Pin markupsafe version in requirements.txt

[Skylake-dev]

When i was trying to run the application as explained in the readme there is an error on the following command

> flask run --port 8000
[.....]
ImportError: cannot import name 'soft_unicode' from 'markupsafe'

After searching online i found that there is a breaking change in the library that has been made recently that causes this issue.
Pinning the version in the requirements fixes the issue.
markupsafe==2.0.1

[tianshanchuan]

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[satwikkansal]

hmm, is markupsafe being used by flask? or requests?

Those are the only two dependencies the project uses.

[Skylake-dev]

here is the full traceback

(.venv) C:\test\python_blockchain_app>flask run --port 8000
Traceback (most recent call last):
  File "C:\Program Files\Python39\lib\runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Program Files\Python39\lib\runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "C:\test\python_blockchain_app\.venv\Scripts\flask.exe\__main__.py", line 4, in <module>
  File "C:\test\python_blockchain_app\.venv\lib\site-packages\flask\__init__.py", line 14, in <module>
    from jinja2 import escape
  File "C:\test\python_blockchain_app\.venv\lib\site-packages\jinja2\__init__.py", line 12, in <module>
    from .environment import Environment
  File "C:\test\python_blockchain_app\.venv\lib\site-packages\jinja2\environment.py", line 25, in <module>
    from .defaults import BLOCK_END_STRING
  File "C:\test\python_blockchain_app\.venv\lib\site-packages\jinja2\defaults.py", line 3, in <module>
    from .filters import FILTERS as DEFAULT_FILTERS  # noqa: F401
  File "C:\test\python_blockchain_app\.venv\lib\site-packages\jinja2\filters.py", line 13, in <module>
    from markupsafe import soft_unicode
ImportError: cannot import name 'soft_unicode' from 'markupsafe' (C:\test\python_blockchain_app\.venv\lib\site-packages\markupsafe\__init__.py)

so markupsafe is a dependency of jinja2 that is a dependency of flask.

You can reproduce the issue following these steps:

• clone repo and cd into the folder
• create a clean python virtual environment python -m venv .venv
• activate the environment .venv\Scripts\activate
• install requirements pip install -r requirements.txt
• set FLASK_APP as shown in the readme export FLASK_APP=node_server.py or set FLASK_APP=node_server.py on windows
• start server flask run --port 8000 <-- this is the line that generates the above exception
  adding markupsafe==2.0.1 to requirements fixes the issue. This is because they made a breaking change in version 2.1 removing soft_unicode, see the issue that i linked in my original post.

[satwikkansal]

Got it, thanks for the details!

[ryan-rober]

• flask run --port 8000

i added markupsafe==2.0.1 to requirements
then run command pip install -r requirements.txt, it's successful but still generate above exception

[tianshanchuan]

这是来自QQ邮箱的假期自动回复邮件。   您好，我最近正在休假中，无法亲自回复您的邮件。我将在假期结束后，尽快给您回复。

[Skylake-dev]

@hwangzh are you sure that the correct version of markupsafe is installed? I just tried and it works.

[satwikkansal]

This has been fixed now, thanks all!