Checking if the .csv file is formatted correctly before importing to avoid embedding wrong data into database

I am working on a django project that requires updating database with bulk data provided in an excelsheet format. So basically, a user can upload a .csv file if it is in a correct format (by correct format i mean, well-formed file with data i expect). I know how to import a file using django-import-export, but the problem is , i don't know how to perform checks like checking if the .csv file has correct column names and information before updating database. I am new to django, please help.

Checking for a well formed file

If you are programmatically importing a file, then if you can load a Dataset object, without any errors being raised, then it is a well-formed csv file. So something like:

import tablib
try:
  with open('data.csv', 'r') as fh:
    imported_data = tablib.Dataset().load(fh, headers=False)
except Exception as e:
  # you can add additional error handling / logging here if you like
  print("import fail")
  raise e

Checking for correct headers

Before the import process, there is a hook you can use to check for valid headers. So you could do something like the following to check for missing columns:

class YourResource(resources.ModelResource):
    fields = ('author', 'email')

    def before_import(self, dataset, using_transactions, dry_run, **kwargs):
        for field_name in self.fields:
            col_name = self.fields[field_name].column_name
            if col_name not in dataset.headers:
                raise ValueError(f"'{col_name}' field not in data file")

Data Validation

You can use the in-built widgets to supply additional validation at the field level. You can extend these as much as you like to enable additional domain-specific validation. For example, if you only want to allow '1' or 0' as your boolean values, you could implement the following:

class StrictBooleanWidget(widgets.BooleanWidget):
    TRUE_VALUES = ["1"]
    FALSE_VALUES = ["0"]
    NULL_VALUES = [""]

    def clean(self, value, row=None, *args, **kwargs):
        if value in self.NULL_VALUES:
            return None
        if value in self.TRUE_VALUES:
            return True
        if value in self.FALSE_VALUES:
            return False
        raise ValueError("Invalid boolean: value must be 1 or 0.")

Then refer to this in your resource:

class YourResource(resources.ModelResource):
    is_active = fields.Field(
        attribute="active",
        column_name="active",
        default=False,
        widget=upload.widgets.StrictBooleanWidget(),
    )

You can also use this approach to check for missing or empty values in the data.

django-import-export really helps a lot with the use-case you describe, but it can be confusing when you are new to it. Read the documentation in depth, and I suggest to download and run the example application (if you haven't already).

The core import logic is fairly straightforward, but it will save a ton of time if you can set breakpoints and step through during dev. That will really help you to understand what is going on.