Made changes including POST-to-GET CORS proxy in order to get NGINX site HTML and disabled CORS for the API.

src/main/java/tech/nevets/ngxinstaller/Server.java

@@ -4,6 +4,11 @@ import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonObject;
 
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.util.Timer;
 import java.util.TimerTask;
 
@@ -11,17 +16,62 @@ import static spark.Spark.*;
 
 public class Server {
     private static final Gson GSON = new GsonBuilder().setPrettyPrinting().create();
+    public static String cachedNginxSite = "";
     public static void main(String[] args) {
+        try {
+            cachedNginxSite = getHTML("https://nginx.org/download/");
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
         port(8080);
+        options("/*",
+                (request, response) -> {
+
+                    String accessControlRequestHeaders = request
+                            .headers("Access-Control-Request-Headers");
+                    if (accessControlRequestHeaders != null) {
+                        response.header("Access-Control-Allow-Headers",
+                                accessControlRequestHeaders);
+                    }
+
+                    String accessControlRequestMethod = request
+                            .headers("Access-Control-Request-Method");
+                    if (accessControlRequestMethod != null) {
+                        response.header("Access-Control-Allow-Methods",
+                                accessControlRequestMethod);
+                    }
+
+                    return "OK";
+                });
+
+        before((request, response) -> response.header("Access-Control-Allow-Origin", "*"));
+        post("/ngx/dhv", (req, res) -> {
+            System.out.println(req.body());
+            JsonObject jsonObject = GSON.fromJson(req.body(), JsonObject.class);
+            String version = jsonObject.get("version").getAsString();
+            System.out.println(version);
+            try {
+                if (cachedNginxSite.contains(version + ".tar.gz")) {
+                    System.out.println("true");
+                    return "{ \"url\":\"true\" }";
+                }
+            } catch (Exception ignore) {
+                System.out.println("false");
+                return "{ \"url\":\"false\" }";
+            }
+            System.out.println("false");
+            return "{ \"url\":\"false\" }";
+        });
         post("/ngx/create", (req, res) -> {
             JsonObject jsonObject = GSON.fromJson(req.body(), JsonObject.class);
-            TextStorage ts = TextStorage.createPaste(jsonObject.get("content").getAsString());
+            TextStorage ts = TextStorage.createPaste(java.net.URLDecoder.decode(jsonObject.get("content").getAsString(), StandardCharsets.UTF_8));
             return "{ \"url\":\"https://api.nevets.tech/ngx/raw/" + ts.getId() + "\" }";
         });
         get("/ngx/raw/*", (req, res) -> {
             String id = req.splat()[0];
             TextStorage ts = TextStorage.getPaste(id);
-            return GSON.toJson(ts);
+            res.type("raw");
+            return ts.getText();
         });
 
 
@@ -30,6 +80,21 @@ public class Server {
         timer.schedule(tt, 0, 60000);
     }
 
+    public static String getHTML(String urlToRead) throws Exception {
+        StringBuilder result = new StringBuilder();
+        URL url = new URL(urlToRead);
+        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+        conn.setRequestMethod("GET");
+        try (BufferedReader reader = new BufferedReader(
+                new InputStreamReader(conn.getInputStream()))) {
+            for (String line; (line = reader.readLine()) != null; ) {
+                result.append(line);
+            }
+        }
+        return result.toString();
+    }
+
+
     static class GCTask extends TimerTask {
         @Override
         public void run() {

src/main/java/tech/nevets/ngxinstaller/TextStorage.java

@@ -19,6 +19,10 @@ public class TextStorage {
         this.expiration = expiration;
     }
 
+    public String getText() {
+        return text;
+    }
+
     public String getId() {
         return this.id;
     }