没有这样的文件或目录：Python CSV

Question

I'm trying to create a csv file into a different directory. While running the code on development server it works fine, but on production, it raises an error that No such file or directory:

Following is my code:-

def write_operation(filename,data):
    with open("./static/" + filename, "wb") as f:
        writer = csv.writer(f)
        writer.writerows(data)

@csrf_exempt
def download_data(request):

    if request.POST.has_key('download_data'):
        start_date = str(request.POST['start_date']).replace('/','-')
        end_date = str(request.POST['end_date']).replace('/','-')

        start_date = datetime.datetime.strptime(start_date, "%Y-%m-%d %H:%M")
        end_date = datetime.datetime.strptime(end_date, "%Y-%m-%d %H:%M")


        data.insert(0,('Barcode','Weight', 'Length','Breadth','Height'))
        write_operation('data.csv',data)

        return HttpResponse(json.dumps('Success'),content_type = "application/json")
    ctx = {}
    return render(request, 'dummy/download_data.html', ctx)

The error that I receive is :-

Exception Value: [Errno 2] No such file or directory: 'static/data.csv'

Here is my directory structure:-

├── modules
|   ├── dummy
│   │   └── views.py
├── static

Answer 1

You can use full path to prevent these errors. For example, your project folder /home/project-name/ . You can define a constant to your config and set your project home folder as base_dir . Then change your code the following:

def write_operation(filename,data):
    with open(config.base_dir + "static/" + filename, "wb") as f:
        writer = csv.writer(f)
        writer.writerows(data)

Edit: I missed the script related with the django. Above solution is a general solution for python. Django version is almost the same.

Add your settings.py file the following lines

import os

BASE_DIR = os.path.dirname(os.path.dirname(__file__))

And change your method with following:

from django.conf import settings
...

def write_operation(filename,data):
with open(settings.BASE_DIR + "static/" + filename, "wb") as f:
    writer = csv.writer(f)
    writer.writerows(data)

In fact, both of them is the same on the base.

Answer 2

For avoiding such a problem just use BASE_DIR value, that is initialized and assigned in your project settings.py

As it is said in official documentation:

Build paths inside the project like this: os.path.join(BASE_DIR, ...)