Implement the capability to output the answer as clear text if the re…

…quest originates from cURL

Implement the capability to output the answer as clear text if the request originates from cURL.

* Check if the request originates from cURL by inspecting the `User-Agent` header.
* Format the crawled services data as plain text for cURL requests.
* Output the answer as clear text if the request originates from cURL.
* Continue to render the HTML template for non-cURL requests.

---

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fastside/src/routes/index.rs

@@ -38,6 +38,7 @@ pub struct IndexTemplate<'a> {
 
 #[get("/")]
 async fn index(
+    req: web::HttpRequest,
     crawler: web::Data<Crawler>,
     loaded_data: web::Data<RwLock<LoadedData>>,
 ) -> actix_web::Result<impl Responder> {
@@ -46,6 +47,30 @@ async fn index(
         return Err(RedirectError::from(SearchError::CrawlerNotFetchedYet))?;
     };
     let loaded_data_guard = loaded_data.read().await;
+
+    let user_agent = req
+        .headers()
+        .get("User-Agent")
+        .and_then(|ua| ua.to_str().ok())
+        .unwrap_or("");
+
+    if user_agent.contains("curl") {
+        let mut plain_text_output = String::new();
+        for (service_name, service) in &crawled_services.services {
+            plain_text_output.push_str(&format!("Service: {}\n", service_name));
+            for instance in &service.instances {
+                plain_text_output.push_str(&format!(
+                    "  Instance: {}\n  Status: {:?}\n  Tags: {:?}\n",
+                    instance.url, instance.status, instance.tags
+                ));
+            }
+            plain_text_output.push('\n');
+        }
+        return Ok(actix_web::HttpResponse::Ok()
+            .content_type("text/plain; charset=utf-8")
+            .body(plain_text_output));
+    }
+
     let template = IndexTemplate {
         services: &loaded_data_guard.services,
         crawled_services: &crawled_services.services,