1 00:00:00,540 --> 00:00:06,800 Good, I have the script running at the moment and ass you can see the loop is doing its job. 2 00:00:06,810 --> 00:00:12,960 So it's printing out the working hours in the command line here every five seconds. 3 00:00:13,680 --> 00:00:18,530 And now it's 15 past 12. 4 00:00:18,840 --> 00:00:21,950 So that is between 8:00 a.m. and 4:00 p.m.. 5 00:00:21,970 --> 00:00:24,480 Now I will go ahead and add some lines here. 6 00:00:24,570 --> 00:00:33,270 So I'm thinking of keeping these statements here, this print statements but also adding more lines here 7 00:00:33,270 --> 00:00:43,110 which corresponds to file handling methods which will access these hosts file and modify it depending 8 00:00:43,170 --> 00:00:45,270 on the time. 9 00:00:45,330 --> 00:00:52,680 Now something that you should be aware about is this host file can only be modified by the administrator 10 00:00:53,160 --> 00:01:01,830 which is if I run the Python program I would have to open a command line to run the command line 11 00:01:02,490 --> 00:01:04,990 as administrator. 12 00:01:05,010 --> 00:01:11,000 So if you're on a Linux or Mac you would do the same by using sudo for instance. 13 00:01:11,040 --> 00:01:17,600 In this case I opened this command line and by just right clicking in here so shift right click and open 14 00:01:17,610 --> 00:01:22,450 command window here but that will not run the command line as an administrator. 15 00:01:22,660 --> 00:01:26,730 Which underlies that with this simple console 16 00:01:26,760 --> 00:01:30,140 I cannot access these host file. 17 00:01:30,510 --> 00:01:37,560 So in other words you need to run your Python program with a command line or a terminal where you 18 00:01:37,560 --> 00:01:45,270 have administrative rights and for the sake of building a program it's more wise to just copy this 19 00:01:45,360 --> 00:01:52,370 host file and just paste it here where the script file is. 20 00:01:52,770 --> 00:01:58,950 The reason I'm doing that is because here I'll not have to open a command line as administrator every 21 00:01:58,950 --> 00:02:00,940 time I test my script. 22 00:02:01,140 --> 00:02:06,720 So once I'm sure that things are working well then I just change the path. 23 00:02:06,720 --> 00:02:11,270 So at the moment I will not work with this path. I will work with this. 24 00:02:11,460 --> 00:02:21,390 Let's say hosts temp for temporary which is equal to the host file name because host 25 00:02:21,480 --> 00:02:26,300 is just here in the same folder with web site blocker.py. 26 00:02:26,300 --> 00:02:33,450 And besides making a working copy of this host file, you also want to make a backup copy of the host file just 27 00:02:33,450 --> 00:02:39,420 in case you make some errors in your Python code and you delete the file or you just 28 00:02:39,750 --> 00:02:42,420 delete some content from your existing host file. 29 00:02:42,540 --> 00:02:48,210 And I'm just going to copy this and just put it here. 30 00:02:48,750 --> 00:02:59,400 So paste it there in my D drive and yeah, I'll just close the path of the real host file for now until 31 00:02:59,400 --> 00:03:03,700 I have a working script that modifies this host file successfully. 32 00:03:03,760 --> 00:03:05,410 This one here. 33 00:03:05,550 --> 00:03:06,330 Great. 34 00:03:06,360 --> 00:03:07,410 Now. 35 00:03:07,890 --> 00:03:17,170 I can open this actually here on the right. Close here. 36 00:03:19,120 --> 00:03:19,880 Good. 37 00:03:19,890 --> 00:03:25,260 I think this is a good layout for you to do see the code well. And what do we have to do now? 38 00:03:25,260 --> 00:03:25,860 39 00:03:26,150 --> 00:03:34,740 Oh well we are checking the current time against these two other date time values and we have two scenarios. 40 00:03:34,750 --> 00:03:34,900 41 00:03:35,040 --> 00:03:38,070 So in the first scenario we are between these two times. 