WEBVTT 00:05.210 --> 00:05.940 By everyone. 00:05.940 --> 00:06.970 Welcome back. 00:07.410 --> 00:14.520 So in this video we're going to be talking about what a restful API is so we always hear that term restful 00:16.430 --> 00:17.250 API. 00:17.510 --> 00:23.000 So we're going to be talking about what is a restful API before we build one. 00:23.270 --> 00:26.610 Again this is not going to be you know comprehensive sense. 00:26.630 --> 00:31.040 There are like even books about what restfully be I should be. 00:31.160 --> 00:38.540 And we can't possibly cover everything in the scope of course but we will be talking about what really 00:38.540 --> 00:41.960 constitutes arrest for what is what is it. 00:42.050 --> 00:44.190 What it basically is in this video. 00:44.320 --> 00:44.660 OK. 00:44.690 --> 00:45.850 So let's get started. 00:46.160 --> 00:55.520 So to begin with just to give you know a definition it's basically an architectural style architecture. 00:57.640 --> 01:01.910 Style upbuilding API. 01:03.330 --> 01:09.450 So that's simply a definition and you might not even know you are not sure what that really means. 01:09.450 --> 01:12.250 Let's let's let's break it down part by part. 01:12.300 --> 01:14.030 So what is an API. 01:14.250 --> 01:18.600 An API is basically code that allows you to take a request 01:22.330 --> 01:29.980 and then this code takes the request and then it does some process for you and prepares a response. 01:32.220 --> 01:39.350 And returns this response you know it eyes are not nothing fancy or nothing you can think of a library. 01:39.360 --> 01:39.870 Right. 01:39.990 --> 01:47.230 When you For example in any in Python when you do you know important and then some library library right 01:47.730 --> 01:53.760 library as you know something let's say non-P as an MP. 01:53.790 --> 01:54.590 Right. 01:54.600 --> 01:58.830 So we're importing non-P here as an IP. 01:59.080 --> 02:05.720 Now you can think of Numby really as an API non-P offers you lots of functions right. 02:05.730 --> 02:14.010 You have no and pede array and then you have you know all these hundreds of functions and you can think 02:14.010 --> 02:17.640 that Numby takes in your request is made you do. 02:17.650 --> 02:23.470 And Peter arrays so you're telling them hey I want an array that does this function. 02:24.030 --> 02:30.480 And then non-P does under the hood does some computation and then it returns you a response which is 02:30.480 --> 02:32.830 your array that you want to write. 02:33.240 --> 02:35.120 Similarly for all these functions. 02:35.140 --> 02:35.470 No. 02:35.510 --> 02:41.970 He's basically offering you all its API so that you can use your give it a request and then you get 02:41.970 --> 02:42.710 the responses. 02:42.720 --> 02:46.770 And that's what most of our programming is really using API. 02:46.770 --> 02:49.890 So you guys are nothing new now. 02:50.190 --> 02:56.760 So define what an API mean is there's a very classical example where I think when you're in a restaurant 02:56.760 --> 02:57.190 right. 02:57.330 --> 03:04.890 So there is you know you and maybe you know your girlfriend maybe you or your wife and then think here 03:04.950 --> 03:06.530 is the waiter. 03:07.050 --> 03:08.360 And then here is the kitchen. 03:08.410 --> 03:09.230 Right. 03:09.780 --> 03:15.690 So in this context here the waiter acts as an API and the waiter takes in your request. 03:15.690 --> 03:21.190 He says OK you want this chicken or vegetables or whatever. 03:21.390 --> 03:27.900 And then it takes that request and then sends it over to the kitchen where and where sometimes the waiter 03:27.900 --> 03:30.330 would cook but that's not what happens right. 03:30.610 --> 03:32.790 You know the kitchen is where cooks. 