From fc62fac9864ad8d07a644c9e67505204baf64a88 Mon Sep 17 00:00:00 2001
From: Oleg Broytman <phd@phdru.name>
Date: Sun, 12 Jan 2025 23:36:11 +0300
Subject: [PATCH] Feat: List content of a torrent metafile

---
 eff_bdecode.py | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++
 ls-torrent     | 12 ++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 eff_bdecode.py
 create mode 100755 ls-torrent

diff --git a/eff_bdecode.py b/eff_bdecode.py
new file mode 100644
index 0000000..a3172ed
--- /dev/null
+++ b/eff_bdecode.py
@@ -0,0 +1,77 @@
+# effbot.org/zone/bencode.htm
+#
+# Copyright (C) 1995-2013 by Fredrik Lundh
+#
+# By obtaining, using, and/or copying this software and/or its associated
+# documentation, you agree that you have read, understood, and will comply with
+# the following terms and conditions:
+#
+# Permission to use, copy, modify, and distribute this software and its
+# associated documentation for any purpose and without fee is hereby granted,
+# provided that the above copyright notice appears in all copies, and that both
+# that copyright notice and this permission notice appear in supporting
+# documentation, and that the name of Secret Labs AB or the author not be used
+# in advertising or publicity pertaining to distribution of the software
+# without specific, written prior permission.
+#
+# SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+# SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
+# NO EVENT SHALL SECRET LABS AB OR THE AUTHOR BE LIABLE FOR ANY SPECIAL,
+# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+# PERFORMANCE OF THIS SOFTWARE.
+
+from functools import partial
+import re
+
+
+def tokenize(text, match=re.compile(b"([idel])|(\\d+):|(-?\\d+)").match):
+    i = 0
+    while i < len(text):
+        m = match(text, i)
+        s = m.group(m.lastindex)
+        i = m.end()
+        if m.lastindex == 2:
+            yield "s"
+            yield text[i:i+int(s)]
+            i = i + int(s)
+        else:
+            yield s.decode('ascii')
+
+
+def decode_item(next_, token):
+    if token == "i":
+        # integer: "i" value "e"
+        data = int(next_())
+        if next_() != "e":
+            raise ValueError
+    elif token == "s":
+        # string: "s" value (virtual tokens)
+        data = next_()
+    elif token == "l" or token == "d":
+        # container: "l" (or "d") values "e"
+        data = []
+        tok = next_()
+        while tok != "e":
+            data.append(decode_item(next_, tok))
+            try:
+                tok = next_()
+            except StopIteration:
+                break
+        if token == "d":
+            data = dict(zip(data[0::2], data[1::2]))
+    else:
+        raise ValueError
+    return data
+
+
+def eff_bdecode(text):
+    try:
+        src = tokenize(text)
+        data = decode_item(partial(next, src), next(src))
+        for token in src:  # look for more tokens
+            raise SyntaxError("trailing junk")
+    except (AttributeError, ValueError, StopIteration):
+        raise SyntaxError("syntax error")
+    return data
diff --git a/ls-torrent b/ls-torrent
new file mode 100755
index 0000000..2804c85
--- /dev/null
+++ b/ls-torrent
@@ -0,0 +1,12 @@
+#! /usr/bin/env python3
+
+import sys
+from pprint import pprint
+from eff_bdecode import eff_bdecode
+
+torrent_file = open(sys.argv[1], 'rb')
+data = torrent_file.read()
+torrent_file.close()
+
+torrent = eff_bdecode(data)
+pprint(torrent)
-- 
2.39.5