From fa6720574520719540bdfc0044ddbb58dece147c Mon Sep 17 00:00:00 2001
From: Filipp Lepalaan <filipp@mekanisti.fi>
Date: Tue, 20 Oct 2009 06:13:04 +0300
Subject: Initial commit

---
 config.yaml |   3 ++
 relay.py    | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 config.yaml
 create mode 100644 relay.py

diff --git a/config.yaml b/config.yaml
new file mode 100644
index 0000000..bd2ccdb
--- /dev/null
+++ b/config.yaml
@@ -0,0 +1,3 @@
+- default:
+    source: user:pass@server/folder
+    destination: user:pass@otherserver/folder
diff --git a/relay.py b/relay.py
new file mode 100644
index 0000000..495e6e9
--- /dev/null
+++ b/relay.py
@@ -0,0 +1,117 @@
+"""
+  MediaRelay/relay.py
+  Uploads new FTP files to other server.
+  This doesn't synchronize stuff, just copies new things from A to B
+  @author Filipp Lepalaan <filipp@mac.com>
+  @created 19.10.2009
+  
+  1. Poll folder on FTP server A for changes
+  2. Copy changed files to local machine
+  3. Upload changed files to FTP server B
+  - What if the changed file is just being uploaded to server A? (must use separate folder? Maybe the
+  server is smart enough not to list an incomplete file?)
+  - What if the poller runs before the last upload finishes? (fixed with PID checking)
+  - Does "LIST -T" work on any FTP server? (no, but we don't need it)
+  - What does "changes on server A" mean? (aything not in the local skiplist)
+  - What if the new item is a folder? (will throw exception)
+  - What if there are more than 1 new file? (it's OK)
+"""
+import yaml, pickle, os, sys, re
+from ftplib import FTP
+
+tmp_path    = ""
+sl_path     = ".skiplist"
+pfile_path  = "/private/tmp/MediaRelay.pid"
+
+# Borrowed from http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/
+try:
+  pf = file(pfile_path, "r")
+  pid = int(pf.read().strip())
+  pf.close()
+except Exception, e:
+  pid = None
+  
+if pid:
+  sys.stderr.write("Relay already running with PID %d\n" % (pid))
+  sys.exit(1)
+
+try:
+  c = yaml.load(file("config.yaml", "r"))
+except Exception, e:
+  sys.stderr.write("Cannot load config file")
+  sys.exit(1)
+
+# Remember who we are just in case this gets called during transfer
+pid = str(os.getpid())
+pf = file(pfile_path, "w")
+pf.write(pid)
+pf.close()
+
+# The global skiplist stores the listings of all configs
+g_skiplist = {}
+
+# Loop through the config
+for l in c:
+  for k in l:
+    (src_auth, src_url) = re.split("@", l[k]['source'])
+    (src_uname, src_pwd) = re.split(":", src_auth)
+    (src_host, src_path) = re.split("/", src_url, maxsplit=1)
+    (dst_auth, dst_url) = re.split("@", l[k]['destination'])
+    (dst_uname, dst_pwd) = re.split(":", dst_auth)
+    (dst_host, dst_path) = re.split("/", dst_url, maxsplit=1)
+
+    ftp_source = FTP(src_host)
+    ftp_source.login(src_uname, src_pwd)
+
+    ftp_destination = FTP(dst_host)
+    ftp_destination.login(dst_uname, src_pwd)
+    
+    new = []; srv_list = []; skiplist = []
+    
+    # Load skiplist from file
+    try:
+      skiplist = pickle.load(file(sl_path, "r"))
+    except Exception, e:
+      skiplist = {k:[]}
+      g_skiplist[k] = []
+    
+    # Load current list from source server
+    srv_list = ftp_source.nlst(src_path)
+    # Filter out skiplist
+    new = filter(lambda i: i not in skiplist[k], srv_list)
+      
+    print "-- checking %s" % (k)
+
+    # Download new files
+    for f in new:
+      try:
+        print "  <- getting %s" % (f)
+        ftp_cmd = "RETR %s/%s" % (src_path, f)
+        ftp_source.retrbinary(ftp_cmd, open(f, "wb").write)
+      except Exception, e:
+        sys.stderr.write("Error getting %s - %s\n" % (f, e))
+      else:
+        try:
+          # Upload new file to destination
+          print "  -> sending %s" % (f)
+          ftp_cmd = "STOR %s/%s" % (dst_path, f)
+          ftp_destination.storbinary(ftp_cmd, open(f, "r"))
+        except Exception, e:
+          sys.stderr.write("Error sending %s - %s\n" % (f, e))
+  
+      os.remove(f)
+
+    if len(new) < 1:
+      print "  -- nothing to download"
+    
+    # Update global skiplist
+    g_skiplist[k] = srv_list
+    
+    # Close FTP connections
+    ftp_source.close(); ftp_destination.close()
+
+# Update skiplist
+pickle.dump(g_skiplist, file(sl_path, "w"))
+
+# Remove PID file
+os.remove(pfile_path)
-- 
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