1 files changed, 316 insertions, 0 deletions
diff --git a/libmproxy/filt.py b/libmproxy/filt.py
new file mode 100644
index 00000000..49fff6c7
--- /dev/null
+++ b/libmproxy/filt.py
@@ -0,0 +1,316 @@
+
+# Copyright (C) 2010  Aldo Cortesi
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+    The following operators are understood:
+
+        ~q          Request
+        ~s          Response
+    
+    Headers:
+
+        Patterns are matched against "name: value" strings. Field names are
+        all-lowercase.
+
+        ~h rex      Header line in either request or response
+        ~hq rex     Header in request
+        ~hs rex     Header in response
+
+        ~b rex      Expression in the body of either request or response
+        ~bq rex     Expression in the body of request
+        ~bq rex     Expression in the body of response
+        ~t rex      Shortcut for content-type header.
+
+        ~u rex      URL
+        ~c CODE     Response code.
+        rex         Equivalent to ~u rex 
+"""
+import re, sys
+import pyparsing as pp
+
+
+class _Token:
+    def dump(self, indent=0, fp=sys.stdout):
+        print >> fp, "\t"*indent, self.__class__.__name__,
+        if hasattr(self, "expr"):
+            print >> fp, "(%s)"%self.expr,
+        print >> fp
+
+
+class _Action(_Token):
+    @classmethod
+    def make(klass, s, loc, toks):
+        return klass(*toks[1:])
+
+
+class FReq(_Action):
+    code = "q"
+    help = "Match request"
+    def __call__(self, conn):
+        return not conn.is_response()
+
+
+class FResp(_Action):
+    code = "s"
+    help = "Match response"
+    def __call__(self, conn):
+        return conn.is_response()
+    
+
+class _Rex(_Action):
+    def __init__(self, expr):
+        self.expr = expr
+        self.re = re.compile(self.expr)
+
+
+def _check_content_type(expr, o):
+    val = o.headers.get("content-type")
+    if val and re.search(expr, val[0]):
+        return True
+    return False
+    
+
+class FContentType(_Rex):
+    code = "t"
+    help = "Content-type header"
+    def __call__(self, o):
+        if _check_content_type(self.expr, o):
+            return True
+        elif o.is_response() and _check_content_type(self.expr, o.request):
+            return True
+        else:
+            return False
+
+
+class FRequestContentType(_Rex):
+    code = "tq"
+    help = "Request Content-Type header"
+    def __call__(self, o):
+        if o.is_response():
+            return _check_content_type(self.expr, o.request)
+        else:
+            return _check_content_type(self.expr, o)
+
+
+class FResponseContentType(_Rex):
+    code = "ts"
+    help = "Request Content-Type header"
+    def __call__(self, o):
+        if o.is_response():
+            return _check_content_type(self.expr, o)
+        else:
+            return False
+
+
+class FHead(_Rex):
+    code = "h"
+    help = "Header"
+    def __call__(self, o):
+        val = o.headers.match_re(self.expr)
+        if not val and o.is_response():
+            val = o.request.headers.match_re(self.expr)
+        return val
+    
+
+class FHeadRequest(_Rex):
+    code = "hq"
+    help = "Request header"
+    def __call__(self, o):
+        if o.is_response():
+            h = o.request.headers
+        else:
+            h = o.headers
+        return h.match_re(self.expr)
+
+
+class FHeadResponse(_Rex):
+    code = "hs"
+    help = "Response header"
+    def __call__(self, o):
+        if not o.is_response():
+            return False
+        return o.headers.match_re(self.expr)
+
+
+class FBod(_Rex):
+    code = "b"
+    help = "Body"
+    def __call__(self, o):
+        if o.content and re.search(self.expr, o.content):
+            return True
+        elif o.is_response() and o.request.content and re.search(self.expr, o.request.content):
+            return True
+        return False
+
+
+class FBodRequest(_Rex):
+    code = "bq"
+    help = "Request body"
+    def __call__(self, o):
+        if o.is_response() and o.request.content and re.search(self.expr, o.request.content):
+            return True
+        elif not o.is_response() and o.content and re.search(self.expr, o.content):
+            return True
+        return False
+
+
+class FBodResponse(_Rex):
+    code = "bs"
+    help = "Response body"
+    def __call__(self, o):
+        if not o.is_response():
+            return False
+        elif o.content and re.search(self.expr, o.content):
+            return True
+        return False
+        
+
+class FUrl(_Rex):
+    code = "u"
+    help = "URL"
+    # FUrl is special, because it can be "naked".
