WEBVTT 00:05.050 --> 00:05.840 I over. 00:05.900 --> 00:06.830 Welcome back. 00:07.130 --> 00:15.070 So in this video we're going to be installing a flask restful which is basically a library on top of 00:15.070 --> 00:15.740 flasks. 00:15.740 --> 00:20.870 That helps us build a restful API and it makes things much much easier. 00:20.870 --> 00:25.600 So let me zoom in just for this box here. 00:25.700 --> 00:26.760 And then the terminal. 00:26.840 --> 00:31.180 And then we're basically going to first install the flask restful. 00:31.180 --> 00:33.200 It's just a head package. 00:33.200 --> 00:38.850 So when we go three and stock and then flask restful. 00:39.500 --> 00:46.070 And each has already have a flask restful so it's just I can't get it from the cash that I have. 00:46.070 --> 00:51.360 Yours should download it and basically you know if you want to check that it's there. 00:51.420 --> 00:58.950 You can write eyes on or should be in three right where you install it using three. 00:59.070 --> 01:08.220 So import flask restful underscore restful as f. 01:08.870 --> 01:10.160 And there's no errors. 01:10.170 --> 01:11.580 All right good. 01:12.080 --> 01:12.710 OK. 01:12.950 --> 01:18.590 So now that we have a flask restful Let's see how this will translate or how we can build a restful 01:18.590 --> 01:22.410 API a very basic one in flask. 01:22.460 --> 01:32.540 So we're going to first imported from flask restful implored Ravana Boyd method called API which is 01:32.540 --> 01:38.750 actually a constructor and we're also going to call for now let's just leave it for API and let's import 01:38.810 --> 01:40.650 whenever we need anything. 01:41.060 --> 01:52.870 And then we're going to say API API is equal to the constructor API and this constructor takes an our 01:52.880 --> 01:53.810 app. 01:55.450 --> 01:56.120 Okay great. 01:56.150 --> 01:57.710 So far so good. 01:57.740 --> 02:06.770 Now the next step is if you remember in this here we defined here in this video here we define our resources 02:06.830 --> 02:10.430 as a plus minus divide and multiply. 02:10.430 --> 02:17.290 So the first step in in developing this is to is to do exactly that to define our resources. 02:17.450 --> 02:25.160 So to do to do that we're going to also import from flask restful resource to indicate that some class 02:25.190 --> 02:27.350 is a resource. 02:27.350 --> 02:30.330 Now we're gonna say well we have four classes right. 02:30.370 --> 02:34.980 Class add which is a resource. 02:35.760 --> 02:44.650 Let's just fast for now and then we have a class subtract which is also going to inherit from resource. 02:44.690 --> 02:47.120 And then we're going to pass. 02:47.480 --> 02:49.850 And then the same thing for multiply 02:54.230 --> 02:57.350 and the same thing for divide. 02:58.210 --> 02:58.860 OK. 02:58.930 --> 03:01.350 So so far so good. 03:01.370 --> 03:06.580 Now inside these functions we're not going to do an app to route just like we did here. 03:06.830 --> 03:13.550 So instead we're going to be defining functions called Get or post depending on whether we want this 03:13.850 --> 03:17.810 resource to support so let's say for example let's go back here. 03:17.930 --> 03:20.160 We want this to support post. 03:20.270 --> 03:29.660 Then I would come here and then I would write define post as self. 03:30.170 --> 03:32.890 And then I would assume that if I'm here. 03:32.890 --> 03:42.850 So if I'm here then the resource add was requested using the method post. 03:42.890 --> 03:45.010 It's just simple as that. 03:45.020 --> 03:49.000 Now let's say for example I can support for and either post or again. 03:49.040 --> 03:51.920 Then I would define another function called get. 03:52.700 --> 04:04.380 And again here I would be if I'm here then the resource and wasn't requested using get. 04:04.880 --> 04:07.270 Similar thing for Prid put a new lease. 04:07.280 --> 04:14.090 I can do it or I can do the same thing for 04:16.820 --> 04:20.500 delete. 04:21.890 --> 04:25.640 OK so now that we know that we don't need any get or put or delete. 