1 1 00:00:00,680 --> 00:00:01,580 Hi and welcome back. 2 2 00:00:01,580 --> 00:00:02,810 In this video we're going to be 3 3 00:00:02,810 --> 00:00:05,750 talking about logging in users. 4 4 00:00:05,750 --> 00:00:09,520 We will create a new template inside the users folder, 5 5 00:00:09,520 --> 00:00:13,230 called login dot html and it's going to be 6 6 00:00:13,230 --> 00:00:16,080 basically the same as a register dot html 7 7 00:00:16,080 --> 00:00:18,330 because we still need the email and password 8 8 00:00:18,330 --> 00:00:20,993 in order to actually log in. 9 9 00:00:22,650 --> 00:00:25,290 I'm gonna call this login at the top, 10 10 00:00:25,290 --> 00:00:30,290 login form and login form, there we go, 11 11 00:00:31,750 --> 00:00:36,750 like this and the rest is going to stay the same. 12 12 00:00:37,540 --> 00:00:40,850 So we have our email, and our password 13 13 00:00:40,850 --> 00:00:42,410 and then down here instead of sign up 14 14 00:00:42,410 --> 00:00:47,010 we're gonna say login and then we have our login form. 15 15 00:00:47,010 --> 00:00:51,140 Now in the users view, we're going 16 16 00:00:51,140 --> 00:00:53,050 to be adding a new Enpoint. 17 17 00:00:53,050 --> 00:00:55,090 This Enpoint is going to once again deal 18 18 00:00:55,090 --> 00:00:57,310 with the email and password but this time 19 19 00:00:57,310 --> 00:01:00,180 instead of registering users it's going to check 20 20 00:01:00,180 --> 00:01:03,600 whether the details are correct and if they are, 21 21 00:01:03,600 --> 00:01:06,600 it's just going to populate the session email. 22 22 00:01:06,600 --> 00:01:08,540 If you remember from a previous video, 23 23 00:01:08,540 --> 00:01:11,020 session email is what keeps tract of 24 24 00:01:11,020 --> 00:01:13,020 whether a user has logged in or not. 25 25 00:01:13,020 --> 00:01:16,090 When a browser can send us some data, 26 26 00:01:16,090 --> 00:01:17,970 we will match that data from 27 27 00:01:17,970 --> 00:01:21,360 the cookie with a session in our app. 28 28 00:01:21,360 --> 00:01:24,030 If the session contains an email, 29 29 00:01:24,030 --> 00:01:27,300 that means the user has either recently registered, 30 30 00:01:27,300 --> 00:01:29,180 or recently logged in. 31 31 00:01:29,180 --> 00:01:30,013 Let's do that. 32 32 00:01:31,290 --> 00:01:35,700 We're gonna create a user blueprint dot route 33 33 00:01:35,700 --> 00:01:37,590 and this is gonna be slash login. 34 34 00:01:37,590 --> 00:01:40,310 Once again the methods are gonna be get and post 35 35 00:01:40,310 --> 00:01:42,160 because we'll need that for the form. 36 36 00:01:49,110 --> 00:01:53,120 And there we have the body of our Endpoint 37 37 00:01:53,120 --> 00:01:58,120 and we can do email is this request form email, 38 38 00:01:58,530 --> 00:02:02,640 password as well, and then we will try 39 39 00:02:02,640 --> 00:02:06,280 to say if the user is login valid, 40 40 00:02:06,280 --> 00:02:07,620 there's a new method we're gonna create 41 41 00:02:07,620 --> 00:02:10,690 with the email and password, then we will set 42 42 00:02:10,690 --> 00:02:14,120 the session email to be equal to email. 43 43 00:02:14,120 --> 00:02:16,200 And we would also return email for now. 44 44 00:02:16,200 --> 00:02:19,520 Eventually you're going to want to return something else 45 45 00:02:19,520 --> 00:02:21,850 like a page or redirect them to 46 46 00:02:21,850 --> 00:02:24,130 their alerts or something like that. 47 47 00:02:24,130 --> 00:02:25,380 We're gonna do that soon. 48 48 00:02:26,230 --> 00:02:30,270 If we failed for some reason, then we're gonna say 49 49 00:02:30,270 --> 00:02:35,270 user errors, user error as e and return e message. 