1 1 00:00:00,880 --> 00:00:02,480 Hi and welcome back. 2 2 00:00:02,480 --> 00:00:04,380 In this video we're going to start adding 3 3 00:00:04,380 --> 00:00:06,923 user registration to our app. 4 4 00:00:07,910 --> 00:00:11,880 Up til now we've been able to add alerts and stores, 5 5 00:00:11,880 --> 00:00:15,400 but no matter how many people are using our application 6 6 00:00:15,400 --> 00:00:18,130 they're all going to see the same alerts. 7 7 00:00:18,130 --> 00:00:20,940 That is because we've got no way in our app 8 8 00:00:20,940 --> 00:00:23,473 of distinguishing between multiple users. 9 9 00:00:25,380 --> 00:00:27,330 For example, if we were to put this out there 10 10 00:00:27,330 --> 00:00:28,990 and share it with users, 11 11 00:00:28,990 --> 00:00:31,940 and then all of the users were to go over 12 12 00:00:31,940 --> 00:00:35,480 to say our alerts page, at the moment I don't have any, 13 13 00:00:35,480 --> 00:00:39,149 but they would all see the same alerts. 14 14 00:00:39,149 --> 00:00:41,300 What we have to do is we have to 15 15 00:00:41,300 --> 00:00:43,930 allow users to create an account, 16 16 00:00:43,930 --> 00:00:47,087 and then we have to keep track of the users 17 17 00:00:47,087 --> 00:00:50,550 and allow them to login. 18 18 00:00:50,550 --> 00:00:54,170 When they login we will be able to show them their alerts 19 19 00:00:54,170 --> 00:00:57,120 as opposed to everybody's alerts. 20 20 00:00:57,120 --> 00:01:00,110 Also having user details will allow us 21 21 00:01:00,110 --> 00:01:02,290 to notify them individually 22 22 00:01:02,290 --> 00:01:05,783 when the alerts reach the desired price. 23 23 00:01:07,160 --> 00:01:09,050 So this video going to be a bit longer. 24 24 00:01:09,050 --> 00:01:12,600 We're going to be doing a lot of work in this one. 25 25 00:01:12,600 --> 00:01:15,840 We'll begin by going over to our templates 26 26 00:01:15,840 --> 00:01:17,723 and add a new folder. 27 27 00:01:18,590 --> 00:01:20,370 I'm gonna call this Users. 28 28 00:01:20,370 --> 00:01:23,400 And then here I'm going to add an HTML file called 29 29 00:01:23,400 --> 00:01:25,490 register.html. 30 30 00:01:25,490 --> 00:01:29,900 This is the file that is going to contain our form. 31 31 00:01:29,900 --> 00:01:32,740 I'm going to just go over to something like 32 32 00:01:32,740 --> 00:01:33,803 a new alert, 33 33 00:01:35,020 --> 00:01:37,483 copy it because the form is going to be similar. 34 34 00:01:38,360 --> 00:01:39,410 But instead of creating an alert 35 35 00:01:39,410 --> 00:01:41,363 we're gonna call it register. 36 36 00:01:43,640 --> 00:01:46,430 And we're gonna make a few changes here. 37 37 00:01:46,430 --> 00:01:50,300 We're gonna have two things that the user needs to enter, 38 38 00:01:50,300 --> 00:01:53,683 their email and the password that they want. 39 39 00:01:54,640 --> 00:01:58,920 Now, it's important that your input has a type of password 40 40 00:01:58,920 --> 00:02:01,470 as that is going to hide away the characters 41 41 00:02:01,470 --> 00:02:02,700 as you type on it. 42 42 00:02:02,700 --> 00:02:05,407 Everything else is gonna stay the same, 43 43 00:02:05,407 --> 00:02:07,190 so all that we need to have in here 44 44 00:02:07,190 --> 00:02:09,870 is just this section with this form. 45 45 00:02:09,870 --> 00:02:14,800 And now we can move over and start creating our view. 46 46 00:02:14,800 --> 00:02:16,370 For a view we're gonna right click it 47 47 00:02:16,370 --> 00:02:17,720 and create a new Python file. 48 48 00:02:17,720 --> 00:02:19,663 And I'm gonna call it user.py. 49 49 00:02:21,560 --> 00:02:23,410 And before we do anything here 50 50 00:02:23,410 --> 00:02:25,660 I'm just going to go over to app.py 51 51 00:02:25,660 --> 00:02:28,110 and I'm going to make sure to add 52 52 00:02:28,110 --> 00:02:30,523 the user blueprint that we're about to create. 53 53 00:02:34,640 --> 00:02:37,010 And now that we're here we'll do something 54 54 00:02:37,010 --> 00:02:38,583 that we forgot to do earlier. 55 55 00:02:39,830 --> 00:02:44,100 And it is this blueprint, the store blueprint. 56 56 00:02:44,100 --> 00:02:45,550 So we'll also add it in here. 57 57 00:02:46,630 --> 00:02:47,463 That's good. 58 58 00:02:48,870 --> 00:02:51,190 Let's move over to our user views 59 59 00:02:51,190 --> 00:02:53,180 and start coding it. 60 60 00:02:53,180 --> 00:02:55,280 We'll need the user imports 61 61 00:02:57,830 --> 00:03:00,280 including this new one that we've not seen yet 62 62 00:03:00,280 --> 00:03:01,210 called session. 63 63 00:03:01,210 --> 00:03:02,690 We're gonna need that in just a moment. 64 64 00:03:02,690 --> 00:03:04,810 And I'll explain what the session is 65 65 00:03:04,810 --> 00:03:07,600 as we do this. 66 66 00:03:07,600 --> 00:03:10,070 We'll also need redirect. 67 67 00:03:10,070 --> 00:03:12,100 And of course we will need 68 68 00:03:13,420 --> 00:03:16,453 our user model that we will be creating in just a moment. 69 69 00:03:18,690 --> 00:03:20,040 Let's create our blueprint, 70 70 00:03:24,645 --> 00:03:27,812 and then let's add our first endpoint. 71 71 00:03:38,322 --> 00:03:40,380 Nothing new here, 72 72 00:03:40,380 --> 00:03:41,410 pretty much exactly the same 73 73 00:03:41,410 --> 00:03:44,684 as creating an alert or a new store. 74 74 00:03:44,684 --> 00:03:45,560 What we've done is we have created 75 75 00:03:45,560 --> 00:03:47,560 this structure of our endpoint 76 76 00:03:47,560 --> 00:03:49,323 and now we have to fill it in. 77 77 00:03:50,721 --> 00:03:54,220 And so when the browser arrives at our page 78 78 00:03:54,220 --> 00:03:57,361 we're going to render this register.html form. 79 79 00:03:57,361 --> 00:03:59,900 When the form is submitted we're gonna 80 80 00:03:59,900 --> 00:04:03,156 receive a post request with some form data, 81 81 00:04:03,156 --> 00:04:05,620 so we're gonna deal with it inside this if statement. 82 82 00:04:05,620 --> 00:04:07,243 We're gonna receive two fields, 83 83 00:04:08,660 --> 00:04:11,593 the email and the password field. 84 84 00:04:14,800 --> 00:04:18,490 And this password is just gonna be plain text. 85 85 00:04:18,490 --> 00:04:20,480 We're gonna talk about password encryption 86 86 00:04:20,480 --> 00:04:22,137 later on in this course, 87 87 00:04:22,137 --> 00:04:23,780 so don't worry about perceiving passwords in plain text 88 88 00:04:23,780 --> 00:04:26,150 if you're concerned about security. 89 89 00:04:26,150 --> 00:04:28,993 We'll be working around that in just a moment. 