03:32.790 --> 03:38.910 And then once the cooking has happened then the waiter takes the response which is your dish dish that 03:38.910 --> 03:44.570 you ordered foie gras and then takes it back and gives it back to you. 03:44.580 --> 03:48.450 So in a way the waiter is acting really is an API. 03:48.910 --> 03:54.630 So yeah that's just you know our classical example of what a weather API is. 03:54.630 --> 03:58.930 So we're saying that a restful API is a method of designing API. 03:59.110 --> 04:01.890 It's an architectural style it's one way of doing it. 04:01.880 --> 04:03.050 Not the only way. 04:03.150 --> 04:04.870 Style of building an API. 04:04.890 --> 04:06.500 But it's one way. 04:07.110 --> 04:11.610 And if you feel like this request response here is very familiar. 04:11.620 --> 04:19.260 Well it's because when we were talking about the Web how the web was working and how DTP was working 04:19.260 --> 04:24.010 we always said that you always do a request and then you get a response back. 04:24.390 --> 04:25.900 Well that's the idea here. 04:25.900 --> 04:33.480 The idea is the communication in arrest for API uses the web. 04:33.510 --> 04:36.900 So rest for API really it's just an API right. 04:37.090 --> 04:38.790 We're just a normal API. 04:39.060 --> 04:47.520 But instead of using you know the on and off line version of the code you're actually using HTP or the 04:47.520 --> 04:52.550 web to communicate with with this kitchen. 04:52.630 --> 04:53.310 So. 04:53.370 --> 04:55.760 So instead of having this kitchen locally. 04:55.770 --> 04:56.280 Right. 04:56.430 --> 04:59.780 This kitchen is in the cloud or on the web. 05:00.210 --> 05:03.940 And then your waiter here is HTP right. 05:04.040 --> 05:11.040 You're preparing a request to go to the kitchen using as you can be and that she gives you the response 05:11.040 --> 05:14.000 back using a to keep your response. 05:14.160 --> 05:19.800 So this request response pattern is basically what an API is expected to do. 05:20.070 --> 05:29.920 And the means of communication between you and your girlfriend or wife and the kitchen is using HTP. 05:30.240 --> 05:31.200 Right. 05:31.740 --> 05:39.090 So in other words really a restful AB is nothing more than just a normal API just a normal library that 05:39.090 --> 05:46.310 offers a bunch of functions for you but these functions can be consumed or can be used right. 05:46.320 --> 05:49.770 So here I can just consume them by calling the function right. 05:49.950 --> 05:53.160 But here in this case they're not a local library. 05:53.160 --> 06:01.560 In this case what I do is I use HTP over the web to send a response to send a request to this API over 06:01.560 --> 06:09.400 the web make the API do some stuff for me and then get their response back to my web application or 06:09.460 --> 06:12.180 it or get their response back in general. 06:12.210 --> 06:18.520 So that's basically the whole idea of a restful API restful API is you have your own server. 06:18.570 --> 06:19.430 Right. 06:20.040 --> 06:22.350 Let's say you're building a restful API. 06:22.530 --> 06:25.860 So you have your server and then you open a few and boy. 06:25.860 --> 06:33.720 So just like we did previously it is like Slash by Slash add two nuns you know slash the other. 06:33.740 --> 06:34.610 And so on. 06:34.610 --> 06:42.060 So you open a bunch of you know and points on your server and you say to people hey these are my points. 06:42.290 --> 06:43.850 This is my API here. 06:43.850 --> 06:45.400 So this is my API. 06:45.590 --> 06:49.930 All these functions you can use by just accessing this endpoint. 06:50.180 --> 06:52.130 So a user or a developer. 06:52.130 --> 06:55.430 Most people who use Abiah eyes are really developers. 06:55.490 --> 06:58.090 So let's say you're making a mobile app right. 06:58.790 --> 07:03.700 And then the more about how you want to add you know to numbers right. 07:03.740 --> 07:07.030 You could just add you know be calls a plus one. 07:07.030 --> 07:07.320 Right. 07:07.320 --> 07:08.660 It's simple. 07:08.860 --> 07:14.970 Let's say you're using like a really crappy crappy programming language that doesn't support too. 07:15.020 --> 07:22.340 Adding two numbers right or say even a more realistic example is let's say your function here adds really 07:22.340 --> 07:23.200 huge numbers. 