This document discusses improving proto types when using them in collections for RPC applications. It recommends adding an empty message type for void parameters and repeatable types for data collections. Sample code shows defining request/response messages for getting a user by name including a repeated field for the user collection. The server code returns the collection while the client code iterates over it. Implementing an online shop sample is suggested along with using the template method pattern for server internal logic. The document recommends a design patterns book and thanks the reader.

1. eleks.comeleks.com
RPC. part 2. My Project.
Using some patterns

2. Improve proto types for using them in
collections
- Add Empty message type for void input or output
parameters.
- Add some repeatable types for data collections.
- Improve Client and server to use those types
- Don’t forget to add “Google.Protobuf.Custom v3.0.0-beta”
reference to Client and Server

3. // The request message containing the user's name.
message stringRequest {
string str = 1;
}
// The response message containing User
message User {
int32 id = 1;
string name = 2;
string surname = 3;
}
// The response message containing the USERS
message UsersCollection {
repeated User users = 1;
}
message Empty {
}

4. Server side code sample
//private server field
Google.Protobuf.Collections.RepeatedField<User> users;
public Task<UsersCollection> GetUserByName(stringRequest request, ServerCallContext context)
{
var reply = new UsersCollection();
var enumerator = users.GetEnumerator();
do
{
if (enumerator.Current != null)
{
if (enumerator.Current.Name == request.Str)
{
reply.Users.Add(enumerator.Current);
}
}
} while (enumerator.MoveNext());
return Task.FromResult(reply);
}

5. Client side code sample
var users = client.GetUserByName(new stringRequest { Str = user }).Users;
var enumerator = users.GetEnumerator();
do
{
if (enumerator.Current != null)
{
//do smth with user element
}
}
while (enumerator.MoveNext());

6. Online Shop sample

7. Interfaces
Client:
- Order a good (returns order id, or 0)
- Cancel order (by order id)
- Get my orders
Server:
- Buy, Cancel handling
- Some internal logic

8. Lets CODE IT!

9. Server Internal Logic. How to
implement?
What is Template Method?
Can we use it here?

10. What to do, if need to switch between
RPC and non-RPC Server ?
Need to Adapt!
Real-Time Switching (Strategy)

11. To Learn From:
I Strongly Recommend this book for Patterns explanation:
“Freeman Er, Freeman El - design patterns”
(clear explanation, funny)

12. eleks.com
Thanks!

13. eleks.com
Inspired by Technology.
Driven by Value.