90 90 00:04:30,170 --> 00:04:33,200 Then we're going to try to do something, 91 91 00:04:33,200 --> 00:04:35,308 and I'm not sure if we've looked at 92 92 00:04:35,308 --> 00:04:36,810 try except blocks in Python. 93 93 00:04:36,810 --> 00:04:39,270 But essentially what a try except block allows us to do 94 94 00:04:39,270 --> 00:04:41,640 is to try to run a code block, 95 95 00:04:41,640 --> 00:04:44,780 and if there an error or an exception that happens 96 96 00:04:44,780 --> 00:04:48,170 during that block, then we can catch it a the end 97 97 00:04:48,170 --> 00:04:51,810 and do something different rather than crashing our app. 98 98 00:04:51,810 --> 00:04:52,680 So what were going to do is 99 99 00:04:52,680 --> 00:04:55,990 we're going to try to register the user, 100 100 00:04:55,990 --> 00:04:58,650 so we're gonna do something like user.register user 101 101 00:05:01,200 --> 00:05:03,250 passing in the email and password. 102 102 00:05:03,250 --> 00:05:06,340 And if we have an error 103 103 00:05:07,610 --> 00:05:10,140 then we're gonna return the errors message. 104 104 00:05:10,140 --> 00:05:13,050 So normally if you encounter an error 105 105 00:05:13,050 --> 00:05:16,120 when you are performing some code in Flask 106 106 00:05:16,120 --> 00:05:20,353 what you'll get out is you'll get a pretty nasty error page. 107 107 00:05:21,270 --> 00:05:23,610 Instead what we're gonna do is if we encounter an error 108 108 00:05:23,610 --> 00:05:25,670 we're gonna just return the message 109 109 00:05:25,670 --> 00:05:27,423 included within the error. 110 110 00:05:28,350 --> 00:05:33,350 In order to do that, we're going to have to do this. 111 111 00:05:33,850 --> 00:05:37,370 So what this does is try to catch all the exceptions, 112 112 00:05:37,370 --> 00:05:40,430 or any exception that happens during this code block 113 113 00:05:40,430 --> 00:05:44,360 we're gonna call it e inside this other block 114 114 00:05:44,360 --> 00:05:46,750 so that we can access its properties. 115 115 00:05:46,750 --> 00:05:48,830 So there's gonna be e.message 116 116 00:05:48,830 --> 00:05:51,500 will access the message property of e, 117 117 00:05:51,500 --> 00:05:54,210 which will be the exception that happened in this block 118 118 00:05:54,210 --> 00:05:55,043 if it happened. 119 119 00:05:55,043 --> 00:05:57,550 If it didn't happen, then we'll just run this 120 120 00:05:57,550 --> 00:05:59,053 and never run this. 121 121 00:06:00,330 --> 00:06:02,800 Now when we register a user 122 122 00:06:02,800 --> 00:06:07,041 we're going to have something saved into our database. 123 123 00:06:07,041 --> 00:06:11,610 But it would also be nice if we could 124 124 00:06:11,610 --> 00:06:16,020 somehow store that information in the user's browser, 125 125 00:06:16,020 --> 00:06:18,040 store some information in the user's browser 126 126 00:06:18,040 --> 00:06:20,360 so that when they come back to our site 127 127 00:06:20,360 --> 00:06:22,743 we know that they are logged in. 128 128 00:06:24,040 --> 00:06:25,950 We're gonna look at this in more detail 129 129 00:06:25,950 --> 00:06:27,910 when we look at logging in. 130 130 00:06:27,910 --> 00:06:30,530 But essentially when a user registers, 131 131 00:06:30,530 --> 00:06:31,980 after they finish registering 132 132 00:06:32,914 --> 00:06:33,900 they should already be logged in 133 133 00:06:33,900 --> 00:06:36,573 so they don't have to register and then login. 134 134 00:06:37,970 --> 00:06:42,430 When we talk about logging in what we really mean is 135 135 00:06:42,430 --> 00:06:44,950 every time the user visits our page 136 136 00:06:44,950 --> 00:06:48,210 we should be able to tell that that user 137 137 00:06:48,210 --> 00:06:51,613 is the user that registered, and not somebody else. 138 138 00:06:52,960 --> 00:06:55,400 It's impossible to do that unless 139 139 00:06:55,400 --> 00:06:58,210 the browser sends us some data 140 140 00:06:58,210 --> 00:07:01,700 that allows us to identify that browser 141 141 00:07:01,700 --> 00:07:04,510 as the browser that performed this registration. 142 142 00:07:04,510 --> 00:07:06,893 The browser that sent us the data in the form. 143 143 00:07:08,550 --> 00:07:11,420 So when the browser sends us the data in the form 144 144 00:07:11,420 --> 00:07:13,160 we will register that user 145 145 00:07:13,160 --> 00:07:16,252 and then we will send the browser back some data, 146 146 00:07:16,252 --> 00:07:20,120 and that browser in future accesses to our website 147 147 00:07:20,120 --> 00:07:22,400 will send us that data, and with it 148 148 00:07:22,400 --> 00:07:24,453 we'll be able to tell that that is the same browser 149 149 00:07:24,453 --> 00:07:27,400 that sent us the initial form data. 150 150 00:07:27,400 --> 00:07:29,060 So there is a back and forth there 151 151 00:07:29,060 --> 00:07:31,990 between us and the browser sending this data 152 152 00:07:31,990 --> 00:07:34,003 that allows us to uniquely identify it. 153 153 00:07:35,000 --> 00:07:38,150 And that data is a cookie. 154 154 00:07:38,150 --> 00:07:39,740 So if you don't know what cookies are, 155 155 00:07:39,740 --> 00:07:43,079 they're just pieces of data that are stored on the browser. 156 156 00:07:43,079 --> 00:07:46,990 And alongside the data we also store 157 157 00:07:46,990 --> 00:07:51,230 what webpage sets the cookie. 158 158 00:07:51,230 --> 00:07:55,417 So in this case it's gonna be 127.0.0.1;5000 159 159 00:07:55,417 --> 00:07:57,860 that's our current site. 160 160 00:07:57,860 --> 00:07:59,640 So we're gonna set a cookie 161 161 00:07:59,640 --> 00:08:02,370 and set that that is the address of the cookie. 162 162 00:08:02,370 --> 00:08:05,850 Whenever the browser makes a request to that webpage 163 163 00:08:05,850 --> 00:08:08,290 it will automatically include the cookie. 164 164 00:08:08,290 --> 00:08:10,470 So the user doesn't have to do anything 165 165 00:08:10,470 --> 00:08:12,480 and we have to do very little. 166 166 00:08:12,480 --> 00:08:14,520 We just have to send that data 167 167 00:08:14,520 --> 00:08:17,943 and then every time it will be returned back to us. 168 168 00:08:19,820 --> 00:08:23,410 Flask has a very nice way of dealing with that data 169 169 00:08:23,410 --> 00:08:25,023 which is by using this session. 170 170 00:08:25,900 --> 00:08:30,000 A session is a piece of data that is stored 171 171 00:08:30,000 --> 00:08:32,422 inside our application 172 172 00:08:32,422 --> 00:08:37,422 and it is stored for each user differently. 