42 00:03:38,070 --> 00:03:45,150 And in that case where we are between these two times we want to make sure that we have four lines of 43 00:03:45,180 --> 00:03:53,640 text here in a host file where each corresponds with each of these least items of course together with 44 00:03:53,940 --> 00:04:04,050 redirecting IP in the front. So the same format as you see here but without the comment tag. And yeah, 45 00:04:04,050 --> 00:04:11,820 we can go ahead and open this host file now with the open method and write the list items in the host file. 46 00:04:11,820 --> 00:04:12,150 47 00:04:12,180 --> 00:04:19,700 However we may also want to check first if these four lines already exist in the host file because 48 00:04:19,710 --> 00:04:21,750 the host file can have two statues. 49 00:04:21,880 --> 00:04:27,490 So the first status is the host file is without these four lines there. 50 00:04:27,720 --> 00:04:35,150 The other status is the host file has this these four lines therefore you want to check for them. 51 00:04:35,490 --> 00:04:37,100 And to check these lines 52 00:04:37,230 --> 00:04:40,710 you first need to read the host file in Python. 53 00:04:41,040 --> 00:04:49,000 So you want to apply read method to your file and then maybe add a loop that iterates through this list 54 00:04:49,350 --> 00:04:57,060 and in each iteration you apply a conditional that says if a list item in content where content 55 00:04:57,060 --> 00:05:00,070 Is a text you have from the host file. 56 00:05:00,270 --> 00:05:08,260 So if that item is in the content then don't do anything otherwise add that item in the host file. 57 00:05:08,520 --> 00:05:11,400 So let's go ahead and do that with open 58 00:05:14,440 --> 00:05:22,830 hosts path. Sorry, that would be host temp. Host path is a path that we will be using later. 59 00:05:22,880 --> 00:05:28,800 So host temp and we want to open that file using� 60 00:05:28,950 --> 00:05:39,570 Well if we use the read method so R, we could read the file content but we wouldn't be able to write within 61 00:05:39,610 --> 00:05:42,510 this statement within the with statement. 62 00:05:42,790 --> 00:05:49,660 And if you pass W you wouldn't be able to read. So the middle solution that is to use our R plus. 63 00:05:49,990 --> 00:05:53,290 With that you would be able to read and write. 64 00:05:53,340 --> 00:05:54,300 So as file. 65 00:05:57,110 --> 00:06:01,380 And yeah, before writing anything we want to first check there. 66 00:06:01,720 --> 00:06:11,580 So let's say content equals file.read and what content will contain is the entire text 67 00:06:12,220 --> 00:06:13,780 of the host file. 68 00:06:14,230 --> 00:06:21,510 And actually we could print that out just to see what we have this far. 69 00:06:21,750 --> 00:06:27,690 So normally you don't want to print that out but in this case just for demonstration. 70 00:06:27,720 --> 00:06:31,020 And it's also good to check where we are this far. 71 00:06:31,370 --> 00:06:40,340 So python website blocker and so yeah, we got the text of host file printed out. 72 00:06:41,590 --> 00:06:48,180 And before that a working hours was printed out and now every five seconds the working hours and the 73 00:06:48,190 --> 00:06:50,490 content of the host file are being printed out. 74 00:06:50,760 --> 00:06:53,160 So I'll stop this. 75 00:06:53,160 --> 00:06:53,920 We're doing well. 76 00:06:56,990 --> 00:07:10,600 Now that we have content we want to iterate through the website list. So for web site in website list. 77 00:07:10,600 --> 00:07:12,680 78 00:07:13,380 --> 00:07:16,160 For instance the first item will be this one. 79 00:07:16,480 --> 00:07:19,620 So if Facebook dot com. 80 00:07:19,720 --> 00:07:27,110 If website in content. 81 00:07:27,490 --> 00:07:38,800 So if this is in this content, in this text and we are in the working hours in this part of the if conditional. 82 00:07:38,800 --> 00:07:39,220 83 00:07:39,220 --> 00:07:46,400 So if Facebook is there already we don't want to do anything because that will already block all our 84 00:07:46,380 --> 00:07:55,590 Facebook website so we pass that which means that Python will go ahead and check for other lines. 85 00:07:55,840 --> 00:08:06,790 So it will go here so it says else will not be executed in this case because if was executed. 