Twisted下的Flash文件上传

Daniel Yang 撰写  

Flash Player的文件上传很是让人憋火。除了PHP,CF,Asp.net和它配合良好–不会有差错。
Python下就没有那么方便了。
我曾经在web.py下,试了几天,后来没法子用Django才搞定的。
总是有莫名其妙的问题。

我在Twisted的邮件列表里发了一通:

I’ve been trying to upload files to twisted.web2 backend(FileSaver) with Adobe Flex and I am always getting IOError.
(code see below)
After some sniffing work, I found the error messages returned by twisted.web2:

Unexpected data on same line as boundary: ‘–’

I believe this flex app works with php backend. So this might be with twisted.web2 or flash player’s malformed post data.

It seems the twisted error comes from fileupload.py:
(I added 2 prints)

    def _readBoundaryLine(self):
        print "_readBoundaryLine"
        line = self.stream.readline(size=1024)
        if isinstance(line, defer.Deferred):
            line = defer.waitForDeferred(line)
            yield line
            line = line.getResult()
        print line
        if line == "--\r\n":
            # THE END!
            yield False
            return
        elif line != "\r\n":
            raise MimeFormatError("Unexpected data on same line as boundary: %r" % (line,))
        yield True
        return
    _readBoundaryLine = defer.deferredGenerator(_readBoundaryLine)

with html uploading form, it outputs:

2009-08-20 23:06:08+0800 [-] _readBoundaryLine
2009-08-20 23:06:08+0800 [-] –
2009-08-20 23:06:08+0800 [-]
2009-08-20 23:06:08+0800 [-] ——–
2009-08-20 23:06:08+0800 [-] FileUpload

but with flex uploading:

2009-08-20 23:06:27+0800 [-] _readBoundaryLine
2009-08-20 23:06:27+0800 [-]
2009-08-20 23:06:27+0800 [-]
2009-08-20 23:06:27+0800 [-] _readBoundaryLine
2009-08-20 23:06:27+0800 [-]
2009-08-20 23:06:27+0800 [-]
2009-08-20 23:06:27+0800 [-] _readBoundaryLine
2009-08-20 23:06:27+0800 [-] –

Same file, different posted data.

Any ideas?

Does this happen to be a bug, or is there any way to walk around this?

My testing code:

python code:

from twisted.web2 import http_headers, resource, \
	static, server, channel, http, responsecode
from twisted.python import util

FORMHTML = """
<html>
<p>for test</p>
<form action="/upload" method="post" enctype="multipart/form-data">
	<input type="file" name="FileUpload" />
	<input type="submit" value="Upload"/>
</form>
</html>
"""

class MyFileSaver(static.FileSaver):
	"""for test only"""
	def render(self, req):
		print req, '--------'
		if req.files:
			for fieldName in req.files:
				print fieldName

		return http.Response(responsecode.OK, {}, stream='ok')

class Toplevel(resource.Resource):
  addSlash = True
  def render(self, ctx):
	return http.Response(stream=FORMHTML)

  child_upload = MyFileSaver(util.sibpath(__file__, ''),
  	expectedFields=['FileUpload'],
  		allowedTypes=(
  			http_headers.MimeType('image', 'jpeg'),
  			http_headers.MimeType('image', 'png'),
  			http_headers.MimeType('image', 'gif'),
  		)
  	)
  child_swf = static.File(util.sibpath(__file__, 'FileUpload.swf'))
site = server.Site(Toplevel())

# Standard twisted application Boilerplate
from twisted.application import service, strports
application = service.Application("demoserver")
s = strports.service('tcp:8080', channel.HTTPFactory(site))
s.setServiceParent(application)

My flex code:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/09/21/uploading-files-in-flex-using-the-filereference-class/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        creationComplete="init();">

    <mx:Script>
        <![CDATA[
            private var fileRef:FileReference;

            private const FILE_UPLOAD_URL:String = "http://127.0.0.1:8080/upload";

            private function init():void {
                fileRef = new FileReference();
                fileRef.addEventListener(Event.SELECT, fileRef_select);
                fileRef.addEventListener(ProgressEvent.PROGRESS, fileRef_progress);
                fileRef.addEventListener(Event.COMPLETE, fileRef_complete);
                fileRef.addEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler);
                fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onSec);
            }

            private function browseAndUpload():void {
                fileRef.browse();
                message.text = "";
            }

            private function ioErrorHandler(event:IOErrorEvent):void {
            	trace(event);
            }

            private function onSec(event:SecurityErrorEvent):void{
            	trace(event);
            }

            private function fileRef_select(evt:Event):void {
                try {
                    message.text = "size (bytes): " + numberFormatter.format(fileRef.size);

                    var req:URLRequest = new URLRequest();
                    req.url = FILE_UPLOAD_URL;
                    req.method = URLRequestMethod.POST;

                    fileRef.upload(req, "FileUpload");
                } catch (err:Error) {
                    message.text = "ERROR: zero-byte file";
                }
            }

            private function fileRef_progress(evt:ProgressEvent):void {
                progressBar.visible = true;
            }

            private function fileRef_complete(evt:Event):void {
                message.text += " (complete)";
                progressBar.visible = false;
            }
        ]]>
    </mx:Script>

    <mx:NumberFormatter id="numberFormatter" />

    <mx:Button label="Upload file"
            click="browseAndUpload();" />
    <mx:Label id="message" />
    <mx:ProgressBar id="progressBar"
            indeterminate="true"
            visible="false" />

</mx:Application>

解决方法:
暂时没有,但是有一个patch:

http://twistedmatrix.com/trac/ticket/2113

一起哭吧。。。


3 条评论

  1. 发表了 2009年09月8日 在 11:10 上午 | 永久链接 |

    虽然不会python,还是顶一个!

  2. peerless
    发表了 2009年09月8日 在 9:39 下午 | 永久链接 |

    额,过几天和你一起哭

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