, tokio, urdf-rs, and wasm-bindgen are public dependencies.
 [dependencies]
@@ -33,6 +33,7 @@ urdf-rs = "0.7.2"
 
 assimp-crate = { package = "assimp", version = "0.3.1", optional = true }
 assimp-sys = { version = "0.3.1", optional = true }
+tempfile = { version = "3.8", optional = true }
 
 [target.'cfg(not(target_family = "wasm"))'.dependencies]
 axum = "0.6"

src/mesh.rs

@@ -102,7 +102,13 @@ pub fn load_mesh(
     let file_string = filename.as_ref();
 
     #[cfg(feature = "assimp")]
-    if use_assimp && !file_string.starts_with("https://") && !file_string.starts_with("http://") {
+    if use_assimp {
+        let is_url = file_string.starts_with("https://") || file_string.starts_with("http://");
+        if is_url {
+            let file = crate::utils::fetch_tempfile(file_string)?;
+            let path = file.path().to_str().unwrap();
+            return load_mesh_assimp(path, scale, opt_color, group, use_texture);
+        }
         return load_mesh_assimp(file_string, scale, opt_color, group, use_texture);
     }
 

src/utils.rs

@@ -105,6 +105,28 @@ mod native {
             mem::take(&mut self.package_path)
         }
     }
+
+    #[cfg(feature = "assimp")]
+    /// http request -> write to tempfile -> return that file
+    pub(crate) fn fetch_tempfile(url: &str) -> Result<tempfile::NamedTempFile> {
+        use std::io::{Read, Write};
+
+        const RESPONSE_SIZE_LIMIT: usize = 10 * 1_024 * 1_024;
+
+        let mut buf: Vec<u8> = vec![];
+        ureq::get(url)
+            .call()
+            .map_err(|e| crate::Error::Other(e.to_string()))?
+            .into_reader()
+            .take((RESPONSE_SIZE_LIMIT + 1) as u64)
+            .read_to_end(&mut buf)?;
+        if buf.len() > RESPONSE_SIZE_LIMIT {
+            return Err(crate::Error::Other(format!("{url} is too big")));
+        }
+        let mut file = tempfile::NamedTempFile::new()?;
+        file.write_all(&buf)?;
+        Ok(file)
+    }
 }
 
 #[cfg(target_family = "wasm")]