173 173 00:08:37,750 --> 00:08:41,880 So each user will have a separate, individual session. 174 174 00:08:41,880 --> 00:08:45,960 And what Flask does is when we get one of those cookies, 175 175 00:08:45,960 --> 00:08:50,920 Flask will tell us the session that is associated to it. 176 176 00:08:50,920 --> 00:08:52,860 So when a browser sends us the cookie 177 177 00:08:52,860 --> 00:08:56,660 Flask will say okay, the session is for this user 178 178 00:08:56,660 --> 00:08:59,910 and we can store whatever we want in that session. 179 179 00:08:59,910 --> 00:09:04,013 So we will say session, email, equal email. 180 180 00:09:05,000 --> 00:09:08,255 And what this does is once we've registered the user 181 181 00:09:08,255 --> 00:09:12,380 we're going to store the users email inside the session, 182 182 00:09:12,380 --> 00:09:14,030 the session is like a dictionary, 183 183 00:09:14,890 --> 00:09:18,410 so that in the future when the browser sends us the cookie 184 184 00:09:18,410 --> 00:09:21,840 Flask will automatically get the session 185 185 00:09:21,840 --> 00:09:23,920 that is already saved into our application 186 186 00:09:23,920 --> 00:09:27,140 and populate the user's email that we've set here 187 187 00:09:27,140 --> 00:09:29,010 in future requests. 188 188 00:09:29,010 --> 00:09:31,800 That means that if the user sends us the cookie 189 189 00:09:31,800 --> 00:09:34,550 in something like an alert and point for example 190 190 00:09:34,550 --> 00:09:37,110 we could access session email 191 191 00:09:37,110 --> 00:09:39,850 and it would be the same email that we sent 192 192 00:09:39,850 --> 00:09:43,103 when that browser sent us the registration request. 193 193 00:09:45,000 --> 00:09:48,070 So just to recap real quick before we move on, 194 194 00:09:48,070 --> 00:09:49,750 we send the user a cookie 195 195 00:09:49,750 --> 00:09:52,630 and that cookie has a piece of data that allows Flask 196 196 00:09:52,630 --> 00:09:56,170 to identify what session it's related to. 197 197 00:09:56,170 --> 00:09:58,088 When the cookie is received by our application 198 198 00:09:58,088 --> 00:10:00,250 Flask will populate the session 199 199 00:10:00,250 --> 00:10:02,483 with the data that we've set earlier on. 200 200 00:10:03,560 --> 00:10:05,573 So that's how it keeps track of that. 201 201 00:10:07,756 --> 00:10:12,756 Now this register user method has to be created, 202 202 00:10:12,980 --> 00:10:14,480 it doesn't exist yet. 203 203 00:10:14,480 --> 00:10:17,590 And of course this session email 204 204 00:10:17,590 --> 00:10:19,460 will be populated accordingly 205 205 00:10:19,460 --> 00:10:22,210 if this does not return an exception. 206 206 00:10:22,210 --> 00:10:24,560 If we get an exception here 207 207 00:10:24,560 --> 00:10:26,860 then we will jump immediately to this block 208 208 00:10:26,860 --> 00:10:27,973 and this will not run. 209 209 00:10:29,550 --> 00:10:32,886 Finally we're also going to return email just for now 210 210 00:10:32,886 --> 00:10:36,010 so that when a registration succeeds 211 211 00:10:36,010 --> 00:10:37,950 we can see something that tells us 212 212 00:10:37,950 --> 00:10:40,350 as the developer that it went well. 213 213 00:10:40,350 --> 00:10:42,520 Eventually we'll be returning something else here. 214 214 00:10:42,520 --> 00:10:44,530 You can say something like thank you for registering 215 215 00:10:44,530 --> 00:10:45,680 or something like that. 216 216 00:10:46,800 --> 00:10:49,120 The next problem is that in exception 217 217 00:10:49,120 --> 00:10:50,773 does not have a message property. 218 218 00:10:51,980 --> 00:10:54,140 So instead of using a generic exception 219 219 00:10:54,140 --> 00:10:55,970 that comes built in in Python 220 220 00:10:55,970 --> 00:10:58,250 we're going to create our own exception class 221 221 00:10:58,250 --> 00:10:59,920 that will contain a message. 222 222 00:10:59,920 --> 00:11:01,733 So we're gonna call that UserError 223 223 00:11:04,560 --> 00:11:06,903 and we do have to import that. 224 224 00:11:11,530 --> 00:11:14,870 However, because we're gonna have many different user errors 225 225 00:11:14,870 --> 00:11:16,710 that's gonna be like user not found, 226 226 00:11:16,710 --> 00:11:20,680 or password incorrect, or email with a bad format, 227 227 00:11:20,680 --> 00:11:22,230 there's gonna be a few of them. 228 228 00:11:22,230 --> 00:11:24,330 So what we're gonna do is we're gonna have 229 229 00:11:25,276 --> 00:11:27,050 a set of user errors. 230 230 00:11:27,050 --> 00:11:29,053 And we're gonna say UserErrors.UserError. 231 231 00:11:31,394 --> 00:11:34,210 This is gonna make a bit more sense as we move along. 232 232 00:11:34,210 --> 00:11:36,260 Don't worry too much about it. 233 233 00:11:36,260 --> 00:11:37,543 But this is our endpoint. 234 234 00:11:38,732 --> 00:11:40,020 And what we've done here is 235 235 00:11:40,020 --> 00:11:42,810 we've started at what the user sees 236 236 00:11:42,810 --> 00:11:45,959 and now we're moving down and down into our application 237 237 00:11:45,959 --> 00:11:48,040 by creating this view 238 238 00:11:48,040 --> 00:11:51,280 and now we're gonna move over and create the model. 239 239 00:11:51,280 --> 00:11:54,430 And then we'll be creating the errors and so on. 240 240 00:11:54,430 --> 00:11:58,400 So I like starting at what the user sees 241 241 00:11:58,400 --> 00:12:01,400 and defining how that's gonna be used 242 242 00:12:01,400 --> 00:12:04,580 before moving into implementation details. 243 243 00:12:04,580 --> 00:12:06,120 What I've defined here is 244 244 00:12:06,120 --> 00:12:09,550 I want a very simple way of registering a user in the model. 245 245 00:12:09,550 --> 00:12:12,016 I wanna be able to say user.register user, 246 246 00:12:12,016 --> 00:12:16,150 puts in an email and password, and that should either 247 247 00:12:16,150 --> 00:12:18,290 save the user to the database no problem 248 248 00:12:18,290 --> 00:12:20,483 or return an error. 249 249 00:12:22,500 --> 00:12:25,943 Now we have to go into the user model and create it. 250 250 00:12:27,040 --> 00:12:29,050 Notice though that for models user 251 251 00:12:29,050 --> 00:12:32,400 we're importing two things, user and user errors. 252 252 00:12:32,400 --> 00:12:34,670 So what we are gonna do in this model 253 253 00:12:34,670 --> 00:12:36,290 is we are going to learn about something new 254 254 00:12:36,290 --> 00:12:37,990 in Python that we've not looked at yet, 255 255 00:12:37,990 --> 00:12:41,520 and I'm gonna create a new Python package called user. 256 256 00:12:41,520 --> 00:12:42,810 And here we're going to create 257 257 00:12:42,810 --> 00:12:45,057 a new Python file called user.py, 258 258 00:12:45,057 --> 00:12:49,623 and we're also gonna create a new Python file called errors. 