fix(fs): fix writeFile and writeTextFile converting UTF-8 characters in path into replacement character

closes #1849

Author: amrbashir

.changes/fs-path-utf8.md

@@ -0,0 +1,6 @@
+---
+"fs": "patch"
+"fs-js": "patch"
+---
+
+Fix `writeFile` and `writeTextFile` converting UTF-8 characters (for example `äöü`) in the given path into replacement character (`�`)

plugins/fs/api-iife.js

@@ -1040,9 +1040,21 @@ async function writeFile(
     throw new TypeError('Must be a file URL.')
   }
 
-  await invoke('plugin:fs|write_file', data, {
+  // because headers only allows ISO-8859-1 strings, characters like `äöü` are not allowed
+  // so we encode them into bytes and append them at the end of the data to be written
+  // then we can only send the path bytes length in the headers
+  // and on rust we split the data into two parts, data and path
+  // and decode path into a valid `std::ffi::OsString`
+  const pathStr = path instanceof URL ? path.toString() : path
+  const pathBytes = new TextEncoder().encode(pathStr)
+
+  const bytes = new Uint8Array(data.byteLength + pathBytes.byteLength)
+  bytes.set(data)
+  bytes.set(pathBytes, data.byteLength)
+
+  await invoke('plugin:fs|write_file', bytes, {
     headers: {
-      path: encodeURIComponent(path instanceof URL ? path.toString() : path),
+      path: pathBytes.byteLength.toString(),
       options: JSON.stringify(options)
     }
   })
@@ -1070,9 +1082,23 @@ async function writeTextFile(
 
   const encoder = new TextEncoder()
 
-  await invoke('plugin:fs|write_text_file', encoder.encode(data), {
+  const textData = encoder.encode(data)
+
+  // because headers only allows ISO-8859-1 strings, characters like `äöü` are not allowed
+  // so we encode them into bytes and append them at the end of the data to be written
+  // then we can only send the path bytes length in the headers
+  // and on rust we split the data into two parts, data and path
+  // and decode path into a valid `std::ffi::OsString`
+  const pathStr = path instanceof URL ? path.toString() : path
+  const pathBytes = encoder.encode(pathStr)
+
+  const bytes = new Uint8Array(textData.byteLength + pathBytes.byteLength)
+  bytes.set(textData)
+  bytes.set(pathBytes, textData.byteLength)
+
+  await invoke('plugin:fs|write_text_file', bytes, {
     headers: {
-      path: path instanceof URL ? path.toString() : path,
+      path: pathBytes.byteLength.toString(),
       options: JSON.stringify(options)
     }
   })