feat: use URL hash as filename for fetched models

Cargo.toml

@@ -59,7 +59,7 @@ training = [ "ort-sys/training" ]
 
 operator-libraries = [ "libc", "winapi" ]
 
-fetch-models = [ "ureq" ]
+fetch-models = [ "ureq", "sha2" ]
 download-binaries = [ "ort-sys/download-binaries" ]
 load-dynamic = [ "libloading", "ort-sys/load-dynamic" ]
 copy-dylibs = [ "ort-sys/copy-dylibs" ]
@@ -89,6 +89,7 @@ ort-sys = { version = "2.0.0-rc.4", path = "ort-sys" }
 libloading = { version = "0.8", optional = true }
 
 ureq = { version = "2.1", optional = true, default-features = false, features = [ "tls" ] }
+sha2 = { version = "0.10", optional = true }
 tracing = "0.1"
 half = { version = "2.1", optional = true }
 

src/session/builder.rs

@@ -1,9 +1,9 @@
 #[cfg(any(feature = "operator-libraries", not(windows)))]
 use std::ffi::CString;
+#[cfg(feature = "fetch-models")]
+use std::fmt::Write;
 #[cfg(not(target_arch = "wasm32"))]
 use std::path::Path;
-#[cfg(feature = "fetch-models")]
-use std::path::PathBuf;
 use std::{
 	any::Any,
 	marker::PhantomData,
@@ -259,7 +259,10 @@ impl SessionBuilder {
 		}
 
 		let url = model_url.as_ref();
-		let model_filename = PathBuf::from(url.split('/').last().expect("Missing filename in model URL"));
+		let model_filename = <sha2::Sha256 as sha2::Digest>::digest(url).into_iter().fold(String::new(), |mut s, b| {
+			let _ = write!(&mut s, "{:02x}", b);
+			s
+		});
 		let model_filepath = download_dir.join(model_filename);
 		let downloaded_path = if model_filepath.exists() {
 			tracing::info!(model_filepath = format!("{}", model_filepath.display()).as_str(), "Model already exists, skipping download");