259 259 00:12:52,530 --> 00:12:54,183 Alright, so now we have that. 260 260 00:12:55,020 --> 00:12:57,570 In the user model we're going to define 261 261 00:12:57,570 --> 00:13:00,436 everything that we need in order to use 262 262 00:13:00,436 --> 00:13:03,400 a user in our application. 263 263 00:13:03,400 --> 00:13:07,350 So for now we'll have the UID, 264 264 00:13:07,350 --> 00:13:09,100 we're gonna have data classes, 265 265 00:13:09,100 --> 00:13:11,030 we're gonna have some typing, 266 266 00:13:11,030 --> 00:13:13,650 we're gonna have the model, 267 267 00:13:13,650 --> 00:13:15,530 we're gonna need the database, 268 268 00:13:15,530 --> 00:13:18,310 and we're gonna need also a couple other things. 269 269 00:13:18,310 --> 00:13:20,733 But we're gonna start with this just for now. 270 270 00:13:21,687 --> 00:13:23,733 We'll set the data class first of all, 271 271 00:13:26,230 --> 00:13:29,570 and then we'll define the things that a user needs. 272 272 00:13:29,570 --> 00:13:32,630 So we need a collection, which is going to be a string 273 273 00:13:32,630 --> 00:13:34,220 not in the init method. 274 274 00:13:34,220 --> 00:13:37,180 And the default is gonna be users, 275 275 00:13:37,180 --> 00:13:39,020 then it's gonna have an email, 276 276 00:13:39,020 --> 00:13:40,620 then it's gonna have a password, 277 277 00:13:42,620 --> 00:13:45,710 and finally an id_id property, 278 278 00:13:45,710 --> 00:13:49,500 which doesn't have a default value 279 279 00:13:49,500 --> 00:13:51,053 but it has a default factory. 280 280 00:13:53,390 --> 00:13:54,890 There we go. 281 281 00:13:54,890 --> 00:13:58,812 So that is our init method essentially created. 282 282 00:13:58,812 --> 00:13:59,980 It'll take an email and a password 283 283 00:13:59,980 --> 00:14:02,300 and optionally an _id field, 284 284 00:14:02,300 --> 00:14:04,380 but normally it will just be generated 285 285 00:14:04,380 --> 00:14:06,223 automatically by this function. 286 286 00:14:07,740 --> 00:14:09,603 Then we're gonna create a method, 287 287 00:14:11,190 --> 00:14:14,470 which is gonna be a class method called find by email. 288 288 00:14:14,470 --> 00:14:16,280 And the reason I'm making a separate one 289 289 00:14:16,280 --> 00:14:19,570 and not using the ones that are coming from model 290 290 00:14:19,570 --> 00:14:22,440 is because this one is also gonna try something. 291 291 00:14:22,440 --> 00:14:26,384 It's gonna try to return find one by of email 292 292 00:14:26,384 --> 00:14:29,650 using the email property that this gets passed. 293 293 00:14:29,650 --> 00:14:30,790 But if it fails 294 294 00:14:32,580 --> 00:14:34,470 with a type error because that's what'll happen 295 295 00:14:34,470 --> 00:14:36,790 if this doesn't exist in the database, 296 296 00:14:36,790 --> 00:14:39,083 then we're gonna raise a user error. 297 297 00:14:42,400 --> 00:14:45,460 Something like a user with this email was not found 298 298 00:14:45,460 --> 00:14:46,620 or something like that. 299 299 00:14:46,620 --> 00:14:49,200 Notice that that doesn't exist yet, but it will. 300 300 00:14:49,200 --> 00:14:51,150 And here what I'm defining is 301 301 00:14:51,150 --> 00:14:56,150 I would like to be able to raise one of these custom errors, 302 302 00:14:56,160 --> 00:14:58,500 or custom exceptions, when we fail 303 303 00:14:58,500 --> 00:15:01,003 to find a user on the database. 304 304 00:15:02,240 --> 00:15:04,407 And that method is going to be used 305 305 00:15:04,407 --> 00:15:09,030 by this register user method that we are gonna want. 306 306 00:15:09,030 --> 00:15:11,500 And that takes in an email and a password 307 307 00:15:11,500 --> 00:15:14,540 and it's gonna return a Boolean. 308 308 00:15:14,540 --> 00:15:15,720 The first thing this is going to do 309 309 00:15:15,720 --> 00:15:19,160 is it's going to check whether the email that the user 310 310 00:15:19,160 --> 00:15:21,520 is trying to register with is a valid email. 311 311 00:15:21,520 --> 00:15:23,663 I.e., it has the appropriate format. 312 312 00:15:29,160 --> 00:15:31,880 And if it doesn't then we're going to return 313 313 00:15:31,880 --> 00:15:33,433 an invalid email error. 314 314 00:15:38,160 --> 00:15:39,820 Okay, so there's a couple of new things here 315 315 00:15:39,820 --> 00:15:41,273 that we're going to import. 316 316 00:15:43,520 --> 00:15:46,771 We'll say from common utils import utils, 317 317 00:15:46,771 --> 00:15:47,604 that's where it's gonna live. 318 318 00:15:47,604 --> 00:15:51,970 And from the models user errors 319 319 00:15:54,650 --> 00:15:56,517 we're gonna import user errors. 320 320 00:15:58,219 --> 00:15:59,193 Okay? 321 321 00:16:00,740 --> 00:16:02,360 There we have that. 322 322 00:16:02,360 --> 00:16:04,740 Now if the email is valid 323 323 00:16:04,740 --> 00:16:08,880 then the next step is to see if the user already exists. 324 324 00:16:08,880 --> 00:16:13,880 So we'll say try to do a cls find by email. 325 325 00:16:18,100 --> 00:16:21,870 Now this method here is going to 326 326 00:16:21,870 --> 00:16:25,913 either return a user, which has been found in the database. 327 327 00:16:26,984 --> 00:16:29,360 Or it's going to raise an error 328 328 00:16:29,360 --> 00:16:32,090 saying the user could not be found. 329 329 00:16:32,090 --> 00:16:36,380 If the user can be found, that means that it already exists. 330 330 00:16:36,380 --> 00:16:38,570 So we don't want to create a new one. 331 331 00:16:38,570 --> 00:16:41,170 What we will do if this succeeds 332 332 00:16:41,170 --> 00:16:43,780 is we'll say, we'll raise a user error 333 333 00:16:43,780 --> 00:16:45,573 saying user already registered. 334 334 00:16:49,330 --> 00:16:54,310 Otherwise, if we get something like a user not found error 335 335 00:16:54,310 --> 00:16:57,710 which is what this raises, 336 336 00:16:57,710 --> 00:17:00,800 we're then going to create a user. 337 337 00:17:00,800 --> 00:17:04,583 And this may seem like a bit of a backward thing, 338 338 00:17:06,150 --> 00:17:08,710 we're actually doing what the method wants to do 339 339 00:17:08,710 --> 00:17:11,850 inside an except block, but that is find in Python. 