upload_image() is the originator of the request, and also the upload
handler. it gets a URL from google that redirects to itself after image
upload.
blob_info = blobstore.parse_blob_info(request.vars.blob_key)
gets the blob key from request.vars (where google puts it when calling the
upload handler), and then gets the blob info from the blobstore using the
blobstore API.
hopefully the rest of the form processing code makes sense.
On Wednesday, March 7, 2012 12:34:56 PM UTC-8, Sushant Taneja wrote:
>
> As available in the google documentation, we need a UploadHandler ? How it
> is achieved in the above code ?
>
> On Thursday, March 8, 2012 1:38:04 AM UTC+5:30, Sushant Taneja wrote:
>>
>> Hi,
>>
>> Can you explain some of the code like how and in which variable the
>> blob_key is saved after the image successfully uploaded in the blobstore ?
>>
>> On Thursday, March 1, 2012 10:53:30 PM UTC+5:30, howesc wrote:
>>>
>>> my blobstore_image model:
>>>
>>> db.define_table('blobstore_image',
>>> db.version_info,
>>> Field('blob_key', 'upload', notnull=True,
>>> requires=IS_LENGTH(1048576),
>>> represent=lambda image : A('download', _href=URL(
>>> r=request, c='gae_blobstore', f='download',
>>> args=[image])),
>>> label="Image"),
>>> Field('image_url', length=500),
>>> Field('name', length=128,
>>> requires=IS_NOT_IN_DB(db, 'blobstore_image.name')),
>>> Field('type', length=128, requires=IS_IN_SET(['i_classify',
>>> 'my_images',
>>> 'by_type'],
>>> zero=None)),
>>> migrate=True)
>>>
>>>
>>> my upload controller:
>>>
>>> def upload_image():
>>> """
>>> This is the integration of the GAE blobstore with the image upload
>>> process
>>>
>>> @TODO: figure out how to test this. image upload is going to be kinda
>>> difficult to spoof
>>> """
>>> #@TODO: how do we deal with deleting an image?
>>> logging.info(repr(request.post_vars))
>>>
>>> fields=['name',
>>> 'type',
>>> 'blob_key']
>>>
>>> form = SQLFORM(db.blobstore_image, fields=fields,
>>> formstyle='divs')
>>> if request.args and request.args[0]:
>>> form = SQLFORM(db.blobstore_image, request.args[0], fields=fields,
>>> upload=URL(r=request, c='gae_blobstore', f='preview'),
>>> formstyle='divs')
>>>
>>> if request.env.web2py_runtime_gae:
>>> from google.appengine.ext import blobstore
>>> from google.appengine.api.images import get_serving_url
>>> import uuid
>>> #get the blob_info. NOTE this MUST be done before any other
>>> operations on
>>> # the request vars. otherwise something modifies them (perhaps the
>>> form
>>> # validators) in a way that makes this not work
>>> blob_info = None
>>> if request.vars.blob_key == '':
>>> #it seems that prod blobstore returns empty string instead of
>>> None when
>>> #there are no changes to the image
>>> request.vars.blob_key = None
>>> if request.vars.blob_key != None:
>>> blob_info = blobstore.parse_blob_info(request.vars.blob_key)
>>> del request.vars['blob_key']
>>>
>>> upload_url =
>>> blobstore.create_upload_url(URL(r=request,f='upload_image',
>>> args=request.args,
>>>
>>> vars={'redir':URL(r=request,c='dataadmin', f='index')}))
>>>
>>> form['_action']=upload_url
>>> #since we are setting the action after the form was initially
>>> created we
>>> # need to reset the form.custom.begin
>>> (begin, end) = form._xml()
>>> form.custom.begin = XML("<%s %s>" % (form.tag, begin))
>>>
>>> if form.accepts(request.vars,session, formname="uploadimage"):
>>> #@TODO: can this be a post-validation function?
>>> #get the record we just inserted/modified
>>> row = db(db.blobstore_image.id == form.vars.id).select().first()
>>> if request.vars.blob_key__delete == 'on' or \
>>> (blob_info and (row and row.blob_key)):
>>> #remove from blobstore because of delete or update of image
>>> decoded_key = base64.b64decode(row.blob_key.split('.')[0])
>>> blobstore.delete(decoded_key)
>>> #remove reference in the artwork record
>>> row.update_record(blob_key=None)
>>> if blob_info:
>>> logging.info("adding blob_key " + str(blob_info.key()))
>>> #add reference to image in this record
>>> key = base64.b64encode(str(blob_info.key())) +"." +
>>> blob_info.content_type.split('/')[1]
>>> url = get_serving_url(str(blob_info.key()))
>>>
>>> row.update_record(blob_key = key, image_url = url)
>>>
>>> crud.archive(form)
>>> session.flash="Image saved"
>>> #Raise the HTTP exception so that the response content stays
>>> empty.
>>> #calling redirect puts content in the body which fails the blob
>>> upload
>>> raise HTTP(303,
>>> Location= URL(r=request,f='upload_image', args=
>>> form.vars.id))
>>> elif form.errors:
>>> #logging.info("form not accepted")
>>> logging.info(form.errors)
>>> session.flash=BEAUTIFY(form.errors)
>>> #there was an error, let's delete the newly uploaded image
>>> if blob_info:
>>> blobstore.delete(blob_info.key())
>>> #Raise the HTTP exception so that the response content stays
>>> empty.
>>> #calling redirect puts content in the body which fails the blob
>>> upload
>>> redirvars = {}
>>> redirvars['form_errors']=True
>>> redirvars['error_dict'] = form.errors
>>> raise HTTP(303,
>>> Location= URL(r=request,f='upload_image',
>>> args=request.args,
>>> vars=redirvars))
>>> return dict(form=form,
>>> aahome=A("data Home", _href=URL(r=request, f='index')),
>>> back=A("Query view",
>>> _href=URL(r=request, f='query',
>>> args=['blobstore_image'])))
>>>
>>>
>>> hope that helps!
>>>
>>> cfh
>>>
>>
