Source Code for Module gluon.streamer

  1  #!/usr/bin/env python 
  2  # -*- coding: utf-8 -*- 
  3   
  4  """ 
  5  This file is part of the web2py Web Framework 
  6  Copyrighted by Massimo Di Pierro <mdipierro@cs.depaul.edu> 
  7  License: LGPLv3 (http://www.gnu.org/licenses/lgpl.html) 
  8  """ 
  9   
 10  import os 
 11  import stat 
 12  import time 
 13  import re 
 14  import errno 
 15  import rewrite 
 16  from gluon.http import HTTP 
 17  from gluon.contenttype import contenttype 
 18   
 19   
 20  regex_start_range = re.compile('\d+(?=\-)') 
 21  regex_stop_range = re.compile('(?<=\-)\d+') 
 22   
 23  DEFAULT_CHUNK_SIZE = 64 * 1024 
 24   
 25   
 26 -def streamer(stream, chunk_size=DEFAULT_CHUNK_SIZE, bytes=None): 
 27      offset = 0 
 28      while bytes is None or offset < bytes: 
 29          if not bytes is None and bytes - offset < chunk_size: 
 30              chunk_size = bytes - offset 
 31          data = stream.read(chunk_size) 
 32          length = len(data) 
 33          if not length: 
 34              break 
 35          else: 
 36              yield data 
 37          if length < chunk_size: 
 38              break 
 39          offset += length 
 40      stream.close() 
 41   
 42   
 43 -def stream_file_or_304_or_206( 
 44      static_file, 
 45      chunk_size=DEFAULT_CHUNK_SIZE, 
 46      request=None, 
 47      headers={}, 
 48      status=200, 
 49      error_message=None 
 50      ): 
 51      if error_message is None: 
 52          error_message = rewrite.THREAD_LOCAL.routes.error_message % 'invalid request' 
 53      try: 
 54          fp = open(static_file) 
 55      except IOError, e: 
 56          if e[0] == errno.EISDIR: 
 57              raise HTTP(403, error_message, web2py_error='file is a directory') 
 58          elif e[0] == errno.EACCES: 
 59              raise HTTP(403, error_message, web2py_error='inaccessible file') 
 60          else: 
 61              raise HTTP(404, error_message, web2py_error='invalid file') 
 62      else: 
 63          fp.close() 
 64      stat_file = os.stat(static_file) 
 65      fsize = stat_file[stat.ST_SIZE] 
 66      modified = stat_file[stat.ST_MTIME] 
 67      mtime = time.strftime('%a, %d %b %Y %H:%M:%S GMT', time.gmtime(modified)) 
 68      headers.setdefault('Content-Type', contenttype(static_file)) 
 69      headers.setdefault('Last-Modified', mtime) 
 70      headers.setdefault('Pragma', 'cache') 
 71      headers.setdefault('Cache-Control', 'private') 
 72   
 73      # if this is a normal response and not a respnse to an error page 
 74      if status == 200: 
 75          if request and request.env.http_if_modified_since == mtime: 
 76              raise HTTP(304, **{'Content-Type': headers['Content-Type']}) 
 77   
 78          elif request and request.env.http_range: 
 79              start_items = regex_start_range.findall(request.env.http_range) 
 80              if not start_items: 
 81                  start_items = [0] 
 82              stop_items = regex_stop_range.findall(request.env.http_range) 
 83              if not stop_items or int(stop_items[0]) > fsize - 1: 
 84                  stop_items = [fsize - 1] 
 85              part = (int(start_items[0]), int(stop_items[0]), fsize) 
 86              bytes = part[1] - part[0] + 1 
 87              try: 
 88                  stream = open(static_file, 'rb') 
 89              except IOError, e: 
 90                  if e[0] in (errno.EISDIR, errno.EACCES): 
 91                      raise HTTP(403) 
 92                  else: 
 93                      raise HTTP(404) 
 94              stream.seek(part[0]) 
 95              headers['Content-Range'] = 'bytes %i-%i/%i' % part 
 96              headers['Content-Length'] = '%i' % bytes 
 97              status = 206 
 98      # in all the other cases (not 304, not 206, but 200 or error page) 
 99      if status != 206: 
100          enc = request.env.http_accept_encoding 
101          if enc and 'gzip' in enc and not 'Content-Encoding' in headers: 
102              gzipped = static_file + '.gz' 
103              if os.path.isfile(gzipped) and os.path.getmtime(gzipped) >= modified: 
104                  static_file = gzipped 
105                  fsize = os.path.getsize(gzipped) 
106                  headers['Content-Encoding'] = 'gzip' 
107                  headers['Vary'] = 'Accept-Encoding' 
108          try: 
109              stream = open(static_file, 'rb') 
110          except IOError, e: 
111              # this better does not happer when returning an error page ;-) 
112              if e[0] in (errno.EISDIR, errno.EACCES): 
113                  raise HTTP(403) 
114              else: 
115                  raise HTTP(404) 
116          headers['Content-Length'] = fsize 
117          bytes = None 
118      if request and request.env.web2py_use_wsgi_file_wrapper: 
119          wrapped = request.env.wsgi_file_wrapper(stream, chunk_size) 
120      else: 
121          wrapped = streamer(stream, chunk_size=chunk_size, bytes=bytes) 
122      raise HTTP(status, wrapped, **headers) 
123