Merge pull request #200 from ikatson/decode-torrent

[Feature] Decode torrent as JSON in the /torrents/resolve_magnet API

crates/bencode/src/bencode_value.rs

@@ -1,9 +1,9 @@
-use std::{collections::HashMap, marker::PhantomData};
+use std::{collections::HashMap, fmt::Display, marker::PhantomData};
 
 use buffers::{ByteBuf, ByteBufOwned};
 use bytes::Bytes;
 use clone_to_owned::CloneToOwned;
-use serde::Deserializer;
+use serde::{Deserialize, Deserializer, Serialize};
 
 use crate::serde_bencode_de::from_bytes;
 
@@ -136,6 +136,44 @@ where
 pub type BencodeValueBorrowed<'a> = BencodeValue<ByteBuf<'a>>;
 pub type BencodeValueOwned = BencodeValue<ByteBufOwned>;
 
+// A wrapper to deserialize dyn values as strings.
+#[derive(PartialEq, Eq, Hash)]
+pub struct AsDisplay<T>(T);
+
+impl<'de, T> From<&'de [u8]> for AsDisplay<T>
+where
+    T: From<&'de [u8]>,
+{
+    fn from(value: &'de [u8]) -> Self {
+        Self(T::from(value))
+    }
+}
+
+impl<T> Serialize for AsDisplay<T>
+where
+    T: Display,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&format!("{}", self.0))
+    }
+}
+
+impl<'de, T> Deserialize<'de> for AsDisplay<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value = T::deserialize(deserializer)?;
+        Ok(AsDisplay(value))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::serde_bencode_ser::bencode_serialize_to_writer;

crates/buffers/src/lib.rs

@@ -42,6 +42,9 @@ impl<'a> std::fmt::Display for HexBytes<'a> {
 }
 
 fn debug_bytes(b: &[u8], f: &mut std::fmt::Formatter<'_>, debug_strings: bool) -> std::fmt::Result {
+    if b.is_empty() {
+        return Ok(());
+    }
     if b.iter().all(|b| *b == 0) {
         return write!(f, "<{} bytes, all zeroes>", b.len());
     }

crates/librqbit/src/http_api.rs

@@ -3,6 +3,8 @@ use axum::body::Bytes;
 use axum::extract::{Path, Query, State};
 use axum::response::IntoResponse;
 use axum::routing::{get, post};
+use bencode::AsDisplay;
+use buffers::ByteBuf;
 use futures::future::BoxFuture;
 use futures::{FutureExt, TryStreamExt};
 use http::{HeaderMap, HeaderValue, StatusCode};
@@ -190,6 +192,7 @@ impl HttpApi {
 
         async fn resolve_magnet(
             State(state): State<ApiState>,
+            inp_headers: HeaderMap,
             url: String,
         ) -> Result<impl IntoResponse> {
             let added = state
@@ -219,7 +222,21 @@ impl HttpApi {
                     ))
                 }
             };
+
             let mut headers = HeaderMap::new();
+
+            if inp_headers
+                .get("Accept")
+                .and_then(|v| std::str::from_utf8(v.as_bytes()).ok())
+                == Some("application/json")
+            {
+                let data = bencode::dyn_from_bytes::<AsDisplay<ByteBuf>>(&content)
+                    .context("error decoding .torrent file content")?;
+                let data = serde_json::to_string(&data).context("error serializing")?;
+                headers.insert("Content-Type", HeaderValue::from_static("application/json"));
+                return Ok((headers, data).into_response());
+            }
+
             headers.insert(
                 "Content-Type",
                 HeaderValue::from_static("application/x-bittorrent"),
@@ -234,7 +251,7 @@ impl HttpApi {
                     }
                 }
             }
-            Ok((headers, content))
+            Ok((headers, content).into_response())
         }
 
         async fn torrent_playlist(