04:25.640 --> 04:26.480 In this case right. 04:26.490 --> 04:30.560 Because if we look at our diagram only hand posts here. 04:30.590 --> 04:35.360 So for this case we're only going to leave it as post right now. 04:35.360 --> 04:42.330 Once I'm here then I'm assuming that I've entered this function here so what do I do. 04:42.410 --> 04:44.980 Well I want to get the two numbers right. 04:45.110 --> 04:48.170 So for example at the store there's no errors. 04:48.350 --> 04:51.050 So first of all I want to get the posted data. 04:51.050 --> 04:59.960 So first steps step 1 get the post and lose data. 05:00.650 --> 05:11.250 So we're going to send a post to data as equals you request get Jaisalmer just like we saw pre-decided 05:11.270 --> 05:12.830 you OK. 05:13.020 --> 05:24.120 And now we're going to say x is equal to the posted data and then we're going to access X. And I say 05:24.240 --> 05:28.080 Y is equal to the posted data. 05:28.680 --> 05:34.260 Why now we're going to say that X is and x to make sure that it's in. 05:34.280 --> 05:46.590 And even though we're supposed to have received but let's just verify that their ends and then return 05:46.950 --> 05:57.330 is equal to x plus y and then turn Jaison or you return even Mao is equal to 06:00.570 --> 06:04.560 some and then the sum is returned. 06:04.800 --> 06:05.800 Right. 06:05.920 --> 06:11.360 Then finally return on a FI return now. 06:11.490 --> 06:16.890 So before that we also need to put the status code and we said that if we succeed in this then we would 06:16.890 --> 06:25.890 say status code and then put 200 right because we succeeded in this in this if we if we get here and 06:25.890 --> 06:29.810 we have added the two numbers then the status quo should be 200. 06:30.100 --> 06:37.650 There should be a comma here now instead of some what we can do is we could always put a message here 06:38.220 --> 06:41.460 to just simulate what HDB really is like. 06:41.550 --> 06:44.680 So we always put a message here and we will get the response. 06:44.680 --> 06:48.430 And we also have the status which will store the status code. 06:48.480 --> 06:52.610 So this message if if if it's a 200 then it would have the response. 06:52.770 --> 06:58.910 If it's not a 200 if it's a variable like 301 or a 302 then we would stand here. 06:59.040 --> 06:59.420 Right. 06:59.460 --> 07:01.420 And a message for example. 07:01.560 --> 07:10.700 You forgot to say you know the parameters are not there or your numbers are are not integers or so on. 07:10.740 --> 07:13.750 OK so if we're here then we're good. 07:13.760 --> 07:18.380 So let's first test this less Now before we can test this. 07:18.400 --> 07:21.270 So for defined our resource here. 07:21.300 --> 07:27.810 This is our resource but if you look here we see that map to slash and right. 07:27.840 --> 07:31.380 So we need to do this mapping over here. 07:31.950 --> 07:34.540 Now how do we do this mapping. 07:35.580 --> 07:43.870 Well you go back here and then we're going to say after we have defined all our resources we're going 07:43.880 --> 07:46.240 to say API. 07:46.350 --> 07:58.020 So if you don't remember AB AIs this API here then we're going to write API is equal to add and then 07:58.230 --> 08:06.930 underscore and then resource and then we're going to say which resource we want to do so we want to 08:06.930 --> 08:15.120 add this resource here and we're going to do add and then in here we're going to say where we want that 08:15.120 --> 08:17.690 resource to be routed or ahead. 08:17.850 --> 08:24.760 So in this example we said we aren't at slash and so let's go back here and then we do slash. 08:24.760 --> 08:28.120 And so now we've added this resource. 08:28.470 --> 08:29.830 It's listening and slashed. 08:29.850 --> 08:38.940 And if you add this resource gets a post request this function is going to start running and then we're 08:38.940 --> 08:51.120 going to get the posted data and then step 2 gone and and the posted data and then step three is we're 08:51.150 --> 08:58.810 going to return our response to the user which is the message and the status quo. 08:59.750 --> 09:00.240 OK. 09:00.240 --> 09:03.560 So let's make sure everything is running here no problems. 