340 340 00:17:11,850 --> 00:17:14,940 We're trying to do something 341 341 00:17:14,940 --> 00:17:19,330 and this is our positive scenario 342 342 00:17:19,330 --> 00:17:23,063 where the user tries to register but they already exist. 343 343 00:17:24,060 --> 00:17:26,513 If they already exist we just return an error. 344 344 00:17:26,513 --> 00:17:29,410 And otherwise if we get to the end 345 345 00:17:29,410 --> 00:17:32,360 and there was an error, meaning the user was not found, 346 346 00:17:32,360 --> 00:17:35,040 then we are gonna create a user 347 347 00:17:35,040 --> 00:17:36,360 and save it to MongoDB. 348 348 00:17:36,360 --> 00:17:38,260 We actually don't need the user equal. 349 349 00:17:39,190 --> 00:17:42,110 Notice that you could rewrite this 350 350 00:17:42,110 --> 00:17:45,274 so that it doesn't use a try except. 351 351 00:17:45,274 --> 00:17:47,802 But the resulting code is much longer 352 352 00:17:47,802 --> 00:17:51,773 and you do have to change this method as well. 353 353 00:17:52,700 --> 00:17:56,200 So I think this is a good way of going about it. 354 354 00:17:56,200 --> 00:17:57,870 Now the last thing we do need, 355 355 00:17:57,870 --> 00:18:00,220 of course because this is a model 356 356 00:18:00,220 --> 00:18:03,723 is we need the json method which returns a dictionary. 357 357 00:18:06,170 --> 00:18:08,490 And this is going to return 358 358 00:18:08,490 --> 00:18:10,483 all of the properties of the user. 359 359 00:18:15,738 --> 00:18:18,150 And remember this is only to be used 360 360 00:18:18,150 --> 00:18:19,730 when saving to the database. 361 361 00:18:19,730 --> 00:18:22,949 We are never going to return the user's json 362 362 00:18:22,949 --> 00:18:26,350 in our application because it contains the user's password. 363 363 00:18:26,350 --> 00:18:28,340 And we don't wanna be sharing that publicly 364 364 00:18:28,340 --> 00:18:29,373 with anybody else. 365 365 00:18:30,680 --> 00:18:33,080 There are a couple things we now need to create. 366 366 00:18:34,160 --> 00:18:37,030 Oh actually we don't need database here, my bad. 367 367 00:18:37,030 --> 00:18:40,300 Or list for now. 368 368 00:18:40,300 --> 00:18:42,020 We need to create the utils, 369 369 00:18:42,020 --> 00:18:44,270 and we need to create the user errors. 370 370 00:18:44,270 --> 00:18:46,240 Let's start with the utils. 371 371 00:18:46,240 --> 00:18:48,680 I'm gonna go over to common, right click it, 372 372 00:18:48,680 --> 00:18:50,846 Python file and create utils.py. 373 373 00:18:50,846 --> 00:18:55,281 And in here we're gonna have a class utils 374 374 00:18:55,281 --> 00:18:59,740 in which a static method, email is valid, 375 375 00:18:59,740 --> 00:19:00,680 is going to exist. 376 376 00:19:00,680 --> 00:19:04,150 It's gonna take a string and it's gonna return a Boolean 377 377 00:19:04,150 --> 00:19:07,350 saying whether the email has a valid format or not. 378 378 00:19:07,350 --> 00:19:09,340 We're gonna use the regex module 379 379 00:19:10,900 --> 00:19:13,410 in order to determine whether the email is valid. 380 380 00:19:13,410 --> 00:19:16,370 So we'll create an email address matcher, 381 381 00:19:16,370 --> 00:19:17,523 that's just a pattern. 382 382 00:19:20,320 --> 00:19:22,860 And this pattern is going to be 383 383 00:19:22,860 --> 00:19:27,860 something that starts with a set of words, or dashes, 384 384 00:19:30,332 --> 00:19:34,140 and there's gonna have at least one word or a dash, 385 385 00:19:34,140 --> 00:19:36,960 or sorry this is a character or dash. 386 386 00:19:36,960 --> 00:19:39,090 Then it's gonna have an at sign, 387 387 00:19:39,090 --> 00:19:44,090 and then it's going to have more characters or dashes, 388 388 00:19:45,378 --> 00:19:49,593 then it's gonna have a period. 389 389 00:19:50,440 --> 00:19:52,330 And it's going to have many of those. 390 390 00:19:52,330 --> 00:19:56,830 And eventually it's going to end with a set of characters 391 391 00:19:56,830 --> 00:19:59,280 and that's going to be the end of the string, so. 392 392 00:19:59,280 --> 00:20:02,680 A bit of a complicated irregular expression here. 393 393 00:20:02,680 --> 00:20:06,070 This character means the start of a string, 394 394 00:20:06,070 --> 00:20:08,350 and this character means the end of the string. 395 395 00:20:08,350 --> 00:20:10,240 When you have a regular expression pattern 396 396 00:20:10,240 --> 00:20:13,030 that is fully contained between these two characters 397 397 00:20:13,030 --> 00:20:17,230 it means that the email string cannot have anything else. 398 398 00:20:17,230 --> 00:20:22,230 So this stuff here must match the entire string. 399 399 00:20:22,590 --> 00:20:25,200 If it doesn't, it has anything more 400 400 00:20:25,200 --> 00:20:27,670 that would not match this entire string 401 401 00:20:27,670 --> 00:20:31,140 as the whole variable, it won't match 402 402 00:20:31,140 --> 00:20:35,543 because it has to reach the end and the start of the string. 403 403 00:20:36,460 --> 00:20:39,100 Then we've got words and dashes, 404 404 00:20:39,100 --> 00:20:41,310 sorry letters and dashes, any amount, 405 405 00:20:41,310 --> 00:20:45,730 for example Jose, that is letters. 406 406 00:20:45,730 --> 00:20:50,730 Jose pricing would also be letters and dashes. 407 407 00:20:51,000 --> 00:20:55,090 Then it's got the at sign, which would be an at sign. 408 408 00:20:55,090 --> 00:21:00,090 And then it's got letters and dashes or periods. 409 409 00:21:01,090 --> 00:21:05,430 For example, google.co. 410 410 00:21:05,430 --> 00:21:07,250 This is letters and dashes or periods, 411 411 00:21:07,250 --> 00:21:09,100 and it's got multiple of those groups. 412 412 00:21:09,100 --> 00:21:11,620 So this is letters and dashes and periods. 413 413 00:21:11,620 --> 00:21:13,010 This is letters and dashes and periods, 414 414 00:21:13,010 --> 00:21:14,760 but doesn't have dashes or periods, 415 415 00:21:17,210 --> 00:21:19,500 sorry that's the letters and dashes and periods. 416 416 00:21:19,500 --> 00:21:22,990 And eventually it's also got just letters at the end, 417 417 00:21:22,990 --> 00:21:24,513 for example uk. 418 418 00:21:25,580 --> 00:21:27,800 And it must be at the end of the string, 419 419 00:21:27,800 --> 00:21:30,980 this character must be the last one in the string. 420 420 00:21:30,980 --> 00:21:33,580 So this is how we're matching this sort of email. 