WEBVTT 00:01.040 --> 00:01.360 Okay. 00:01.360 --> 00:02.160 Welcome back. 00:02.240 --> 00:13.000 In the previous lecture, we covered how to use the exit keyword to exit this program from running. 00:13.040 --> 00:14.040 Okay. 00:14.080 --> 00:17.160 Now again if I came back here if I do. 00:19.280 --> 00:24.680 Clear and execute this program and then go back to Windows Machine. 00:25.480 --> 00:31.800 And here again if I run this program, the reverse back to here. 00:31.800 --> 00:38.760 If I use a simple command like this, it is showing all the details within a folder okay. 00:38.800 --> 00:44.400 If I use exit command, you see it is exiting without any error. 00:44.400 --> 00:48.280 And also if I go back here now you see that it is also exited. 00:48.320 --> 00:53.600 Okay, so what if I use city command? 00:53.600 --> 00:56.640 You know that city command is not going to work here. 00:56.880 --> 01:04.820 We need to handle that separately here Into the listener and also the back door which is inside windows 01:04.820 --> 01:05.300 machine. 01:05.820 --> 01:16.020 So while we are here, okay, while we are sending this command, okay. 01:17.140 --> 01:25.660 Right here and then we are sending here the first one, which is just exit command right now. 01:26.780 --> 01:31.540 And in Windows Machine we are just receiving the first one, not the second one. 01:31.540 --> 01:41.020 For example, if I use city to desktop so I will be able to only receive or get the city command, not 01:41.020 --> 01:46.220 the second one which is the desktop. 01:46.860 --> 01:51.260 And if I remove this from here, this zero. 01:51.260 --> 02:03.760 So it is now this command will be a list and it will say that uh, command list do not have input uh 02:03.760 --> 02:05.040 attribute to use. 02:05.560 --> 02:10.680 So here we need to use another thing that is called JSON. 02:10.720 --> 02:10.920 Okay. 02:10.960 --> 02:13.800 For handling this we need to use JSON. 02:14.160 --> 02:18.120 So let's import that JSON here. 02:22.000 --> 02:24.920 Okay now I imported this. 02:25.280 --> 02:33.480 And here okay when I receive this this I need to serialize this data. 02:33.520 --> 02:34.640 Okay. 02:34.640 --> 02:41.520 So after I serialize this data then I can send this data. 02:41.560 --> 02:44.840 Not using this index okay. 02:44.880 --> 02:50.560 That means I can send the whole list from here to the back door. 02:50.600 --> 02:56.000 Okay, so how can I serialize this data? 02:56.480 --> 02:58.720 If you try to. 02:58.760 --> 03:07.930 If you want to know this, we have, uh, with, uh, JSON, we can use dump method that will handle 03:07.930 --> 03:08.450 this for us. 03:08.490 --> 03:08.850 Okay. 03:09.090 --> 03:10.730 So let's use serialize. 03:10.770 --> 03:11.290 Okay. 03:11.330 --> 03:14.970 Serialize the data. 03:15.930 --> 03:22.090 It is going to be equal to JSON dot dumps. 03:23.050 --> 03:30.970 And right here we are going to give the command because that is what we receive from user. 03:31.010 --> 03:31.810 Okay. 03:31.850 --> 03:32.970 So let's give it. 03:33.530 --> 03:33.810 Okay. 03:33.850 --> 03:42.170 Now we give this command to this um dumps method okay. 03:42.610 --> 03:43.130 And now. 03:45.370 --> 03:45.970 Okay. 03:46.010 --> 03:49.490 Or even I can do one more thing here. 03:51.010 --> 03:55.530 I can put this right here. 03:59.930 --> 04:01.550 And now I can use it again. 04:01.950 --> 04:03.350 Now it looks better. 04:03.870 --> 04:06.550 So. 04:08.590 --> 04:18.150 Okay, now that I'm trying to send this data using send function, we also have another method called 04:18.190 --> 04:21.590 send all okay with the socket. 