+    @classmethod
+    def make(klass, s, loc, toks):
+        if len(toks) > 1:
+            toks = toks[1:]
+        return klass(*toks)
+
+    def __call__(self, o):
+        if o.is_response():
+            c = o.request
+        else:
+            c = o
+        return re.search(self.expr, c.url())
+
+
+class _Int(_Action):
+    def __init__(self, num):
+        self.num = int(num)
+
+
+class FCode(_Int):
+    code = "c"
+    help = "HTTP response code"
+    def __call__(self, o):
+        if o.is_response():
+            return o.code == self.num
+        return False
+
+
+class FAnd(_Token):
+    def __init__(self, lst):
+        self.lst = lst
+
+    def dump(self, indent=0, fp=sys.stdout):
+        print >> fp, "\t"*indent, self.__class__.__name__
+        for i in self.lst:
+            i.dump(indent+1, fp)
+
+    def __call__(self, o):
+        return all([i(o) for i in self.lst])
+
+
+class FOr(_Token):
+    def __init__(self, lst):
+        self.lst = lst
+
+    def dump(self, indent=0, fp=sys.stdout):
+        print >> fp, "\t"*indent, self.__class__.__name__
+        for i in self.lst:
+            i.dump(indent+1, fp)
+
+    def __call__(self, o):
+        return any([i(o) for i in self.lst])
+
+
+class FNot(_Token):
+    def __init__(self, itm):
+        self.itm = itm[0]
+
+    def dump(self, indent=0, fp=sys.stdout):
+        print >> fp, "\t"*indent, self.__class__.__name__
+        self.itm.dump(indent + 1, fp)
+
+    def __call__(self, o):
+        return not self.itm(o)
+
+filt_unary = [
+    FReq,
+    FResp
+]
+filt_rex = [
+    FHeadRequest,
+    FHeadResponse,
+    FHead,
+    FBodRequest,
+    FBodResponse,
+    FBod,
+    FUrl,
+    FRequestContentType,
+    FResponseContentType,
+    FContentType,
+]
+filt_int = [
+    FCode
+]
+def _make():
+    # Order is important - multi-char expressions need to come before narrow
+    # ones.
+    parts = []
+    for klass in filt_unary:
+        f = pp.Literal("~%s"%klass.code)
+        f.setParseAction(klass.make)
+        parts.append(f)
+
+    simplerex = "".join([c for c in pp.printables if c not in  "()~'\""])
+    rex = pp.Word(simplerex) |\
+          pp.QuotedString("\"", escChar='\\') |\
+          pp.QuotedString("'", escChar='\\')
+    for klass in filt_rex:
+        f = pp.Literal("~%s"%klass.code) + rex.copy()
+        f.setParseAction(klass.make)
+        parts.append(f)
+
+    for klass in filt_int:
+        f = pp.Literal("~%s"%klass.code) + pp.Word(pp.nums)
+        f.setParseAction(klass.make)
+        parts.append(f)
+
+    # A naked rex is a URL rex:
+    f = rex.copy()
+    f.setParseAction(FUrl.make)
+    parts.append(f)
+
+    atom = pp.MatchFirst(parts)
+    expr = pp.operatorPrecedence(
+                atom,
+                [
+                    (pp.Literal("!").suppress(), 1, pp.opAssoc.RIGHT, lambda x: FNot(*x)),
+                    (pp.Literal("&").suppress(), 2, pp.opAssoc.LEFT, lambda x: FAnd(*x)),
+                    (pp.Literal("|").suppress(), 2, pp.opAssoc.LEFT, lambda x: FOr(*x)),
+                ]
+           )
+    expr = pp.OneOrMore(expr)
+    return expr.setParseAction(lambda x: FAnd(x) if len(x) != 1 else x)
+bnf = _make()
+
+
+def parse(s):
+    try:
+        return bnf.parseString(s, parseAll=True)[0]
+    except pp.ParseException:
+        return None
+