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Information about blobs in Blobstore.
Inherits From: expected_type
google.appengine.ext.blobstore.BlobInfo(
entity_or_blob_key, _values=None
)
This is a db.Model
-like class that contains information about blobs that are
stored by an application. Like db.Model
, this class is backed by a
Datastore entity; however, BlobInfo
instances are read-only and have a much
more limited interface.
Each BlobInfo
has a key of type BlobKey
associated with it. This key is
specific to the Blobstore API and is not compatible with db.get
. The key
can be used for quick lookup by passing it to BlobInfo.get
. This key
converts easily to a string, which is web safe and can be embedded in URLs.
Properties:
- content_type: The content type of the blob.
- creation: The creation date of the blob, or when it was uploaded.
- filename: The file name that the user selected from their machine.
- size: The size of the uncompressed blob.
md5_hash: The MD5 hash value of the uploaded blob.
gs_object_name
: The name of the object, if the blob is stored in Google Cloud Storage, in the form /[bucket-name]/[object-name]
All properties are read-only. Attempting to assign a value to a property
will raise a NotImplementedError
.
Args | |
---|---|
entity_or_blob_key
|
The datastore entity or blob key that represents the blob reference. |
_values
|
Optional; not recommended. This argument passes the associated
entity when entity_or_blob_key is a blob key.
|
Attributes | |
---|---|
content_type
|
Returns the content type of the blob. |
creation
|
Returns the creation date or time of upload of the blob. |
filename
|
Returns the file name that the user selected from their machine. |
gs_object_name
|
|
md5_hash
|
Returns the MD5 hash value of the uncompressed blob. |
size
|
Returns the size of the uncompressed blob. |
Methods
all
@classmethod
all()
Creates a query for all BlobInfo
objects associated with the app.
Returns | |
---|---|
A db.Query object that queries over BlobInfo 's datastore kind.
|
delete
delete(
_token=None
)
Permanently deletes a blob from Blobstore.
from_entity
@classmethod
from_entity( entity )
Converts an entity to BlobInfo
.
Note:
This method is required for compatibility with the current db.py
query
mechanism but will be removed in the future. DO NOT USE.
Args | |
---|---|
entity
|
The entity that you are trying to convert. |
Returns | |
---|---|
The BlobInfo that was converted from the entity.
|
get
@classmethod
get( blob_keys )
Retrieves a BlobInfo
by key or by a list of keys.
Args | |
---|---|
blob_keys
|
A key or a list of keys. Keys can be in string, Unicode, or
BlobKey format.
|
Returns | |
---|---|
A BlobInfo instance that is associated with the provided key or a list
of BlobInfo instances if a list of keys was provided. Keys that are not
found in Blobstore return None .
|
gql
@classmethod
gql( query_string, *args, **kwds )
Returns a query using a GQL query string.
See the GQL source
for more information about GQL.
Args | |
---|---|
query_string
|
A properly formatted GQL query string that omits
SELECT * FROM <entity>
|
*args
|
The remaining positional arguments that are used to bind numeric references in the query. |
**kwds
|
The dictionary-based arguments for named parameters. |
Returns | |
---|---|
A gql.GqlQuery object that queries over BlobInfo 's datastore kind.
|
.. _GQL source: https://cloud.google.com/appengine/docs/python/refdocs/google.appengine.ext.gql
key
key()
Gets the key for a blob.
Returns | |
---|---|
The BlobKey instance that identifies this blob.
|
kind
@classmethod
kind()
Gets the entity kind for the BlobInfo
.
Note:
This method is required for compatibility with the current db.py
query
mechanism but will be removed in the future. DO NOT USE.
Returns | |
---|---|
The entity kind for BlobInfo .
|
open
open(
*args, **kwargs
)
Returns a BlobReader
for this blob.
Args | |
---|---|
*args
|
Arguments to pass to the BlobReader constructor.
|
**kwargs
|
Keyword arguments to pass to the BlobReader constructor.
|
Returns | |
---|---|
A BlobReader instance.
|
properties
@classmethod
properties()
Defines the set of properties that belong to BlobInfo
.
Note:
This method is required for compatibility with the current db.py
query
mechanism but will be removed in the future. DO NOT USE.
Returns | |
---|---|
A set of all of the properties that belong to BlobInfo .
|