04:21.990 --> 04:31.470 Now instead of sending the command I can send the serialized data dot encode okay. 04:33.350 --> 04:42.470 And now this serialized data had been sent by using send all method from here. 04:42.910 --> 04:47.910 So let me save this and let's go back to Windows Machine here. 04:47.910 --> 04:50.070 We need to handle that okay. 04:50.550 --> 04:55.790 Let me zoom this a little more okay. 04:55.790 --> 04:57.550 Here also we need to use two things. 04:57.550 --> 04:59.230 One of them is the OS module. 04:59.230 --> 05:04.930 The next one is um, uh, Jason again. 05:05.210 --> 05:08.330 Okay, so for that, we need to import that. 05:08.690 --> 05:12.770 So let's import JSON. 05:15.330 --> 05:17.530 And also import. 05:20.090 --> 05:20.690 OS. 05:20.970 --> 05:25.050 OS will allow you to use a system command. 05:25.330 --> 05:25.730 Okay. 05:27.090 --> 05:30.090 With your code within your code. 05:30.130 --> 05:35.610 Um, so we're trying to get that here. 05:35.650 --> 05:36.130 Okay. 05:36.170 --> 05:40.370 Actually, uh, we are receiving the command right here. 05:40.370 --> 05:47.290 And we're storing the command into inside a variable called commands here. 05:47.330 --> 05:52.370 Right now we are not going to receive that as byte. 05:52.410 --> 05:52.850 Okay. 05:54.370 --> 05:55.890 So I need to remove this. 05:57.370 --> 06:01.500 And also let's create another way. 06:01.540 --> 06:05.260 Another method here for handling this. 06:05.300 --> 06:05.500 Okay. 06:05.540 --> 06:06.740 So let's use div. 06:07.340 --> 06:13.020 Div of I'm going to name this changing or change working directory. 06:19.060 --> 06:19.860 To something. 06:20.500 --> 06:23.060 So here we need to provide the path. 06:23.100 --> 06:23.500 Okay. 06:25.020 --> 06:34.700 So after that I am going to use this OS dot Chdir means change directory to what to path. 06:35.100 --> 06:39.500 And at the end I need to return this path. 06:39.540 --> 06:42.220 Okay, after it is changed I need to return it. 06:42.220 --> 06:46.380 And here inside the run method I can use it okay. 06:47.580 --> 06:48.100 Okay. 06:48.140 --> 06:48.820 Perfect. 06:49.460 --> 06:51.580 So we have the command here. 06:51.620 --> 06:52.260 Okay. 06:52.340 --> 06:54.020 That is something we are receiving. 06:54.460 --> 06:58.100 So right now this is not a byte. 06:58.140 --> 07:00.060 It is serialized data. 07:00.560 --> 07:04.680 So when it is serialized data, we need to use again JSON. 07:04.720 --> 07:09.360 Okay, so let me create a variable here called data. 07:10.000 --> 07:17.120 Use JSON dot loads and give the commands to this. 07:17.600 --> 07:24.400 And now instead of using command here I can use data. 07:24.440 --> 07:27.840 And I can tell this that check for the first one. 07:27.840 --> 07:34.880 If the first one is equal to exit then close the connection. 07:35.960 --> 07:44.800 So this will check the first one and it will handle the exit method here. 07:45.440 --> 07:52.120 And now the main purpose of this lecture is to handle the city command. 07:52.160 --> 08:01.060 Okay so here let's use Elsif or Elif Elif data which is the first one. 08:01.060 --> 08:01.500 Okay. 08:02.980 --> 08:14.780 If this is equal to city that user enter and length of this data. 08:15.020 --> 08:21.340 The first one okay is greater than one okay. 08:21.380 --> 08:28.940 For example if it is two then I want this to be executed. 08:28.980 --> 08:29.860 Okay. 08:29.900 --> 08:30.220 All right. 08:30.260 --> 08:31.300 Now let's hit enter. 