1 files changed, 79 insertions, 0 deletions
diff --git a/azalea-auth/src/sessionserver.rs b/azalea-auth/src/sessionserver.rs
new file mode 100644
index 00000000..31857bc0
--- /dev/null
+++ b/azalea-auth/src/sessionserver.rs
@@ -0,0 +1,79 @@
+//! Tell Mojang you're joining a multiplayer server.
+//!
+use serde::Deserialize;
+use serde_json::json;
+use thiserror::Error;
+use uuid::Uuid;
+
+#[derive(Debug, Error)]
+pub enum SessionServerError {
+    #[error("Error sending HTTP request to sessionserver: {0}")]
+    HttpError(#[from] reqwest::Error),
+    #[error("Multiplayer is not enabled for this account")]
+    MultiplayerDisabled,
+    #[error("This account has been banned from multiplayer")]
+    Banned,
+    #[error("Unknown sessionserver error: {0}")]
+    Unknown(String),
+    #[error("Unexpected response from sessionserver (status code {status_code}): {body}")]
+    UnexpectedResponse { status_code: u16, body: String },
+}
+
+#[derive(Deserialize)]
+pub struct ForbiddenError {
+    pub error: String,
+    pub path: String,
+}
+
+/// Tell Mojang's servers that you are going to join a multiplayer server,
+/// which is required to join online-mode servers. The server ID is an empty
+/// string.
+pub async fn join(
+    access_token: &str,
+    public_key: &[u8],
+    private_key: &[u8],
+    uuid: &Uuid,
+    server_id: &str,
+) -> Result<(), SessionServerError> {
+    let client = reqwest::Client::new();
+
+    let server_hash = azalea_crypto::hex_digest(&azalea_crypto::digest_data(
+        server_id.as_bytes(),
+        public_key,
+        private_key,
+    ));
+
+    let mut encode_buffer = Uuid::encode_buffer();
+    let undashed_uuid = uuid.simple().encode_lower(&mut encode_buffer);
+
+    let data = json!({
+        "accessToken": access_token,
+        "selectedProfile": undashed_uuid,
+        "serverId": server_hash
+    });
+    println!("data: {:?}", data);
+    let res = client
+        .post("https://sessionserver.mojang.com/session/minecraft/join")
+        .json(&data)
+        .send()
+        .await?;
+
+    match res.status() {
+        reqwest::StatusCode::NO_CONTENT => Ok(()),
+        reqwest::StatusCode::FORBIDDEN => {
+            let forbidden = res.json::<ForbiddenError>().await?;
+            match forbidden.error.as_str() {
+                "InsufficientPrivilegesException" => Err(SessionServerError::MultiplayerDisabled),
+                "UserBannedException" => Err(SessionServerError::Banned),
+                _ => Err(SessionServerError::Unknown(forbidden.error)),
+            }
+        }
+        status_code => {
+            let body = res.text().await?;
+            Err(SessionServerError::UnexpectedResponse {
+                status_code: status_code.as_u16(),
+                body,
+            })
+        }
+    }
+}