monitor/cherrypy/tutorial/tut09_files.py

   1 """
   2
   3 Tutorial: File upload and download
   4
   5 Uploads
   6 -------
   7
   8 When a client uploads a file to a CherryPy application, it's placed
   9 on disk immediately. CherryPy will pass it to your exposed method
  10 as an argument (see "myFile" below); that arg will have a "file"
  11 attribute, which is a handle to the temporary uploaded file.
  12 If you wish to permanently save the file, you need to read()
  13 from myFile.file and write() somewhere else.
  14
  15 Note the use of 'enctype="multipart/form-data"' and 'input type="file"'
  16 in the HTML which the client uses to upload the file.
  17
  18
  19 Downloads
  20 ---------
  21
  22 If you wish to send a file to the client, you have two options:
  23 First, you can simply return a file-like object from your page handler.
  24 CherryPy will read the file and serve it as the content (HTTP body)
  25 of the response. However, that doesn't tell the client that
  26 the response is a file to be saved, rather than displayed.
  27 Use cherrypy.lib.static.serve_file for that; it takes four
  28 arguments:
  29
  30 serve_file(path, content_type=None, disposition=None, name=None)
  31
  32 Set "name" to the filename that you expect clients to use when they save
  33 your file. Note that the "name" argument is ignored if you don't also
  34 provide a "disposition" (usually "attachement"). You can manually set
  35 "content_type", but be aware that if you also use the encoding tool, it
  36 may choke if the file extension is not recognized as belonging to a known
  37 Content-Type. Setting the content_type to "application/x-download" works
  38 in most cases, and should prompt the user with an Open/Save dialog in
  39 popular browsers.
  40
  41 """
  42
  43 import os
  44 localDir = os.path.dirname(__file__)
  45 absDir = os.path.join(os.getcwd(), localDir)
  46
  47 import cherrypy
  48 from cherrypy.lib import static
  49
  50
  51 class FileDemo(object):
  52
  53     def index(self):
  54         return """
  55         <html><body>
  56             <h2>Upload a file</h2>
  57             <form action="upload" method="post" enctype="multipart/form-data">
  58             filename: <input type="file" name="myFile" /><br />
  59             <input type="submit" />
  60             </form>
  61             <h2>Download a file</h2>
  62             <a href='download'>This one</a>
  63         </body></html>
  64         """
  65     index.exposed = True
  66
  67     def upload(self, myFile):
  68         out = """<html>
  69         <body>
  70             myFile length: %s<br />
  71             myFile filename: %s<br />
  72             myFile mime-type: %s
  73         </body>
  74         </html>"""
  75
  76         # Although this just counts the file length, it demonstrates
  77         # how to read large files in chunks instead of all at once.
  78         # CherryPy reads the uploaded file into a temporary file;
  79         # myFile.file.read reads from that.
  80         size = 0
  81         while True:
  82             data = myFile.file.read(8192)
  83             if not data:
  84                 break
  85             size += len(data)
  86
  87         return out % (size, myFile.filename, myFile.content_type)
  88     upload.exposed = True
  89
  90     def download(self):
  91         path = os.path.join(absDir, "pdf_file.pdf")
  92         return static.serve_file(path, "application/x-download",
  93                                  "attachment", os.path.basename(path))
  94     download.exposed = True
  95
  96
  97 import os.path
  98 tutconf = os.path.join(os.path.dirname(__file__), 'tutorial.conf')
  99
 100 if __name__ == '__main__':
 101     # CherryPy always starts with app.root when trying to map request URIs
 102     # to objects, so we need to mount a request handler root. A request
 103     # to '/' will be mapped to HelloWorld().index().
 104     cherrypy.quickstart(FileDemo(), config=tutconf)
 105 else:
 106     # This branch is for the test suite; you can ignore it.
 107     cherrypy.tree.mount(FileDemo(), config=tutconf)