每次使用不同的文件夹在特定根目录下的django数据库中上载文件

Question

I´m trying to upload file into database, but when i want put the function uoload to and i want to that function store the file in a root with the data the user submit in the for, for example year, course, section, I get that information and the file they uploaded I want to store in that subfolders, the code that I´m using only store the data in the Media_root, but not in the carpets how can I do in order to store the files in the subfolder I want. I'n my model document I store the information of the document, like the autor, the title,etc.

class File(models.Model):
     titulo_file=models.ForeignKey(Document,on_delete=models.CASCADE,null=True,verbose_       name='Título de la Tesis')
     file = models.FileField(null=True,blank=True, upload_to=generate_path)

Here the function I use to upload the file, Int only works to store the file into a folder with it´s same name.

def generate_path(instance, filename):

      path =os.path.join(instance.file.name,filename)
      return path

In my view, after the user submit the information, I use a os.path.join , that do the path with the information submited like this:

year/course/section

I want to send that path to my generate_path and store in that location the file, I tried with session but it doesn't work, what can I do?

models.py

class Year(models.Model):
    year_number=models.CharField(max_length=10,primary_key=True)

class Course(models.Model):
    name=models.CharField(max_length=50,primary_key=True)

class Section(models.Model):
    numberSection=models.IntegerField(null=True,blank=True)
    year = models.ForeignKey(Year, on_delete=models.CASCADE, null=True)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)

thopic_documents=(
       ('CS','CS'),
       ('SE','SE'),
       ('IS','IS'),
       ('IT','IT'),
    )

class Document(models.Model):
     title=models.CharField(max_length=200,primary_key=True)
     thopic=models.CharField(max_length=50,choices=thopic_documents, default=None,null=True)

class Historial(models.Model):
      id_section=models.ForeignKey(Section,on_delete=models.CASCADE)
      title_document=models.ForeignKey(Document,on_delete=models.CASCADE,)

Answer 1

To get the year/course/section you need to be able to navigate from a File to a Section . However, the many-many relationship that exists between Document and Section through Historical makes it unclear how you would do that. Which Historical would you choose?

It may be better if File was linked directly to Historical :

class File(models.Model):
     titulo_file=models.ForeignKey(Historical, on_delete=models.CASCADE,null=True,verbose_name='Título de la Tesis')
     file = models.FileField(null=True,blank=True, upload_to=generate_path)

If that was the case, you could then implement your generate_path() such as:

def generate_path(instance, filename):
    section = instance.titulo_file.id_section
    year = section.year.year_number
    course = section.course.name
    return os.path.join(str(year), course, str(section.numberSection), filename)

To do the same thing with the model as it currently stands, you would have to do something like this:

def generate_path(instance, filename):
    section = instance.titulo_file.historical_set.first().id_section
    year = section.year.year_number
    course = section.course.name
    return os.path.join(str(year), course, str(section.numberSection), filename)

That example uses historical_set.first() to get the first Historical linked the Document . Maybe that would be ok, but otherwise you'd need to know which Historical to use.

Where a file with the same name is uploaded and you don't want to overwrite it, you could implement your own storage :

from django.core.files.storage import FileSystemStorage

class UseExistingStorage(FileSystemStorage):

    def save(self, name, content, max_length=None):
        if not self.exists(name):
            return super().save(name, content, max_length)
        return name  # Don't save when the file exists, just return the name

Then reference the UseExistingStorage from your File model.

file = models.FileField(null=True,blank=True, upload_to=generate_path, storage=UseExistingStorage())