1 00:00:00,330 --> 00:00:03,450 Instructor: Our next web API is GraphQL. 2 00:00:03,450 --> 00:00:07,950 GraphQL was developed internally in 2012 by Facebook. 3 00:00:07,950 --> 00:00:11,010 And released to the public in 2015. 4 00:00:11,010 --> 00:00:12,930 The biggest advantage of GraphQL 5 00:00:12,930 --> 00:00:15,480 is that it enables a very flexible querying, 6 00:00:15,480 --> 00:00:18,630 updating and subscribing to data tech changes. 7 00:00:18,630 --> 00:00:21,960 Now, what it means is that in contrast to rest 8 00:00:21,960 --> 00:00:24,330 that allows you to query an entity 9 00:00:24,330 --> 00:00:26,610 and then get the whole entity back. 10 00:00:26,610 --> 00:00:29,610 GraphQL allows you to specify exactly 11 00:00:29,610 --> 00:00:32,040 which fields you want to get back, 12 00:00:32,040 --> 00:00:34,740 and in addition, you can specify what parameters 13 00:00:34,740 --> 00:00:36,900 to use in the query itself. 14 00:00:36,900 --> 00:00:39,510 So you get a very, very flexible querying 15 00:00:39,510 --> 00:00:41,010 and operating capabilities. 16 00:00:41,010 --> 00:00:43,650 And in addition, you have a subscribing capabilities 17 00:00:43,650 --> 00:00:46,533 meaning you can get notifications about updates 18 00:00:46,533 --> 00:00:48,870 for the entities that you have retrieved 19 00:00:48,870 --> 00:00:51,483 and merge those updates in the entities. 20 00:00:53,550 --> 00:00:57,840 GraphQL, similar to rest, is based on JSON in and out. 21 00:00:57,840 --> 00:01:00,210 So, let's say an example for it. 22 00:01:00,210 --> 00:01:03,030 Here is a typical query in GraphQL. 23 00:01:03,030 --> 00:01:06,030 As you can see, it begins with query. 24 00:01:06,030 --> 00:01:09,008 Then, it tells us what kind of entity 25 00:01:09,008 --> 00:01:10,920 we want to query for. 26 00:01:10,920 --> 00:01:12,483 In this case, posts. 27 00:01:13,320 --> 00:01:15,870 And then, we can specify which fields 28 00:01:15,870 --> 00:01:18,210 we want to retrieve for the posts. 29 00:01:18,210 --> 00:01:21,690 In this case, we want to retrieve the id, title, body 30 00:01:21,690 --> 00:01:24,690 the publishing date, and the author. 31 00:01:24,690 --> 00:01:27,630 And in the author, we need to specify which field 32 00:01:27,630 --> 00:01:29,910 of the author we want to retrieve. 33 00:01:29,910 --> 00:01:33,600 In this case, we want to retrieve the name of the author. 34 00:01:33,600 --> 00:01:36,570 So, this is how a GraphQL request looks like 35 00:01:36,570 --> 00:01:39,300 and the response looks like this. 36 00:01:39,300 --> 00:01:42,630 And you can see that we've got exactly what we asked for. 37 00:01:42,630 --> 00:01:45,030 We get only the fields that we asked for 38 00:01:45,030 --> 00:01:47,070 including the name of the author 39 00:01:47,070 --> 00:01:50,910 which is a field stored in a different table in this case. 40 00:01:50,910 --> 00:01:53,820 Now, what you need to know about GraphQL is first, 41 00:01:53,820 --> 00:01:57,480 it's very flexible as we just demonstrated 42 00:01:57,480 --> 00:02:00,390 but it requires some upfront dev effort. 43 00:02:00,390 --> 00:02:03,630 In contrast to rest, which is extremely easy to implement, 44 00:02:03,630 --> 00:02:05,550 GraphQL is not so easy 45 00:02:05,550 --> 00:02:08,130 and there is some developments that need to be made 46 00:02:08,130 --> 00:02:09,543 in order to make it useful. 47 00:02:10,470 --> 00:02:13,260 In addition, GraphQL performance wise, 48 00:02:13,260 --> 00:02:18,260 is a little bit, let's say, less optimized than rest. 49 00:02:18,600 --> 00:02:20,850 So you should look very, very closely 50 00:02:20,850 --> 00:02:23,313 on the performance metrics when using GraphQL. 51 00:02:24,510 --> 00:02:27,870 GraphQL is gaining ground all around the world. 52 00:02:27,870 --> 00:02:31,200 GitHub, for example, announced a few months ago 53 00:02:31,200 --> 00:02:33,870 that they are migrating all their APIs 54 00:02:33,870 --> 00:02:36,720 to expose GraphQL instead of rest 55 00:02:36,720 --> 00:02:39,210 because they identified that most users 56 00:02:39,210 --> 00:02:42,480 wants to retrieve only specific fields and almost no one 57 00:02:42,480 --> 00:02:44,820 wanted the whole bunch of fields 58 00:02:44,820 --> 00:02:47,577 that was exposed by the REST API of GitHub.