fix(http): Properly URL-encode key and values during x-www-form-urlencoded POSTs (#8037)

Co-authored-by: jcesarmobile <jcesarmobile@gmail.com>

Author: theproducer

android/capacitor/src/main/java/com/getcapacitor/plugin/util/CapacitorHttpUrlConnection.java

@@ -248,7 +248,7 @@ private void writeObjectRequestBody(JSObject object) throws IOException, JSONExc
             while (keys.hasNext()) {
                 String key = keys.next();
                 Object d = object.get(key);
-                os.writeBytes(key);
+                os.writeBytes(URLEncoder.encode(key, "UTF-8"));
                 os.writeBytes("=");
                 os.writeBytes(URLEncoder.encode(d.toString(), "UTF-8"));
 

ios/Capacitor/Capacitor/Plugins/CapacitorUrlRequest.swift

@@ -40,8 +40,11 @@ open class CapacitorUrlRequest: NSObject, URLSessionTaskDelegate {
             throw CapacitorUrlRequestError.serializationError("[ data ] argument for request with content-type [ multipart/form-data ] may only be a plain javascript object")
         }
 
+        let allowed = CharacterSet(charactersIn: "-._*").union(.alphanumerics)
+
         obj.keys.forEach { (key: String) in
-            components.queryItems?.append(URLQueryItem(name: key, value: "\(obj[key] ?? "")"))
+            let value = obj[key] as? String ?? ""
+            components.queryItems?.append(URLQueryItem(name: key.addingPercentEncoding(withAllowedCharacters: allowed)?.replacingOccurrences(of: "%20", with: "+") ?? key, value: value.addingPercentEncoding(withAllowedCharacters: allowed)?.replacingOccurrences(of: "%20", with: "+")))
         }
 
         if components.query != nil {