Merge from trunk

[plcapi.git] / trunk / PLC / API.py

diff --git a/trunk/PLC/API.py b/trunk/PLC/API.py
new file mode 100644 (file)
index 0000000..7fcfa09
--- /dev/null
+++ b/trunk/PLC/API.py
@@ -0,0 +1,174 @@
+#
+# PLCAPI XML-RPC and SOAP interfaces
+#
+# Aaron Klingaman <alk@absarokasoft.com>
+# Mark Huang <mlhuang@cs.princeton.edu>
+#
+# Copyright (C) 2004-2006 The Trustees of Princeton University
+# $Id$
+#
+
+import sys
+import traceback
+import string
+
+import xmlrpclib
+
+# See "2.2 Characters" in the XML specification:
+#
+# #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD]
+# avoiding
+# [#x7F-#x84], [#x86-#x9F], [#xFDD0-#xFDDF]
+
+invalid_xml_ascii = map(chr, range(0x0, 0x8) + [0xB, 0xC] + range(0xE, 0x1F))
+xml_escape_table = string.maketrans("".join(invalid_xml_ascii), "?" * len(invalid_xml_ascii))
+
+def xmlrpclib_escape(s, replace = string.replace):
+    """
+    xmlrpclib does not handle invalid 7-bit control characters. This
+    function augments xmlrpclib.escape, which by default only replaces
+    '&', '<', and '>' with entities.
+    """
+
+    # This is the standard xmlrpclib.escape function
+    s = replace(s, "&", "&amp;")
+    s = replace(s, "<", "&lt;")
+    s = replace(s, ">", "&gt;",)
+
+    # Replace invalid 7-bit control characters with '?'
+    return s.translate(xml_escape_table)
+
+def xmlrpclib_dump(self, value, write):
+    """
+    xmlrpclib cannot marshal instances of subclasses of built-in
+    types. This function overrides xmlrpclib.Marshaller.__dump so that
+    any value that is an instance of one of its acceptable types is
+    marshalled as that type.
+
+    xmlrpclib also cannot handle invalid 7-bit control characters. See
+    above.
+    """
+
+    # Use our escape function
+    args = [self, value, write]
+    if isinstance(value, (str, unicode)):
+        args.append(xmlrpclib_escape)
+
+    try:
+        # Try for an exact match first
+        f = self.dispatch[type(value)]
+    except KeyError:
+        # Try for an isinstance() match
+        for Type, f in self.dispatch.iteritems():
+            if isinstance(value, Type):
+                f(*args)
+                return
+        raise TypeError, "cannot marshal %s objects" % type(value)
+    else:
+        f(*args)
+
+# You can't hide from me!
+xmlrpclib.Marshaller._Marshaller__dump = xmlrpclib_dump
+
+# SOAP support is optional
+try:
+    import SOAPpy
+    from SOAPpy.Parser import parseSOAPRPC
+    from SOAPpy.Types import faultType
+    from SOAPpy.NS import NS
+    from SOAPpy.SOAPBuilder import buildSOAP
+except ImportError:
+    SOAPpy = None
+
+from PLC.Config import Config
+from PLC.Faults import *
+import PLC.Methods
+
+class PLCAPI:
+    methods = PLC.Methods.methods
+
+    def __init__(self, config = "/etc/planetlab/plc_config", encoding = "utf-8"):
+        self.encoding = encoding
+
+        # Better just be documenting the API
+        if config is None:
+            return
+
+        # Load configuration
+        self.config = Config(config)
+       
+       # Initialize database connection
+        if self.config.PLC_DB_TYPE == "postgresql":
+            from PLC.PostgreSQL import PostgreSQL
+            self.db = PostgreSQL(self)
+
+        else:
+            raise PLCAPIError, "Unsupported database type " + self.config.PLC_DB_TYPE
+
+    def callable(self, method):
+        """
+        Return a new instance of the specified method.
+        """
+
+        # Look up method
+        if method not in self.methods:
+            raise PLCInvalidAPIMethod, method
+
+        # Get new instance of method
+        try:
+            classname = method.split(".")[-1]
+            module = __import__("PLC.Methods." + method, globals(), locals(), [classname])
+            return getattr(module, classname)(self)
+        except ImportError, AttributeError:
+            raise PLCInvalidAPIMethod, method
+
+    def call(self, source, method, *args):
+        """
+        Call the named method from the specified source with the
+        specified arguments.
+        """
+
+        function = self.callable(method)
+        function.source = source
+        return function(*args)
+
+    def handle(self, source, data):
+        """
+        Handle an XML-RPC or SOAP request from the specified source.
+        """
+
+        # Parse request into method name and arguments
+        try:
+            interface = xmlrpclib
+            (args, method) = xmlrpclib.loads(data)
+            methodresponse = True
+        except Exception, e:
+            if SOAPpy is not None:
+                interface = SOAPpy
+                (r, header, body, attrs) = parseSOAPRPC(data, header = 1, body = 1, attrs = 1)
+                method = r._name
+                args = r._aslist()
+                # XXX Support named arguments
+            else:
+                raise e
+
+        try:
+            result = self.call(source, method, *args)
+        except PLCFault, fault:
+            # Handle expected faults
+            if interface == xmlrpclib:
+                result = fault
+                methodresponse = None
+            elif interface == SOAPpy:
+                result = faultParameter(NS.ENV_T + ":Server", "Method Failed", method)
+                result._setDetail("Fault %d: %s" % (fault.faultCode, fault.faultString))
+
+        # Return result
+        if interface == xmlrpclib:
+            if not isinstance(result, PLCFault):
+                result = (result,)
+            data = xmlrpclib.dumps(result, methodresponse = True, encoding = self.encoding, allow_none = 1)
+        elif interface == SOAPpy:
+            data = buildSOAP(kw = {'%sResponse' % method: {'Result': result}}, encoding = self.encoding)
+
+        return data