Attach wsssh stdin/stdout/stderr to xterm.js using threaded output reading

wssshd.py

@@ -29,7 +29,6 @@ import os
 import threading
 import uuid
 import subprocess
-import fcntl
 from flask import Flask, render_template, request, redirect, url_for, flash, jsonify, send_from_directory
 from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
 from flask_sqlalchemy import SQLAlchemy
@@ -190,15 +189,31 @@ def connect_terminal(client_id):
         command,
         stdout=subprocess.PIPE,
         stdin=subprocess.PIPE,
-        stderr=subprocess.STDOUT,
-        bufsize=0
+        stderr=subprocess.STDOUT
     )
-    # Set stdout to non-blocking
-    fd = proc.stdout.fileno()
-    fl = fcntl.fcntl(fd, fcntl.F_GETFL)
-    fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
 
-    active_terminals[request_id] = {'client_id': client_id, 'username': username, 'proc': proc}
+    # Start a thread to read output
+    output_buffer = []
+    def read_output():
+        while proc.poll() is None:
+            try:
+                data = proc.stdout.read(1024)
+                if data:
+                    output_buffer.append(data.decode('utf-8', errors='ignore'))
+            except:
+                break
+        # Read any remaining data
+        try:
+            data = proc.stdout.read()
+            if data:
+                output_buffer.append(data.decode('utf-8', errors='ignore'))
+        except:
+            pass
+
+    thread = threading.Thread(target=read_output, daemon=True)
+    thread.start()
+
+    active_terminals[request_id] = {'client_id': client_id, 'username': username, 'proc': proc, 'output_buffer': output_buffer}
     return jsonify({'request_id': request_id, 'command': ' '.join(command)})
 
 
@@ -218,13 +233,12 @@ def terminal_data(client_id):
         request_id = request.args.get('request_id')
         if request_id in active_terminals:
             proc = active_terminals[request_id]['proc']
-            if proc.poll() is None:
-                try:
-                    data = proc.stdout.read(1024).decode('utf-8', errors='ignore')
-                    return data
-                except:
-                    return ''
-            else:
+            output_buffer = active_terminals[request_id]['output_buffer']
+            if output_buffer:
+                data = ''.join(output_buffer)
+                output_buffer.clear()
+                return data
+            elif proc.poll() is not None:
                 # Process terminated
                 return '\r\nProcess terminated.\r\n'
         return ''