1 00:00:00,540 --> 00:00:02,231 - [Instructor] Hi and welcome back to the course. 2 00:00:02,231 --> 00:00:03,605 In this video we're going to be creating 3 00:00:03,605 --> 00:00:06,247 our first flask_restful app. 4 00:00:06,247 --> 00:00:08,354 It's going to be a really simple app just to get you 5 00:00:08,354 --> 00:00:10,548 acquainted with sort of what it looks like 6 00:00:10,548 --> 00:00:11,381 and then in the next video we're really gonna 7 00:00:11,381 --> 00:00:15,850 get into creating the project for this section. 8 00:00:15,850 --> 00:00:18,062 The first thing to do is to in the folder that 9 00:00:18,062 --> 00:00:19,953 you've got your venv, 10 00:00:19,953 --> 00:00:21,408 as you can see I'm going to list the structure 11 00:00:21,408 --> 00:00:22,669 of this folder and there is 12 00:00:22,669 --> 00:00:25,030 a folder in here called venv. 13 00:00:25,030 --> 00:00:26,879 So, not inside this folder, 14 00:00:26,879 --> 00:00:30,719 but beside the folder I'm going to create another 15 00:00:30,719 --> 00:00:32,082 folder called code. 16 00:00:32,082 --> 00:00:34,967 So, as you can see if I do ls now we've got two folders, 17 00:00:34,967 --> 00:00:39,134 venv and code and then we're going to cd into code 18 00:00:40,002 --> 00:00:42,835 or change that actually into code. 19 00:00:43,990 --> 00:00:46,317 Now, we are in code I'm going to launch Atom 20 00:00:46,317 --> 00:00:49,675 and you can do so by typing Atom dot, 21 00:00:49,675 --> 00:00:51,961 this I think only works in Mac and Linux, 22 00:00:51,961 --> 00:00:54,649 if you're on Windows just load Atom as normal, 23 00:00:54,649 --> 00:00:57,721 it really doesn't take much longer. 24 00:00:57,721 --> 00:01:00,221 And then when Atom is running, 25 00:01:01,154 --> 00:01:04,237 which it is just starting up in here, 26 00:01:06,264 --> 00:01:07,803 here we've got Atom. 27 00:01:07,803 --> 00:01:09,298 Now that Atom's running we can go ahead 28 00:01:09,298 --> 00:01:11,249 and create a new file. 29 00:01:11,249 --> 00:01:15,323 I'm going to call that app.py as normal. 30 00:01:15,323 --> 00:01:18,601 Remember, we're going to be running this file from 31 00:01:18,601 --> 00:01:22,332 our virtual environment and therefore we have flask 32 00:01:22,332 --> 00:01:25,896 and flask_restful already available. 33 00:01:25,896 --> 00:01:30,665 So, the first thing to do is to import those two. 34 00:01:30,665 --> 00:01:33,122 So, from flask I'm gonna import flask 35 00:01:33,122 --> 00:01:37,644 and from flask_restful, I'm going to import resource 36 00:01:37,644 --> 00:01:42,179 and API and these two things are going to be necessary. 37 00:01:42,179 --> 00:01:45,004 A resource represents something 38 00:01:45,004 --> 00:01:47,671 that our API sort of represents. 39 00:01:48,571 --> 00:01:50,898 That was too many represents in one phrase. 40 00:01:50,898 --> 00:01:54,759 For example, if our API is concerned with students 41 00:01:54,759 --> 00:01:57,710 and it can return students and create students, 42 00:01:57,710 --> 00:01:59,707 a student would be a resource. 43 00:01:59,707 --> 00:02:02,983 If our API is concerned with items, 44 00:02:02,983 --> 00:02:04,734 then an item may be a resource. 45 00:02:04,734 --> 00:02:07,016 If our API is concerned with pianos, 46 00:02:07,016 --> 00:02:09,210 a piano might be resource and so on. 47 00:02:09,210 --> 00:02:11,277 So, our resource is just a thing that our API 48 00:02:11,277 --> 00:02:15,640 can return and create and things like that. 49 00:02:15,640 --> 00:02:19,839 Resource are usually mapped into database tables as well, 50 00:02:19,839 --> 00:02:23,119 so that's something to keep in mind. 51 00:02:23,119 --> 00:02:25,027 Okay, and then we're gonna create our app 52 00:02:25,027 --> 00:02:29,675 just by typing app = flask(__name__), 53 00:02:29,675 --> 00:02:32,208 we know the drill with this one. 54 00:02:32,208 --> 00:02:36,697 And here's