50 50 00:02:35,340 --> 00:02:36,740 Some of the reasons it may fail 51 51 00:02:36,740 --> 00:02:39,220 is if the user doesn't exist for example 52 52 00:02:39,220 --> 00:02:43,480 we may raise an exception or if the email 53 53 00:02:43,480 --> 00:02:46,130 is malformed we could raise an exception potentially. 54 54 00:02:47,090 --> 00:02:49,780 Let's go over to the user model 55 55 00:02:49,780 --> 00:02:54,123 and write our is login valid method. 56 56 00:03:04,810 --> 00:03:07,290 Okay so what this is gonna do is once again, 57 57 00:03:07,290 --> 00:03:11,050 is gonna try to find a user by email. 58 58 00:03:11,050 --> 00:03:13,950 If this fails, it will raise an error 59 59 00:03:14,810 --> 00:03:19,180 and that error will essentially be raised over to the caller 60 60 00:03:19,180 --> 00:03:21,550 which is this is login valid function. 61 61 00:03:21,550 --> 00:03:24,770 Because we're not gonna put this inside a try except log 62 62 00:03:24,770 --> 00:03:27,890 that error would just bubble up to the next caller. 63 63 00:03:27,890 --> 00:03:32,510 So from is login valid it would go up to the login user 64 64 00:03:32,510 --> 00:03:34,930 and there it would be caught by this except block 65 65 00:03:34,930 --> 00:03:36,800 and we would return the message. 66 66 00:03:36,800 --> 00:03:39,610 So this message here would be returned 67 67 00:03:39,610 --> 00:03:41,793 if we cannot find the user by email. 68 68 00:03:42,650 --> 00:03:45,180 Notice that in the register user method, 69 69 00:03:45,180 --> 00:03:49,050 we actually caught that and used it for our benefit 70 70 00:03:49,050 --> 00:03:50,910 but here we're just gonna let it bubble up 71 71 00:03:50,910 --> 00:03:54,463 and be caught by our Endpoint. 72 72 00:03:55,970 --> 00:03:59,000 Then if not utils dot check hashed password 73 73 00:03:59,000 --> 00:04:03,003 for the password and the user's password, 74 74 00:04:05,340 --> 00:04:07,190 then we're gonna raise another error. 75 75 00:04:08,910 --> 00:04:12,027 And that's gonna be an incorrect password error 76 76 00:04:12,027 --> 00:04:15,123 and we're gonna say your password was incorrect. 77 77 00:04:17,820 --> 00:04:19,700 Finally if that doesn't happen, 78 78 00:04:19,700 --> 00:04:24,700 meaning this did match, then we're just gonna return true. 79 79 00:04:28,310 --> 00:04:30,380 We need to create this error here, 80 80 00:04:30,380 --> 00:04:35,083 so we're gonna say class that, user error, do nothing. 81 81 00:04:37,840 --> 00:04:41,530 Then we'll return true down here and that will then go 82 82 00:04:41,530 --> 00:04:43,740 into session email equal email. 83 83 00:04:43,740 --> 00:04:45,690 So what's going on in the is login valid 84 84 00:04:45,690 --> 00:04:48,200 is we first find the user in the database. 85 85 00:04:48,200 --> 00:04:50,950 If the user is not found, that will produce an error 86 86 00:04:50,950 --> 00:04:53,630 which will then be caught by our Endpoint. 87 87 00:04:53,630 --> 00:04:57,000 Then we'll check whether the hashed passwords match. 88 88 00:04:57,000 --> 00:05:00,440 If they don't match, then we will raise another error 89 89 00:05:00,440 --> 00:05:02,860 saying your password was incorrect. 