From 7aff2e1d279a4e442b32f49ca0a0eca065355787 Mon Sep 17 00:00:00 2001
From: murilo ijanc
Date: Wed, 25 Mar 2026 02:07:37 -0300
Subject: Initial commit: tesseras-paste decentralized pastebin

DHT-backed encrypted pastebin with two binaries (tp/tpd),
XChaCha20-Poly1305 encryption, content-addressed storage,
and Unix socket + HTTP interfaces.
---
 src/protocol.rs | 173 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 src/protocol.rs

(limited to 'src/protocol.rs')

diff --git a/src/protocol.rs b/src/protocol.rs
new file mode 100644
index 0000000..d45cdd8
--- /dev/null
+++ b/src/protocol.rs
@@ -0,0 +1,173 @@
+//! Unix socket protocol for daemon ↔ CLI.
+//!
+//! Simple line-oriented text protocol:
+//!   PUT <ttl_secs> <content>\n
+//!   PUTP <ttl_secs> <content>\n
+//!   GET <key>\n
+//!   DEL <key>\n
+//!   PIN <key>\n
+//!   UNPIN <key>\n
+//!   STATUS\n
+//!   SHUTDOWN\n
+//!
+//! Responses:
+//!   OK <data>\n
+//!   ERR <message>\n
+
+/// A parsed request received from the CLI over the Unix socket.
+pub enum Request {
+    Put {
+        ttl_secs: u64,
+        content_b58: String,
+        encrypt: bool,
+    },
+    Get {
+        key: String,
+    },
+    Del {
+        key: String,
+    },
+    Pin {
+        key: String,
+    },
+    Unpin {
+        key: String,
+    },
+    Status,
+    Shutdown,
+}
+
+/// A response sent back to the CLI over the Unix socket.
+pub enum Response {
+    Ok(String),
+    Err(String),
+}
+
+/// Parse a single protocol line into a [`Request`].
+pub fn parse_request(line: &str) -> Result<Request, String> {
+    let line = line.trim();
+    if line.is_empty() {
+        return Err("empty request".into());
+    }
+
+    let mut parts = line.splitn(3, ' ');
+    let cmd = parts.next().unwrap();
+
+    match cmd {
+        "PUT" | "PUTP" => {
+            let ttl_str =
+                parts.next().ok_or("PUT requires: PUT <ttl> <data>")?;
+            let content_b58 =
+                parts.next().ok_or("PUT requires: PUT <ttl> <data>")?;
+            let ttl_secs: u64 =
+                ttl_str.parse().map_err(|_| "invalid TTL number")?;
+            Ok(Request::Put {
+                ttl_secs,
+                content_b58: content_b58.to_string(),
+                encrypt: cmd == "PUT",
+            })
+        }
+        "GET" => {
+            let key = parts.next().ok_or("GET requires: GET <key>")?;
+            Ok(Request::Get {
+                key: key.to_string(),
+            })
+        }
+        "DEL" => {
+            let key = parts.next().ok_or("DEL requires: DEL <key>")?;
+            Ok(Request::Del {
+                key: key.to_string(),
+            })
+        }
+        "PIN" => {
+            let key = parts.next().ok_or("PIN requires: PIN <key>")?;
+            Ok(Request::Pin {
+                key: key.to_string(),
+            })
+        }
+        "UNPIN" => {
+            let key = parts.next().ok_or("UNPIN requires: UNPIN <key>")?;
+            Ok(Request::Unpin {
+                key: key.to_string(),
+            })
+        }
+        "STATUS" => Ok(Request::Status),
+        "SHUTDOWN" => Ok(Request::Shutdown),
+        _ => Err(format!("unknown command: {cmd}")),
+    }
+}
+
+/// Serialize a [`Response`] into a protocol line (`OK ...\n` or `ERR ...\n`).
+pub fn format_response(r: &Response) -> String {
+    match r {
+        Response::Ok(data) => format!("OK {data}\n"),
+        Response::Err(msg) => format!("ERR {msg}\n"),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parse_put() {
+        let r = parse_request("PUT 3600 deadbeef").unwrap();
+        match r {
+            Request::Put {
+                ttl_secs,
+                content_b58,
+                encrypt,
+            } => {
+                assert_eq!(ttl_secs, 3600);
+                assert_eq!(content_b58, "deadbeef");
+                assert!(encrypt);
+            }
+            _ => panic!("expected Put"),
+        }
+    }
+
+    #[test]
+    fn parse_putp() {
+        let r = parse_request("PUTP 60 abc").unwrap();
+        match r {
+            Request::Put { encrypt, .. } => assert!(!encrypt),
+            _ => panic!("expected Put"),
+        }
+    }
+
+    #[test]
+    fn parse_get() {
+        let r = parse_request("GET abc123#key456").unwrap();
+        match r {
+            Request::Get { key } => assert_eq!(key, "abc123#key456"),
+            _ => panic!("expected Get"),
+        }
+    }
+
+    #[test]
+    fn parse_status() {
+        assert!(matches!(parse_request("STATUS").unwrap(), Request::Status));
+    }
+
+    #[test]
+    fn parse_empty_fails() {
+        assert!(parse_request("").is_err());
+    }
+
+    #[test]
+    fn parse_unknown_fails() {
+        assert!(parse_request("FOOBAR").is_err());
+    }
+
+    #[test]
+    fn format_ok() {
+        let r = format_response(&Response::Ok("hello".into()));
+        assert_eq!(r, "OK hello\n");
+    }
+
+    #[test]
+    fn format_err() {
+        let r = format_response(&Response::Err("oops".into()));
+        assert_eq!(r, "ERR oops\n");
+    }
+}
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