the new thing, flask is going to be our app 55 00:02:36,697 --> 00:02:39,813 and our app is gonna have all these routes 56 00:02:39,813 --> 00:02:41,600 as we saw in the last section 57 00:02:41,600 --> 00:02:42,667 and then we can create new routes 58 00:02:42,667 --> 00:02:45,611 and assign methods to them and things like that. 59 00:02:45,611 --> 00:02:46,512 And we're gonna create something else 60 00:02:46,512 --> 00:02:49,246 which is gonna be the API. 61 00:02:49,246 --> 00:02:53,808 And the API as you can see is imported from flask_restful 62 00:02:53,808 --> 00:02:58,196 and that's just going to allow us to very easily 63 00:02:58,196 --> 00:03:00,299 add these resources to it. 64 00:03:00,299 --> 00:03:01,852 And we're gonna be able to say okay, 65 00:03:01,852 --> 00:03:05,345 for this resource you can get and post, 66 00:03:05,345 --> 00:03:08,597 for this other resource you can get and delete, 67 00:03:08,597 --> 00:03:11,629 for this other resource you can get, put, post, and delete 68 00:03:11,629 --> 00:03:12,872 and so on. 69 00:03:12,872 --> 00:03:15,600 So, it's going to be making things a lot easier, 70 00:03:15,600 --> 00:03:18,577 but obviously there's no way to explain this without 71 00:03:18,577 --> 00:03:20,513 like a proper sort of example, 72 00:03:20,513 --> 00:03:24,478 so I'm gonna give you a quick example now. 73 00:03:24,478 --> 00:03:26,329 The API works with resources 74 00:03:26,329 --> 00:03:29,412 and every resource has to be a class. 75 00:03:30,377 --> 00:03:34,544 So, for example, a class student then inherits from 76 00:03:36,957 --> 00:03:39,109 the class resource. 77 00:03:39,109 --> 00:03:40,817 If you've not looked at an inheritance before 78 00:03:40,817 --> 00:03:43,006 I'd suggest you go back to the first section 79 00:03:43,006 --> 00:03:45,618 of this course and quickly go through the object oriented 80 00:03:45,618 --> 00:03:48,272 programming refresher that's in the first section, 81 00:03:48,272 --> 00:03:50,602 sorry the second section, apologies. 82 00:03:50,602 --> 00:03:53,203 Because that will cover sort of what inheritance is. 83 00:03:53,203 --> 00:03:56,407 Essentially all we're doing is we're also retrieving 84 00:03:56,407 --> 00:03:59,527 some stuff from the resource class. 85 00:03:59,527 --> 00:04:02,520 So, our student class now becomes essentially 86 00:04:02,520 --> 00:04:05,052 a copy of the resource class, 87 00:04:05,052 --> 00:04:07,552 but we can also change things. 88 00:04:08,808 --> 00:04:10,458 So, it is not gonna be an exact copy 89 00:04:10,458 --> 00:04:14,326 it's gonna be a copy with a couple of things changed. 90 00:04:14,326 --> 00:04:15,802 The first thing that it's gonna change 91 00:04:15,802 --> 00:04:17,302 is the get method. 92 00:04:20,396 --> 00:04:24,146 So, this get method is going to take in self, 93 00:04:25,174 --> 00:04:28,723 which is just normal, whenever you create a method 94 00:04:28,723 --> 00:04:30,753 and an object and also a name. 95 00:04:30,753 --> 00:04:34,379 And that's gonna be a name of the student. 96 00:04:34,379 --> 00:04:38,546 Okay, and then we're going to do something like return 97 00:04:39,858 --> 00:04:42,775 a dictionary where student is name. 98 00:04:43,914 --> 00:04:46,270 So, this is gonna be a really basic API, 99 00:04:46,270 --> 00:04:48,907 it's not really gonna do anything except return 100 00:04:48,907 --> 00:04:51,179 whatever we give it. 101 00:04:51,179 --> 00:04:53,665 Okay, so now we have our resource 102 00:04:53,665 --> 00:04:56,226 and what we've sent is that this resource can only 103 00:04:56,226 --> 00:04:58,726 be accessed with a get method. 104 00:05:00,533 --> 00:05:02,734 If we wanted, for example, to allow post, 105 00:05:02,734 --> 00:05:06,582 we would create a post method here and so on. 106 00:05:06,582 --> 00:05:08,450 But we're gonna look at that just in the next 107 00:05:08,450 --> 00:05:09,972 couple of videos. 