add 'output.stdout', '.stdin', and '.stderr' options

(#1621, #2152, #2529)

Allow setting custom input/output encodings and options
without having to rely on Python's defaults.

docs/configuration.rst

@@ -3808,6 +3808,42 @@ Description
     * ``{3}`` is percent of bytes downloaded to total bytes
 
 
+output.stdout & .stdin & .stderr
+--------------------------------
+Type
+    * ``string``
+    * ``object``
+Example
+    .. code:: json
+
+        "utf-8"
+
+    .. code:: json
+
+        {
+            "encoding": "utf-8",
+            "errors": "replace",
+            "line_buffering": true
+        }
+
+Description
+    `Reconfigure <https://docs.python.org/3/library/io.html#io.TextIOWrapper.reconfigure>`__
+    a `standard stream <https://docs.python.org/3/library/sys.html#sys.stdin>`__.
+
+    Possible options are
+
+    * ``encoding``
+    * ``errors``
+    * ``newline``
+    * ``line_buffering``
+    * ``write_through``
+
+    When this option is specified as a simple ``string``,
+    it is interpreted as ``{"encoding": "<string-value>", "errors": "replace"}``
+
+    Note: ``errors`` always defaults to ``"replace"``
+
+
 output.shorten
 --------------
 Type

gallery_dl/__init__.py

@@ -33,9 +33,6 @@ def progress(urls, pformat):
 
 def main():
     try:
-        if sys.stdout and sys.stdout.encoding.lower() != "utf-8":
-            output.replace_std_streams()
-
         parser = option.build_parser()
         args = parser.parse_args()
         log = output.initialize_logging(args.loglevel)
@@ -77,6 +74,8 @@ def main():
         for opts in args.options:
             config.set(*opts)
 
+        output.configure_standard_streams()
+
         # signals
         signals = config.get((), "signals-ignore")
         if signals:

gallery_dl/output.py

@@ -271,16 +271,32 @@ def stderr_write(s):
     stderr_write = stderr_write_flush
 
 
-def replace_std_streams(errors="replace"):
-    """Replace standard streams and set their error handlers to 'errors'"""
-    for name in ("stdout", "stdin", "stderr"):
-        stream = getattr(sys, name)
-        if stream:
+def configure_standard_streams():
+    for name in ("stdout", "stderr", "stdin"):
+        options = config.get(("output",), name)
+        if not options:
+            continue
+
+        stream = getattr(sys, name, None)
+        if not stream:
+            continue
+
+        if isinstance(options, str):
+            options = {"encoding": options, "errors": "replace"}
+        elif not options.get("errors"):
+            options["errors"] = "replace"
+
+        try:
+            stream.reconfigure(**options)
+        except AttributeError:
+            # no 'reconfigure' support
+            oget = options.get
             setattr(sys, name, stream.__class__(
                 stream.buffer,
-                errors=errors,
-                newline=stream.newlines,
-                line_buffering=stream.line_buffering,
+                encoding=oget("encoding", stream.encoding),
+                errors=oget("errors", "replace"),
+                newline=oget("newline", stream.newlines),
+                line_buffering=oget("line_buffering", stream.line_buffering),
             ))