How to install npm package from python script?

Question

How to install npm package from a python script?

When I use subprocess.Popen([\"node\", \"app.js\"]) it is OK.

Answer 1

set the shell argument to True

subprocess.Popen(["node", "npm", "install", "open"], shell=True)

Answer 2

On Windows, many of the Node.js "binaries" are actually suffixed with the .cmd filename extension, which for whatever reason during the invocation through subprocess.Popen, it doesn't expand (even though PATHEXT might contain .cmd).

So for a proper solution (that does not use shell=True), try append .cmd to the Node.js binaries needed:

Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) [MSC v.1900 32 bit (In
tel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> subprocess.Popen(['npm.cmd', 'install'])
<subprocess.Popen object at 0x005E18B0>
>>> npm ERR! install Couldn't read dependencies

Of course it throws an error because I don't have a package.json in that directory. Try again using some other commonly used programs, such as webpack:

>>> subprocess.Popen(['webpack'])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
...
FileNotFoundError: [WinError 2] The system cannot find the file specified

Oh right, add that .cmd:

>>> subprocess.Popen(['webpack.cmd'])
<subprocess.Popen object at 0x008A18B0>
>>> No configuration file found and no output filename configured via CLI option