90 90 00:05:02,860 --> 00:05:05,600 If they do match, this will not be ran 91 91 00:05:05,600 --> 00:05:06,993 so we'll just return true. 92 92 00:05:07,870 --> 00:05:12,210 If we return true, then the session's email 93 93 00:05:12,210 --> 00:05:15,023 will be populated and we will return email. 94 94 00:05:22,280 --> 00:05:24,770 Hopefully that makes sense, let's run our app 95 95 00:05:24,770 --> 00:05:26,140 and see what happens. 96 96 00:05:26,140 --> 00:05:28,180 So I'm gonna go over to Chrome 97 97 00:05:29,084 --> 00:05:31,710 and recently registered bob@example.com 98 98 00:05:31,710 --> 00:05:36,060 so we're going to go to users log in 99 99 00:05:36,060 --> 00:05:39,920 and we're gonna do bob@example.com, 1, 2, 3, 4, 100 100 00:05:39,920 --> 00:05:42,040 and there we have Bob's email. 101 101 00:05:42,040 --> 00:05:45,500 If we go back and we try with bob2@example.com 102 102 00:05:45,500 --> 00:05:49,400 we get an error saying a user with this email was not found. 103 103 00:05:49,400 --> 00:05:51,140 That's it, this is everything we need 104 104 00:05:51,140 --> 00:05:54,550 in order to add log in to our app. 105 105 00:05:54,550 --> 00:05:57,460 Because we've got the user's data already stored 106 106 00:05:57,460 --> 00:06:00,320 from the registration, all we have to do is check it. 107 107 00:06:00,320 --> 00:06:03,530 Make sure the user's email and password exist 108 108 00:06:03,530 --> 00:06:06,070 and match what we've got saved 109 109 00:06:06,070 --> 00:06:08,773 and we can populate the session. 110 110 00:06:09,910 --> 00:06:13,970 Remember, as long as the app does not restart, 111 111 00:06:13,970 --> 00:06:18,362 and the browser is the same, then the session 112 112 00:06:18,362 --> 00:06:22,080 will be matched with the data the browser sends us 113 113 00:06:22,080 --> 00:06:25,700 and we can use this session anywhere else in our application 114 114 00:06:25,700 --> 00:06:28,870 to see if the user is logged in or not. 115 115 00:06:28,870 --> 00:06:32,020 By that I mean, if in any of our other Endpoints 116 116 00:06:32,020 --> 00:06:35,040 we check session and it has an email, 117 117 00:06:35,040 --> 00:06:36,380 that means the user logged in 118 118 00:06:36,380 --> 00:06:39,480 because the only way that the session could have an email, 119 119 00:06:39,480 --> 00:06:42,410 is if they logged in or registered. 120 120 00:06:42,410 --> 00:06:44,730 There's no other way for session to be populated 121 121 00:06:44,730 --> 00:06:47,630 with an email so that tells us the user logged in. 122 122 00:06:47,630 --> 00:06:49,600 And we're going to use that later on 123 123 00:06:49,600 --> 00:06:52,830 to show a user's alerts for example. 124 124 00:06:52,830 --> 00:06:55,820 We will be able to get all the alerts 125 125 00:06:55,820 --> 00:06:57,860 like we do here in the alert index 126 126 00:06:57,860 --> 00:07:01,410 but filter them so that we only get the user 127 127 00:07:01,410 --> 00:07:04,030 that is currently logged in's alerts. 128 128 00:07:04,030 --> 00:07:06,420 And that's gonna make this much more powerful 129 129 00:07:06,420 --> 00:07:08,030 and it's actually gonna do what we wanted 130 130 00:07:08,030 --> 00:07:13,030 which is cater each web to the user that is using it 131 131 00:07:13,460 --> 00:07:16,910 and not show every user all of the alerts 132 132 00:07:16,910 --> 00:07:19,960 including for items that they're not interested in. 133 133 00:07:19,960 --> 00:07:21,430 Thanks for joining me in this video, 134 134 00:07:21,430 --> 00:07:23,220 I hope you've enjoyed it and learned something. 135 135 00:07:23,220 --> 00:07:24,763 I'll see you in the next one.