421 421 00:21:33,580 --> 00:21:35,890 This is not a perfect email matcher 422 422 00:21:36,940 --> 00:21:40,680 because as you know some emails can have other characters, 423 423 00:21:40,680 --> 00:21:43,050 especially nowadays where emails are getting 424 424 00:21:43,050 --> 00:21:45,080 more and more Unicode friendly, 425 425 00:21:45,080 --> 00:21:47,250 you can have lots of other stuff in them. 426 426 00:21:47,250 --> 00:21:48,840 But for now it'll do. 427 427 00:21:48,840 --> 00:21:51,410 And you can always find better 428 428 00:21:51,410 --> 00:21:53,350 email matchers on the internet. 429 429 00:21:53,350 --> 00:21:54,870 They can be really long though, 430 430 00:21:54,870 --> 00:21:57,420 so I didn't want to write it out for you guys here. 431 431 00:21:59,574 --> 00:22:00,480 And then we're going to return true 432 432 00:22:00,480 --> 00:22:05,480 if the email matcher matches this email variable 433 433 00:22:06,600 --> 00:22:09,750 that we've received, otherwise we're gonna return false. 434 434 00:22:09,750 --> 00:22:11,160 This is just a short cut 435 435 00:22:11,995 --> 00:22:14,388 return to the operator here in Python. 436 436 00:22:14,388 --> 00:22:17,503 So true is that, otherwise false. 437 437 00:22:19,350 --> 00:22:22,250 Finally were going to move over to our errors, 438 438 00:22:22,250 --> 00:22:24,730 and we're gonna create a user error class 439 439 00:22:24,730 --> 00:22:26,580 which is gonna inherit from exception. 440 440 00:22:26,580 --> 00:22:28,140 And it's going to define an innate method 441 441 00:22:28,140 --> 00:22:29,763 that takes in a message. 442 442 00:22:32,834 --> 00:22:37,179 Now all our other classes like user not found error, 443 443 00:22:37,179 --> 00:22:39,408 is going to inherit from user error 444 444 00:22:39,408 --> 00:22:41,023 and it's gonna do nothing. 445 445 00:22:43,460 --> 00:22:46,978 And similarly for our user already registered error 446 446 00:22:46,978 --> 00:22:49,523 which is gonna inherit from user error. 447 447 00:22:51,005 --> 00:22:54,120 And for our invalid email error 448 448 00:22:55,600 --> 00:22:58,630 which is also going to inherit from user and do nothing. 449 449 00:22:58,630 --> 00:23:01,960 That means all of these are just names 450 450 00:23:01,960 --> 00:23:04,667 for a user error really. 451 451 00:23:04,667 --> 00:23:08,320 However, they can be caught individually. 452 452 00:23:08,320 --> 00:23:10,890 So when we go to a user model 453 453 00:23:10,890 --> 00:23:14,540 we can catch user not found error individually, 454 454 00:23:14,540 --> 00:23:15,880 or raise it individually, 455 455 00:23:15,880 --> 00:23:19,460 but it behaves just in the same way as a user error would. 456 456 00:23:19,460 --> 00:23:22,600 I.e. it just has an innate method that takes in a message 457 457 00:23:22,600 --> 00:23:24,733 and sets self message to be that. 458 458 00:23:25,733 --> 00:23:27,360 What that means is later on in our user views 459 459 00:23:27,360 --> 00:23:29,990 we can return e.message, 460 460 00:23:29,990 --> 00:23:33,520 and we know that if we caught a user error 461 461 00:23:33,520 --> 00:23:35,500 or any of its subclasses, 462 462 00:23:35,500 --> 00:23:37,563 it's going to have a message property. 463 463 00:23:40,010 --> 00:23:42,280 Now a couple more things. 464 464 00:23:42,280 --> 00:23:44,550 Here we imported user errors 465 465 00:23:44,550 --> 00:23:47,650 but we never defined user errors. 466 466 00:23:47,650 --> 00:23:49,280 What we're going to do is 467 467 00:23:49,280 --> 00:23:51,510 we're going to change this slightly to say 468 468 00:23:51,510 --> 00:23:56,510 import the entire module as user errors. 469 469 00:23:57,074 --> 00:23:59,930 Don't worry about that warning by the way, 470 470 00:23:59,930 --> 00:24:02,960 what this does is it takes all of these 471 471 00:24:02,960 --> 00:24:05,890 things that are exported by this module, 472 472 00:24:05,890 --> 00:24:07,760 so all of these classes, 473 473 00:24:07,760 --> 00:24:12,720 and essentially puts them inside an object 474 474 00:24:12,720 --> 00:24:15,763 that allows us to access them like this. 475 475 00:24:16,780 --> 00:24:18,840 Python complains saying lowercase variable 476 476 00:24:18,840 --> 00:24:20,300 imported as non-lowercase 477 477 00:24:20,300 --> 00:24:22,440 because we've imported this module 478 478 00:24:22,440 --> 00:24:23,650 and then we've renamed it 479 479 00:24:23,650 --> 00:24:25,460 so that it's no longer all lowercase, 480 480 00:24:25,460 --> 00:24:26,470 now it has uppercase letters, 481 481 00:24:26,470 --> 00:24:29,010 which makes it look a bit like a class. 482 482 00:24:29,010 --> 00:24:30,080 But I think that's okay, 483 483 00:24:30,080 --> 00:24:32,960 you could import it as errors if you prefer, 484 484 00:24:32,960 --> 00:24:34,003 it's up to you. 485 485 00:24:36,490 --> 00:24:40,320 The other problem we've got is in the user's view 486 486 00:24:40,320 --> 00:24:44,773 we've sent from models.user import user and user errors. 487 487 00:24:46,150 --> 00:24:49,310 So this won't work, evidently. 488 488 00:24:49,310 --> 00:24:52,210 Firstly because models.user is a folder 489 489 00:24:52,210 --> 00:24:56,590 it is not a file, so how can you import from it? 490 490 00:24:56,590 --> 00:24:59,660 And you maybe thinking hold on, 491 491 00:24:59,660 --> 00:25:03,800 what we should do here is from models.user.user import user. 492 492 00:25:03,800 --> 00:25:08,000 And from models.user.errors import, 493 493 00:25:08,000 --> 00:25:10,763 oh sorry, like this user errors. 494 494 00:25:11,680 --> 00:25:13,320 There we go, import. 495 495 00:25:13,320 --> 00:25:15,359 Maybe this is what we should be doing? 496 496 00:25:15,359 --> 00:25:16,192 Right? 497 497 00:25:16,192 --> 00:25:20,620 And you are right, that is what you should be doing 498 498 00:25:20,620 --> 00:25:25,320 but you can do this if you copy that 499 499 00:25:25,320 --> 00:25:29,770 and put it in the dunder init.py file. 500 500 00:25:29,770 --> 00:25:31,100 Now you can see the error disappears 501 501 00:25:31,100 --> 00:25:32,280 and Python likes that. 502 502 00:25:32,280 --> 00:25:33,510 Why is that? 503 503 00:25:33,510 --> 00:25:36,040 Because when you import from a package, 504 504 00:25:36,040 --> 00:25:40,497 i.e. a folder that has a dunder init.py file, 505 505 00:25:40,497 --> 00:25:45,497 Python will automatically import from that file. 506 506 00:25:46,520 --> 00:25:50,660 So what we can do is we can use that file as a shortcut. 507 507 00:25:50,660 --> 00:25:54,360 We can import everything that is inside the folder 508 508 00:25:54,360 --> 00:25:57,250 into this init file, 509 509 00:25:57,250 --> 00:25:59,500 and then other parts of our application 510 510 00:25:59,500 --> 00:26:03,440 can just directly import from the folder itself. 