#!/usr/local/bin/python
import os
import stat
import sys
import BaseHTTPServer
import string
import email.feedparser

global gImageDirPath

class HTTPError (Exception):
    def __init__(self, statusCode, statusMessage=None):
        self.statusCode    = statusCode
        self.statusMessage = statusMessage

class MyHandler(BaseHTTPServer.BaseHTTPRequestHandler):

    def do_PUT(self):
        print "Server has accepted a client."
        global gImageDirPath
        
        try:
            assert self.path[0] == "/"

            fileName = self.path[1:]
            if fileName.translate(string.maketrans("", ""), string.ascii_letters + string.digits + "_") != ".":
                # Non-alphanumeric characters must be limited to exactly 
                # one dot, that is, the extension delimiter.
                raise HTTPError(403)

            # These Content-Type comparisons are too naive (they should be 
            # case insensitive, and they should ignore training parameters), 
            # but this is only a test server, not a real server.
            
            contentType = self.headers.get('Content-Type')
            if contentType == None or (contentType not in ["image/png", "image/jpeg", "image/gif"]):
                raise HTTPError(406)

            if contentType == "image/png" and not fileName.endswith(".png"):
                raise HTTPError(406)

            if contentType == "image/jpeg" and not fileName.endswith(".jpg"):
                raise HTTPError(406)
            
            contentLength = self.headers.get('Content-Length')
            if contentLength == None:
                raise HTTPError(411)

            try:
                fileLength = int(contentLength)
                print "fileLength == " + contentLength
                assert fileLength > 0
            except:
                raise HTTPError(411)

            filePath = os.path.join(gImageDirPath, fileName)
            print "filePath == \"" + filePath + "\""
            fileExists = os.path.exists(filePath)

            imageFile = open(filePath, "w")
            
            # Transfer the data in MB chunks to prevent us being run out of 
            # memory with large files.
            
            bytesReadSoFar = 0
            while bytesReadSoFar != fileLength:
                bytesToRead = (fileLength - bytesReadSoFar)
                if bytesToRead > (1024 * 1024):
                    bytesToRead = (1024 * 1024)
                
                data = self.rfile.read(bytesToRead)
                bytesReadSoFar += len(data)

                imageFile.write(data)

                data = None

            imageFile.close()
            
            if fileExists:
                self.send_response(200)
            else:
                self.send_response(201)                
            self.end_headers()

            # Change the mode bits of the downloaded image file to r--r--r--.
            os.chmod(filePath, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)

        except HTTPError, e:
            self.send_error(e.statusCode, e.statusMessage)
        except:
            self.send_error(500, "Internal Server Error")

def main():
    global gImageDirPath
    
    gImageDirPath = os.path.join(os.curdir, "images")
    print "gImageDirPath == \"" + gImageDirPath + "\""
    if not os.path.exists(gImageDirPath):
        os.mkdir(gImageDirPath)
    
    server = BaseHTTPServer.HTTPServer(('', 3000), MyHandler)
    print "Server is running on i5.nyu.edu."
    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print ""

if __name__ == "__main__":
    main()