Added configurable user agents that get served the text version by default

src/main.rs

@@ -5,11 +5,13 @@ use axum::{
 		State,
 		Extension,
 	},
+	headers,
 	http::Request,
 	middleware::{self, Next},
 	response::Response,
 	Router,
 	routing::get,
+	TypedHeader,
 };
 use axum_client_ip::SecureClientIp;
 use clap::Parser;
@@ -244,12 +246,26 @@ async fn main() {
 async fn format_and_language_middleware<B>(
 	Query(query): Query<BaseQuery>,
 	Extension(config): Extension<config::EchoIpServiceConfig>,
+	user_agent_header: Option<TypedHeader<headers::UserAgent>>,
 	mut req: Request<B>,
 	next: Next<B>
 ) -> Response {
-	let format = query.format.unwrap_or(ResponseFormat::TextHtml);
+	let mut format = query.format;
+	// Try to guess type from user agent
+	if format.is_none() {
+		if let Some(TypedHeader(user_agent)) = user_agent_header {
+			let ua = user_agent.as_str();
+			for tua in config.template.text_user_agents {
+				if ua.starts_with(&tua) {
+					format = Some(ResponseFormat::TextPlain);
+					break;
+				}
+			}
+		}
+	}
+	// Add the request settings extension
 	req.extensions_mut().insert(TemplateSettings{
-		format: format,
+		format: format.unwrap_or(ResponseFormat::TextHtml),
 		lang: query.lang.unwrap_or("en".to_string()),
 	});
 	next.run(req).await