1 00:00:03,560 --> 00:00:07,745 In this exercise, we will learn more about loopback. 2 00:00:07,745 --> 00:00:13,635 Loopback itself started its journey with a small company called StrongLoop. 3 00:00:13,635 --> 00:00:20,775 This company was thereafter acquired by IBM and Loopback has become part of 4 00:00:20,775 --> 00:00:28,725 the IBM Bluemix platform but loopback is still available as an open source platform. 5 00:00:28,725 --> 00:00:36,205 So, you can install and make use of Loopback to build your backend as a service, 6 00:00:36,205 --> 00:00:43,850 as we will demonstrate in this exercise and the remaining two exercises of this lesson. 7 00:00:43,850 --> 00:00:51,230 As I mentioned, Loopback itself is available as an NPM module. 8 00:00:51,230 --> 00:00:56,445 So we're going to be installing Loopback command line interface first. 9 00:00:56,445 --> 00:01:00,810 So to install the Loopback command line interface, 10 00:01:00,810 --> 00:01:02,875 CLI, at the prompt, 11 00:01:02,875 --> 00:01:13,030 type npminstall loopback CLI minus minus save. 12 00:01:13,030 --> 00:01:18,170 Now, if you are doing it on a Mac or a Linux machine, 13 00:01:18,170 --> 00:01:22,025 make sure to use sudo in front of it and then 14 00:01:22,025 --> 00:01:26,855 let the Loopback command line interface get installed. 15 00:01:26,855 --> 00:01:29,024 Once that gets installed, 16 00:01:29,024 --> 00:01:31,195 you can get started with the exercise. 17 00:01:31,195 --> 00:01:32,510 As you can see, right now, 18 00:01:32,510 --> 00:01:37,380 I'm using the Loopback CLI version 4.2.0 in this course. 19 00:01:37,380 --> 00:01:45,380 Now, to scaffold out a loopback framework based application is very straightforward. 20 00:01:45,380 --> 00:01:47,725 Once you install the command line interface, 21 00:01:47,725 --> 00:01:50,690 you may need to restart your terminal in order for 22 00:01:50,690 --> 00:01:53,970 the command to be available at your prompt. 23 00:01:53,970 --> 00:02:00,080 So make sure to restart your terminal or your command window. 24 00:02:00,080 --> 00:02:01,810 Then, at the prompt, 25 00:02:01,810 --> 00:02:06,560 you should have this command called lb available for us. 26 00:02:06,560 --> 00:02:08,695 LB standing for Loopback. 27 00:02:08,695 --> 00:02:14,560 So. To scaffold out a Loopback application at the terminal prompt, 28 00:02:14,560 --> 00:02:18,850 type lb conFusionServer-Loopback, 29 00:02:21,490 --> 00:02:25,650 at a convenient location on your computer. 30 00:02:25,650 --> 00:02:27,845 When we do that, 31 00:02:27,845 --> 00:02:34,530 the Loopback CLI will end up creating the application for us, 32 00:02:34,530 --> 00:02:36,950 and for the application name, 33 00:02:36,950 --> 00:02:39,585 I'm just going to accept the same name, 34 00:02:39,585 --> 00:02:45,389 and then I'll ask it to create the project in that specific directory, 35 00:02:45,389 --> 00:02:53,090 and then we'll select the 3.X version of Loopback for us to scaffold out an application. 36 00:02:53,090 --> 00:02:55,880 Then, for the API server, 37 00:02:55,880 --> 00:03:02,070 we will select the API server as the option for this. 38 00:03:02,070 --> 00:03:07,170 Then wait for Loopback to scaffold out our application. 39 00:03:12,230 --> 00:03:14,355 Once that is done, 40 00:03:14,355 --> 00:03:16,110 the next step is, of course, 41 00:03:16,110 --> 00:03:24,605 to go to the conFusionServer-Loopback folder. 42 00:03:24,605 --> 00:03:30,415 Then, we will start configuring our server. 43 00:03:30,415 --> 00:03:35,870 Now, Loopback supports data through data modeling. 44 00:03:35,870 --> 00:03:38,060 So we can define data models. 45 00:03:38,060 --> 00:03:42,030 To do this, the Loopback command line interface provides us with 46 00:03:42,030 --> 00:03:46,975 the various commands for developing the data models. 47 00:03:46,975 --> 00:03:50,960 So, in this case, I'm going to develop one example 48 00:03:50,960 --> 00:03:55,130 of a data of a model for my dishes here. 49 00:03:55,130 --> 00:03:56,620 So, at the prompt, 50 00:03:56,620 --> 00:03:59,560 let me type lb model. 