07:23.240 --> 07:27.380 So let's say you do be equal a times two here. 07:27.410 --> 07:31.940 This would lead to an overflow and you don't want to handle all the overflow stuff. 07:31.940 --> 07:36.300 So you're going to leave it up to that API to add two numbers safely. 07:36.320 --> 07:44.120 So what you do is instead of doing it because times do what you do as you do every request to that end 07:44.120 --> 07:52.560 point and slash add two numbers and you send you know a and a right to A's so be equals daytime's two 07:52.610 --> 07:54.940 is the same as me call a plus a right. 07:55.010 --> 08:03.350 So you send a twice and you posted to the API twice and then that API adds it for you no matter how 08:03.350 --> 08:04.610 big your numbers are right. 08:04.610 --> 08:06.870 Because it handles this safely. 08:07.130 --> 08:11.720 And then once the API is done it replies you response. 08:12.110 --> 08:16.970 And then you just take the response and store it and b whether it's a B or you know just a training 08:16.970 --> 08:19.100 representation of B or whatever. 08:19.310 --> 08:19.890 Right. 08:19.910 --> 08:26.770 So in a way instead of you know handling instead of doing for example NPE not peanuts. 08:27.000 --> 08:35.120 And then a in a right instead if you're doing it locally you're using HGT be here to access this API 08:35.120 --> 08:42.200 server that has a bunch of end points that act as functions and these functions do some operations for 08:42.200 --> 08:44.490 you and return the response for you. 08:44.780 --> 08:46.750 So this is your request going. 08:46.850 --> 08:52.670 And then this is the response that you're receiving back and this is exactly what a KPI server is. 08:52.850 --> 08:56.260 We are building a product for developers to use. 08:56.270 --> 09:04.790 So let's say developers usually you know in most languages have relatively good overflow handy. 09:04.810 --> 09:11.930 Right but one of the one of the projects we'll do in this course is we're going to build our image recognition 09:12.860 --> 09:13.390 API. 09:13.400 --> 09:20.220 So we're going to build that API which is made off you know slash recognize. 09:20.320 --> 09:21.080 Right. 09:21.560 --> 09:29.000 And then the user here is going to send us an image and we're going to apply a machine learning model 09:29.320 --> 09:34.940 or a pre trained machine learning model and we're going to recognize or say the user sends us an image 09:34.940 --> 09:35.710 of a panda. 09:35.720 --> 09:36.310 Right. 09:36.590 --> 09:44.930 So we want to get recognize it and then we're going to say going to reply to the user image with a Jason 09:45.170 --> 09:46.320 image. 09:46.380 --> 09:50.010 Kanda and so on. 09:50.210 --> 09:56.200 And then the user would get this request and you know instant instead of him having to you know implement 09:56.530 --> 10:04.000 locally all these machine learning algorithms and image recognition all the stuff with just one call 10:04.000 --> 10:07.110 to slash recognize and giving us the photo. 10:07.180 --> 10:09.930 He's essentially got going back. 10:09.940 --> 10:17.850 The result of panda in which we used here the the in our server we did the computation work for him 10:17.860 --> 10:23.620 we figured out what this photo is and we're blind to him as as a panda. 10:23.710 --> 10:30.130 So this is the power off of API and this is why many people nowadays nobody you know does very heavy 10:30.130 --> 10:36.610 computations like image recognition and all the stuff no one does it locally because if you do it locally 10:36.640 --> 10:41.950 then it's really you're doing for example a mobile application then you're running this on the mobile 10:42.250 --> 10:45.750 and mobile capabilities are nowhere near as powerful as a server. 10:45.770 --> 10:51.120 You know it's a really bad idea to run a machine learning model on a mobo. 10:51.210 --> 10:52.200 You know it will crash. 10:52.210 --> 10:53.610 Oh most definitely. 