Am I parsing this HTTP POST request properly?
Let me start off by saying, I'm using the twisted.web framework. Twisted.web's file uploading didn't work like I wanted it to (it only included the file data, and not any other information), cgi.parse_multipart doesn't work like I want it to (same thing, twisted.web uses this function), cgi.FieldStorage didn't work ('cause I'm getting the POST data through twisted, not a CGI interface -- so far as I can tell, FieldStorage tries to get the request via stdin), and twisted.web2 didn't work for me because the use of Deferred confused and infuriated me (too complicated for what I want).
That being said, I decided to try and just parse the HTTP request myself.
Using Chrome, the HTTP request is formed like this:
------WebKitFormBoundary7fouZ8mEjlCe92pq
Content-Disposition: form-data; name="upload_file_nonce"
11b03b61-9252-11df-a357-00266c608adb
------WebKitFormBoundary7fouZ8mEjlCe92pq
Content-Disposition: form-data; name="file"; filename="login.html"
Content-Type: text/html
<!DOCTYPE html>
<html>
<head>
...
------WebKitFormBoundary7fouZ8mEjlCe92pq
Content-Disposition: form-data; name="file"; filename=""
------WebKitFormBoundary7fouZ8mEjlCe92pq--
Is this always how it will be formed? I'm parsing it with regular expressions, like so (pardon the wall of code):
(note, I snipped out most of the code to show only what I thought was relevant (the regular expressions (yeah, nested parentheses), this is an __init__ method (the only method so far) in an Uploads class I built. The full code can be seen in the revision history (I hope I didn't mismatch any parentheses)
if line == "--{0}--".format(boundary):
finished = True
if in_header == True and not line:
in_header = False
if 'type' not in current_file:
ignore_current_file = True
if in_header == True:
m = re.match(
"Content-Disposition: form-data; name=\"(.*?)\"; filename=\"(.*?)\"$", line)
if m:
input_name, current_file['filename'] = m.group(1), m.group(2)
m = re.match("Content-Type: (.*)$", line)
if m:
current_file['type'] = m.group(1)
else:
if 'data' not in current_file:
current_file['data'] = line
else:
current_file['data'] += line
you can see that I start a new "file" dict whenever a boundary is reached. I set in_header to True to say that I'm parsing headers. When I reach a blank line, I switch it to False -- but not before checking if a Content-Type was set for that form value -- if not, I set ignore_current_file since I'm only looking for file uploads.
I know I should be using a library, but I'm sick to death of reading documentation, trying to get different solutions to work in my project, and still having the code look reasonable. I just want to get past this part -- and if开发者_如何学编程 parsing an HTTP POST with file uploads is this simple, then I shall stick with that.
Note: this code works perfectly for now, I'm just wondering if it will choke on/spit out requests from certain browsers.
My solution to this Problem was parsing the content with cgi.FieldStorage like:
class Root(Resource):
def render_POST(self, request):
self.headers = request.getAllHeaders()
# For the parsing part look at [PyMOTW by Doug Hellmann][1]
img = cgi.FieldStorage(
fp = request.content,
headers = self.headers,
environ = {'REQUEST_METHOD':'POST',
'CONTENT_TYPE': self.headers['content-type'],
}
)
print img["upl_file"].name, img["upl_file"].filename,
print img["upl_file"].type, img["upl_file"].type
out = open(img["upl_file"].filename, 'wb')
out.write(img["upl_file"].value)
out.close()
request.redirect('/tests')
return ''
You're trying to avoid reading documentation, but I think the best advice is to actually read:
- rfc 2388 Returning Values from Forms: multipart/form-data
- rfc 1867 Form-based File Upload in HTML
to make sure you don't miss any cases. An easier route might be to use the poster library.
The content-disposition header has no defined order for fields, plus it may contain more fields than just the filename. So your match for filename may fail - there may not even be a filename!
See rfc2183 (edit that's for mail, see rfc1806, rfc2616 and maybe more for http)
Also I would suggest in these kind of regexps to replace every space by \s*, and not to rely on character case.
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