Add new methods set_config_filename and set_config_content

Author: cboulay

src/pylsl/__init__.py

@@ -34,6 +34,8 @@
 from .util import library_version as library_version
 from .util import library_info as library_info
 from .util import local_clock as local_clock
+from .util import set_config_filename as set_config_filename
+from .util import set_config_content as set_config_content
 from .lib import cf_int8 as cf_int8
 from .lib import cf_int16 as cf_int16
 from .lib import cf_int32 as cf_int32

src/pylsl/lib/__init__.py

@@ -314,6 +314,15 @@ def find_liblsl_libraries(verbose=False):
     lib.lsl_create_continuous_resolver_byprop.restype = ctypes.c_void_p
 except Exception:
     print("pylsl: ContinuousResolver not (fully) available in your liblsl version.")
+# noinspection PyBroadException
+try:
+    lib.lsl_set_config_filename.argtypes = [ctypes.c_char_p]
+    lib.lsl_set_config_filename.restype = None
+    lib.lsl_set_config_content.argtypes = [ctypes.c_char_p]
+    lib.lsl_set_config_content.restype = None
+except Exception:
+    # Available in liblsl >= 1.17.7; older versions don't expose these.
+    pass
 
 
 # int64 support on windows and 32bit OSes isn't there yet

src/pylsl/util.py

@@ -60,6 +60,36 @@ def library_info():
     return lib.lsl_library_info().decode("utf-8")
 
 
+def set_config_filename(filename: str) -> None:
+    """Set the path of the configuration file to be used by liblsl.
+
+    Must be called before any other LSL function; the configuration is loaded
+    lazily on first use, so calling this afterwards has no effect.
+    """
+    if not hasattr(lib, "lsl_set_config_filename"):
+        raise NotImplementedError(
+            "lsl_set_config_filename is not available in your liblsl version "
+            "(requires liblsl >= 1.17.7)."
+        )
+    lib.lsl_set_config_filename(filename.encode("utf-8"))
+
+
+def set_config_content(content: str) -> None:
+    """Set the configuration content (as an INI string) to be used by liblsl.
+
+    Must be called before any other LSL function; the configuration is loaded
+    lazily on first use, so calling this afterwards has no effect. When set,
+    this content takes precedence over any configuration file. The content is
+    discarded after liblsl has initialized.
+    """
+    if not hasattr(lib, "lsl_set_config_content"):
+        raise NotImplementedError(
+            "lsl_set_config_content is not available in your liblsl version "
+            "(requires liblsl >= 1.17.7)."
+        )
+    lib.lsl_set_config_content(content.encode("utf-8"))
+
+
 def local_clock():
     """Obtain a local system time stamp in seconds.
 

test/test_set_config.py

@@ -0,0 +1,72 @@
+"""Tests for set_config_filename and set_config_content.
+
+Both functions must run before liblsl's config is loaded (on first use), so
+the effect-verifying tests run in a fresh Python subprocess. In-process smoke
+tests only verify that the call path works — they may be no-ops if liblsl has
+already initialized in the current process.
+"""
+
+import subprocess
+import sys
+import textwrap
+
+import pytest
+
+import pylsl
+
+
+def test_set_config_content_accepts_string():
+    # Safe to call even after init — content is simply ignored once liblsl has loaded.
+    pylsl.set_config_content("[lab]\nSessionID = ignored_after_init\n")
+
+
+def test_set_config_filename_accepts_string():
+    pylsl.set_config_filename("/nonexistent/path/to/lsl.cfg")
+
+
+def test_set_config_content_rejects_non_string():
+    with pytest.raises(AttributeError):
+        pylsl.set_config_content(b"not a str")
+
+
+def test_set_config_filename_rejects_non_string():
+    with pytest.raises(AttributeError):
+        pylsl.set_config_filename(12345)
+
+
+def _run_in_subprocess(script: str) -> str:
+    result = subprocess.run(
+        [sys.executable, "-c", script],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    return result.stdout.strip()
+
+
+def test_set_config_content_applies_session_id():
+    """Setting content before any LSL call should update the session id that
+    outlets inherit from the library config."""
+    session_id = "pytest_content_session"
+    script = textwrap.dedent(f"""
+        import pylsl
+        pylsl.set_config_content('[lab]\\nSessionID = {session_id}\\n')
+        info = pylsl.StreamInfo('T', 'EEG', 1, 100, 'float32', 'src')
+        outlet = pylsl.StreamOutlet(info)
+        print(outlet.get_info().session_id())
+    """)
+    assert _run_in_subprocess(script) == session_id
+
+
+def test_set_config_filename_applies_session_id(tmp_path):
+    session_id = "pytest_filename_session"
+    cfg = tmp_path / "lsl.cfg"
+    cfg.write_text(f"[lab]\nSessionID = {session_id}\n")
+    script = textwrap.dedent(f"""
+        import pylsl
+        pylsl.set_config_filename({str(cfg)!r})
+        info = pylsl.StreamInfo('T', 'EEG', 1, 100, 'float32', 'src')
+        outlet = pylsl.StreamOutlet(info)
+        print(outlet.get_info().session_id())
+    """)
+    assert _run_in_subprocess(script) == session_id