provide metadata map (#9)

This evolves our implementation of providing addtional context to
messages by introducing an optional metadata parameter to message
creation.

Cargo.toml

@@ -17,6 +17,7 @@ axum-core = "0.4.3"
 http = "1.0.0"
 parking_lot = "0.12.1"
 serde = { version = "1.0.195", features = ["derive"] }
+serde_json = "1"
 tower = "0.4"
 tower-sessions-core = "0.11.0"
 

src/lib.rs

@@ -88,6 +88,9 @@ use tower_sessions_core::{session, Session};
 
 // N.B.: Code structure directly borrowed from `axum-flash`: https://github.com/davidpdrsn/axum-flash/blob/5e8b2bded97fd10bb275d5bc66f4d020dec465b9/src/lib.rs
 
+/// Mapping of key-value pairs which provide additional context to the message.
+pub type Metadata = HashMap<String, serde_json::Value>;
+
 /// Container for a message which provides a level and message content.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Message {
@@ -99,9 +102,9 @@ pub struct Message {
  #[serde(rename = "m")]
  pub message: String,
 
- /// adding extra args
- #[serde(rename = "a")]
- pub extra_args: HashMap<String, String>,
+ /// Additional context related to the message.
+ #[serde(rename = "d")]
+ pub metadata: Option<Metadata>,
 }
 
 impl fmt::Display for Message {
@@ -110,14 +113,6 @@ impl fmt::Display for Message {
  }
 }
 
-impl Message {
- /// adding extra arg to the message
- pub fn add_arg(mut self, name: String, value: impl Into<String>) -> Self {
- self.extra_args.insert(name, value.into());
- self
- }
-}
-
 type MessageQueue = VecDeque<Message>;
 
 /// Enumeration of message levels.
@@ -185,38 +180,67 @@ impl Messages {
 
  /// Push a `Debug` message.
  pub fn debug(self, message: impl Into<String>) -> Self {
- self.push(Level::Debug, message)
+ self.push(Level::Debug, message, None)
  }
 
  /// Push an `Info` message.
  pub fn info(self, message: impl Into<String>) -> Self {
- self.push(Level::Info, message)
+ self.push(Level::Info, message, None)
  }
 
  /// Push a `Success` message.
  pub fn success(self, message: impl Into<String>) -> Self {
- self.push(Level::Success, message)
+ self.push(Level::Success, message, None)
  }
 
  /// Push a `Warning` message.
  pub fn warning(self, message: impl Into<String>) -> Self {
- self.push(Level::Warning, message)
+ self.push(Level::Warning, message, None)
  }
 
  /// Push an `Error` message.
  pub fn error(self, message: impl Into<String>) -> Self {
- self.push(Level::Error, message)
+ self.push(Level::Error, message, None)
+ }
+
+ /// Push a `Debug` message with metadata.
+ pub fn debug_with_metadata(self, message: impl Into<String>, metadata: Metadata) -> Self {
+ self.push(Level::Debug, message, Some(metadata))
+ }
+
+ /// Push an `Info` message with metadata.
+ pub fn info_with_metadata(self, message: impl Into<String>, metadata: Metadata) -> Self {
+ self.push(Level::Info, message, Some(metadata))
+ }
+
+ /// Push a `Success` message with metadata.
+ pub fn success_with_metadata(self, message: impl Into<String>, metadata: Metadata) -> Self {
+ self.push(Level::Success, message, Some(metadata))
+ }
+
+ /// Push a `Warning` message with metadata.
+ pub fn warning_with_metadata(self, message: impl Into<String>, metadata: Metadata) -> Self {
+ self.push(Level::Warning, message, Some(metadata))
+ }
+
+ /// Push an `Error` message with metadata.
+ pub fn error_with_metadata(self, message: impl Into<String>, metadata: Metadata) -> Self {
+ self.push(Level::Error, message, Some(metadata))
  }
 
  /// Push a message with the given level.
- pub fn push(self, level: Level, message: impl Into<String>) -> Self {
+ pub fn push(
+ self,
+ level: Level,
+ message: impl Into<String>,
+ metadata: Option<Metadata>,
+ ) -> Self {
  {
  let mut data = self.data.lock();
  data.pending_messages.push_back(Message {
  message: message.into(),
  level,
- // default initial value for extra args
- extra_args: HashMap::new(),
+ metadata,
  });
  }
 
@@ -361,7 +385,7 @@ impl<S> Layer<S> for MessagesManagerLayer {
 #[cfg(test)]
 mod tests {
  use axum::{response::Redirect, routing::get, Router};
- use axum_core::{body::Body, extract::Request, response::IntoResponse};
+ use axum_core::{body::Body, response::IntoResponse};
  use http::header;
  use http_body_util::BodyExt;
  use tower::ServiceExt;
@@ -383,15 +407,18 @@ mod tests {
  async fn root(messages: Messages) -> impl IntoResponse {
  messages
  .into_iter()
- .map(|message| format!("{}: {}", message.level, message))
+ .map(|message| format!("{}: {} {:?}", message.level, message, message.metadata))
  .collect::<Vec<_>>()
  .join(", ")
  }
 
  #[axum::debug_handler]
  async fn set_message(messages: Messages) -> impl IntoResponse {
+ let mut metadata = Metadata::default();
+ metadata.insert("foo".to_string(), "bar".into());
+
  messages
- .debug("Hello, world!")
+ .debug_with_metadata("Hello, world!", metadata)
  .info("This is an info message.");
  Redirect::to("/")
  }
@@ -413,6 +440,10 @@ mod tests {
 
  let bytes = response.into_body().collect().await.unwrap().to_bytes();
  let body = String::from_utf8(bytes.to_vec()).unwrap();
- assert_eq!(body, "Debug: Hello, world!, Info: This is an info message.");
+ assert_eq!(
+ body,
+ "Debug: Hello, world! Some({\"foo\": String(\"bar\")}), Info: This is an info \
+ message. None"
+ );
  }
 }