51 00:03:59,560 --> 00:04:01,905 Then, as we go through the steps, 52 00:04:01,905 --> 00:04:04,600 I'll explain to you what 53 00:04:04,600 --> 00:04:12,860 the Loopback command line interface and how it creates the data model for the dishes. 54 00:04:12,860 --> 00:04:14,840 So, in this case, 55 00:04:14,840 --> 00:04:16,720 we'll just type lb model, 56 00:04:16,720 --> 00:04:21,460 and then we'll be prompted with the name for the model, 57 00:04:21,460 --> 00:04:24,165 and then I will type the name of the model as dishes. 58 00:04:24,165 --> 00:04:28,059 As you recall, we have been using dishes, promotions, 59 00:04:28,059 --> 00:04:34,339 and leaders as the three major data sources for our application. 60 00:04:34,339 --> 00:04:39,420 So, we'll create our first model named dishes, and this model, 61 00:04:39,420 --> 00:04:46,580 at this moment, will be stored in the in-memory database of our computer for the moment. 62 00:04:46,580 --> 00:04:47,840 In the next exercise, 63 00:04:47,840 --> 00:04:52,940 we will add in MongoDB as the backend persistence for our data. 64 00:04:52,940 --> 00:04:58,110 Now, this dishes model will be a persistent model. 65 00:04:58,110 --> 00:05:03,890 So, we'll select the persistent model as the option for the model, 66 00:05:03,890 --> 00:05:09,350 and then we'll say expose the dishes via a REST API, 67 00:05:09,350 --> 00:05:13,060 and then, by default, 68 00:05:13,060 --> 00:05:17,880 it'll expose it slash dishes endpoint and that'll be perfectly fine for us. 69 00:05:17,880 --> 00:05:19,680 So, we can just say yes. 70 00:05:19,680 --> 00:05:23,865 Then, the model will be created in a folder named common. 71 00:05:23,865 --> 00:05:27,950 Now, once the Loopback application is scaffolded out, 72 00:05:27,950 --> 00:05:34,020 we'll see where all this data is stored in the folder itself and in the subfolder, 73 00:05:34,020 --> 00:05:38,295 and this model will be created at the common sub folder. 74 00:05:38,295 --> 00:05:40,580 So, we'll select that. 75 00:05:40,580 --> 00:05:42,110 Then, at this point, 76 00:05:42,110 --> 00:05:45,860 it will prompt us to select all the properties that we want to 77 00:05:45,860 --> 00:05:50,750 specify for the dishes model. 78 00:05:50,750 --> 00:05:54,710 So, for this, we will specify 79 00:05:54,710 --> 00:06:00,880 the name as the first property and then we'll specify the property type as string. 80 00:06:00,880 --> 00:06:02,380 So, as you see, 81 00:06:02,380 --> 00:06:09,060 it is prompting us and obtaining information about the various parts of our model, 82 00:06:09,060 --> 00:06:12,425 and then helps us to configure the model for us. 83 00:06:12,425 --> 00:06:18,355 So, this is of the string type and this is required and the default value will be empty. 84 00:06:18,355 --> 00:06:22,230 So. That'll be name, then description, 85 00:06:22,370 --> 00:06:29,270 which will be of the string type required and the default value is empty. 86 00:06:29,270 --> 00:06:36,570 Then, category, which will be of the string type required and the default value is empty. 87 00:06:36,570 --> 00:06:40,930 Image which will be of the string type, 88 00:06:40,930 --> 00:06:43,934 and this is required, 89 00:06:43,934 --> 00:06:47,550 and the default value will be empty. 90 00:06:47,950 --> 00:06:52,885 Label, which will be also of the string type. 91 00:06:52,885 --> 00:06:58,310 This is required but the default value we'll specify as an empty string. 92 00:06:58,310 --> 00:07:01,360 Then, the last one would be price, 93 00:07:01,360 --> 00:07:05,870 which will be required and the default value is zero. 94 00:07:05,870 --> 00:07:10,115 Now, you see why I have configured all these various properties. 95 00:07:10,115 --> 00:07:19,070 All these are part of the dishes object that we use on our server side. 96 00:07:19,070 --> 00:07:22,580 Now, once you have completed entering all the properties, 97 00:07:22,580 --> 00:07:23,760 and which we have, 98 00:07:23,760 --> 00:07:25,565 then at that point the, 99 00:07:25,565 --> 00:07:27,080 last one, of course, 100 00:07:27,080 --> 00:07:31,270 is to add the featured property, 101 00:07:31,270 --> 00:07:34,265 which will be of the type Boolean, 102 00:07:34,265 --> 00:07:36,665 and this is required, 103 00:07:36,665 --> 00:07:39,440 and the default value is false. 