10:53.620 --> 11:01.120 So what users end up doing or what developers end up doing is they offload this this huge you know recognizer 11:01.120 --> 11:11.080 or this huge computation required and they offloaded from the mobile app and then they offloaded to 11:11.080 --> 11:17.120 a server a dedicated server which does all this computation for them and then replies Their response 11:17.120 --> 11:18.610 that they need. 11:18.610 --> 11:24.750 And this is basically what you know and a restful API here this this here is not only the API. 11:24.770 --> 11:27.370 This is actually a restful API. 11:27.580 --> 11:31.740 So this is basically what it restfully be eyes into the normal API. 11:31.900 --> 11:34.400 That just supports HGP. 11:34.450 --> 11:43.000 It's implemented using the communication means from one end to the other is just using HTP. 11:43.060 --> 11:47.470 So yeah that's basically what a restful API is. 11:47.470 --> 11:52.830 One last point to talk about is you know this is very very useful for developers right. 11:53.020 --> 11:59.030 Before if you wanted to build a mobile application for example which which you know you would you would 11:59.050 --> 12:03.490 implement some machine learning algorithms and you would have to implement this from scratch. 12:03.490 --> 12:05.400 And this is a really bad idea. 12:05.410 --> 12:06.020 Right. 12:06.040 --> 12:08.780 Again you're going to be running it on a mobile phone. 12:08.880 --> 12:15.220 Superslow you're on you're you know you're going to be doing everything offline even if you use library 12:15.370 --> 12:15.880 libraries. 12:15.880 --> 12:22.210 It's still going to be on the phone but now with the idea or restful API is is is that you can think 12:22.210 --> 12:22.550 of. 12:22.690 --> 12:29.530 So as the developer has so many API eyes on the cloud right mean not only this API but so many clouds. 12:29.680 --> 12:35.660 And then now you can just click with one or one request he says hey give me that time. 12:35.710 --> 12:40.750 And then this this you know maybe I convert the time for him and then he does another request. 12:40.840 --> 12:49.570 Hey you know convert that timeframe from UTC to PSTN for example and then you convert the time for him 12:49.840 --> 12:55.500 and then all these guys are basically like services to the developer which she can. 12:55.500 --> 12:56.490 It's like a dream. 12:56.500 --> 12:57.080 Right. 12:57.100 --> 12:59.270 You have an API for everything. 12:59.310 --> 13:06.670 So you want to numbers use an API you know even though it's it's it's not that you know doesn't make 13:06.670 --> 13:13.810 sense to add to a numbers using an API but the you get the idea is like that you have you know machine 13:13.810 --> 13:20.920 learning API and you have time you have you know prices let's say you want to get the prices the current 13:20.920 --> 13:29.440 prices in in in in for example for the stocks you can get at an API for Stop prices. 13:29.440 --> 13:31.140 So the ideas are limitless. 13:31.150 --> 13:39.670 And in exchange for the developer for accessing this this model here this API here then the API I would 13:39.750 --> 13:42.630 would make the developer pay a little bit of money right. 13:42.630 --> 13:50.020 Or maybe most guys are like zero point zero zero zero one dollars per hour per call right. 13:50.200 --> 13:57.290 So in that way the rest for API builder gets a little bit of money for the server that is running right 13:57.300 --> 14:04.600 because this costs money race running Serbin costs money and in response the developer can code a super 14:04.600 --> 14:11.470 hard machine learning application and just a few hours using all these you know are by offloading all 14:11.470 --> 14:16.160 the heavy work or heavy lifting to these restful API. 14:16.540 --> 14:21.970 So for me the idea was clear here and we're going to be discussing more about how to build restful Adrianne's 14:22.060 --> 14:23.350 in the next video. 14:23.500 --> 14:25.420 So until the next thing you have Piccoli.