JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Question

I am getting error Expecting value: line 1 column 1 (char 0) when trying to decode JSON.

The URL I use for the API call works fine in the browser, but gives this error when done through a curl request. The following is the code I use for the curl request.

The error happens at return simplejson.loads(response_json)

response_json = self.web_fetch(url) response_json = response_json.decode('utf-8') return json.loads(response_json)   def web_fetch(self, url):     buffer = StringIO()     curl = pycurl.Curl()     curl.setopt(curl.URL, url)     curl.setopt(curl.TIMEOUT, self.timeout)     curl.setopt(curl.WRITEFUNCTION, buffer.write)     curl.perform()     curl.close()     response = buffer.getvalue().strip()     return response 

Traceback:

File "/Users/nab/Desktop/myenv2/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response   111.                         response = callback(request, *callback_args, **callback_kwargs) File "/Users/nab/Desktop/pricestore/pricemodels/views.py" in view_category   620.     apicall=api.API().search_parts(category_id= str(categoryofpart.api_id), manufacturer = manufacturer, filter = filters, start=(catpage-1)*20, limit=20, sort_by='[["mpn","asc"]]') File "/Users/nab/Desktop/pricestore/pricemodels/api.py" in search_parts   176.         return simplejson.loads(response_json) File "/Users/nab/Desktop/myenv2/lib/python2.7/site-packages/simplejson/__init__.py" in loads   455.         return _default_decoder.decode(s) File "/Users/nab/Desktop/myenv2/lib/python2.7/site-packages/simplejson/decoder.py" in decode   374.         obj, end = self.raw_decode(s) File "/Users/nab/Desktop/myenv2/lib/python2.7/site-packages/simplejson/decoder.py" in raw_decode   393.         return self.scan_once(s, idx=_w(s, idx).end())  Exception Type: JSONDecodeError at /pricemodels/2/dir/ Exception Value: Expecting value: line 1 column 1 (char 0) 

Answer 1

Your code produced an empty response body, you'd want to check for that or catch the exception raised. It is possible the server responded with a 204 No Content response, or a non-200-range status code was returned (404 Not Found, etc.). Check for this.

Note:

• There is no need to use simplejson library, the same library is included with Python as the json module.

• There is no need to decode a response from UTF8 to unicode, the simplejson / json .loads() method can handle UTF8 encoded data natively.

• pycurl has a very archaic API. Unless you have a specific requirement for using it, there are better choices.

Either the requests or httpx offers much friendlier APIs, including JSON support. If you can, replace your call with:

import requests  response = requests.get(url) response.raise_for_status()  # raises exception when not a 2xx response if response.status_code != 204:     return response.json() 

Of course, this won't protect you from a URL that doesn't comply with HTTP standards; when using arbirary URLs where this is a possibility, check if the server intended to give you JSON by checking the Content-Type header, and for good measure catch the exception:

if (     response.status_code != 204 and     response.headers["content-type"].strip().startswith("application/json") ):     try:         return response.json()     except ValueError:         # decide how to handle a server that's misbehaving to this extent 

Answer 2

Be sure to remember to invoke json.loads() on the contents of the file, as opposed to the file path of that JSON:

json_file_path = "/path/to/example.json"  with open(json_file_path, 'r') as j:      contents = json.loads(j.read()) 

I think a lot of people are guilty of doing this every once in a while (myself included):

contents = json.loads(json_file_path)