511 511 00:26:03,440 --> 00:26:05,380 Just makes the import a little bit cleaner 512 512 00:26:05,380 --> 00:26:06,720 and a little bit simpler. 513 513 00:26:07,670 --> 00:26:10,480 So there's like a small trick for you 514 514 00:26:10,480 --> 00:26:11,780 if you're learning Python. 515 515 00:26:13,510 --> 00:26:16,183 We haven't made use of url for, or redirect use yet, 516 516 00:26:17,056 --> 00:26:18,700 but we will do when we get to logging in, 517 517 00:26:18,700 --> 00:26:22,770 so don't worry too much about the unused methods there. 518 518 00:26:22,770 --> 00:26:26,080 But we are ready now to register users. 519 519 00:26:26,080 --> 00:26:29,310 So let's go ahead and run our app, 520 520 00:26:29,310 --> 00:26:30,460 make sure it's working. 521 521 00:26:31,320 --> 00:26:33,240 Load it up on Chrome, 522 522 00:26:33,240 --> 00:26:37,680 and we're gonna go to users/register 523 523 00:26:37,680 --> 00:26:41,050 and we have here our email and password. 524 524 00:26:41,050 --> 00:26:42,990 Make sure MongoDB is running 525 525 00:26:42,990 --> 00:26:45,985 and then I'm gonna type jose@example.com, 526 526 00:26:45,985 --> 00:26:48,033 password is gonna be one-two-three-four. 527 527 00:26:49,220 --> 00:26:50,053 Sign it up. 528 528 00:26:50,910 --> 00:26:53,454 And we have a problem, our first problem. 529 529 00:26:53,454 --> 00:26:55,700 It says runtime error, 530 530 00:26:55,700 --> 00:26:59,060 this session is unavailable because no secret key was set. 531 531 00:26:59,060 --> 00:27:00,770 Set the secret key on the application 532 532 00:27:00,770 --> 00:27:02,510 to something unique and secret. 533 533 00:27:02,510 --> 00:27:04,350 Okay, that's a pretty nice error. 534 534 00:27:04,350 --> 00:27:06,590 Whenever we use cookies, 535 535 00:27:06,590 --> 00:27:11,330 i.e. whenever we send data from our app into the browser 536 536 00:27:11,330 --> 00:27:14,270 and we want that data to be secure 537 537 00:27:14,270 --> 00:27:17,410 so the users can't change it. 538 538 00:27:17,410 --> 00:27:19,700 For example, if a user has a cookie 539 539 00:27:19,700 --> 00:27:21,800 and it says hey, this cookie is associated 540 540 00:27:21,800 --> 00:27:24,640 with that session in your application, 541 541 00:27:24,640 --> 00:27:26,560 a user could potentially go and change it 542 542 00:27:26,560 --> 00:27:29,370 and associate their cookie with somebody else's session. 543 543 00:27:29,370 --> 00:27:31,466 Essentially accessing somebody else's data. 544 544 00:27:31,466 --> 00:27:36,360 So that is why we want to secure the data 545 545 00:27:36,360 --> 00:27:38,143 when it's stored in a cookie. 546 546 00:27:39,270 --> 00:27:41,900 Flask secures the data by using something 547 547 00:27:41,900 --> 00:27:43,350 called a secret key, 548 548 00:27:43,350 --> 00:27:45,720 but we haven't set a secret key. 549 549 00:27:45,720 --> 00:27:48,210 So we're going to set one just now. 550 550 00:27:48,210 --> 00:27:51,220 Go into app.py, and under app declaration 551 551 00:27:51,220 --> 00:27:56,043 say app.secret key equal os.urandom 64. 552 552 00:27:58,318 --> 00:28:00,343 This will not work on Windows, 553 553 00:28:00,343 --> 00:28:02,730 so this only works on Mac. 554 554 00:28:02,730 --> 00:28:04,140 You do have to import OS. 555 555 00:28:04,140 --> 00:28:06,040 I think it also works on Linux 556 556 00:28:06,040 --> 00:28:08,426 but don't think it'll work on Windows. 557 557 00:28:08,426 --> 00:28:10,510 So if you are using Windows just type in a string here 558 558 00:28:10,510 --> 00:28:12,950 that is long and random. 559 559 00:28:12,950 --> 00:28:14,820 It can be anything you like. 560 560 00:28:14,820 --> 00:28:15,980 For now I'm gonna type 561 561 00:28:15,980 --> 00:28:17,330 app.secretkey = Jose 562 562 00:28:17,330 --> 00:28:19,300 which is neither long or random, 563 563 00:28:19,300 --> 00:28:23,060 so don't use this when we deploy our application. 564 564 00:28:23,060 --> 00:28:24,580 Because if they know the secret key 565 565 00:28:24,580 --> 00:28:28,302 the users can still change the contents of the cookie. 566 566 00:28:28,302 --> 00:28:32,060 So again, if you're using Mac or Linux, 567 567 00:28:32,060 --> 00:28:37,060 os.urandom 64 will generate a 64 character long 568 568 00:28:37,170 --> 00:28:39,270 random, Unicode string, 569 569 00:28:39,270 --> 00:28:43,330 which is a pretty good way of getting something fairly safe. 570 570 00:28:43,330 --> 00:28:46,930 If you're using Windows, do you just a string 571 571 00:28:46,930 --> 00:28:49,204 with letters and numbers and symbols and all that stuff. 572 572 00:28:49,204 --> 00:28:53,593 Okay, we can restart our app and try again. 573 573 00:28:58,050 --> 00:28:58,883 Brilliant. 574 574 00:28:58,883 --> 00:29:01,350 So it says the email used to register already exists 575 575 00:29:02,814 --> 00:29:04,320 because well I'd been testing this earlier on, 576 576 00:29:04,320 --> 00:29:07,673 but I will type bob@example.com, 577 577 00:29:08,940 --> 00:29:11,160 and there we get back the email. 578 578 00:29:11,160 --> 00:29:14,530 So what we saw there was that 579 579 00:29:14,530 --> 00:29:17,650 the user was registered, at first, 580 580 00:29:17,650 --> 00:29:19,600 and that created an error. 581 581 00:29:19,600 --> 00:29:22,428 If we find the user by email 582 582 00:29:22,428 --> 00:29:25,839 this will raise a UserError.UserAlreadyRegisteredError. 583 583 00:29:25,839 --> 00:29:30,508 When that happens it automatically stops execution 584 584 00:29:30,508 --> 00:29:35,473 and jumps over to the caller of this function. 585 585 00:29:35,473 --> 00:29:40,473 Notice that if this was caught here 586 586 00:29:40,800 --> 00:29:43,490 then it would jump to the appropriate except block, 587 587 00:29:43,490 --> 00:29:45,652 but it is not caught. 588 588 00:29:45,652 --> 00:29:47,628 Here we're not catching user not found error, 589 589 00:29:47,628 --> 00:29:49,690 we're not catching user already registered error. 590 590 00:29:49,690 --> 00:29:54,000 So it jumps straight to the caller which is here. 591 591 00:29:54,000 --> 00:29:56,801 And because that error is a subclass of user error 592 592 00:29:56,801 --> 00:30:00,532 we then return e.message. 593 593 00:30:00,532 --> 00:30:04,170 Afterwards we tried with bob@example.com. 594 594 00:30:04,170 --> 00:30:06,960 We registered the user, nothing bad happened, 595 595 00:30:06,960 --> 00:30:09,797 so we set the session's email to be email 596 596 00:30:09,797 --> 00:30:11,663 and then we returned email. 