108 00:05:09,972 --> 00:05:12,450 For this video, let's stick to just get 109 00:05:12,450 --> 00:05:16,758 and not actually do anything just return a dictionary. 110 00:05:16,758 --> 00:05:18,820 Then what we're going to do is we're going to say 111 00:05:18,820 --> 00:05:22,987 API.add_resource(student) and this is going to essentially 112 00:05:24,718 --> 00:05:26,301 tell our API, okay. 113 00:05:27,771 --> 00:05:30,287 This resource that we've created, the student, 114 00:05:30,287 --> 00:05:33,537 now is gonna be accessible via our API, 115 00:05:34,950 --> 00:05:39,501 but as you can see we've never put any endpoints in here, 116 00:05:39,501 --> 00:05:43,668 any routes, so how are we gonna access this student? 117 00:05:44,689 --> 00:05:48,261 Do we have to do something like app.route here? 118 00:05:48,261 --> 00:05:49,094 Student. 119 00:05:50,697 --> 00:05:53,139 Is this the way to do it? 120 00:05:53,139 --> 00:05:56,593 And the answer is fortunately, no. 121 00:05:56,593 --> 00:05:59,257 We have to do something like this. 122 00:05:59,257 --> 00:06:02,436 At the end of the add_resource, put in a comma 123 00:06:02,436 --> 00:06:06,603 and say/student/string:name. 124 00:06:09,787 --> 00:06:13,370 So, we're going to access students like so. 125 00:06:20,063 --> 00:06:20,896 Okay, so it's going to be something 126 00:06:20,896 --> 00:06:25,063 like http://127.0.0.1:5000, just the normal stuff. 127 00:06:26,871 --> 00:06:31,082 And then /student, which is what we got here, 128 00:06:31,082 --> 00:06:32,936 slash and the name. 129 00:06:32,936 --> 00:06:34,913 And we've looked at this in the past as well. 130 00:06:34,913 --> 00:06:38,145 This name variable is going to go straight into 131 00:06:38,145 --> 00:06:39,728 the parameter here. 132 00:06:40,804 --> 00:06:42,827 So, you can imagine that we are doing 133 00:06:42,827 --> 00:06:46,994 @app.route('/student/'). 134 00:06:48,783 --> 00:06:52,335 These two things here are essentially the same, 135 00:06:52,335 --> 00:06:55,921 but we no longer have to do the decorator ourselves, 136 00:06:55,921 --> 00:06:59,790 which kind of save us a bit of hassle as well. 137 00:06:59,790 --> 00:07:03,457 Okay, ad finally app.run and port=5000, 138 00:07:04,667 --> 00:07:07,163 this is not necessary, that's the default, 139 00:07:07,163 --> 00:07:08,635 port=5000's the default, 140 00:07:08,635 --> 00:07:10,199 but nevertheless I like putting it in 141 00:07:10,199 --> 00:07:12,902 just to be a little bit more explicit. 142 00:07:12,902 --> 00:07:16,266 So, here we have our flask_restful app. 143 00:07:16,266 --> 00:07:18,118 It doesn't really do much, 144 00:07:18,118 --> 00:07:21,914 but we are going to essentially follow this structure 145 00:07:21,914 --> 00:07:25,114 over the next few videos, in fact the rest of this section 146 00:07:25,114 --> 00:07:28,443 and we're gonna be creating a more professional rest API 147 00:07:28,443 --> 00:07:30,592 and we're gonna include things like error handling 148 00:07:30,592 --> 00:07:32,575 and authentication and things like that. 149 00:07:32,575 --> 00:07:35,486 On a very small level it's gonna be a small app, 150 00:07:35,486 --> 00:07:39,153 but over the next few sections we're going to be expanding 151 00:07:39,153 --> 00:07:40,206 in each of those areas 152 00:07:40,206 --> 00:07:43,447 and we're gonna create like some really cool projects. 153 00:07:43,447 --> 00:07:47,372 So, what I'm gonna do now is I'm going to launch Postman 154 00:07:47,372 --> 00:07:51,539 that I've got here and what I'm gonna do is just go to 155 00:07:53,345 --> 00:07:57,903 the new tab here and I'm going to do a sample request. 156 00:07:57,903 --> 00:08:01,396 I'm not gonna put in any collection or anything like that. 157 00:08:01,396 --> 00:08:04,604 Of course, first of all, make sure that your app is running. 