Module for generating a random password (#637)

Module for generating a random password and copying it to the clipboard with a double left click. It uses xsel or xclip.

i3pystatus/random_password.py

@@ -0,0 +1,80 @@
+from i3pystatus import Module
+
+import random
+import string
+import subprocess
+
+
+class RandomPassword(Module):
+    """
+    Generates a random password and copies it to the clipboard. Useful if you use any password manager and you want to generate a password in the moment and save it later in you manager's database.
+
+    Uses `SystemRandom` class as a cryptographically secure pseudo-number generator - <https://docs.python.org/3/library/random.html#random.SystemRandom>
+
+    - Requires `xsel` or `xclip` for copying to the clipboard.
+    - Generates a new password with a left click by default.
+    - Generates a password with a default length of 12 and with lowercase, uppercase,  digits and special symbols.
+
+    .. rubric:: Available formatters
+
+    * `{length}` — length of generated password
+    """
+
+    settings = (
+        ("format", "Format string to be displayed in the status bar"),
+        ("length", "Length of the generated password"),
+        ("charset", "Dictionary containing character types to be included in the password"),
+        ("cliptool", "Currently supports xsel and xclip"),
+        ("color", "HTML color hex code #RRGGBB"),
+    )
+
+    format = ''
+    length = 12
+    charset = ['lowercase', 'uppercase', 'digits', 'special']
+    cliptool = None
+    color = None
+
+    on_doubleleftclick = 'generate_password'
+
+    def init(self):
+        # Finds out if either xsel or xclip exist
+        self._find_cliptool()
+
+        cdict = {
+            'length': self.length
+        }
+
+        self.output = {
+            "full_text": self.format.format(**cdict)
+        }
+
+        if self.color:
+            self.output["color"] = self.color
+
+    def _find_cliptool(self):
+        if subprocess.call(['which', 'xsel'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) == 0:
+            self.cliptool = 'xsel'
+            self._clip_params = ['-b', '-i']
+        elif subprocess.call(['which', 'xclip'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) == 0:
+            self.cliptool = 'xclip'
+            self._clip_params = ['-selection', 'c']
+
+        # Asserts that either xsel or xclip was found
+        assert self.cliptool and self._clip_params, 'It was no possible to find xsel or xclip installed in your system.'
+
+    def generate_password(self):
+        # If a blank list is provided for the charset, it will generate an empty password
+        chars = ''
+        if 'lowercase' in self.charset:
+            chars = string.ascii_lowercase
+        if 'uppercase' in self.charset:
+            chars += string.ascii_uppercase
+        if 'digits' in self.charset:
+            chars += string.digits
+        if 'special' in self.charset:
+            chars += string.punctuation
+
+        passwd = ''.join(random.SystemRandom().choice(chars) for x in range(self.length))
+
+        p = subprocess.Popen([self.cliptool, self._clip_params[0], self._clip_params[1]], stdin=subprocess.PIPE, close_fds=True)
+        p.communicate(input=passwd.encode('utf-8'))