09:03.750 --> 09:07.580 Let's see if there's any problems clearing this. 09:07.680 --> 09:14.610 And then flask question and we have a couple of errors here. 09:14.880 --> 09:23.550 So the first thing is oh ok so it shouldn't be API does it add resource. 09:23.550 --> 09:25.840 It's not equal to and resource. 09:26.130 --> 09:28.800 So it's API and resource. 09:28.920 --> 09:31.900 So we're adding our resource to that API. 09:32.520 --> 09:37.350 And they're not saying you have any other problems and we don't. 09:37.620 --> 09:38.200 OK. 09:38.280 --> 09:44.260 So let's open up postman here let's try posting some information. 09:44.520 --> 09:47.670 So we're going to select coast from here. 09:47.910 --> 09:53.800 And then here we're going to use localhost five thousand. 09:53.820 --> 09:57.950 And then at the far southern port then we're going to listen to that right. 09:57.960 --> 10:06.160 This is how we this is the end point slash add right at it and then we're going to read in the message 10:06.160 --> 10:12.810 of the body or the body we're going to be sending a message wrong which wishes and Jaison format. 10:13.330 --> 10:23.280 And then inside this case I'm really going to have X and he's going to be five and then yours and then 10:23.410 --> 10:27.930 Y and it's going to be reasonable six. 10:28.090 --> 10:33.970 And then let's see what happens when we sent this and their response and we get their response back. 10:33.970 --> 10:40.160 So the message is that then and the status code is 200 So we got to success to use God. 10:40.390 --> 10:42.610 And this is the dish. 10:42.610 --> 10:45.560 Now what happens if x is not given it right. 10:45.580 --> 10:48.290 If we don't have X and we send it. 10:49.330 --> 10:52.450 Well this will cause internal server error right. 10:52.450 --> 10:53.860 We don't want that. 10:53.860 --> 11:01.480 We want you want to give the user an understanding of what to do when when there's an error right. 11:01.480 --> 11:04.420 We want to give him an area that makes sense. 11:04.420 --> 11:05.480 In other words. 11:06.070 --> 11:09.460 OK so let's see how we can we can change that. 11:09.460 --> 11:10.050 Right. 11:10.060 --> 11:22.670 So first of all once we get our posted data let's make a function code check posted data anti-acid post 11:23.120 --> 11:25.000 and data right. 11:25.270 --> 11:31.460 So what's so this here is step 1 be right. 11:31.630 --> 11:37.930 Verify validity of. 11:38.230 --> 11:40.560 And also we should pass in what functions. 11:40.570 --> 11:42.220 So this is and. 11:42.280 --> 11:43.770 Right. 11:43.870 --> 11:47.450 So verify the validity of posted data. 11:47.860 --> 11:48.610 Right. 11:48.780 --> 11:49.440 OK. 11:49.660 --> 11:51.660 So let's write this function over here. 11:51.670 --> 11:54.550 So we're gonna define a function called a shack. 11:54.680 --> 11:58.460 Most of the data is going to have the posted data. 11:58.840 --> 12:05.130 And we're also going to have the function name so function name. 12:05.650 --> 12:13.290 OK so we're going do is the function name is equal to add. 12:13.460 --> 12:14.730 Right. 12:14.890 --> 12:15.960 And what do we do. 12:16.340 --> 12:19.990 Well in that case we want to we have two types of errors right. 12:19.990 --> 12:21.830 We have 200 which is OK. 12:21.850 --> 12:26.330 So we don't return any errors but there is also 301. 12:26.620 --> 12:32.450 So 301 would be a problem right because we have a missing parameter. 12:32.650 --> 12:44.880 So let's go back here and then we say if x not in posted data in the posted data dictionary. 12:45.160 --> 12:50.660 Or why not an posted data. 12:51.230 --> 13:01.150 And what do we do then we would apply return 3 3 0 1 or else we simply response. 13:01.220 --> 13:03.190 We're we're with 200. 13:03.370 --> 13:03.970 Right. 