[feature] save to one temp file and use uuid for file names

Author: marmoure

pom.xml

@@ -104,6 +104,13 @@
             <artifactId>csv-validator-java-api</artifactId>
             <version>1.4.1</version>
         </dependency>
+
+         <!-- https://mvnrepository.com/artifact/com.fasterxml.uuid/java-uuid-generator -->
+        <dependency>
+            <groupId>com.fasterxml.uuid</groupId>
+            <artifactId>java-uuid-generator</artifactId>
+            <version>5.2.0</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/com/evolvedbinary/bblValidator/controller/ValidateController.java

@@ -59,7 +59,7 @@ public ValidationResponse validateForm(@Body ValidationForm form) {
     public ValidationResponse validateCsv(@QueryValue("schema-id") String schemaId,
                                           @Body String csvContent) {
         try {
-            Path tempFile = fileDownloadService.saveContentToTemp(csvContent, "uploaded-content.csv");
+            Path tempFile = fileDownloadService.saveContentToTemp(csvContent);
             LOG.info("CSV content saved to: {}", tempFile);
             return performValidation(tempFile, schemaId);
         } catch (IOException e) {

src/main/java/com/evolvedbinary/bblValidator/service/FileDownloadService.java

@@ -1,5 +1,6 @@
 package com.evolvedbinary.bblValidator.service;
 
+import com.fasterxml.uuid.Generators;
 import jakarta.inject.Singleton;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -13,34 +14,45 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
+import java.util.UUID;
 
 @Singleton
 public class FileDownloadService {
 
     private static final Logger LOG = LoggerFactory.getLogger(FileDownloadService.class);
-    private static final String TEMP_DIR_PREFIX = "bbl-validator-";
-    private static final String DEFAULT_FILENAME = "downloaded-file.csv";
+    private static final String TEMP_DIR_NAME = "bbl-validator";
     private final HttpClient httpClient;
+    private final Path sharedTempDir;
 
     public FileDownloadService() {
         this.httpClient = HttpClient.newBuilder()
                 .followRedirects(HttpClient.Redirect.NORMAL)
                 .build();
+        try {
+            Path systemTempDir = Path.of(System.getProperty("java.io.tmpdir"));
+            this.sharedTempDir = systemTempDir.resolve(TEMP_DIR_NAME);
+            if (!Files.exists(sharedTempDir)) {
+                Files.createDirectories(sharedTempDir);
+                LOG.info("Created persistent temp directory: {}", sharedTempDir);
+            } else {
+                LOG.info("Using existing persistent temp directory: {}", sharedTempDir);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException("Failed to create or access persistent temp directory", e);
+        }
     }
 
     /**
-     * Downloads a file from the given URL and stores it in a temporary directory.
+     * Downloads a file from the given URL and stores it with a UUID v4 filename.
      *
      * @param url The URL to download from
-     * @return Path to the downloaded file in the temp directory
+     * @return Path to the downloaded file in the shared temp directory
      * @throws IOException if download or file operations fail
-     * @throws IllegalArgumentException if url is null or empty
      */
     public Path downloadToTemp(String url) throws IOException {        
         try {
-            Path tempDir = createTempDirectory();
-            String filename = extractFilename(url);
-            Path tempFile = tempDir.resolve(filename);
+            String filename = generateUuidFilename();
+            Path tempFile = sharedTempDir.resolve(filename);
 
             HttpRequest request = HttpRequest.newBuilder()
                     .uri(URI.create(url))
@@ -66,17 +78,15 @@ public Path downloadToTemp(String url) throws IOException {
     }
 
     /**
-     * Saves content to a temporary file.
+     * Saves content to a temporary file with a UUID v4 filename.
      *
      * @param content The content to save
-     * @param filename The filename to use
      * @return Path to the created temp file
      * @throws IOException if file operations fail
-     * @throws IllegalArgumentException if content or filename is null or empty
      */
-    public Path saveContentToTemp(String content, String filename) throws IOException {        
-        Path tempDir = createTempDirectory();
-        Path tempFile = tempDir.resolve(filename);
+    public Path saveContentToTemp(String content) throws IOException {
+        String uuidFilename = generateUuidFilename();
+        Path tempFile = sharedTempDir.resolve(uuidFilename);
 
         Files.writeString(tempFile, content);
 
@@ -85,40 +95,12 @@ public Path saveContentToTemp(String content, String filename) throws IOExceptio
     }
 
     /**
-     * Creates a temporary directory with the standard prefix.
-     *
-     * @return Path to the created temp directory
-     * @throws IOException if directory creation fails
-     */
-    private Path createTempDirectory() throws IOException {
-        return Files.createTempDirectory(TEMP_DIR_PREFIX);
-    }
-
-    
-    /**
-     * Extracts filename from URL or returns a default name.
+     * Generates a UUID v4 filename.
      *
-     * @param url The URL to extract filename from
-     * @return The extracted filename or default filename
+     * @return A UUID v4 string to be used as filename
      */
-    private String extractFilename(String url) {
-        try {
-            String path = URI.create(url).getPath();
-            if (path == null || path.isEmpty()) {
-                return DEFAULT_FILENAME;
-            }
-            
-            int lastSlash = path.lastIndexOf('/');
-            if (lastSlash >= 0 && lastSlash < path.length() - 1) {
-                String filename = path.substring(lastSlash + 1);
-                // Ensure filename is not empty after extraction
-                if (!filename.trim().isEmpty()) {
-                    return filename;
-                }
-            }
-        } catch (Exception e) {
-            LOG.warn("Could not extract filename from URL: {}", url, e);
-        }
-        return DEFAULT_FILENAME;
+    private String generateUuidFilename() {
+        UUID uuid = Generators.randomBasedGenerator().generate();
+        return uuid.toString();
     }
 }