Fixed stdout/stderr redirection with extern Python controllers on Win…

…dows (cyberbotics#5807) * Fixed stdout/stderr redirection with extern Python controllers on Windows * Update changelog-r2023.md * Fixed PEP8 * Support for UTF-8 strings * Cleaner support for UTF-8 strings
SahaRobotik · Feb 1, 2023 · 6cbc643 · 6cbc643
1 parent aa631d1
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diff --git a/docs/reference/changelog-r2023.md b/docs/reference/changelog-r2023.md
@@ -11,6 +11,7 @@ Released on ??
     - Improved plot representation in default robot window when a NaN value is received from a device ([#5680](https://github.com/cyberbotics/webots/pull/5680)).
     - Improved default selected tab in Field Editor when nodes are selected ([#5726](https://github.com/cyberbotics/webots/pull/5726)).
   - Bug Fixes
+    - Fixed redirection of stdout/stderr for Python controllers on Windows ([#5807](https://github.com/cyberbotics/webots/pull/5807)).
     - Fixed crash in Python API when a robot controller was using several cameras with different resolutions ([#5705](https://github.com/cyberbotics/webots/pull/5705)).
     - Fixed Python API `Supervisor.setSimulationMode` which was failing ([#5603](https://github.com/cyberbotics/webots/pull/5603)).
     - Fixed Python API `Node.enableContactPointsTracking` which was failing ([#5633](https://github.com/cyberbotics/webots/pull/5633)).

diff --git a/lib/controller/python/controller/robot.py b/lib/controller/python/controller/robot.py
@@ -48,6 +48,53 @@
 from .mouse import Mouse
 
 
+if sys.platform == 'win32':
+    import atexit
+    import os
+    import threading
+
+    class StdStreamRedirect:
+        def __init__(self, stream):
+            r, w = os.pipe()
+            r, w = os.fdopen(r, 'r', encoding='utf-8'), os.fdopen(w, 'w', buffering=1, encoding='utf-8')
+            self._r = r
+            self._w = w
+            if stream == 1:  # stdout
+                sys.stdout = self._w
+            elif stream == 2:  # stderr
+                sys.stderr = self._w
+            self._stream = stream
+            self._thread = threading.Thread(target=self._handler)
+            self._thread.start()
+
+        def __del__(self):
+            self._w.close()
+            self._thread.join()
+            self._r.close()
+
+        def _handler(self):
+            libc = ctypes.CDLL('msvcrt')
+            while not self._w.closed:
+                try:
+                    while True:
+                        line = self._r.readline()
+                        if len(line) == 0:
+                            break
+                        encoded = line.encode('utf-8')
+                        libc._write(self._stream, encoded, len(encoded), 0)
+                except Exception:
+                    break
+
+    def _delete_object(object):
+        del object
+    if 'WEBOTS_STDOUT_REDIRECT' in os.environ and os.environ['WEBOTS_STDOUT_REDIRECT']:
+        _stdout_redirect = StdStreamRedirect(1)
+        atexit.register(_delete_object, _stdout_redirect)
+    if 'WEBOTS_STDERR_REDIRECT' in os.environ and os.environ['WEBOTS_STDERR_REDIRECT']:
+        _stderr_redirect = StdStreamRedirect(2)
+        atexit.register(_delete_object, _stderr_redirect)
+
+
 class Robot:
     EVENT_QUIT = -1
     EVENT_NO_EVENT = 0