1 00:00:01,760 --> 00:00:10,710 OK I think it's an odd time to code and I'll be putting everything in one script. 2 00:00:10,710 --> 00:00:15,230 So let's call this website blocker.py. 3 00:00:16,090 --> 00:00:16,440 And yeah again 4 00:00:16,500 --> 00:00:22,560 The idea is that I'll be accessing this host file which is this directory. 5 00:00:22,590 --> 00:00:30,300 If you are on Windows you'll get it here. If you are on a Mac or Linux that would be directly at this 6 00:00:30,300 --> 00:00:33,250 folder and then you have the host file. 7 00:00:33,400 --> 00:00:39,510 So you get the idea and so let's keep that path in a variable. 8 00:00:40,210 --> 00:00:47,970 Let's say hosts path and that would be equal to� I had copied this earlier. 9 00:00:47,970 --> 00:00:51,750 So I'm just pasting it here. So on Windows 10 00:00:51,750 --> 00:01:00,680 these are backslashes on the Mac or Linux you'd have forward slash and then etc and then you have of course the hosts 11 00:01:01,840 --> 00:01:03,540 name so the name of the file. 12 00:01:03,770 --> 00:01:08,310 If you are on Windows you should be careful about something. These back slashes 13 00:01:08,310 --> 00:01:15,870 sometimes you might have something like let's say N. A folder that starts with the N character. 14 00:01:16,140 --> 00:01:20,460 What that will do is Python will read this as a special character. 15 00:01:20,640 --> 00:01:24,600 And what this special character means is� It means a break line. 16 00:01:24,600 --> 00:01:32,070 So when you pass backslash and Python thinks you're passing a Python keyword not actually a string. 17 00:01:32,070 --> 00:01:32,600 18 00:01:32,670 --> 00:01:38,940 In that case what you could do is you could pass R prefix there which raw. 19 00:01:39,240 --> 00:01:42,310 That means� Remove this. 20 00:01:42,590 --> 00:01:51,360 With this you'd tell Python that you're actually passing a raw string in there so you're not planning to pass any 21 00:01:51,440 --> 00:01:54,000 brake lines in there like a backslash. 22 00:01:54,170 --> 00:01:56,720 And I hope that is clear. 23 00:01:56,760 --> 00:02:04,680 Or alternatively you can remove this and you can add two backslashes in each of these directories separators. 24 00:02:04,700 --> 00:02:05,010 . 25 00:02:05,340 --> 00:02:07,070 So that would be an alternative solution. 26 00:02:07,080 --> 00:02:10,800 But let's keep it like this. 27 00:02:11,120 --> 00:02:18,510 Good. And maybe two other variables let's say redirect equals to this string. 28 00:02:19,890 --> 00:02:26,310 So the I.P where your browse visit will be redirected when you browse Facebook or other things that 29 00:02:26,310 --> 00:02:28,280 you find distracting. 30 00:02:28,760 --> 00:02:35,220 And then let's say website so you need to pass the websites that you want to block. 31 00:02:36,000 --> 00:02:38,430 That could be a list. 32 00:02:38,490 --> 00:02:40,540 So I'm calling this website list here. 33 00:02:40,560 --> 00:02:47,510 Here I'll pass the www.Facebook.com. 34 00:02:47,820 --> 00:02:55,610 And also you want to pass Facebook.com as well because sometimes these websites use 3 w there 35 00:02:55,920 --> 00:02:58,560 for their domain but sometimes they don't. 36 00:02:58,680 --> 00:03:07,240 So you want to pass both of these domains in the host file and then maybe my hotmail account. 37 00:03:09,240 --> 00:03:11,570 So how do I know that this is the domain? 38 00:03:11,580 --> 00:03:19,760 Well if I typed Hotmail.com and I can see that Hotmail.com is sending me to this domain in 39 00:03:19,760 --> 00:03:23,310 the browser so I can see this domain in the browser. 40 00:03:23,580 --> 00:03:27,400 This opens up my email displays. 41 00:03:27,420 --> 00:03:29,320 So this is what you want to pass. 42 00:03:29,340 --> 00:03:37,230 You want to see the final landing domain and maybe the other version. 43 00:03:37,810 --> 00:03:40,940 And yeah, we should be good to go. We have a list with four elements. 44 00:03:41,010 --> 00:03:45,720 That means the host file we will have four lines. 45 00:03:45,810 --> 00:03:52,570 I currently have this Facebook's here. So I am gonna save the host again with all those. 46 00:03:53,510 --> 00:04:00,980 And I'll make sure I don't have any Python scripts running here in the processes. 47 00:04:01,190 --> 00:04:03,440 I don't have any. 48 00:04:03,790 --> 00:04:08,210 And I was afraid that I had a running script, a Python script there. 49 00:04:08,460 --> 00:04:11,710 So that's why I checked in the processes. 50 00:04:11,850 --> 00:04:13,930 So how are we going to do this? 51 00:04:14,370 --> 00:04:17,670 Let me put this here and this here. 52 00:04:17,910 --> 00:04:25,980 Well our goal is to have this this file modified at let's say 8 a.m.. 53 00:04:26,190 --> 00:04:33,490 So at that time I want these four Web sites these four lines to be added in here together with this IP. 54 00:04:33,510 --> 00:04:34,050 55 00:04:34,480 --> 00:04:42,870 And then I want these four lines to be removed at let's say 4:00 p.m. and there are maybe two ways to do 56 00:04:42,870 --> 00:04:43,340 this. 57 00:04:43,350 --> 00:04:49,920 One way would be to write a simple Python script that all it does is it opens this file. 58 00:04:50,130 --> 00:04:58,720 Let's say with open host path as file and then write these elements of the list in that file in that host file. 59 00:04:58,800 --> 00:04:59,530 60 00:05:00,140 --> 00:05:01,730 And that's all. 61 00:05:01,900 --> 00:05:09,930 And then what you do is you may use this task scheduler on Windows or Cron on Linux or other 62 00:05:09,930 --> 00:05:16,290 packages that do schedules tasks and you may set this Python scripts to run in certain times. 