Initial commit, basic helper classes created

py/Process.py

@@ -0,0 +1,107 @@
+#!/usr/bin/python
+
+from subprocess import Popen, call, PIPE
+
+class Process(object):
+    ''' Represents a running/ran process '''
+
+    @staticmethod
+    def devnull():
+        ''' Helper method for opening devnull '''
+        return open('/dev/null', 'w')
+
+    @staticmethod
+    def call(command):
+        '''
+            Calls a command (either string or list of args).
+            Returns tuple:
+                (stdout, stderr)
+        '''
+        if type(command) != str or ' ' in command:
+            shell = True
+        else:
+            shell = False
+        pid = Popen(command, stdout=PIPE, stderr=PIPE, shell=shell)
+        pid.wait()
+        return pid.communicate()
+
+    @staticmethod
+    def exists(program):
+        ''' Checks if program is installed on this system '''
+        p = Process(['which', program])
+        if p.stdout().strip() == '' and p.stderr().strip() == '':
+            return False
+        return True
+
+
+    def __init__(self, command):
+        ''' Starts executing command '''
+        if type(command) == str:
+            # Commands have to be a list
+            command = command.split(' ')
+        self.command = command
+        self.out = None
+        self.err = None
+        self.pid = Popen(command, stdout=PIPE, stderr=PIPE)
+
+    def stdout(self):
+        ''' Waits for process to finish, returns stdout output '''
+        self.get_output()
+        return self.out
+
+    def stderr(self):
+        ''' Waits for process to finish, returns stderr output '''
+        self.get_output()
+        return self.err
+
+    def get_output(self):
+        ''' Waits for process to finish, returns stdout & stderr '''
+        if self.pid.poll() == None:
+            self.pid.wait()
+        if self.out == None:
+            (self.out, self.err) = self.pid.communicate()
+
+    def poll(self):
+        ''' Returns exit code if process is dead, otherwise "None" '''
+        return self.pid.poll()
+
+    def kill(self):
+        ''' Kill current process '''
+        if self.pid.poll() == None:
+            # Process is already killed
+            return
+        try:
+            self.pid.kill()
+        except OSError, e:
+            if 'No such process' in e.__str__():
+                return
+            raise e
+
+    def interrupt(self):
+        ''' Send interrupt to current process '''
+        from signal import SIGINT
+        from os import kill
+        try:
+            kill(self.pid.pid, SIGINT)
+        except OSError, e:
+            if 'No such process' in e.__str__():
+                return
+            raise e  # process cannot be killed
+
+if __name__ == '__main__':
+    p = Process('ls')
+    print p.stdout(), p.stderr()
+    p.interrupt()
+
+    # Calling as list of arguments
+    (out,err) = Process.call(['ls', '-lah'])
+    print out,err
+
+    print '\n---------------------\n'
+
+    # Calling as string
+    (out,err) = Process.call('ls -l | head -2')
+    print out,err
+
+    print '"reaver" exists:', Process.exists('reaver')
+