Package requests==2.32.0 fails to import package ssl is not available

[larsmoa]

The latest release of requests (2.32.x) fails to work with error TypeError: Can't create an SSLContext object without an ssl module.

Minimal reproducible example:

streamlit_app.py:

import requests

requirements.txt:

requests==2.32.2

Available on share.stlite.net

Discussion

I've done some investigation and this seems to happen because of the code that patches requests (

stlite/packages/kernel/py/stlite-server/stlite_server/bootstrap.py

Line 153 in d8d376b

pyodide_http.patch_all() # Patch all libraries

):

• pyodide_http.patch_all() calls patch_requests()
• patch_requests() imports "from requests.adapters import BaseAdapter"
• requests.adapters imports "from urllib3.util.ssl_ import create_urllib3_context"
  and calls create_urllib3_context()
• create_urllib3_context() throws exception from this code snippet:

  if SSLContext is None:
      raise TypeError("Can't create an SSLContext object without an ssl module")
  

• This happens because there SSLContext is initialized as None in the "static initializer"
  on import
• SSLContext is overriden by code snippet from ssl_.py:

  try:  # Do we have ssl at all?
      import ssl
      from ssl import (  # type: ignore[assignment]
          CERT_REQUIRED,
          HAS_NEVER_CHECK_COMMON_NAME,
          OP_NO_COMPRESSION,
          OP_NO_TICKET,
          OPENSSL_VERSION,
          OPENSSL_VERSION_NUMBER,
          PROTOCOL_TLS,
          PROTOCOL_TLS_CLIENT,
          OP_NO_SSLv2,
          OP_NO_SSLv3,
          SSLContext,
          TLSVersion,
      )
      ...
  

Since ssl is not installed, the import fails.

[whitphx]

Thank you for reporting this.

You can workaround it by adding ssl to the requirements list explicitly.

Let me consider how we should fix it for a while.
Pyodide made ssl optional (https://pyodide.org/en/stable/usage/wasm-constraints.html) so you need to add it to the requirements list to use, then the issue is whether we should install it automatically for requests or leave it as-is only documenting it.

[aotombielecki]

When attempting to use the online demo linked from the readme, the application fails with the following error message:

Error during booting up

Traceback (most recent call last):
  File "/lib/python3.10/asyncio/futures.py", line 201, in result
    raise self._exception
  File "/lib/python3.10/asyncio/tasks.py", line 232, in __step
    result = coro.send(None)
  File "/lib/python3.10/_pyodide/_base.py", line 532, in eval_code_async
    await CodeRunner(
  File "/lib/python3.10/_pyodide/_base.py", line 355, in run_async
    coroutine = eval(self.code, globals, locals)
  File "<exec>", line 2, in <module>
  File "/lib/python3.10/site-packages/streamlit/__init__.py", line 50, in <module>
    from streamlit.version import STREAMLIT_VERSION_STRING as _STREAMLIT_VERSION_STRING
  File "/lib/python3.10/site-packages/streamlit/version.py", line 19, in <module>
    import requests
  File "/lib/python3.10/site-packages/requests/__init__.py", line 164, in <module>
    from .api import delete, get, head, options, patch, post, put, request
  File "/lib/python3.10/site-packages/requests/api.py", line 11, in <module>
    from . import sessions
  File "/lib/python3.10/site-packages/requests/sessions.py", line 15, in <module>
    from .adapters import HTTPAdapter
  File "/lib/python3.10/site-packages/requests/adapters.py", line 76, in <module>
    _preloaded_ssl_context = create_urllib3_context()
  File "/lib/python3.10/site-packages/urllib3/util/ssl_.py", line 252, in create_urllib3_context
    raise TypeError("Can't create an SSLContext object without an ssl module")
TypeError: Can't create an SSLContext object without an ssl module

Steps to Reproduce:

1. Open the online demo.
2. Wait for the application to install Streamlit.

[whitphx]

@aotombielecki Thanks for the catch! It's been fixed now 👍
Just updating the stlite version to 0.55.1 from 0.31.0 solved it somehow.

[larsmoa]

This seems to be resolved with requests==2.32.3:

Fixed issue where Requests started failing to run on Python versions compiled without the ssl module. (#6724)

(Changelog)

I've verified that my original example works with this version of the package. Suggesting to close this issue as won't fix.

[whitphx]

Thanks!