Base64编码的连接code二进制上传的AppEngine上的数据 [英] Base64 encode binary uploaded data on the AppEngine

问题描述

我以尽可能多地调用，因为我可能可以跳到BLOBSTORE一直在努力为Base64途中从用户（在这种情况下，一个值得信赖的管理员）code图像数据。每次我试图连接code，我收到一条错误消息：

I've been trying to Base64 encode image data from the user (in this case a trusted admin) in order to skip as many calls to the BlobStore as I possibly can. Every time I attempt to encode it, I recieve an error saying:

Error uploading image: 'ascii' codec can't decode byte 0x89 in position 0: ordinal not in range(128)

我GOOGLE了错误（少部分显著），并发现它可能有一些做的Uni code（？）。模板部分仅仅是一个基本的上传表单，而处理器包含以下code：

I've googled the error (the less significant parts) and found that it may have something to do with Unicode (?). The template portion is just a basic upload form, while the handler contains the following code:

  def post(self,id):
    logging.info("ImagestoreHandler#post %s", self.request.path)
    fileupload = self.request.POST.get("file",None)
    if fileupload is None : return self.error(400)

    content_type = fileupload.type or getContentType( fileupload.filename )
    if content_type is None: 
      self.error(400)
      self.response.headers['Content-Type'] = 'text/plain'
      self.response.out.write( "Unsupported image type: " + fileupload.filename )
      return
    logging.debug( "File upload: %s, mime type: %s", fileupload.filename, content_type )

    try:
      (img_name, img_url) = self._store_image(
        fileupload.filename, fileupload.file, content_type )
      self.response.headers['Location'] = img_url
      ex=None
    except Exception, err:
      logging.exception( "Error while storing image" )
      self.error(400)
      self.response.headers['Content-Type'] = 'text/plain'
      self.response.out.write("Error uploading image: " + str(err))
      return
    #self.redirect(urlBase % img.key() )  #dummy redirect is acceptable for non-AJAX clients,
    # location header should be acceptable for true REST clients, however AJAX requests 
    # might not be able to access the location header so we'll write a 200 response with 
    # the new URL in the response body:

    acceptType = self.request.accept.best_match( listRenderers.keys() )
    out = self.response.out
    if acceptType == 'application/json':
      self.response.headers['Content-Type'] = 'application/json'
      out.write( '{"name":"%s","href":"%s"}' % ( img_name, img_url ) )
    elif re.search( 'html|xml', acceptType ):
      self.response.headers['Content-Type'] = 'text/html'
      out.write( '<a href="%s">%s</a>' % ( img_url, img_name) )

  def _store_image(self, name, file, content_type):
    """POST handler delegates to this method for actual image storage; as
    a result, alternate implementation may easily override the storage
    mechanism without rewriting the same content-type handling. 

    This method returns a tuple of file name and image URL."""

    img_enc = base64.b64encode(file.read())
    img_enc_struct = "data:%s;base64,%s" % (content_type, img_enc)

    img = Image( name=name, data=img_enc_struct )
    img.put()
    logging.info("Saved image to key %s", img.key() ) 
    return ( str(img.name), img.key() )

我的图像模型：

from google.appengine.ext import db

class Image(db.Model):

  name = db.StringProperty(required=True)
  data = db.TextProperty(required=True)
  created = db.DateTimeProperty(auto_now_add=True)
  owner = db.UserProperty(auto_current_user_add=True)

任何帮助是极大AP preciated。这code，在零下_store_image我的图像编码，来源于gvdent 的blooger分支这里。

推荐答案

店面形象code可能是这样的....

your store image code could be like this....

img = Image( name=name, data=file.read() )
img.put()
return ( str(img.name), img.key() )

操作的二进制数据base64en code可以增加数据本身的尺寸和增加的CPU的编码和解码时间

doing base64encode of binary data may increase the size of data itself and increase the cpu encoding and decoding time.

和Blob存储使用相同的存储sturcuture数据存储，所以它只是让​​更容易
使用文件上传商店下载。

and Blobstore uses the same storage sturcuture as datastore, so it is just making easier to use file upload store download.

这篇关于Base64编码的连接code二进制上传的AppEngine上的数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！