App Engine Python SDK  v1.6.9 rev.445
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Public Member Functions | Static Public Attributes | List of all members
google.appengine.ext.blobstore.blobstore.BlobReferenceProperty Class Reference
Inheritance diagram for google.appengine.ext.blobstore.blobstore.BlobReferenceProperty:
google.appengine.ext.db.Property

Public Member Functions

def get_value_for_datastore
 
def make_value_from_datastore
 
def validate
 
- Public Member Functions inherited from google.appengine.ext.db.Property
def __init__
 
def __property_config__
 
def __get__
 
def __set__
 
def default_value
 
def validate
 
def empty
 
def get_value_for_datastore
 
def get_updated_value_for_datastore
 
def make_value_from_datastore_index_value
 
def make_value_from_datastore
 
def datastore_type
 

Static Public Attributes

 data_type = BlobInfo
 
- Static Public Attributes inherited from google.appengine.ext.db.Property
int creation_counter = 0
 
 data_type = str
 

Additional Inherited Members

- Public Attributes inherited from google.appengine.ext.db.Property
 verbose_name
 
 name
 
 default
 
 required
 
 validator
 
 choices
 
 indexed
 
 creation_counter
 
 model_class
 

Detailed Description

Property compatible with db.Model classes.

Add references to blobs to domain models using BlobReferenceProperty:

  class Picture(db.Model):
    title = db.StringProperty()
    image = blobstore.BlobReferenceProperty()
    thumbnail = blobstore.BlobReferenceProperty()

To find the size of a picture using this model:

  picture = Picture.get(picture_key)
  print picture.image.size

BlobInfo objects are lazily loaded so iterating over models with
for BlobKeys is efficient, the following does not need to hit
Datastore for each image key:

  list_of_untitled_blobs = []
  for picture in Picture.gql("WHERE title=''"):
    list_of_untitled_blobs.append(picture.image.key())

Member Function Documentation

def google.appengine.ext.blobstore.blobstore.BlobReferenceProperty.get_value_for_datastore (   self,
  model_instance 
)
Translate model property to datastore value.
def google.appengine.ext.blobstore.blobstore.BlobReferenceProperty.make_value_from_datastore (   self,
  value 
)
Translate datastore value to BlobInfo.
def google.appengine.ext.blobstore.blobstore.BlobReferenceProperty.validate (   self,
  value 
)
Validate that assigned value is BlobInfo.

Automatically converts from strings and BlobKey instances.

The documentation for this class was generated from the following file: