Add initial pass at proxy server.

See __doc__ on run_server, or do "script/tsapp help".

The goal here is to be able to work on local files that are
currently formatted for use on the remote server without having
to change them, and then once those files are "good" being able to
get them to the server without changes.

In order to be fully effective the proxy will need to proxy PUT
as well as GET, but this just does GET for now.

script/tsapp

@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+
+import sys, os
+
+# extend module search path for dev access and use
+cwd = os.getcwd()
+sys.path.insert(0, cwd)
+
+from tsapp import handle
+
+if __name__ == '__main__':
+    args = [unicode(arg, 'UTF-8') for arg in sys.argv[1:]]
+    handle(args)

tsapp/__init__.py

@@ -1,3 +1,81 @@
 """
-holder
+Basic starting point for tsapp commands.
 """
+
+import sys
+
+def error_exit(code, message=""):
+    """
+    Exit with code and provided message.
+    """
+    if message:
+        sys.stderr.write("%s\n" % message)
+    sys.exit(code)
+
+
+def read_config():
+    """
+    Read the local config to manage options.
+
+    TODO: Get local overrides for things like target server.
+    """
+    pass
+
+
+def run_server(args):
+    """
+    Run a wsgi server at :8080 which will look locally for content
+    and if not found there, look remotely. A path which takes the
+    form /bags/something/tiddlers/filename will look in the local
+    dir called "assets" for "filename". If the file is not found, the
+    full path will be looked up at tiddlyspace.com.
+    
+    If the path is a single file or begins with "/" then the file
+    will be looked for in the local dir without failover to the
+    remote server.
+
+    At the moment only GET is handled. PUT is recognized, but not
+    yet proxied. When it is implemented it will only proxy, no
+    local handing will be done.
+    """
+    read_config()
+
+    from wsgiref.simple_server import make_server
+    from tsapp.proxy import app
+
+    httpd = make_server('', 8080, app)
+
+    print "Serving on http://0.0.0.0:8080/index.html"
+
+    try:
+        httpd.serve_forever()
+    except KeyboardInterrupt:
+        sys.exit(0)
+
+
+def show_help(args):
+    """
+    Display this help.
+    """
+    for command in COMMANDS:
+        print '%s%s' % (command, COMMANDS[command].__doc__)
+
+
+COMMANDS = {
+        'serve': run_server,
+        'help': show_help
+        }
+
+def handle(args):
+    """
+    Process command line arguments to call commands.
+    """
+    try:
+        command = args.pop(0)
+        functor = COMMANDS[command]
+        functor(args)
+    except IndexError:
+        error_exit(1, "command required")
+    except KeyError:
+        error_exit(1, "command unknown")
+    # let others raise themselves, for now

tsapp/proxy.py

@@ -0,0 +1,57 @@
+"""
+WSGI app that provides a proxy to tiddlyspace as needed.
+"""
+
+import os
+import mimetypes
+import urllib2
+
+
+def app(environ, start_response):
+    if environ['REQUEST_METHOD'].upper() == 'PUT':
+        return handle_put(environ, start_response)
+    else:
+        return handle_get(environ, start_response)
+
+def handle_put(environ, start_response):
+    pass
+
+def handle_get(environ, start_response):
+    path = environ['PATH_INFO']
+
+    path = path.lstrip('/')
+    path_parts = path.split('/')
+
+    if len(path_parts) == 1:
+        try:
+            filehandle = open(path)
+            mime_type = mimetypes.guess_type(path)[0]
+        except IOError:
+            start_response('404 Not Found', [])
+            return []
+    else:
+        local_path = path_parts[-1]
+        try:
+            filehandle = in_assets(local_path)
+            mime_type = mimetypes.guess_type(local_path)[0]
+        except IOError:
+            try:
+                filehandle = at_server(path)
+                mime_type = filehandle.info().gettype()
+            except IOError, exc:
+                code = exc.getcode()
+                start_response(str(code) + ' error', [])
+                return []
+
+    start_response('200 OK', [('Content-Type', mime_type)])
+    return filehandle
+
+
+def in_assets(path):
+    return open(os.path.join('.', 'assets', path))
+
+def at_server(path):
+    if not path.startswith('/'):
+        path = '/%s' % path
+    return urllib2.urlopen('http://tiddlyspace.com' + path)
+