Setting FileField from UploadedFile

Using Django
1

Hello, I’m stuck on something that should be fairly simple and can’t figure it out.

Basically, I have a model like this:

class Attachment(models.Model):
    report = models.ForeignKey(Report, on_delete=models.PROTECT)
    thefile = models.FileField()

and I want to create it from a multipart POST request like (pseudocode):

POST /upload-attachment
    report_id = 5
    thefile = (file content)

Now, it sounds like ModelForm classes can’t deal with raw IDs, so that’s a no-go.
I can use a normal Form or even get the data manually from the Request object.
But how would I set Attachment.thefile from request.FILES["thefile"]?

I’ve found the method FieldFile.save(name, content, save=True) but that seems to expect content to be a File instance.

2

Hi!

What do you mean by this?

Did you look at this part of the documentation?

3

Also, when you’re working with uploading files, you’ll want to review the File Uploads docs.

4

I meant that a models.ForeignKey is mapped to a forms.ModelChoiceField and that seemed to use some special values to select the model instance, however I now realize I have misinterpreted the documentation. Specifically, in ModelChoiceField.to_field_name:

<select id="id_field1" name="field1">
<option value="obj1.pk">Object1</option>
<option value="obj2.pk">Object2</option>
...
</select>

I thought “obj1.pk” was what would actually be generated, so I got the impression that it was some special format used by Django. Reading that again, I understand it’s just pseudocode and the actual code will use the object id:

<select id="id_field1" name="field1">
<option value="1">Object1</option>
<option value="2">Object2</option>
...
</select>

In other words, it looks exactly what I need. Thanks for pointing that out.

5

Looks like I missed something there too. From that doc, the manual way to do it seems to be:

instance = ModelWithFileField(file_field=request.FILES['file'])
instance.save()

Thanks for the hint. It’s what I wanted to know, although using a ModelForm is even easier than doing it manually.