[Hidden-tech] Python 3.7 on Mac

[Robert Heller]

At Sun, 31 Mar 2019 14:49:04 -0400 David Greenberg <david.greenberg3 at gmail.com> wrote:

> 
> 
> 
> Hi All,
> I've got it installed and running, but I can't figure out how to make it
> the default as far as Apache is concerned. I have an extremely simple
> script:
> 
> #!/usr/bin/env python
> print ("Content-Type: plain;charset=utf-8\r\n")
> print()
> 
> print("Hello World!")
> 
> which runs as a Python 2.7 script as expected after enabling
> LoadModule cgi_module libexec/apache2/mod_cgi.so
> in https.conf, but if I try to change 'python' to 'python3' I get a 500
> error and the Apache error log says:
> 
> [Sun Mar 31 13:34:38.253331 2019] [cgi:error] [pid 26370] [client
> ::1:52412] End of script output before headers: testLocalHost.py
> 
> I tried adding the two lines below in httpd.conf but that just resulted in
> the same 500 error.
> 
> LoadModule wsgi_module
> /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/mod_wsgi/server/
> mod_wsgi-py37.cpython-37m-darwin.so
> WSGIPythonHome /Library/Frameworks/Python.framework/Versions/3.7
> 
> I was on the verge of trying this:
> 
> ln -s /Library/Frameworks/Python.framework/Versions/3.7 /usr/bin/python3
> 
> but since I really don't know what I'm doing, I got cold feet and decided
> to ask for help. Thanks.

This is one option, but I am guessing it really should be:

ln -s /Library/Frameworks/Python.framework/Versions/3.7/python3 /usr/bin/python3

(or something like that, depending on the actual program name, and I'm 
guessing it isn't "3.7", which is more likely a directory name containing the 
program, unless the the "3.7" directory contains a whole tree (eg, bin/, lib/, 
etc.), in which case you would need to include that:

ln -s /Library/Frameworks/Python.framework/Versions/3.7/bin/python3 /usr/bin/python3
 

The other is to just replace '#!/usr/bin/env python' at the top of your 
scripts with '#!/Library/Frameworks/Python.framework/Versions/3.7/python3' (or 
whatever is the name of the actual executable, presumable under 
/Library/Frameworks/Python.framework/Versions/3.7/ -- it could just be python 
or it might be python3.7 and it is entirely possible any of these (with two 
already being symlinks).

The '#!/usr/bin/env python' hack is great when running from the command line 
in a shell terminal, but rarely works well otherwise, since the environment 
for other environments is harder to control or even know what it is.  For 
something like a CGI script running from a webserver it is just better to 
explicitly and specificly name the executable you want to run.

Oh, and the Content-Type: should be "text/plain", not just "plain".

> 
> David
> 
> MIME-Version: 1.0
> 
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