subxt: use utils from core

subxt/src/utils.rs

@@ -0,0 +1,36 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+//! Utility functions used in subxt. Reexports all elements from [`subxt_core::utils`];
+
+pub use subxt_core::utils::*;
+
+use url::Url;
+
+use crate::{error::RpcError, Error};
+
+/// A URL is considered secure if it uses a secure scheme ("https" or "wss") or is referring to localhost.
+///
+/// Returns an error if the the string could not be parsed into a URL.
+pub fn url_is_secure(url: &str) -> Result<bool, Error> {
+    let url = Url::parse(url).map_err(|e| Error::Rpc(RpcError::ClientError(Box::new(e))))?;
+
+    let secure_scheme = url.scheme() == "https" || url.scheme() == "wss";
+    let is_localhost = url.host().is_some_and(|e| match e {
+        url::Host::Domain(e) => e == "localhost",
+        url::Host::Ipv4(e) => e.is_loopback(),
+        url::Host::Ipv6(e) => e.is_loopback(),
+    });
+
+    Ok(secure_scheme || is_localhost)
+}
+
+/// Validates, that the given Url is secure ("https" or "wss" scheme) or is referring to localhost.
+pub fn validate_url_is_secure(url: &str) -> Result<(), Error> {
+    if !url_is_secure(url)? {
+        Err(Error::Rpc(crate::error::RpcError::InsecureUrl(url.into())))
+    } else {
+        Ok(())
+    }
+}