63 00:05:16,290 --> 00:05:16,560 64 00:05:16,560 --> 00:05:18,140 That is one solution. 65 00:05:18,160 --> 00:05:23,100 But why would I use third party tools when I know Python. 66 00:05:23,190 --> 00:05:29,670 I mean I know Python better than these tools and I'm not 100 percent sure that with these tools I'll 67 00:05:29,670 --> 00:05:32,440 do exactly what I'm after. 68 00:05:32,670 --> 00:05:37,830 But with Python that is a programming language if you set to doing something if you think about something 69 00:05:38,370 --> 00:05:43,500 that's almost a hundred percent sure that you will do that because you have a lot of flexibility 70 00:05:43,500 --> 00:05:49,380 with a programming language so it's good that if you know programming language then you should seek 71 00:05:49,380 --> 00:05:51,040 for a native solution. 72 00:05:51,050 --> 00:05:57,270 And yeah, that's what I'll do in this case. I will not just write a simple script that adds to these four 73 00:05:57,270 --> 00:05:59,240 lines of code in this host file. 74 00:05:59,430 --> 00:06:07,170 Instead I'll have this script running all the time and to do that I'll use a while loop. 75 00:06:09,990 --> 00:06:16,500 While true and then everything goes inside this while loop. What while loop does 76 00:06:16,530 --> 00:06:18,630 is it execute an action 77 00:06:18,720 --> 00:06:23,190 very very fast so it depends on your processor speed. 78 00:06:23,190 --> 00:06:29,290 But in my case for instance what this will do it will print out one every� 79 00:06:29,370 --> 00:06:30,910 Let me guess, one millisecond. 80 00:06:31,050 --> 00:06:35,360 So it depends on your processor speed but maybe faster then one millisecond. 81 00:06:35,700 --> 00:06:39,740 And let me open a command line and execute this script. 82 00:06:39,820 --> 00:06:41,540 Shift right click here. 83 00:06:41,970 --> 00:06:48,280 Or command window here. This terminal plus package of atom is having a problem of the moment. 84 00:06:48,540 --> 00:06:53,980 It has a bug so I'll be using a simple command line. 85 00:06:53,980 --> 00:06:59,410 Terminal plus is probably more convenient but this shouldn't be a problem. So Python 86 00:07:00,120 --> 00:07:09,540 and the script name is website blocker. And yeah, one is being printed out as you see. Control C to interrupt the 87 00:07:09,570 --> 00:07:10,710 process. 88 00:07:11,130 --> 00:07:18,820 What I'm thinking about is to have some code here that checks the time every millisecond. 89 00:07:19,090 --> 00:07:24,200 So that would be something like East time between 8 a.m. and 4 p.m.. 90 00:07:24,320 --> 00:07:31,590 If it, then keep these lines in this host file. If it's not then remove these lines from the host file. 91 00:07:31,830 --> 00:07:35,880 And that action would be performed I am saying every millisecond. 92 00:07:36,450 --> 00:07:39,580 But that's not a very smart thing to do. 93 00:07:39,600 --> 00:07:42,490 Why would you want your program to run every millisecond. 94 00:07:42,540 --> 00:07:45,480 That doesn't sound very memory efficient. 95 00:07:45,490 --> 00:07:49,320 So what we could do here is a simple trick. 96 00:07:49,350 --> 00:07:56,710 We import time and then here we say time sleep and let's say 5. 97 00:08:00,840 --> 00:08:07,990 This time we execute this and one we will be printed every 5 seconds. 98 00:08:08,140 --> 00:08:10,980 So that's it. 99 00:08:10,980 --> 00:08:20,070 Which means if we write now the code that accesses these lines here in this host file, that code will run every five 100 00:08:20,070 --> 00:08:22,280 seconds and not every millisecond. 101 00:08:22,500 --> 00:08:25,410 So that's enough accuracy for us. 102 00:08:25,410 --> 00:08:34,080 That means that if time is 4 pm and then it goes four and one second we will still have this line. 103 00:08:34,330 --> 00:08:34,520 104 00:08:34,530 --> 00:08:42,770 We will have this website blocked yet 4 pm plus one second so there will be a delay of 5 seconds which 105 00:08:42,770 --> 00:08:43,770 is not a problem. 106 00:08:43,970 --> 00:08:51,550 And you can also put this higher number so you can make it 5 minutes which should be 300 300 seconds 107 00:08:52,400 --> 00:08:54,890 but let me keep it 5. 5 is good. 108 00:08:55,170 --> 00:08:56,520 5 seconds. 109 00:08:56,870 --> 00:08:59,080 I think this is starting to make more sense for you. 110 00:08:59,080 --> 00:09:02,100 I would like to stop here. In the next lecture 111 00:09:02,100 --> 00:09:07,800 we will go ahead and write the code that writes these lines in this host file.