86 00:08:06,810 --> 00:08:07,290 87 00:08:07,650 --> 00:08:14,850 So if that is not executed then Python goes to the next line and it sleeps for five seconds and then once 88 00:08:14,880 --> 00:08:19,040 it sleeps for five seconds the loop starts all over again. 89 00:08:19,040 --> 00:08:22,390 The condition is being evaluated again. 90 00:08:22,380 --> 00:08:24,210 Working hours is printed out. 91 00:08:24,220 --> 00:08:32,380 If we are between these two times then we open the file again in the second iteration of the while loop 92 00:08:32,950 --> 00:08:40,260 and we read the text and then we iterate in our list and check if any of our list of items is 93 00:08:40,260 --> 00:08:42,570 in the text of the host file. 94 00:08:43,600 --> 00:08:54,190 And then we pass to the next lines if it is not there and if it is there we want to file.right. 95 00:08:54,230 --> 00:08:55,330 96 00:08:55,920 --> 00:09:00,550 You do something like website and yeah, we are almost there. 97 00:09:00,750 --> 00:09:09,390 We can check what we got this far so lets you understand. So I executed this and now you see that 98 00:09:09,420 --> 00:09:13,950 www.Facebook.com was added in the host file. 99 00:09:14,290 --> 00:09:17,170 And then the next item of the list, Facebook.com 100 00:09:20,760 --> 00:09:22,860 and then my Hotmail account and so on. 101 00:09:22,890 --> 00:09:31,620 So the four items of the list which means the structure of our code is working well. We just need to work 102 00:09:31,620 --> 00:09:35,080 a bit on the style on the text formatting. 103 00:09:35,560 --> 00:09:38,030 So we are printing out the website 104 00:09:38,160 --> 00:09:48,220 but we also want the redirect IP in there. Actually the first one should be redirect variable. This one. 105 00:09:48,220 --> 00:09:51,570 And then according to the host file style 106 00:09:51,730 --> 00:09:59,620 we should have a space there as you can see it say the IP address and the host name should be separated 107 00:09:59,620 --> 00:10:04,100 by at least one space and that is what we will do. 108 00:10:05,050 --> 00:10:13,710 So redirect what you can do here is plus one space within double quotes and then we have plus website 109 00:10:13,700 --> 00:10:26,020 and to avoid the text being passed in one single line you want to pass here the backslash and special 110 00:10:26,010 --> 00:10:31,520 character that will create brake lines between these text items. 111 00:10:31,540 --> 00:10:31,980 Great. 112 00:10:31,990 --> 00:10:35,680 Now I can check this. 113 00:10:37,380 --> 00:10:41,180 Well nothing will happen because Facebook is already there. 114 00:10:41,350 --> 00:10:46,250 So it is going to stop this and really this. 115 00:10:51,660 --> 00:10:53,220 And yeah now it's working well. 116 00:10:53,300 --> 00:10:59,110 117 00:11:01,060 --> 00:11:09,070 And by the way if you have an antivirus in your system you probably have some warning there because 118 00:11:09,090 --> 00:11:13,460 the host file is a bit sensitive. 119 00:11:13,620 --> 00:11:21,020 So your antivirus will probably be notifying you that some program is modifying your host file. 120 00:11:21,040 --> 00:11:27,650 If you want to you can just you can cancel this don't do any cleaning. 121 00:11:27,660 --> 00:11:33,300 You don't have to clean it because you know that you're the one who is accessing that host file. 122 00:11:33,790 --> 00:11:37,490 So cancel that and yeah it's working well 123 00:11:37,500 --> 00:11:43,150 I believe. We are done with the first part or the conditional. 124 00:11:43,140 --> 00:11:48,120 So now where we are in this time which is between these two hours. 125 00:11:48,120 --> 00:11:51,880 But if you were let's say 14 here. 126 00:11:54,550 --> 00:11:57,460 Stop this check again. 127 00:11:58,090 --> 00:12:04,740 In this case we get printed out these phone hours but the text in the host file will be still there. 128 00:12:04,750 --> 00:12:04,990 129 00:12:05,230 --> 00:12:11,310 So what we want to do next is remove this text from the host file when this part of the conditional 130 00:12:11,350 --> 00:12:14,010 is satisfied. I will do that 131 00:12:14,010 --> 00:12:15,910 the next lecture, so see you there.