From c21c8713d34b649717fc76e0d6d7afa28409a4a1 Mon Sep 17 00:00:00 2001
From: Fredrik Tolf <fredrik@dolda2000.com>
Date: Wed, 14 Mar 2012 21:26:42 +0100
Subject: [PATCH] Added a, perhaps overly simplistic, multipart form handler.

---
 wrw/form.py | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)

diff --git a/wrw/form.py b/wrw/form.py
index af599e6..1f0e530 100644
--- a/wrw/form.py
+++ b/wrw/form.py
@@ -1,4 +1,5 @@
 import cgi
+import proto
 
 __all__ = ["formdata"]
 
@@ -36,5 +37,143 @@ class formwrap(object):
     def values(self):
         return [val for key, val in self.items()]
 
+class badmultipart(Exception):
+    pass
+
+class formpart(object):
+    def __init__(self, form):
+        self.form = form
+        self.buf = ""
+        self.eof = False
+        self.head = {}
+
+    def parsehead(self):
+        pass
+
+    def fillbuf(self, sz):
+        req = self.form.req
+        mboundary = "\r\n--" + self.form.boundary + "\r\n"
+        lboundary = "\r\n--" + self.form.boundary + "--\r\n"
+        while not self.eof:
+            p = self.form.buf.find(mboundary)
+            if p >= 0:
+                self.buf += self.form.buf[:p]
+                self.form.buf = self.form.buf[p + len(mboundary):]
+                self.eof = True
+                break
+            p = self.form.buf.find(lboundary)
+            if p >= 0:
+                self.buf += self.form.buf[:p]
+                self.form.buf = self.form.buf[p + len(lboundary):]
+                self.eof = True
+                self.form.eof = True
+                break
+            self.buf += self.form.buf[:-len(lboundary)]
+            self.form.buf = self.form.buf[-len(lboundary):]
+            if sz >= 0 and len(self.buf) >= sz:
+                break
+            while len(self.form.buf) <= len(lboundary):
+                ret = req.env["wsgi.input"].read(8192)
+                if ret == "":
+                    raise badmultipart("Missing last multipart boundary")
+                self.form.buf += ret
+
+    def read(self, limit = -1):
+        self.fillbuf(limit)
+        if limit >= 0:
+            ret = self.buf[:limit]
+            self.buf = self.buf[limit:]
+        else:
+            ret = self.buf
+            self.buf = ""
+        return ret
+
+    def readline(self, limit = -1):
+        last = 0
+        while True:
+            p = self.buf.find('\n', last)
+            if p < 0:
+                if self.eof:
+                    ret = self.buf
+                    self.buf = ""
+                    return ret
+                last = len(self.buf)
+                self.fillbuf(last + 128)
+            else:
+                ret = self.buf[:p + 1]
+                self.buf = self.buf[p + 1:]
+                return ret
+
+    def close(self):
+        self.fillbuf(-1)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *excinfo):
+        return False
+
+    def parsehead(self):
+        def headline():
+            ln = self.readline(256)
+            if ln[-1] != '\n':
+                raise badmultipart("Too long header line in part")
+            return ln.rstrip()
+
+        ln = headline()
+        while True:
+            if ln == "":
+                break
+            buf = ln
+            while True:
+                ln = headline()
+                if not ln[1:].isspace():
+                    break
+                buf += ln.lstrip()
+            p = buf.find(':')
+            if p < 0:
+                raise badmultipart("Malformed multipart header line")
+            self.head[buf[:p].strip().lower()] = buf[p + 1:].lstrip()
+
+        val, par = proto.pmimehead(self.head.get("content-disposition", ""))
+        if val != "form-data":
+            raise badmultipart("Unexpected Content-Disposition in form part: %r" % val)
+        if not "name" in par:
+            raise badmultipart("Missing name in form part")
+        self.name = par["name"]
+        self.filename = par.get("filename")
+        val, par = proto.pmimehead(self.head.get("content-type", ""))
+        self.ctype = val
+        self.charset = par.get("charset")
+        encoding = self.head.get("content-transfer-encoding", "binary")
+        if encoding != "binary":
+            raise badmultipart("Form part uses unexpected transfer encoding: %r" % encoding)
+
+class multipart(object):
+    def __init__(self, req):
+        val, par = proto.pmimehead(req.ihead.get("Content-Type", ""))
+        if req.method != "POST" or val != "multipart/form-data":
+            raise badmultipart("Request is not a multipart form")
+        if "boundary" not in par:
+            raise badmultipart("Multipart form lacks boundary")
+        self.boundary = par["boundary"]
+        self.req = req
+        self.buf = "\r\n"
+        self.eof = False
+        self.lastpart = formpart(self)
+        self.lastpart.close()
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        if not self.lastpart.eof:
+            raise RuntimeError("All form parts must be read entirely")
+        if self.eof:
+            raise StopIteration()
+        self.lastpart = formpart(self)
+        self.lastpart.parsehead()
+        return self.lastpart
+
 def formdata(req):
     return req.item(formwrap)
-- 
2.11.0