Decouple core Yaak logic from Tauri (#354)

crates-tauri/yaak-app/src/encoding.rs

@@ -0,0 +1,20 @@
+use mime_guess::{Mime, mime};
+use std::path::Path;
+use std::str::FromStr;
+use tokio::fs;
+
+pub async fn read_response_body(body_path: impl AsRef<Path>, content_type: &str) -> Option<String> {
+    let body = fs::read(body_path).await.ok()?;
+    let body_charset = parse_charset(content_type).unwrap_or("utf-8".to_string());
+    if let Some(decoder) = charset::Charset::for_label(body_charset.as_bytes()) {
+        let (cow, _real_encoding, _exist_replace) = decoder.decode(&body);
+        return cow.into_owned().into();
+    }
+
+    Some(String::from_utf8_lossy(&body).to_string())
+}
+
+fn parse_charset(content_type: &str) -> Option<String> {
+    let mime: Mime = Mime::from_str(content_type).ok()?;
+    mime.get_param(mime::CHARSET).map(|v| v.to_string())
+}