darkfi/doc/src/learn/dchat/creating-dchat/protocol-dchat.md

ProtocolDchat

Let's start tying these concepts together. We'll define a struct called ProtocolDchat that contains a MessageSubscription to DchatMsg and a pointer to the ProtocolJobsManager. We'll also include the DchatMsgsBuffer in the struct as it will come in handy later on.

{{#include ../../../../../example/dchat/src/protocol_dchat.rs:1:13}}

Next we'll implement the trait ProtocolBase. ProtocolBase requires two functions, start() and name(). In start() we will start up the ProtocolJobsManager. name() will return a str of the protocol name.

{{#include ../../../../../example/dchat/src/protocol_dchat.rs:42:46}}
{{#include ../../../../../example/dchat/src/protocol_dchat.rs:48::}}

Once that's done, we'll need to create a ProtocolDchat constructor that we will pass to the ProtocolRegistry to register our protocol. We'll invoke the MessageSubsystem and add DchatMsg as to the list of dispatchers. Next, we'll create a MessageSubscription to DchatMsg using the method subscribe_msg().

We'll also initialize the ProtocolJobsManager and finally return a pointer to the protocol.

{{#include ../../../../../example/dchat/src/protocol_dchat.rs:15:29}}
{{#include ../../../../../example/dchat/src/protocol_dchat.rs:40}}

We're nearly there. But right now the protocol doesn't actually do anything. Let's write a method called handle_receive_msg() which receives a message on our MessageSubscription and adds it to DchatMsgsBuffer.

Put this inside the ProtocolDchat implementation:

{{#include ../../../../../example/dchat/src/protocol_dchat.rs:31:39}}

As a final step, let's add that task to the ProtocolJobManager that is invoked in start():

{{#include ../../../../../example/dchat/src/protocol_dchat.rs:44}}
        //...
{{#include ../../../../../example/dchat/src/protocol_dchat.rs:47}}
        //...
{{#include ../../../../../example/dchat/src/protocol_dchat.rs:50}}