How to put a JSON file's content in a response

Question

I have a file on my computer that I'm trying to serve up as JSON from a django view.

def serve(request):
    file = os.path.join(BASE_DIR, 'static', 'files', 'apple-app-site-association')
    response = HttpResponse(content=file)
    response['Content-Type'] = 'application/json'

What I get back is the path to the file when navigating to the URL

/Users/myself/Developer/us/www/static/files/apple-app-site-association

What am I doing wrong here?

Answer 1

os.path.join returns a string, it's why you get a path in the content of the response. You need to read the file at that path first.

For a static file

If the file is static and on disk, you could just return it using the webserver and avoid using python and django at all. If the file needs authenticating to be downloaded, you could still handle that with django, and return a X-Sendfile header (this is dependant on the webserver).

Serving static files is a job for a webserver, Nginx and Apache are really good at this, while Python and Django are tools to handle application logic.

Simplest way to read a file

def serve(request):
    path = os.path.join(BASE_DIR, 'static', 'files', 'apple-app-site-association')
    with open(path , 'r') as myfile:
        data=myfile.read()
    response = HttpResponse(content=data)
    response['Content-Type'] = 'application/json'

This is inspired by How do I read a text file into a string variable in Python

For a more advanced solution

See dhke's answer on StreamingHttpResponse.

Additional information

• Reading and writing files
• Managing files with Django

Answer 2

If you feed HttpResponse a string a content you tell it to serve that string as HTTP body:

content should be an iterator or a string. If it’s an iterator, it should return strings, and those strings will be joined together to form the content of the response. If it is not an iterator or a string, it will be converted to a string when accessed.

Since you seem to be using your static storage directory, you might as well use staticfiles to handle content:

from django.contrib.staticfiles.storage import staticfiles_storage
from django.http.response import StreamingHttpResponse

file_path = os.path.join('files', 'apple-app-site-association')

response = StreamingHttpResponse(content=staticfiles_storage.open(file_path))
return response

As noted in @Emile Bergeron's answer, for static files, this should already be overkill, since those are supposed to be accessible from outside, anyway. So a simple redirect to static(file_path) should do the trick, too (given your webserver is correctly configured).

To serve an arbitrary file:

from django.contrib.staticfiles.storage import staticfiles_storage
from django.http.response import StreamingHttpResponse

file_path = ...

response = StreamingHttpResponse(content=open(file_path, 'rb'))
return response

Note that from Django 1.10 and on, the file handle will be closed automatically.

Also, if the file is accessible from your webserver, consider using django-sendfile, so that the file's contents don't need to pass through Django at all.