Implement instance info endpoint (JSON, YAML, TXT) (#685)

Co-authored-by: Daniel Valentine <daniel@vielle.ws>
Co-authored-by: spikecodes <19519553+spikecodes@users.noreply.github.com>

src/config.rs

@@ -1,4 +1,5 @@
 use once_cell::sync::Lazy;
+use serde::{Deserialize, Serialize};
 use std::{env::var, fs::read_to_string};
 
 // Waiting for https://github.com/rust-lang/rust/issues/74465 to land, so we
@@ -6,44 +7,53 @@ use std::{env::var, fs::read_to_string};
 //
 // This is the local static that is initialized at runtime (technically at
 // first request) and contains the instance settings.
-static CONFIG: Lazy<Config> = Lazy::new(Config::load);
+pub(crate) static CONFIG: Lazy<Config> = Lazy::new(Config::load);
 
 /// Stores the configuration parsed from the environment variables and the
 /// config file. `Config::Default()` contains None for each setting.
-#[derive(Default, serde::Deserialize)]
+/// When adding more config settings, add it to `Config::load`,
+/// `get_setting_from_config`, both below, as well as
+/// instance_info::InstanceInfo.to_string(), README.md and app.json.
+#[derive(Default, Serialize, Deserialize, Clone)]
 pub struct Config {
 	#[serde(rename = "LIBREDDIT_SFW_ONLY")]
-	sfw_only: Option<String>,
+	pub(crate) sfw_only: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_THEME")]
-	default_theme: Option<String>,
+	pub(crate) default_theme: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_FRONT_PAGE")]
-	default_front_page: Option<String>,
+	pub(crate) default_front_page: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_LAYOUT")]
-	default_layout: Option<String>,
+	pub(crate) default_layout: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_WIDE")]
-	default_wide: Option<String>,
+	pub(crate) default_wide: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_COMMENT_SORT")]
-	default_comment_sort: Option<String>,
+	pub(crate) default_comment_sort: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_POST_SORT")]
-	default_post_sort: Option<String>,
+	pub(crate) default_post_sort: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_SHOW_NSFW")]
-	default_show_nsfw: Option<String>,
+	pub(crate) default_show_nsfw: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_BLUR_NSFW")]
-	default_blur_nsfw: Option<String>,
+	pub(crate) default_blur_nsfw: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_USE_HLS")]
-	default_use_hls: Option<String>,
+	pub(crate) default_use_hls: Option<String>,
 
 	#[serde(rename = "LIBREDDIT_DEFAULT_HIDE_HLS_NOTIFICATION")]
-	default_hide_hls_notification: Option<String>,
+	pub(crate) default_hide_hls_notification: Option<String>,
+
+	#[serde(rename = "LIBREDDIT_DEFAULT_HIDE_AWARDS")]
+	pub(crate) default_hide_awards: Option<String>,
+
+	#[serde(rename = "LIBREDDIT_BANNER")]
+	pub(crate) banner: Option<String>,
 }
 
 impl Config {
@@ -70,6 +80,8 @@ impl Config {
 			default_blur_nsfw: parse("LIBREDDIT_DEFAULT_BLUR_NSFW"),
 			default_use_hls: parse("LIBREDDIT_DEFAULT_USE_HLS"),
 			default_hide_hls_notification: parse("LIBREDDIT_DEFAULT_HIDE_HLS"),
+			default_hide_awards: parse("LIBREDDIT_DEFAULT_HIDE_AWARDS"),
+			banner: parse("LIBREDDIT_BANNER"),
 		}
 	}
 }
@@ -87,6 +99,8 @@ fn get_setting_from_config(name: &str, config: &Config) -> Option<String> {
 		"LIBREDDIT_DEFAULT_USE_HLS" => config.default_use_hls.clone(),
 		"LIBREDDIT_DEFAULT_HIDE_HLS_NOTIFICATION" => config.default_hide_hls_notification.clone(),
 		"LIBREDDIT_DEFAULT_WIDE" => config.default_wide.clone(),
+		"LIBREDDIT_DEFAULT_HIDE_AWARDS" => config.default_hide_awards.clone(),
+		"LIBREDDIT_BANNER" => config.banner.clone(),
 		_ => None,
 	}
 }