104 00:07:39,440 --> 00:07:41,560 That's it. Once we have entered all the properties, 105 00:07:41,560 --> 00:07:47,280 you just hit when it asks for the property name if you type return, 106 00:07:47,280 --> 00:07:49,960 then the model will be scaffolded out. 107 00:07:49,960 --> 00:07:55,050 Now, similarly, we will create the models for promotions and leaders. 108 00:07:55,050 --> 00:08:04,625 So, for promotions, let me go ahead and say lb model and the model name is promotions. 109 00:08:04,625 --> 00:08:08,080 The survey in the DB this is the persister model and we'll 110 00:08:08,080 --> 00:08:12,625 expose this by the API, and the common. 111 00:08:12,625 --> 00:08:23,040 For the promotions, the properties are name of the type string require no default value, 112 00:08:23,040 --> 00:08:25,949 image of the type string, 113 00:08:25,949 --> 00:08:29,535 require no default value, 114 00:08:29,535 --> 00:08:34,030 label of the type string, 115 00:08:34,030 --> 00:08:39,085 required the default value is empty. 116 00:08:39,085 --> 00:08:43,220 Price, string type, required, 117 00:08:43,220 --> 00:08:45,170 the default value is zero, 118 00:08:45,170 --> 00:08:52,150 and then description required and the default value is empty. 119 00:08:52,150 --> 00:08:54,550 That's it for promotions. 120 00:08:54,550 --> 00:08:57,460 Let me now create the leaders model. 121 00:08:57,460 --> 00:09:07,090 So, we'll say LB model and we'll say leaders, 122 00:09:07,090 --> 00:09:10,750 and this would be in the database PersistedModel, 123 00:09:10,750 --> 00:09:14,290 Expose leaders via REST API, custom, common. 124 00:09:14,290 --> 00:09:16,610 So, as you can see creating a model is very, 125 00:09:16,610 --> 00:09:20,175 very straightforward using the LoopBack CLI, 126 00:09:20,175 --> 00:09:24,260 and for the leader the properties of name, 127 00:09:24,260 --> 00:09:27,830 of the type string, required, 128 00:09:27,830 --> 00:09:32,759 default is empty, image of the type string, 129 00:09:32,759 --> 00:09:36,634 required default value is empty, 130 00:09:36,634 --> 00:09:40,190 designation of the type string, 131 00:09:40,190 --> 00:09:44,130 required default value is empty, 132 00:09:44,130 --> 00:09:46,790 abbreviation of the type string, 133 00:09:46,790 --> 00:09:54,425 required an empty, and the last one is description of the type string, required an empty. 134 00:09:54,425 --> 00:10:00,965 That's it. So, we have configured three different models here: promotions, 135 00:10:00,965 --> 00:10:04,280 leaders, and the dishes. 136 00:10:04,280 --> 00:10:09,175 That's it. Now, our LoopBack server would have been configured. 137 00:10:09,175 --> 00:10:12,765 We'll take a look at this in our editor, 138 00:10:12,765 --> 00:10:19,715 and also we'll start up this LoopBack server and then look at what it serves up for us. 139 00:10:19,715 --> 00:10:21,940 To start the LoopBack server, 140 00:10:21,940 --> 00:10:29,205 at the prompt type NPM start or node space dot. 141 00:10:29,205 --> 00:10:32,280 In either case, the LoopBack server will start up, 142 00:10:32,280 --> 00:10:35,620 and the LoopBack server will be available to us. 143 00:10:35,620 --> 00:10:39,210 At this address, you can also browse 144 00:10:39,210 --> 00:10:43,065 the REST API that is supported by the LoopBack server at this end part. 145 00:10:43,065 --> 00:10:45,360 So, let me copy this first, 146 00:10:45,360 --> 00:10:49,670 and then we'll see what the LoopBack server serves up at this point. 147 00:10:49,670 --> 00:10:51,170 In a browser address bar, 148 00:10:51,170 --> 00:10:55,325 let's type that and then see that our LoopBack server, 149 00:10:55,325 --> 00:10:56,990 if you access it, 150 00:10:56,990 --> 00:11:03,010 will show when it was last started and how long it has been running. 