How do I avoid overwrite in django models - django

I have class called AlbumImage
class AlbumImage(models.Model):
album = models.ForeignKey(Album, on_delete=models.PROTECT,related_name="raters")
image = models.ImageField(upload_to="Album")
when i upload first image called (for example) image1.png every thing in ok ,,,,
But if I upload another image with the same name(image1.png), and go back to the first object, I will find the second image in its place.
How do I avoid overwrite ?

The FileField and ImageField will detect this, and will add a random part to avoid overwriting.
It is only if you set it to a string, that it will take that, since then you refer to the name of a file. But if you thus work through a (Model)Form, or the ModelAdmin, or you pass it with a File object.
Indeed, if you want to save twice an item named 3.jpeg, it will generate:
/media/3.jpeg
/media/3_S12ggWF.jpeg

Related

Programmatically saving image to Django ImageField returning 404 in production

I have a Django app where users can upload images and can have a processed version of the images if they want. and the processing function returns the path, so my approach was
model2.processed_image = processingfunction( model1.uploaded_image.path)
and as the processing function returns path here's how it looks in my admin view
not like the normally uploaded images
In my machine it worked correctly and I always get a 404 error for the processed ones while the normally uploaded is shown correctly when I try to change the url of the processed from
myurl.com/media/home/ubuntu/Eyelizer/media/path/to/the/image
to
myurl.com/media/path/to/the/image
so how can I fix this ? is there a better approach to saving the images manually to the database ?
I have the same function but returns a Pil.image.image object and I've tried many methods to save it in a model but I didn't know how so I've made the function return a file path.
I think the problem is from nginx where I define the media path.
should/can I override the url attribute of the processedimage?
making something like
model.processed_image.url = media/somefolder/filename
Instead of using the PIL Image directly, create a django.core.files.File.
Example:
from io import BytesIO
from django.core.files import File
img_io = BytesIO() # create a BytesIO object to temporarily save the file in memory
img = processingfunction( model1.uploaded_image.path)
img.save(img_io, 'PNG') # save the PIL image to the BytesIO object
img_file = File(thumb_io, name='some-name.png') # create the File object
# you can use the `name` from `model1.uploaded_image` and use
# that above
# finally, pass the image file to your model field
model2.processed_image = img_file
To avoid repetition of this code, it would be a good idea to keep this code in processingfunction and return the File object directly from there.
My approach is a bit different from #Xyres's, I thought xyres's would make a duplicate of the existing image and create a new one and when I tried overriding the URL attribute it returned an error of
can't set the attribute
but when I saw this question and this ticket I tried making this and it worked
model2.processed_image = processingfunction(model1.uploaded_image.path)
full_path = model2.processed_image.path
model2.processed_image.name = full_path.split('media')[1]
so that explicitly making the URL media/path/to/image and cut out all of the unneeded parts like home/ubuntu and stuff

Django rest Framework, change filename of ImageField

I have an API endpoint with Django Rest Framework to upload an image.
class MyImageSerializer(serializers.ModelSerializer):
image = serializers.ImageField(source='image')
I can upload images but they are saved with the filename that is sent from the client which can result to collisions. I would like instead to upload the file to my CDN with a timestamp filename.
Generating the filename is not the problem, just saving the image with it.
Any one knows how to do that?
Thanks.
If your image is of type ImageField from django, then you don't really have to do anything, not even declare it in your serializer like you did. It's enough to add it in the fields attribute and django will handle collisions. This means django will add _index on each new file which might generate a collision, so if you upload a file named 'my_pic.jpg' 5 times, you will actually have files 'my_pic.jpg', 'my_pic_1.jpg', 'my_pic_2.jpg', 'my_pic_3.jpg', 'my_pic_4.jpg' on your server.
Now, this is done using django's implementation for FileSystemStorage (see here), but if you want it to append a timestamp to your filename, all you have to do is write a storage class where you overwrite the get_available_name(name) method. Example:
class MyFileSystemStorage(FileSystemStorage):
def get_available_name(self, name):
''' name is the current file name '''
now = time.time()
stamp = datetime.datetime.fromtimestamp(now).strftime('%Y-%m-%d-%H-%M-%S')
return '{0}_{1}'.format(name, str(stamp))
And the image field in your model:
image = models.ImageField(upload_to='your upload dir', storage= MyFileSystemStorage)
Important update
As of August 20, 2014 this is no longer an issue, since Django found a vulnerability related to this behaviour (thanks #mlissner for pointing it out) . Important excerpt :
We’ve remedied the issue by changing the algorithm for generating file
names if a file with the uploaded name already exists.
Storage.get_available_name() now appends an underscore plus a random 7
character alphanumeric string (e.g. "_x3a1gho"), rather than iterating
through an underscore followed by a number (e.g. "_1", "_2", etc.).

