Error with some module in pandas_datareader

[anarinsk]

This nice package has solved most of my user cases with jupyterlite except following one problem for now.

Working env

My working environment is the same as following link:

https://jupyterlite.github.io/demo/lab/index.html

Reproducible code

%pip install -q pyodide-http pandas-datareader requests

import pyodide_http
pyodide_http.patch_all()  # Patch all libraries

import pandas_datareader as pdr
pdr.get_data_fred('GS10')

Error messages

---------------------------------------------------------------------------
JsException                               Traceback (most recent call last)
Cell In[3], line 2
      1 import pandas_datareader as pdr
----> 2 pdr.get_data_fred('GS10')

File /lib/python3.10/site-packages/pandas_datareader/data.py:72, in get_data_fred(*args, **kwargs)
     71 def get_data_fred(*args, **kwargs):
---> 72     return FredReader(*args, **kwargs).read()

File /lib/python3.10/site-packages/pandas_datareader/fred.py:27, in FredReader.read(self)
     18 """Read data
     19 
     20 Returns
   (...)
     24     DataFrame is the outer join of the indicies of each series.
     25 """
     26 try:
---> 27     return self._read()
     28 finally:
     29     self.close()

File /lib/python3.10/site-packages/pandas_datareader/fred.py:62, in FredReader._read(self)
     55             raise IOError(
     56                 "Failed to get the data. Check that "
     57                 "{0!r} is a valid FRED series.".format(name)
     58             )
     59         raise
     61 df = concat(
---> 62     [fetch_data(url, n) for url, n in zip(urls, names)], axis=1, join="outer"
     63 )
     64 return df

File /lib/python3.10/site-packages/pandas_datareader/fred.py:62, in <listcomp>(.0)
     55             raise IOError(
     56                 "Failed to get the data. Check that "
     57                 "{0!r} is a valid FRED series.".format(name)
     58             )
     59         raise
     61 df = concat(
---> 62     [fetch_data(url, n) for url, n in zip(urls, names)], axis=1, join="outer"
     63 )
     64 return df

File /lib/python3.10/site-packages/pandas_datareader/fred.py:41, in FredReader._read.<locals>.fetch_data(url, name)
     39 def fetch_data(url, name):
     40     """Utillity to fetch data"""
---> 41     resp = self._read_url_as_StringIO(url)
     42     data = read_csv(
     43         resp,
     44         index_col=0,
   (...)
     49         na_values=".",
     50     )
     51     try:

File /lib/python3.10/site-packages/pandas_datareader/base.py:119, in _BaseReader._read_url_as_StringIO(self, url, params)
    115 def _read_url_as_StringIO(self, url, params=None):
    116     """
    117     Open url (and retry)
    118     """
--> 119     response = self._get_response(url, params=params)
    120     text = self._sanitize_response(response)
    121     out = StringIO()

File /lib/python3.10/site-packages/pandas_datareader/base.py:155, in _BaseReader._get_response(self, url, params, headers)
    153 last_response_text = ""
    154 for _ in range(self.retry_count + 1):
--> 155     response = self.session.get(
    156         url, params=params, headers=headers, timeout=self.timeout
    157     )
    158     if response.status_code == requests.codes.ok:
    159         return response

File /lib/python3.10/site-packages/requests/sessions.py:600, in Session.get(self, url, **kwargs)
    592 r"""Sends a GET request. Returns :class:`Response` object.
    593 
    594 :param url: URL for the new :class:`Request` object.
    595 :param \*\*kwargs: Optional arguments that ``request`` takes.
    596 :rtype: requests.Response
    597 """
    599 kwargs.setdefault("allow_redirects", True)
--> 600 return self.request("GET", url, **kwargs)

File /lib/python3.10/site-packages/requests/sessions.py:587, in Session.request(self, method, url, params, data, headers, cookies, files, auth, timeout, allow_redirects, proxies, hooks, stream, verify, cert, json)
    582 send_kwargs = {
    583     "timeout": timeout,
    584     "allow_redirects": allow_redirects,
    585 }
    586 send_kwargs.update(settings)
--> 587 resp = self.send(prep, **send_kwargs)
    589 return resp

File /lib/python3.10/site-packages/requests/sessions.py:701, in Session.send(self, request, **kwargs)
    698 start = preferred_clock()
    700 # Send the request
--> 701 r = adapter.send(request, **kwargs)
    703 # Total elapsed time of the request (approximately)
    704 elapsed = preferred_clock() - start

File /lib/python3.10/site-packages/pyodide_http/_requests.py:42, in PyodideHTTPAdapter.send(self, request, **kwargs)
     40     pyodide_request.set_body(request.body)
     41 try:
---> 42     resp = send(pyodide_request, stream)
     43 except _StreamingTimeout:
     44     from requests import ConnectTimeout

File /lib/python3.10/site-packages/pyodide_http/_core.py:113, in send(request, stream)
    110 for name, value in request.headers.items():
    111     xhr.setRequestHeader(name, value)
--> 113 xhr.send(to_js(request.body))
    115 headers = dict(Parser().parsestr(xhr.getAllResponseHeaders()))
    117 if _IN_WORKER:

JsException: NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'https://fred.stlouisfed.org/graph/fredgraph.csv?id=GS10'.

Working case

In the same package, pandas-datareader, following code works well.

from pandas_datareader import wb
matches = wb.search('gdp.*capita.*const')

[koenvo]

Thank you for this report.

The CORS headers are missing: https://cors-test.codehappy.dev/?url=https%3A%2F%2Ffred.stlouisfed.org%2Fgraph%2Ffredgraph.csv%3Fid%3DGS10&method=get

Also see https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS for more info about CORS.

[anarinsk]

Thanks for the answer.