# HG changeset patch # User alfadur # Date 1577308200 -10800 # Node ID 3dfeac5b03db4d637a44b573fc1f2f4e805ea9a2 # Parent 7df4304efaefc644897122fb78a4a59c18854a67 add server walkthrough diff -r 7df4304efaef -r 3dfeac5b03db ServerCodeWalkthrough.wiki --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ServerCodeWalkthrough.wiki Thu Dec 26 00:10:00 2019 +0300 @@ -0,0 +1,40 @@ +#summary Server code walkthrough +#labels Phase-Implementation,Phase-Design + += Praise 🦀 = + +== General Structure == + +The server code consists of the following top level modules (in order of inclusion): + * `core`: contains the types necessary to implement the server logic. + * `protocol`: contains definitions of network protocol messages and code for their (de)serialization. + * `handlers`: acts on parsed protocol messages to modify the server state and generate responses to network clients. + * `server`: contains the code for IO handling. + * `main`: starts the server and runs the main event poll. + +== Important Types == + * `core::client::HwClient` and `core::room::HwRoom` structures are where the most of the game-related data is stored. They are often referenced by `core::types::{ClientId, RoomId}` identifiers + * `core::server::HwServer` is a collection `HwClient`s and `HwRoom`s with some additional global server data, and is responsible for maintaining related invariants. For this reason it doesn't provide a public way to retrieve a mutable `HwClient` or `HwRoom` reference. + * `core::anteroom::HwAnteroom` stores clients that did not yet complete the logic procedure. Those clients are represented by `core::anteroom::HwAnteroomClient` structure, that only contains a relevant subset of full client data. + * `core::server::HwRoomControl` can be requested from a `HwServer` to modify a room that the current client is located in. This interface is not directly provided by `HwServer` to avoid constant checks to ensure the client is still in the room. + + * `protocol::messages::HwProtocolMessage` is a parsed representation of a message from a client. + * `protocol::messages::HwServerMessage` is a messaged generated by the server to be deserialized into text protocol and sent to a client. + * `protocol::ProtocolDecoder` is an entry point to the network protocol parser. + + * `handlers::Response` is the structure handlers use for queueing server messages to be sent out, clients to be removed due to server logic, and IO tasks to be performed asynchronously. + * `handlers::IoTask` type represents a task for the IO thread than can be queued using `Response`. The task result will eventually be returned as a `handlers::IoResult` value. + + * `server::io::IoThread` represents the thread for handling all IO processing apart from writing/reading from clients' network sockets. + * `server::network::NetworkClient` is a structure complements a `HwClient` with data relevant to network connection handling. A `NetworkClient` is referenced by the same `ClientId` as the corresponding `HwClient`. + * `server::network::NetworkLayer` is the top level structure that contains an `IoThread`, a `HwAnteroom`, a `HwServer`, and a collection of `NetworkClients`. It handles all the dispatching between all these components. + +== Client Flow == + * A new client is first created by the `NetworkLayer` when a network connection is established. The relevant network state is stored in a `NetworkClient` structure. + * If the server is built with TLS support, the client will remain in `server::network` module until the TLS handshake is completed. + * Either way, after the connection is successfully established, a new `HwAnteroomClient` structure is created for the client and stored in the `HwAnteroom` + * From there on, when new data received on client's socked, it's parsed by a `ProtocolDecoder` and the resulting `HwProtocolMessage` is passed into `handlers` module for further dispatching + * While some general messages are processed directly by `handlers`, the ones only available in a specific context are passed into a specialized submodule: `handlers::inanteroom` for clients located in `HwAnteroom`, `handlers::inroom` for `HwServer` clients that are in a `HwRoom` and `handlers::inlobby` for those that aren't. + * When processing of a `HwProtocolMessage` results in a `HwAnteroomClient` being successfully logged in, it's immediately moved into the `HwServer` and extended to a full `HwClient`. + * If a handler needs complete remove a client, apart from removing it from `HwAnteroom` of `HwServer` it will also queue a request to delete the corresponding `NetworkClient` on it's `Response`. +