1 00:00:00,480 --> 00:00:03,540 Instructor: So let's talk about OpenAPI. 2 00:00:03,540 --> 00:00:08,100 So OpenAPI is the De-Facto standard for API documentation. 3 00:00:08,100 --> 00:00:11,673 There are a few, but OpenAPI is a leader by far. 4 00:00:12,510 --> 00:00:17,510 OpenAPI specifies a description format for REST API. 5 00:00:18,060 --> 00:00:20,850 We will talk about the details of the format in a minute, 6 00:00:20,850 --> 00:00:25,080 but before it, if the name OpenAPI is not familiar, 7 00:00:25,080 --> 00:00:27,900 you have probably heard about Swagger. 8 00:00:27,900 --> 00:00:30,840 Swagger is the original name of OpenAPI, 9 00:00:30,840 --> 00:00:33,330 and the name was changed recently. 10 00:00:33,330 --> 00:00:36,030 Okay, so what OpenAPI describes? 11 00:00:36,030 --> 00:00:39,570 What contained in the format of OpenAPI? 12 00:00:39,570 --> 00:00:42,630 So OpenAPI describes the endpoints, 13 00:00:42,630 --> 00:00:47,630 and by endpoints, we usually mean the URL and the verb, 14 00:00:48,540 --> 00:00:51,450 and the parameters, which are the parameters 15 00:00:51,450 --> 00:00:54,750 that can be included in every API, 16 00:00:54,750 --> 00:00:57,420 the authentication stream, if any 17 00:00:57,420 --> 00:01:00,300 and some general information about the API, 18 00:01:00,300 --> 00:01:04,860 like the publisher description, title, version, and so on. 19 00:01:04,860 --> 00:01:07,920 Now, OpenAPI can be used to provide documentation 20 00:01:07,920 --> 00:01:09,990 and the test bed for developers. 21 00:01:09,990 --> 00:01:11,400 So what test bed is, 22 00:01:11,400 --> 00:01:14,670 test bed is an automatically generated test client 23 00:01:14,670 --> 00:01:16,140 for the REST API. 24 00:01:16,140 --> 00:01:20,670 So if you provide documentation generated by OpenAPI, 25 00:01:20,670 --> 00:01:23,130 then this documentation automatically creates 26 00:01:23,130 --> 00:01:26,370 also a REST client that the developers 27 00:01:26,370 --> 00:01:28,890 can use to test the API. 28 00:01:28,890 --> 00:01:32,760 Now from my experience, this test bed is an amazing tool 29 00:01:32,760 --> 00:01:35,610 in understanding exactly how to work with the API. 30 00:01:35,610 --> 00:01:39,270 In addition, OpenAPI can generate client libraries. 31 00:01:39,270 --> 00:01:43,350 So not only does it tell you how to use API 32 00:01:43,350 --> 00:01:46,500 but you can also get from it a client library 33 00:01:46,500 --> 00:01:50,460 in various platforms such as Java, .NET, Python, and more. 34 00:01:50,460 --> 00:01:53,070 That will make the call to the API. 35 00:01:53,070 --> 00:01:54,570 In addition to that, 36 00:01:54,570 --> 00:01:57,540 OpenAPI can also generate the API itself. 37 00:01:57,540 --> 00:01:59,700 This approach is called Design-First 38 00:01:59,700 --> 00:02:02,880 and it means that you first write the documentation 39 00:02:02,880 --> 00:02:04,920 using the OpenAPI platform, 40 00:02:04,920 --> 00:02:08,683 and OpenAPI then generates the API to be exactly 41 00:02:08,683 --> 00:02:12,900 compliant with the documentation that you just wrote. 42 00:02:12,900 --> 00:02:15,420 This is a very interesting approach, I must admit. 43 00:02:15,420 --> 00:02:18,870 I don't know of many organizations that use it, but again 44 00:02:18,870 --> 00:02:22,500 keep it in mind and it's important to be familiar with it. 45 00:02:22,500 --> 00:02:26,250 And of course OpenAPI can do much more than that. 46 00:02:26,250 --> 00:02:27,083 Now, 47 00:02:27,083 --> 00:02:30,030 the OpenAPI documentation can be automatically generated 48 00:02:30,030 --> 00:02:31,890 and this is a preferred approach. 49 00:02:31,890 --> 00:02:35,280 We will demonstrate it towards the end of this section 50 00:02:35,280 --> 00:02:38,550 and it is compatible with many API platforms. 51 00:02:38,550 --> 00:02:40,020 So you can assume that, 52 00:02:40,020 --> 00:02:42,600 no matter what is your development platform, 53 00:02:42,600 --> 00:02:46,380 you can automatically generate the OpenAPI documentation 54 00:02:46,380 --> 00:02:47,733 from this platform.