08:31.980 --> 08:39.460 Inside here I want to call that method that we just created called change working directory to something. 08:39.660 --> 08:40.500 Okay. 08:40.580 --> 08:45.980 So here let's again create another variable I am going to name this command result. 08:46.020 --> 08:52.420 It is equal to self dot change working directory to something. 08:53.020 --> 08:56.340 And that is data. 08:56.820 --> 08:59.460 So before we had zero okay. 08:59.500 --> 09:03.640 Because we need the we needed the first one now because we need the second one. 09:03.640 --> 09:06.280 So I'm going to use index one. 09:06.800 --> 09:10.720 And after I use this I need to encode this okay. 09:10.720 --> 09:16.880 So when it is encoded now I can use it again. 09:16.920 --> 09:23.240 So here we are going to use else. 09:23.240 --> 09:28.320 And we put this into else okay. 09:28.440 --> 09:33.800 Command result is equal to self dot execute command data. 09:33.800 --> 09:36.800 So I am sure it is going to work. 09:36.800 --> 09:39.480 Now let's save this. 09:39.480 --> 09:43.440 Let's go back to play machine. 09:43.800 --> 09:49.920 Let's go to cmd or terminal I am going to run the listener. 09:50.520 --> 09:53.680 Go back here again. 09:53.680 --> 09:55.040 Run this one. 09:55.320 --> 09:58.560 Let's go back here okay. 09:58.600 --> 10:00.200 Connection established. 10:00.860 --> 10:05.060 Now I'm going to use a simple command like dir that is not working. 10:05.540 --> 10:06.300 Perfect. 10:06.940 --> 10:08.700 What if I use city? 10:08.740 --> 10:09.260 It's not. 10:09.300 --> 10:10.780 I'm sure it's not going to work. 10:12.460 --> 10:18.100 So here, when we provide dir, it's returning non-zero status code one. 10:20.020 --> 10:21.940 We are having an error here. 10:22.940 --> 10:23.700 Let's see. 10:23.820 --> 10:24.980 What is that okay. 10:25.500 --> 10:33.060 So while we are sending this it is serialized data and it is encoded okay. 10:34.260 --> 10:34.780 So. 10:39.780 --> 10:48.500 I'm sure the problem is not right here because we are we may have some kind of error right in here that 10:48.500 --> 10:49.980 we need to handle that. 10:55.660 --> 10:56.100 Okay. 10:56.100 --> 10:59.460 We have the task city. 10:59.500 --> 11:00.060 Okay. 11:00.150 --> 11:01.390 Command result. 11:01.430 --> 11:02.870 We provide data here. 11:03.630 --> 11:05.310 Command result. 11:05.350 --> 11:06.710 System command. 11:06.870 --> 11:12.950 We provide the command here, which is not allowed to be used here. 11:12.990 --> 11:13.350 Okay. 11:13.390 --> 11:21.910 Here we need to give data instead of commands because here we change the commands to data. 11:21.950 --> 11:22.310 Okay. 11:22.910 --> 11:26.430 Now let me save this again and let's go back to. 11:29.350 --> 11:29.670 Scala. 11:29.670 --> 11:30.190 Linux. 11:31.030 --> 11:32.470 We execute the program. 11:34.830 --> 11:36.510 And come to windows. 11:39.550 --> 11:40.630 Run this again. 11:41.950 --> 11:42.790 Come back here. 11:42.790 --> 11:45.070 So the connection is established. 11:45.350 --> 11:49.790 Now let's use dir which is a simple command is working. 11:49.990 --> 11:50.390 Okay. 11:50.790 --> 11:53.950 Now I'm going to use Siri to go back. 11:53.990 --> 11:54.430 Okay. 11:54.470 --> 11:57.710 One step back and hit enter. 