Twisted server that serves up images in a directory

imageServer.py

from twisted.web.resource import Resource
from twisted.web import server
from twisted.python import log
from twisted.internet import defer
import os
from datetime import datetime
from twisted.protocols.basic import FileSender

##########################
#### Global Variables ####
##########################

BASE_PATH = None
PORT = 8000

###################################
#### Root and utility resources ###
###################################

class RootResource(Resource):
    def __init__(self):
        Resource.__init__(self)
        self.putChild('image', ImageRootResource())

class ImageRootResource(Resource):
    def getChild(self, path, request):
        try:
            return ImageResource(path)
        except ValueError:
            return BadResource()

class ImageResource(Resource):
    def __init__(self, image_key):

        # key will be soemthing like 22_cropped
        self.image_key = image_key
        Resource.__init__(self)

    def render_GET(self, request):
        @defer.inlineCallbacks
        def _showImage():

            # Set up so that you type the name of the file without the extension
            # e.g. host:port/image/photo to see file /path/to/file/photo.jpg
            # could make it so the key is just the full name of the file, but then it can serve up anything

            jpgpath = "%s/%s.jpg" % (BASE_PATH, self.image_key)
            gifpath = "%s/%s.gif" % (BASE_PATH, self.image_key)
            pngpath = "%s/%s.png" % (BASE_PATH, self.image_key)

            print "Image path", jpgpath, gifpath, pngpath

            @defer.inlineCallbacks
            def _setContentDispositionAndSend(file_path, image_key, extension, content_type):
                request.setHeader('content-disposition', 'filename="%s.%s"' % (image_key, extension))
                request.setHeader('content-type', content_type)

                f = open(file_path, "rb")
                yield FileSender().beginFileTransfer(f, request)
                f.close()
                defer.returnValue(0)

            if os.path.exists(jpgpath):
                yield _setContentDispositionAndSend(jpgpath, self.image_key, ".jpg", "image/jpeg")
            elif os.path.exists(gifpath):
                yield _setContentDispositionAndSend(gifpath, self.image_key, ".gif", "image/gif")
            elif os.path.exists(pngpath):
                yield _setContentDispositionAndSend(pngpath, self.image_key, ".png", "image/png")
            else:
                request.setResponseCode(http.NOT_FOUND)
                request.write("No such image '%s'" % request.path)
            
            request.finish()

            defer.returnValue(0)

        _showImage()
        return server.NOT_DONE_YET


##########################
#### Main! ###############
#### Go, little server! ##
##########################

if __name__ == "__main__":
    from twisted.internet import reactor  
    from sys import stdout
    import sys
    from time import gmtime, strftime
    log_file = "log_" + strftime("%Y-%m-%d_%H:%M:%S", gmtime()) + ".txt"
            
    from twisted.python.log import FileLogObserver, startLogging, addObserver, msg

    # First, startLogging to capture stdout
    startLogging(stdout)

    # Now add an observer that logs to a file
    addObserver(FileLogObserver(open(log_file, "w")).emit)
    

    if not BASE_PATH:
        BASE_PATH = sys.path[0]

    print "Base path for images is", BASE_PATH

    reactor.listenTCP(PORT,server.Site(RootResource()))

    log.msg("running...")
    reactor.run()