src/instance_info.rs

@@ -0,0 +1,205 @@
+use crate::{
+	config::{Config, CONFIG},
+	server::RequestExt,
+	utils::{ErrorTemplate, Preferences},
+};
+use askama::Template;
+use build_html::{Container, Html, HtmlContainer, Table};
+use hyper::{http::Error, Body, Request, Response};
+use once_cell::sync::Lazy;
+use serde::{Deserialize, Serialize};
+use time::OffsetDateTime;
+
+// This is the local static that is intialized at runtime (technically at
+// the first request to the info endpoint) and contains the data
+// retrieved from the info endpoint.
+pub(crate) static INSTANCE_INFO: Lazy<InstanceInfo> = Lazy::new(InstanceInfo::new);
+
+/// Handles instance info endpoint
+pub async fn instance_info(req: Request<Body>) -> Result<Response<Body>, String> {
+	// This will retrieve the extension given, or create a new string - which will
+	// simply become the last option, an HTML page.
+	let extension = req.param("extension").unwrap_or(String::new());
+	let response = match extension.as_str() {
+		"yaml" | "yml" => info_yaml(),
+		"txt" => info_txt(),
+		"json" => info_json(),
+		"html" | "" => info_html(req),
+		_ => {
+			let error = ErrorTemplate {
+				msg: "Error: Invalid info extension".into(),
+				prefs: Preferences::new(&req),
+				url: req.uri().to_string(),
+			}
+			.render()
+			.unwrap();
+			Response::builder().status(404).header("content-type", "text/html; charset=utf-8").body(error.into())
+		}
+	};
+	response.map_err(|err| format!("{err}"))
+}
+
+fn info_json() -> Result<Response<Body>, Error> {
+	if let Ok(body) = serde_json::to_string(&*INSTANCE_INFO) {
+		Response::builder().status(200).header("content-type", "application/json").body(body.into())
+	} else {
+		Response::builder()
+			.status(500)
+			.header("content-type", "text/plain")
+			.body(Body::from("Error serializing JSON"))
+	}
+}
+
+fn info_yaml() -> Result<Response<Body>, Error> {
+	if let Ok(body) = serde_yaml::to_string(&*INSTANCE_INFO) {
+		// We can use `application/yaml` as media type, though there is no guarantee
+		// that browsers will honor it. But we'll do it anyway. See:
+		// https://github.com/ietf-wg-httpapi/mediatypes/blob/main/draft-ietf-httpapi-yaml-mediatypes.md#media-type-applicationyaml-application-yaml
+		Response::builder().status(200).header("content-type", "application/yaml").body(body.into())
+	} else {
+		Response::builder()
+			.status(500)
+			.header("content-type", "text/plain")
+			.body(Body::from("Error serializing YAML."))
+	}
+}
+
+fn info_txt() -> Result<Response<Body>, Error> {
+	Response::builder()
+		.status(200)
+		.header("content-type", "text/plain")
+		.body(Body::from(INSTANCE_INFO.to_string(StringType::Raw)))
+}
+fn info_html(req: Request<Body>) -> Result<Response<Body>, Error> {
+	let message = MessageTemplate {
+		title: String::from("Instance information"),
+		body: INSTANCE_INFO.to_string(StringType::Html),
+		prefs: Preferences::new(&req),
+		url: req.uri().to_string(),
+	}
+	.render()
+	.unwrap();
+	Response::builder().status(200).header("content-type", "text/html; charset=utf8").body(Body::from(message))
+}
+#[derive(Serialize, Deserialize, Default)]
+pub(crate) struct InstanceInfo {
+	crate_version: String,
+	git_commit: String,
+	deploy_date: String,
+	compile_mode: String,
+	deploy_unix_ts: i64,
+	config: Config,
+}
+
+impl InstanceInfo {
+	pub fn new() -> Self {
+		Self {
+			crate_version: env!("CARGO_PKG_VERSION").to_string(),
+			git_commit: env!("GIT_HASH").to_string(),
+			deploy_date: OffsetDateTime::now_local().unwrap_or_else(|_| OffsetDateTime::now_utc()).to_string(),
+			#[cfg(debug_assertions)]
+			compile_mode: "Debug".into(),
+			#[cfg(not(debug_assertions))]
+			compile_mode: "Release".into(),
+			deploy_unix_ts: OffsetDateTime::now_local().unwrap_or_else(|_| OffsetDateTime::now_utc()).unix_timestamp(),
+			config: CONFIG.clone(),
+		}
+	}
+	fn to_table(&self) -> String {
+		let mut container = Container::default();
+		let convert = |o: &Option<String>| -> String { o.clone().unwrap_or("<span class=\"unset\"><i>Unset</i></span>".to_owned()) };
+		if let Some(banner) = &self.config.banner {
+			container.add_header(3, "Instance banner");
+			container.add_raw("<br />");
+			container.add_paragraph(banner);
+			container.add_raw("<br />");
+		}
+		container.add_table(
+			Table::from([
+				["Crate version", &self.crate_version],
+				["Git commit", &self.git_commit],
+				["Deploy date", &self.deploy_date],
+				["Deploy timestamp", &self.deploy_unix_ts.to_string()],
+				["Compile mode", &self.compile_mode],
+				["SFW only", &convert(&self.config.sfw_only)],
+			])
+			.with_header_row(["Settings"]),
+		);
+		container.add_raw("<br />");
+		container.add_table(
+			Table::from([
+				["Hide awards", &convert(&self.config.default_hide_awards)],
+				["Theme", &convert(&self.config.default_theme)],
+				["Front page", &convert(&self.config.default_front_page)],
+				["Layout", &convert(&self.config.default_layout)],
+				["Wide", &convert(&self.config.default_wide)],
+				["Comment sort", &convert(&self.config.default_comment_sort)],
+				["Post sort", &convert(&self.config.default_post_sort)],
+				["Show NSFW", &convert(&self.config.default_show_nsfw)],
+				["Blur NSFW", &convert(&self.config.default_blur_nsfw)],
+				["Use HLS", &convert(&self.config.default_use_hls)],
+				["Hide HLS notification", &convert(&self.config.default_hide_hls_notification)],
+			])
+			.with_header_row(["Default preferences"]),
+		);
+		container.to_html_string().replace("<th>", "<th colspan=\"2\">")
+	}
+	fn to_string(&self, string_type: StringType) -> String {
+		match string_type {
+			StringType::Raw => {
+				format!(
+					"Crate version: {}\n
+                Git commit: {}\n
+                Deploy date: {}\n
+                Deploy timestamp: {}\n
+                Compile mode: {}\n
+                Config:\n
+                    Banner: {:?}\n
+                    Hide awards: {:?}\n
+                    SFW only: {:?}\n
+                    Default theme: {:?}\n
+                    Default front page: {:?}\n
+                    Default layout: {:?}\n
+                    Default wide: {:?}\n
+                    Default comment sort: {:?}\n
+                    Default post sort: {:?}\n
+                    Default show NSFW: {:?}\n
+                    Default blur NSFW: {:?}\n
+                    Default use HLS: {:?}\n
+                    Default hide HLS notification: {:?}\n",
+					self.crate_version,
+					self.git_commit,
+					self.deploy_date,
+					self.deploy_unix_ts,
+					self.compile_mode,
+					self.config.banner,
+					self.config.default_hide_awards,
+					self.config.sfw_only,
+					self.config.default_theme,
+					self.config.default_front_page,
+					self.config.default_layout,
+					self.config.default_wide,
+					self.config.default_comment_sort,
+					self.config.default_post_sort,
+					self.config.default_show_nsfw,
+					self.config.default_blur_nsfw,
+					self.config.default_use_hls,
+					self.config.default_hide_hls_notification
+				)
+			}
+			StringType::Html => self.to_table(),
+		}
+	}
+}
+enum StringType {
+	Raw,
+	Html,
+}
+#[derive(Template)]
+#[template(path = "message.html")]
+struct MessageTemplate {
+	title: String,
+	body: String,
+	prefs: Preferences,
+	url: String,
+}

