docs: add doc-comments to client::response

src/client/response.rs

@@ -1,3 +1,5 @@
+//! Client-side response structure
+
 use crate::{status::Status, LibError, ReplyType};
 
 use bytes::Bytes;
@@ -5,6 +7,8 @@ use tokio::io::AsyncReadExt;
 
 type BodyStream = tokio::io::BufReader<tokio_rustls::client::TlsStream<tokio::net::TcpStream>>;
 
+/// Client-side response structure wrapping a [`Status`],
+/// a metadata string and a TLS stream
 #[derive(Debug)]
 pub struct Response {
     status: Status,
@@ -21,11 +25,25 @@ impl Response {
         }
     }
 
+    /// Check if status code is 2x (success).
     #[inline]
     pub fn is_ok(&self) -> bool {
         self.status.reply_type() == ReplyType::Success
     }
 
+    /// Return `Ok(self)` if status code is 2x, otherwise `Err(self)`.
+    ///
+    /// # Examples
+    /// ```
+    /// match client.request("gemini://dc09.ru").await?.ensure_ok() {
+    ///     Ok(resp) => {
+    ///         println!("{}", resp.text().await?);
+    ///     }
+    ///     Err(resp) => {
+    ///         println!("{}", resp.message());
+    ///     }
+    /// }
+    /// ```
     pub fn ensure_ok(self) -> Result<Self, Self> {
         if self.status.reply_type() == ReplyType::Success {
             Ok(self)
@@ -34,28 +52,49 @@ impl Response {
         }
     }
 
+    /// Get the response status code as [`Status`].
     pub fn status(&self) -> Status {
         self.status
     }
 
+    /// Get the response metadata -- the text after a status code + space.
+    /// - In 1x responses (input), it contains an input prompt message.
+    /// - In 2x responses (success), it contains a MIME type of the body.
+    /// - In 3x responses (redirect), it contains a URL.
+    /// - In 4x, 5x (fail), 6x (auth), it contains an error message.
     pub fn message(&self) -> &str {
         &self.message
     }
 
+    /// Get the response body MIME type by parsing the metadata field.
+    /// If you call this method on a non-2x response, you'll get a parse error.
+    /// It's strongly recommended to check the status code first
+    /// (most handy is [`Response::is_ok()`]).
     pub fn mime(&self) -> Result<mime::Mime, LibError> {
         self.message.parse().map_err(LibError::InvalidMime)
     }
 
+    /// Borrow the wrapped TLS stream as `&mut`.
+    ///
+    /// # Reminder
+    /// You can read data from one stream only once,
+    /// so calling `.bytes()` after `.stream().read_to_end(…)`
+    /// (or `.bytes()` twice, or `.text()` after `.bytes()` and vice versa)
+    /// on the same response will result in empty output.
     pub fn stream(&mut self) -> &mut BodyStream {
         &mut self.stream
     }
 
+    /// Read the whole response body and return as [`Bytes`].
+    /// See also [the note](#reminder) to `stream()`.
     pub async fn bytes(&mut self) -> Result<Bytes, LibError> {
         let mut buf = Vec::new();
         self.stream.read_to_end(&mut buf).await?;
         Ok(Bytes::from(buf))
     }
 
+    /// Read the whole response body as a UTF-8 [`String`].
+    /// See also [the note](#reminder) to `stream()`.
     pub async fn text(&mut self) -> Result<String, LibError> {
         let mut buf = String::new();
         self.stream.read_to_string(&mut buf).await?;