13:04.300 --> 13:13.570 So in the function here we're gonna get status code is equal to check the posted data and then re going 13:13.570 --> 13:25.180 to see OK if status code is not 200 That means there are some here that are going to prepare a response 13:25.180 --> 13:29.560 to the user's server or returned Jason and then 13:32.760 --> 13:42.530 so we're going to prepare a response and say an error has happened or let's say let's make it more clear. 13:42.670 --> 13:47.610 So a message and then and there happened. 13:48.870 --> 13:59.990 And then the status quo would so let's make sure the capitalization record was put X back and see how 13:59.990 --> 14:02.110 stupid it looks like. 14:02.240 --> 14:12.970 So copy this exactly and then status code and then we put the status quo that the error status code 14:12.970 --> 14:20.650 that we got and then return on if I returned Jason. 14:21.710 --> 14:26.630 So now we're going to check the posted data if there is any here. 14:26.690 --> 14:27.310 Right. 14:27.320 --> 14:33.440 If x is not in the post data or why is not the posted data then we're going to return 3 or what is the 14:33.540 --> 14:37.090 error elsewhere when I return 200 pages. 14:37.200 --> 14:38.370 OK. 14:38.840 --> 14:41.720 Now I want to see this tax code that I returned. 14:41.900 --> 14:44.850 If it's not 200 then that means there's a failure. 14:45.020 --> 14:49.370 I'm going to say the error happened and then I'm going to return to the user status code that led to 14:49.370 --> 14:50.140 this error. 14:50.360 --> 14:55.220 In this case it means that there's a missing parameter. 14:55.220 --> 14:58.510 Now if this is 200 then that if I'm here right. 14:58.520 --> 15:07.580 So is if I am here then status code is got to do it right because if it wasn't 200 then we would have 15:07.580 --> 15:08.720 returned here. 15:08.820 --> 15:18.740 So here and then this data is 200 so we can now access easily x and y add them together and then return 15:18.770 --> 15:23.380 their response to the user as the message. 15:24.350 --> 15:30.570 OK so let's try and test this and see if there's any ears here syntax or or any other errors. 15:30.590 --> 15:37.000 So this flask can run so return some here. 15:38.180 --> 15:40.470 So this should be equal to. 15:40.500 --> 15:41.240 Right. 15:41.720 --> 15:47.720 And let's see run again and there's no problems here. 15:47.990 --> 15:51.800 Let's go first verify that the normal case is working. 15:52.310 --> 16:00.200 Then we get 11 and 200 maybe try five and fives and then you get 10 and 200 OK. 16:00.410 --> 16:05.480 So what if we get delete x now and then we see what happens what's the status. 16:06.260 --> 16:12.530 So hopefully he shouldn't tell us your message and there happened and status code 3 I want. 16:12.530 --> 16:18.430 So the user would look at the state and say oh three you won so that means that I didn't give that the 16:18.800 --> 16:22.060 the API the parameter x. 16:22.520 --> 16:23.580 Right. 16:23.690 --> 16:26.660 So you what if I send the empty. 16:27.230 --> 16:29.040 Then again get 3 0 1. 16:29.090 --> 16:34.070 So it handles all the edge cases perfectly whether or not there or why is not. 16:34.100 --> 16:36.360 There were 2 3 0 1. 16:36.380 --> 16:39.070 Now you can make this very very specific right. 16:39.080 --> 16:40.600 It doesn't have to stop it. 16:40.760 --> 16:46.730 You know you could make one very close for X one Eyrecourt for why you know you can you can really divide 16:46.730 --> 16:50.330 this chart or here in two very very detailed. 16:50.330 --> 16:53.760 And that's very good for your eyes. 16:53.850 --> 16:59.450 In fact most developers love a guy like that because they can debug their code right away. 16:59.450 --> 17:04.130 But for now we're just going to get like if any of the parameters is not there we're just going to return 17:04.130 --> 17:05.410 3 or what. 17:06.110 --> 17:13.760 OK so now that we're finished this and one in the next video room and I start completing the subtract 17:13.760 --> 17:17.810 one of the multiply 1 until we have the fully working API. 17:18.320 --> 17:18.670 OK. 17:18.680 --> 17:20.900 So until the next video recording.