src/main.rs

@@ -5,6 +5,7 @@
 // Reference local files
 mod config;
 mod duplicates;
+mod instance_info;
 mod post;
 mod search;
 mod settings;
@@ -20,6 +21,7 @@ use hyper::{header::HeaderValue, Body, Request, Response};
 
 mod client;
 use client::{canonical_path, proxy};
+use once_cell::sync::Lazy;
 use server::RequestExt;
 use utils::{error, redirect, ThemeAssets};
 
@@ -158,6 +160,13 @@ async fn main() {
 	// Begin constructing a server
 	let mut app = server::Server::new();
 
+	// Force evaluation of statics. In instance_info case, we need to evaluate
+	// the timestamp so deploy date is accurate - in config case, we need to 
+	// evaluate the configuration to avoid paying penalty at first request.
+
+	Lazy::force(&config::CONFIG);
+	Lazy::force(&instance_info::INSTANCE_INFO);
+
 	// Define default headers (added to all responses)
 	app.default_headers = headers! {
 		"Referrer-Policy" => "no-referrer",
@@ -285,6 +294,10 @@ async fn main() {
 	// Handle about pages
 	app.at("/about").get(|req| error(req, "About pages aren't added yet".to_string()).boxed());
 
+	// Instance info page
+	app.at("/info").get(|r| instance_info::instance_info(r).boxed());
+	app.at("/info.:extension").get(|r| instance_info::instance_info(r).boxed());
+
 	app.at("/:id").get(|req: Request<Body>| {
 		Box::pin(async move {
 			match req.param("id").as_deref() {