1 00:00:00,450 --> 00:00:02,070 Instructor: And the last web API 2 00:00:02,070 --> 00:00:04,620 we will talk about is gRPC. 3 00:00:04,620 --> 00:00:07,200 GRPC was developed by Google in 2015 4 00:00:07,200 --> 00:00:08,610 and what you need to know about it 5 00:00:08,610 --> 00:00:10,950 is that it is based on HTTP/2. 6 00:00:10,950 --> 00:00:14,340 Now, if you're not familiar with HTTP/2 that's fine. 7 00:00:14,340 --> 00:00:16,320 The most important thing that you need to know 8 00:00:16,320 --> 00:00:20,340 about this protocol is that it allows two ways streaming, 9 00:00:20,340 --> 00:00:24,000 meaning instead of a request and then a response 10 00:00:24,000 --> 00:00:26,070 we can implement a duplex, 11 00:00:26,070 --> 00:00:29,070 meaning the server can send messages to the client 12 00:00:29,070 --> 00:00:31,350 and not only the other way around. 13 00:00:31,350 --> 00:00:34,890 GRPC uses protobuf as its transport mechanism 14 00:00:34,890 --> 00:00:36,990 instead of XML or JSON. 15 00:00:36,990 --> 00:00:40,530 Protobuf is a serialization protocol developed by Google 16 00:00:40,530 --> 00:00:43,410 and it allows different development platforms 17 00:00:43,410 --> 00:00:46,380 such as .NET or Java to communicate between them 18 00:00:46,380 --> 00:00:48,330 using code generators 19 00:00:48,330 --> 00:00:51,420 that read the protobuf protocol and message 20 00:00:51,420 --> 00:00:54,753 and generate classes that are compliant with the data. 21 00:00:55,680 --> 00:00:58,260 Because gRPC is based on HTTP/2 22 00:00:58,260 --> 00:01:01,050 it supports bidirectional and streaming messaging 23 00:01:01,050 --> 00:01:01,883 which is something 24 00:01:01,883 --> 00:01:05,580 that neither REST nor GraphQL can support 25 00:01:05,580 --> 00:01:08,040 since they are based on HTTP/1. 26 00:01:08,040 --> 00:01:10,770 So here is a short example of gRPC. 27 00:01:10,770 --> 00:01:14,250 As you can see, we have a service called HelloService 28 00:01:14,250 --> 00:01:18,570 which accepts HelloRequest and returns HelloResponse. 29 00:01:18,570 --> 00:01:20,746 And you can see the structure of HelloRequest 30 00:01:20,746 --> 00:01:21,579 and HelloResponse in this code. 31 00:01:22,530 --> 00:01:25,530 And as you can see, it's a very simple object, 32 00:01:25,530 --> 00:01:29,850 nothing fancy, no JSON, no XML, nothing at all. 33 00:01:29,850 --> 00:01:32,250 GRPC takes care of all serialization 34 00:01:32,250 --> 00:01:34,110 of the request and the response, 35 00:01:34,110 --> 00:01:35,960 and you don't need to worry about it. 36 00:01:37,320 --> 00:01:39,750 So what you need to know about gRPC 37 00:01:39,750 --> 00:01:44,750 is in contrast to GraphQL the performance of gRPC are great. 38 00:01:44,790 --> 00:01:47,310 Again, because it is based on HTTP/2 39 00:01:47,310 --> 00:01:49,860 which is a very performant protocol 40 00:01:49,860 --> 00:01:53,340 then gRPC can provide a very good performance. 41 00:01:53,340 --> 00:01:57,570 But gRPC is not widely used yet, it's not very popular, 42 00:01:57,570 --> 00:01:59,730 and part of it is because that HTTP/2 43 00:01:59,730 --> 00:02:02,070 is still not very popular. 44 00:02:02,070 --> 00:02:04,950 In addition, it requires specialized libraries 45 00:02:04,950 --> 00:02:07,200 at both ends because of protobuf. 46 00:02:07,200 --> 00:02:09,750 We said before that in order to use protobuf 47 00:02:09,750 --> 00:02:12,360 you need to have code generators at both ends 48 00:02:12,360 --> 00:02:14,850 to serialize the protocol to classes 49 00:02:14,850 --> 00:02:16,920 in the platform you are using. 50 00:02:16,920 --> 00:02:20,340 So this is another thing that you need to take into account 51 00:02:20,340 --> 00:02:21,573 when using gRPC.