11:57.990 --> 11:59.950 So it is giving me this one. 12:00.030 --> 12:04.290 That is because I use return here. 12:04.330 --> 12:04.530 Okay. 12:04.570 --> 12:05.890 I'm returning the path. 12:06.170 --> 12:09.850 And after I return the path somewhere here. 12:10.130 --> 12:10.650 Okay. 12:10.690 --> 12:11.890 And then back. 12:11.890 --> 12:20.090 I send this to, uh, the listener and in listener here, I print that. 12:20.090 --> 12:22.450 Okay, I receive it. 12:22.530 --> 12:25.010 And after I receive it, I print that here. 12:25.570 --> 12:29.890 So because of that, it is printing that for me. 12:30.050 --> 12:39.610 Now if again I use dir, you see that we change the directory to this one to this store before it was 12:40.010 --> 12:41.050 Python project. 12:41.090 --> 12:44.090 Now it is this one. 12:44.090 --> 12:49.170 Let's use uh, I want to go back to for example exploit. 12:49.650 --> 12:54.450 I use Siri and now I use dir. 12:54.490 --> 12:59.930 You see, this time we are into exploit cheap and I can go to any of them. 12:59.930 --> 13:00.070 For them. 13:00.070 --> 13:02.110 For example, I want to go to document. 13:02.670 --> 13:03.070 Okay. 13:03.110 --> 13:11.750 So use d o c u m e n t s uh documents. 13:11.750 --> 13:17.950 I think we did not move to writing here. 13:17.990 --> 13:19.070 Let's use dir. 13:20.070 --> 13:20.350 Okay. 13:20.390 --> 13:22.710 We are into here. 13:22.750 --> 13:28.870 Looks like because we have that use city hit enter. 13:31.230 --> 13:36.310 So now you see we are into that document okay. 13:39.550 --> 13:43.990 Let's see if the program is still working on windows Machine or it's closed. 13:44.030 --> 13:46.230 See it is still working bad. 13:47.430 --> 13:48.990 That that means it is working. 13:48.990 --> 13:53.390 Okay, let's go back to here. 13:53.630 --> 13:54.350 Okay. 13:54.390 --> 13:56.910 I want to go back to desktop. 13:58.630 --> 13:59.590 Desktop. 13:59.630 --> 14:05.640 Hit It enter the air and I want to go to. 14:09.080 --> 14:10.800 Looks like it is not working. 14:12.000 --> 14:13.200 Disk up. 14:13.600 --> 14:14.080 Okay. 14:14.120 --> 14:15.160 It is working right now. 14:15.160 --> 14:21.800 You see, it is giving me an error because I am into the desktop and I'm asking for desktop. 14:22.200 --> 14:25.440 So because of that now the program is broken. 14:25.440 --> 14:27.840 And also here the program is broken. 14:29.040 --> 14:33.960 That means it is saying the system cannot find the file that you give that. 14:33.960 --> 14:39.520 Is this because right now the location you are looking for is inside the desktop. 14:39.520 --> 14:43.080 So that means it is working perfect. 14:43.200 --> 14:48.200 Okay, let's try this once again. 14:48.240 --> 14:53.600 Run the program. 14:53.640 --> 14:54.720 Run this one. 14:55.320 --> 15:01.860 Let me go back here I use d I r right now I am into Python project. 15:01.860 --> 15:02.260 Okay. 15:02.660 --> 15:08.140 I use city to come back here if I use dir. 15:08.220 --> 15:13.500 Now you see I am into desktop instead of being in Python project. 15:13.620 --> 15:17.020 Let's go back again here. 15:17.060 --> 15:20.340 Now I am into exploit cheap instead of being right there. 15:20.860 --> 15:22.700 So let me use city. 15:22.740 --> 15:26.220 For example, I want to go back to Windows machine. 15:26.660 --> 15:30.940 I don't know if in windows we use this kind of slash or this one. 15:30.940 --> 15:32.060 I don't know exactly. 15:32.460 --> 15:33.380 Let's try that. 15:33.380 --> 15:34.940 This top hit. 15:34.940 --> 15:36.100 Enter. 15:36.140 --> 15:36.780 Dir. 15:37.420 --> 15:37.940 Dir. 15:38.860 --> 15:40.500 And it's not working. 15:41.540 --> 15:42.220 No problem. 15:42.900 --> 15:52.980 But the program that we are trying to work trying to use now, it is completed and it is working okay. 15:53.020 --> 15:56.380 We can change our directories that we want. 15:56.420 --> 16:00.220 So thanks for watching and I will see you in the next lecture.