151 00:11:03,010 --> 00:11:11,575 There. Now, let's go to the Explorer of our LoopBack server, 152 00:11:11,575 --> 00:11:13,500 and then you will immediately see that 153 00:11:13,500 --> 00:11:17,785 this LoopBack API Explorer uses something called the Swagger 154 00:11:17,785 --> 00:11:25,185 IO format for showing us all the REST API endpoints. 155 00:11:25,185 --> 00:11:28,989 So, here you see that we have dishes, leaders, promotions, 156 00:11:28,989 --> 00:11:30,740 and LoopBack, by default, 157 00:11:30,740 --> 00:11:33,540 adds a User model in there. 158 00:11:33,540 --> 00:11:37,860 The User model is the standard user model for authentication purposes. 159 00:11:37,860 --> 00:11:41,690 We'll see how to make use of that in the next exercise. 160 00:11:41,690 --> 00:11:43,470 Now, let's click on dishes. 161 00:11:43,470 --> 00:11:48,250 When you click on dishes you'll see that the LoopBack server has automatically configured 162 00:11:48,250 --> 00:11:51,160 that slash dishes endpoint and then exposes 163 00:11:51,160 --> 00:11:55,435 various REST API endpoints automatically for us, 164 00:11:55,435 --> 00:12:01,310 and then the corresponding actions that you can perform on each one of them. 165 00:12:01,310 --> 00:12:06,775 Not only that, with the Swagger IO API, 166 00:12:06,775 --> 00:12:11,610 you automatically also get this documented information here, 167 00:12:11,610 --> 00:12:16,670 which gives you details about how to use that REST API endpoint. 168 00:12:16,670 --> 00:12:19,145 So, here when it says get slash dishes, 169 00:12:19,145 --> 00:12:22,185 it says what is the typical. 170 00:12:22,185 --> 00:12:26,490 This is the model structure used there, 171 00:12:26,490 --> 00:12:31,910 and then "let's try this out" and then you will see that it will 172 00:12:31,910 --> 00:12:34,440 return us with an empty body because at 173 00:12:34,440 --> 00:12:37,930 this moment there is nothing in my in-memory database. 174 00:12:37,930 --> 00:12:42,910 So, recall that we configured that with DB in-memory, 175 00:12:42,910 --> 00:12:43,910 which means that this is 176 00:12:43,910 --> 00:12:46,990 the in-memory database and right now it doesn't contain anything. 177 00:12:46,990 --> 00:12:50,400 But in the next exercise we will see how we will connect this to 178 00:12:50,400 --> 00:12:56,610 our MongoDB server and be able to retrieve all the information from our MongoDB server. 179 00:12:56,610 --> 00:13:00,180 Similarly, if you want to post a dish, 180 00:13:00,180 --> 00:13:04,165 then all that you need to do is use this endpoint 'POST dishes', 181 00:13:04,165 --> 00:13:08,280 and it also gives you exactly the structure 182 00:13:08,280 --> 00:13:12,435 of the data that you need to use for supplying information to the model. 183 00:13:12,435 --> 00:13:15,450 So, you can just simply copy that and then paste it into the data, 184 00:13:15,450 --> 00:13:19,120 and then fill in each one of these values here, 185 00:13:19,120 --> 00:13:21,760 and then once you do that you can simply, say, 186 00:13:21,760 --> 00:13:26,060 try it out and then that will be posted to the server. 187 00:13:26,060 --> 00:13:28,935 So, you can perform all the get, put, post, 188 00:13:28,935 --> 00:13:35,575 and delete operations directly by using this Explorer here 189 00:13:35,575 --> 00:13:38,970 to interact with your REST API endpoints 190 00:13:38,970 --> 00:13:42,570 that is automatically constructed for you by LoopBack. 191 00:13:42,570 --> 00:13:45,340 So with this, we complete this exercise. 192 00:13:45,340 --> 00:13:49,805 So, in this exercise we have seen how we can very quickly 193 00:13:49,805 --> 00:13:55,805 configure a REST API server using the LoopBack framework. 194 00:13:55,805 --> 00:13:57,480 In the next couple of exercises, 195 00:13:57,480 --> 00:14:02,030 we will explore more details about the LoopBack framework. 196 00:14:02,030 --> 00:14:06,755 Now, this may be a good time for you to do a Git initialization of 197 00:14:06,755 --> 00:14:10,230 your LoopBack folder and then do a Git 198 00:14:10,230 --> 00:14:15,570 commit with 'Getting Started' LoopBack as the message.