Generating image url using carrierwave in rails

This is somewhat related my question about joins here. By default when I use listing.image.name in my search results view, it does a full query to find the image for every listing in my results array. It even does an extra query just to check if the listing has any images. So to avoid this, I'm adding the following to my Thinking Sphinx query:
#ts_params[:sql][:joins] = "INNER JOIN listing_images ON listing_images.listing_id = listings.id AND listing_images.position = 0"
#ts_params[:sql][:select] = "listings.*, listing_images.image as image_name, listing_images.id as image_id"
This works, however I'm not sure how to generate the full image_url using carrierwave. Previously, where it was doing an extra query per result, I was using listing.image.image_url(:sizename). So, I can find the image name and ID from my join as above, but how to I convert this to a full image url via carrierwave? Is there a built-in method to retrieve the url, that doesn't require an 'image' object?
I tried listing.image_id.image_url(:sizename) but it gave an undefined method error as expected.
From carrierwave's perspective, the answer is obvious:
user.avatar.url
user.avatar.thumbnail.url
Here, user is an instance of a model, and avatar is the field on the model with mount_uploader called on it. In your case this would be something like:
listing_image.image_name.url
listing_image.image_name.thumbnail.url
That probably doesn't work, though, because it looks like you may be loading your listing_image fields into the Listing instead of through includes (or the dreaded N+1 non-eager loads). You may need to resolve your other stackoverflow question before this one will be possible.
Edit:
Per our discussion on your other issue, once you've got a has_one :main_image for just the one ListingImage you want, you're going to use something like #listing.main_image.image_name.url and, if you have a version named "thumbnail", #listing.main_image.image_name.thumbnail.url.
I had the similar issue when I was fetching image using query and wanted to build image url using db field instead of issuing full sql query for each image.
I found out that with couple of field fetched from related image table we can build image which will not run any sql for image if we have three fields id, updated_at and image_name this field should be from the table where image is being saved. It could be from the main table where image is saved as separate column or completely separate table use to specially for image here is a sample code
It can be in your helper or in decorator as per your choice
def logo_url(id, updated_at, name)
return if id.blank? || updated_at.blank? || name.blank?
Company.new(id: id, updated_at: updated_at, logo: name).logo
end
and in view you can call this helper method as
<%= logo_url(company.id, company.updated_at, company.logo).url %>
This way you can have your image with url without executing sql query on each image.

File upload after model save on Django admin

I am using a file upload in my Django model like this :
def upload_path(self, filename):
return 'upload/actualities/%s/%s' % (self.id, filename)
photo = models.ImageField(upload_to=upload_path)
and my adminModel is :
from actualities.models import *
from django.contrib import admin
class ActualityAdmin(admin.ModelAdmin):
class Media:
js = ('/static/js/tiny_mce/tiny_mce.js', '/static/js/textareas.js')
admin.site.register(Actuality, ActualityAdmin)
Everything works fine except when i edit mu model because it has an id. But when I create it, the file upload happens before the model saving... So i put my file in /media/actualities/None/filename.jpg, and I want /media/2/filename.jpg
How can I force to make the file upload after the model saving?
Thank you!!!
You will probably want to override the Model's save() method, and maybe come up with a custom "don't do anything" UploadHandler, then switch back to the original one and call save again.
https://docs.djangoproject.com/en/dev/topics/http/file-uploads/
https://docs.djangoproject.com/en/dev/topics/db/models/
What I would do in this situation however, is make a custom upload handler that saves the file off into some temp space. Then I'd override the save method (in a mixin or something) that moves the file from temp to wherever you wanted it.
#Tomek's answer is also another way. If you have your model generate it's own id, then you can use that.
A second to last suggestion which is what I do with my photo blog is instead of saving all the images in a directory like media/2/filename.jpg I save the image by date uploaded. 2011/10/2/image.jpg This kind of helps any directory from getting too unwieldy.
Finally, you could hash the file names and store them in directories of hash name to kind of equally spread out the images in a directory.
I've picked the date style because that's meaningful for me with that project. Perhaps there is another way you can name an image for saving that would mean something more than "model with id 2's pics" that you could use for this problem.
Good Luck!
As workaround, try generating UUID for file name (instead of using self.id).

Django: Lowercasing filename of the input Image File

I have a model:
class Foo(models.Model):
poster = models.ImageField(u"Poster", upload_to='img')
I'm using the admin to upload posters and save Foo objects. I now need to find a way to lowercase the filename before save. For instance POSTER.png or Poster.png or poster.PNG should be lowercased to poster.png.
What would be the easiest way to achieve this?
FileField.upload_to may also be a callable, per this comment in the documentation:
This may also be a callable, such as a function, which will be called to obtain the upload path, including the filename. This callable must be able to accept two arguments, and return a Unix-style path (with forward slashes) to be passed along to the storage system. The two arguments that will be passed are:
Since ImageField inherits all its attributes and methods from FileField, I think you could use:
def update_filename(instance, filename):
path_you_want_to_upload_to = "img"
return os.path.join(path_you_want_to_upload_to, filename.lower())
class Foo(models.Model):
poster = models.ImageField(u"Poster", upload_to=update_filename)