597 597 00:30:13,240 --> 00:30:16,658 What I'm gonna do now is I'm gonna go over to the alerts 598 598 00:30:16,658 --> 00:30:20,730 and I'm going to in the index do something like print, 599 599 00:30:20,730 --> 00:30:23,067 session, email. 600 600 00:30:23,067 --> 00:30:25,823 And I'm going to import session from Flask. 601 601 00:30:28,410 --> 00:30:29,780 Okay, that restarts my app. 602 602 00:30:29,780 --> 00:30:31,740 Do restart it if it doesn't restart. 603 603 00:30:31,740 --> 00:30:34,703 And then we're gonna go over to alerts. 604 604 00:30:35,920 --> 00:30:37,360 Now we get an error. 605 605 00:30:37,360 --> 00:30:39,252 So, what's happening? 606 606 00:30:39,252 --> 00:30:43,350 The error says key error, email. 607 607 00:30:43,350 --> 00:30:46,190 What that means is a very bad way of saying 608 608 00:30:46,190 --> 00:30:50,283 the email key does not exist inside session. 609 609 00:30:51,660 --> 00:30:53,480 But I thought we just set it? 610 610 00:30:53,480 --> 00:30:56,910 We said session email equal email. 611 611 00:30:56,910 --> 00:30:58,513 So why is it now not set? 612 612 00:30:59,530 --> 00:31:02,250 The answer is because we restarted our app 613 613 00:31:02,250 --> 00:31:05,283 and when you restart your app the session gets cleared. 614 614 00:31:06,160 --> 00:31:10,001 So what you wanna do is go back to registering, 615 615 00:31:10,001 --> 00:31:13,100 register a new user, 616 616 00:31:13,100 --> 00:31:18,100 something like rolf35@gmail.com, 617 617 00:31:19,538 --> 00:31:22,450 sign up, make sure that works. 618 618 00:31:22,450 --> 00:31:25,950 And then you can go into your alerts and now it works. 619 619 00:31:25,950 --> 00:31:27,870 And down here you can see that 620 620 00:31:27,870 --> 00:31:30,900 we've printed out rolf35@gmail.com 621 621 00:31:30,900 --> 00:31:33,683 because our alerts prints the session email. 622 622 00:31:34,820 --> 00:31:36,270 Again if you restart your app 623 623 00:31:37,116 --> 00:31:39,484 you will have to sign up with an entirely new email address 624 624 00:31:39,484 --> 00:31:41,813 in order to get session email to be populated. 625 625 00:31:42,830 --> 00:31:44,730 So that is a very common error 626 626 00:31:44,730 --> 00:31:48,470 that you see when something goes wrong during registration 627 627 00:31:48,470 --> 00:31:50,670 and session email is not set. 628 628 00:31:50,670 --> 00:31:53,230 Then when you go and try to access session email 629 629 00:31:53,230 --> 00:31:54,730 somewhere else in your application 630 630 00:31:54,730 --> 00:31:57,210 you're gonna get an error saying hey, 631 631 00:31:57,210 --> 00:31:59,700 you tried to access the email stored in the session, 632 632 00:31:59,700 --> 00:32:03,890 but there is no email stored in the session, so error. 633 633 00:32:03,890 --> 00:32:06,560 We're gonna learn how to deal with those errors 634 634 00:32:06,560 --> 00:32:09,037 more gracefully in the future. 635 635 00:32:09,037 --> 00:32:12,620 And the reason for that is in many places in our application 636 636 00:32:12,620 --> 00:32:15,010 we'll be accessing session email. 637 637 00:32:15,010 --> 00:32:17,746 And what happens if session email is not set? 638 638 00:32:17,746 --> 00:32:22,030 Well it's going to mean that the user is not logged in. 639 639 00:32:22,030 --> 00:32:23,970 It's not the cause for an error, 640 640 00:32:23,970 --> 00:32:27,050 all we have to do is ask the user to log in. 641 641 00:32:27,050 --> 00:32:29,450 So we're going to be dealing with that later on. 642 642 00:32:30,920 --> 00:32:32,920 For now, I hope this video was useful, 643 643 00:32:32,920 --> 00:32:34,610 it's been a bit of a long one 644 644 00:32:34,610 --> 00:32:36,610 and we've had to do quite a lot of work. 645 645 00:32:37,500 --> 00:32:39,710 Create a template for our users 646 646 00:32:39,710 --> 00:32:41,725 to send us an email and a password. 647 647 00:32:41,725 --> 00:32:45,231 Then we've created a user view that takes them in 648 648 00:32:45,231 --> 00:32:47,730 and registers the user. 649 649 00:32:47,730 --> 00:32:50,960 And also it sets the email in the session 650 650 00:32:50,960 --> 00:32:54,460 so that when the user comes back with the same browser 651 651 00:32:54,460 --> 00:32:56,820 and the same Flask app running, 652 652 00:32:56,820 --> 00:32:58,460 we will be able to identify them 653 653 00:32:58,460 --> 00:33:00,533 and populate the session automatically. 654 654 00:33:01,420 --> 00:33:03,840 Registering a user also does a bunch of stuff, 655 655 00:33:03,840 --> 00:33:05,750 it checks the email is valid, 656 656 00:33:05,750 --> 00:33:07,350 or returns an error if it's not. 657 657 00:33:08,250 --> 00:33:11,318 Then it tries to find the user with the given email 658 658 00:33:11,318 --> 00:33:15,010 and if it's not found then this function up here 659 659 00:33:15,010 --> 00:33:17,960 raises an error which we catch. 660 660 00:33:17,960 --> 00:33:19,260 And if the user was not found 661 661 00:33:19,260 --> 00:33:20,630 it means the user does not exist, 662 662 00:33:20,630 --> 00:33:24,000 which means we can create one and send it to MongoDB 663 663 00:33:24,000 --> 00:33:25,050 and then return true. 664 664 00:33:26,450 --> 00:33:28,233 If the user was found, 665 665 00:33:29,660 --> 00:33:32,660 then that means that we want to raise an error saying 666 666 00:33:32,660 --> 00:33:34,370 hey, the user is already registered 667 667 00:33:34,370 --> 00:33:36,120 because we found it in the database 668 668 00:33:37,178 --> 00:33:38,011 so it means it must exist. 669 669 00:33:38,011 --> 00:33:40,550 So we return a message to the user saying 670 670 00:33:40,550 --> 00:33:43,143 the email you used to register already exists. 671 671 00:33:44,806 --> 00:33:46,896 As part of doing this we also coded our models, 672 672 00:33:46,896 --> 00:33:50,000 our user model, and our errors. 673 673 00:33:50,000 --> 00:33:53,470 And of course the utils common package. 674 674 00:33:53,470 --> 00:33:54,710 More things are gonna go in here 675 675 00:33:54,710 --> 00:33:57,240 related to password encryption later on. 676 676 00:33:57,240 --> 00:33:59,030 And we're also gonna add a couple more errors 677 677 00:33:59,030 --> 00:34:00,163 as we go along, too. 678 678 00:34:01,250 --> 00:34:02,830 Thanks for joining me in this video 679 679 00:34:02,830 --> 00:34:04,480 and I'll see you on the next one.