1 files changed, 53 insertions, 0 deletions
diff --git a/native-apps/librejs-logger.py b/native-apps/librejs-logger.py
new file mode 100755
index 0000000..be79409
--- /dev/null
+++ b/native-apps/librejs-logger.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env -S python3 -u
+
+# Note that running python with the `-u` flag is required on Windows,
+# in order to ensure that stdin and stdout are opened in binary, rather
+# than text, mode.
+
+import sys
+import json
+import struct
+import subprocess
+import os
+import logging
+
+# Read a message from stdin and decode it.
+def getMessage():
+    rawLength = sys.stdin.buffer.read(4)
+    if len(rawLength) == 0:
+        sys.exit(0)
+    messageLength = struct.unpack('@I', rawLength)[0]
+    message = sys.stdin.buffer.read(messageLength).decode('utf-8')
+    return json.loads(message)
+
+# Encode a message for transmission,
+# given its content.
+def encodeMessage(messageContent):
+    # https://docs.python.org/3/library/json.html#basic-usage
+    # To get the most compact JSON representation, you should specify
+    # (',', ':') to eliminate whitespace.
+    # We want the most compact representation because the browser rejects # messages that exceed 1 MB.
+    encodedContent = json.dumps(messageContent, separators=(',', ':')).encode('utf-8')
+    encodedLength = struct.pack('@I', len(encodedContent))
+    return {'length': encodedLength, 'content': encodedContent}
+
+# Send an encoded message to stdout
+def sendMessage(encodedMessage):
+    sys.stdout.buffer.write(encodedMessage['length'])
+    sys.stdout.buffer.write(encodedMessage['content'])
+    sys.stdout.buffer.flush()
+
+
+counter = 0
+logging.basicConfig(filename="/tmp/librejs.log",
+                    filemode='a',
+                    format='%(asctime)s.%(msecs)d %(name)s %(levelname)s %(message)s',
+                    datefmt='%H:%M:%S',
+                    level=logging.DEBUG)
+
+while True:
+    receivedMessage = getMessage()
+    devnull = open(os.devnull, 'w')
+    counter += 1
+    logging.info(f'[{counter}] {receivedMessage}')
+    sendMessage(encodeMessage(f'Logged message No. {counter}'))