158 00:08:04,604 --> 00:08:06,587 So, make sure you are in the virtual environment 159 00:08:06,587 --> 00:08:10,687 and do Python app.py, that should get it running 160 00:08:10,687 --> 00:08:12,750 and then go back to Postman 161 00:08:12,750 --> 00:08:16,917 and what we're gonna do is http://127.0.0.1:5000 162 00:08:20,345 --> 00:08:23,542 and then student and then Rolf, 163 00:08:23,542 --> 00:08:25,709 that's the student's name. 164 00:08:26,900 --> 00:08:29,472 And as you can see we get back the student 165 00:08:29,472 --> 00:08:31,841 in the form of a dictionary just as we said here 166 00:08:31,841 --> 00:08:33,341 in our get method. 167 00:08:35,255 --> 00:08:37,735 We're just returning student is the name 168 00:08:37,735 --> 00:08:40,981 and then Postman makes sure that you're doing a get request 169 00:08:40,981 --> 00:08:42,002 and you're requesting this URL 170 00:08:42,002 --> 00:08:44,170 and you should get back this thing here. 171 00:08:44,170 --> 00:08:48,340 Of course, if you change this for Chris, for example, 172 00:08:48,340 --> 00:08:51,039 that will then return Chris. 173 00:08:51,039 --> 00:08:54,874 If you change the method to be such as a post, 174 00:08:54,874 --> 00:08:58,754 what you'll get is the usual message that the method 175 00:08:58,754 --> 00:09:01,315 is not allowed for the requested URL 176 00:09:01,315 --> 00:09:03,778 because this doesn't accept post, 177 00:09:03,778 --> 00:09:05,445 it only accepts get. 178 00:09:07,191 --> 00:09:09,457 Now, okay, and similarly if you access something 179 00:09:09,457 --> 00:09:14,046 incorrect and you'll just get the usual 404 not found, 180 00:09:14,046 --> 00:09:17,087 that's the error code for not found. 181 00:09:17,087 --> 00:09:19,943 And so make sure that you are accessing the right URL. 182 00:09:19,943 --> 00:09:22,413 And that's really everything for this video. 183 00:09:22,413 --> 00:09:25,746 We've created a simple flask_restful app 184 00:09:27,471 --> 00:09:30,956 that nevertheless gives us a lot of info regarding how these 185 00:09:30,956 --> 00:09:35,174 app are structured, these APIs is a matter of having 186 00:09:35,174 --> 00:09:38,327 the API, defining our resource, 187 00:09:38,327 --> 00:09:42,049 which in this case we've only got one, which is the student, 188 00:09:42,049 --> 00:09:46,512 defining the methods that this resource is going to accept, 189 00:09:46,512 --> 00:09:48,456 in this case it's only get, 190 00:09:48,456 --> 00:09:53,425 but we can have others like post, delete, put and so on. 191 00:09:53,425 --> 00:09:55,586 And then deciding what that method is going to do 192 00:09:55,586 --> 00:09:57,523 when the endpoint is called 193 00:09:57,523 --> 00:09:59,799 and then finally added the resource in here 194 00:09:59,799 --> 00:10:02,547 and determine how it's going to be accessed as well, 195 00:10:02,547 --> 00:10:05,263 in this case /student/' 196 00:10:05,263 --> 00:10:08,122 and the name parameter always goes to the methods 197 00:10:08,122 --> 00:10:10,360 parameter as well. 198 00:10:10,360 --> 00:10:13,680 Finally, run the app and try it out in Postman. 199 00:10:13,680 --> 00:10:15,449 I'd recommend you do this. 200 00:10:15,449 --> 00:10:17,163 Write this code, try it out in Postman, 201 00:10:17,163 --> 00:10:18,810 make sure everything works, 202 00:10:18,810 --> 00:10:21,334 and as we go along in this section, 203 00:10:21,334 --> 00:10:24,106 do code along with me as well. 204 00:10:24,106 --> 00:10:26,290 I've created the videos in such a way that you can 205 00:10:26,290 --> 00:10:29,708 always code along and try things out as we move along, 206 00:10:29,708 --> 00:10:31,021 just for your benefit. 207 00:10:31,021 --> 00:10:33,095 So, it would be silly to waste that opportunity 208 00:10:33,095 --> 00:10:35,012 that you've got now. 209 00:10:35,012 --> 00:10:37,029 Without further ado, thanks for joining in 210 00:10:37,029 --> 00:10:38,856 and I'll see you in the very next video.