From c5e3fcfc99f7a1810bc1fddcafa1af97500eea96 Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <me@steffo.eu>
Date: Sat, 9 Nov 2024 11:01:26 +0100
Subject: [PATCH] Create crate

---
 acrate-nodeinfo/src/lib.rs | 146 ++++++++++++++++++++++++++++++++++---
 1 file changed, 135 insertions(+), 11 deletions(-)

diff --git a/acrate-nodeinfo/src/lib.rs b/acrate-nodeinfo/src/lib.rs
index b93cf3f..c43fef7 100644
--- a/acrate-nodeinfo/src/lib.rs
+++ b/acrate-nodeinfo/src/lib.rs
@@ -1,14 +1,138 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
+use serde::Deserialize;
+
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct Discovery {
+	pub links: Vec<DiscoveryDocument>,
 }
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
+#[derive(Debug, Clone, Deserialize)]
+pub struct DiscoveryDocument {
+	pub rel: String,
+	pub href: String,
+}
+
+impl Discovery {
+	pub async fn get(url: reqwest::Url) -> Result<Self, DiscoveryGetError> {
+		use DiscoveryGetError::*;
+
+		log::debug!("Getting nodeinfo discovery at: {url}");
+
+		log::trace!("Sending GET request to: {url}");
+		let response = reqwest::get(url)
+			.await
+			.map_err(Request)?;
+
+		log::trace!("Checking headers of the response...");
+		response
+			.headers()
+			.get("Content-Type")
+			.ok_or(ContentTypeMissing)?
+			.eq("application/json")
+			.then_some(())
+			.ok_or(ContentTypeInvalid)?;
+
+		log::trace!("Attempting to parse nodeinfo discovery as JSON...");
+		let data = response.json::<Self>()
+			.await
+			.map_err(Parse)?;
+
+		Ok(data)
+	}
+
+	const WELLKNOWN_DISCOVERY_PATH: &str = "/.well-known/nodeinfo";
+
+	pub async fn discover(base: &reqwest::Url) -> Result<Self, DiscoveryDiscoverError> {
+		use DiscoveryDiscoverError::*;
+
+		log::debug!("Discovering nodeinfo at base: {base}");
+
+		let mut url = base.clone();
+
+		let path = Self::WELLKNOWN_DISCOVERY_PATH;
+		log::trace!("Setting URL path to `{path}`...");
+		url.set_path(path);
+
+		log::trace!("Unsetting URL query...");
+		url.set_query(None);
+
+		log::trace!("Unsetting URL fragment...");
+		url.set_fragment(None);
+
+		log::trace!("Setting URL scheme to HTTPS...");
+		url.set_scheme("https")
+			.map_err(UrlManipulation)?;
+
+		log::trace!("Attempting to retrieve nodeinfo via HTTPS...");
+		let https = Self::get(url.clone())
+			.await;
+
+		let https = match https {
+			Ok(data) => {
+				log::trace!("HTTPS retrieval was successful, returning...");
+				return Ok(data)
+			}
+			Err(err) => {
+				log::warn!("HTTPS retrieval failed.");
+				err
+			}
+		};
+
+		log::trace!("Setting URL scheme to HTTP...");
+		url.set_scheme("http")
+			.map_err(UrlManipulation)?;
+
+		log::trace!("Attempting to retrieve nodeinfo via HTTP...");
+		let http = Self::get(url.clone())
+			.await;
+
+		let http = match http {
+			Ok(data) => {
+				log::trace!("HTTP retrieval was successful, returning...");
+				return Ok(data)
+			}
+			Err(err) => {
+				log::warn!("HTTP retrieval failed.");
+				err
+			}
+		};
+
+		Err(
+			DiscoveryDiscoverError::Fetch(
+				DiscoveryDiscoverAttemptsErrors { 
+					https, 
+					http,
+				}
+			)
+		)
+	}
+}
+
+pub enum DiscoveryGetError {
+	/// The HTTP request failed.
+	Request(reqwest::Error),
+	/// The `Content-Type` header of the response is missing.
+	ContentTypeMissing,
+	/// The `Content-Type` header of the response is invalid.
+	ContentTypeInvalid,
+	/// The JSON document failed to be parsed.
+	Parse(reqwest::Error),
+}
+
+pub enum DiscoveryDiscoverError {
+	/// Manipulation of the URL scheme of the given base failed.
+	/// 
+	/// See [reqwest::Url::set_scheme] for possible causes.
+	UrlManipulation(()),
+
+	/// All attempts of fetching the discovery metadata failed.
+	Fetch(DiscoveryDiscoverAttemptsErrors),
+}
+
+pub struct DiscoveryDiscoverAttemptsErrors {
+	/// The error occurred during the HTTPS request.
+	pub https: DiscoveryGetError,
+
+	/// The error occurred during the HTTP request.
+	pub http: DiscoveryGetError,
 }