List dependencies for a specific pip package without downloading it.

check_pip_dependencies.py

import requests
import sys

script_name = sys.argv[0]
USAGE = f'''Lists package dependencies for a pip package without downloading it.
Usage:
    {script_name} package_name (or package_name==version)
e.g.
  To print all versions and depenencies of a given package.
    {script_name} pandas
  To check dendencies of specific version.
    {script_name} pandas==2.0.0
'''
# I created this simple script because:
#   1. Only wanted dependencies and versions for a SINGLE package.
#   2. Did not want to install additional packages.
#   3. Wanted something self-contained that did not requiere any downloads.

# Note: Ideas from the following SO quesiton were used:
#   https://stackoverflow.com/questions/11147667/is-there-a-way-to-list-pip-dependencies-requirements
# If you need something more complex you can look into: pipdeptree, johnnydep, and other options listed above.

if len(sys.argv) < 2:
    print(f"{USAGE}")
    sys.exit(0)

package_input = sys.argv[1]
if len(sys.argv)==3:
    last_count = int(sys.argv[2])
else:
    last_count = 20

# splits package name and version, lazy way I know! :)
package_name, *package_version = package_input.split("==")

print(f"Input: {package_name} {package_version}")

def get_package_url(package, version=None):
    if version:
        if type(version)==list:
            version = version[0]
        #print("VERSIONED")
        pack_url = f'https://pypi.org/pypi/{package}/{version}/json'
    else:
        #print("UNVERSIONED")
        pack_url = f'https://pypi.org/pypi/{package}/json'
    return pack_url

url = get_package_url(package_name, package_version)

pack_data = requests.get(url).json()
if 'message' in pack_data:
    print(pack_data['message'])
    print("Check package name.")
    sys.exit(0)

# pack_data['urls']

dependencies = pack_data['info']['requires_dist']
python_version = pack_data['info']['requires_python']

from packaging.version import parse as parseVersion
if 'releases' in pack_data:
    rel_count = len(pack_data['releases'].keys())

    past_releases = list(pack_data['releases'].keys())
    past_releases.sort(key=parseVersion)
    last_n_releases = past_releases[-1:-1-last_count:-1]
    last_n_releases_out = "\n".join(last_n_releases)
    print(f"Releases count: {rel_count}")
    print(f"Last {last_count} releases (reversed)\n{last_n_releases_out}")

# use the lastest package release version
if not package_version:
    package_version = last_n_releases[0]
else:
    package_version = package_version[0]

if dependencies:
    out_deps = "\n".join(dependencies)
    print(f'Dependencies for {package_name} {package_version}:\n{out_deps}')
else:
    print(f"Can't find dependency details for: {package_name} {package_version}")