feat: Add FileValidator class for multiform validation

Author: gabriel-logan

.gitignore

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 # Compiled class file
 *.class
+/target
 
 # Log file
 *.log

.idea/sonarlint/issuestore/1/0/1035b95fde851fd8381dabb4da89dd79908aed9b

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+package io.github.multiform_validator;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+public class FileValidator {
+    // Prevent instantiation
+    private FileValidator() {
+        throw new IllegalStateException("Utility class");
+    }
+
+    private static final Logger logger = Logger.getLogger(FileValidator.class.getName());
+
+    /**
+     * Validates an image file.
+     *
+     * @param file The image file to validate.
+     * @return true if the file is a valid image, false otherwise.
+     * @throws IllegalArgumentException if the input value is null.
+     */
+    public static boolean validateImage(File file) {
+        return validateImage(file, null);
+    }
+
+    /**
+     * Validates an image file, excluding specific file types.
+     *
+     * @param file    The image file to validate.
+     * @param exclude A list of file types to exclude from validation.
+     * @return true if the file is a valid image, false otherwise.
+     * @throws IllegalArgumentException if the input value is null.
+     */
+    public static boolean validateImage(File file, List<String> exclude) {
+        if (file == null) {
+            throw new IllegalArgumentException("The input value cannot be null.");
+        }
+
+        try {
+            byte[] fileBytes = Files.readAllBytes(file.toPath());
+
+            if (exclude == null) {
+                return isGif(fileBytes) || isIco(fileBytes) || isJpeg(fileBytes) || isPng(fileBytes);
+            }
+
+            List<String> listToValidate = new ArrayList<>();
+            listToValidate.add("gif");
+            listToValidate.add("ico");
+            listToValidate.add("jpeg");
+            listToValidate.add("png");
+
+            List<String> filteredList = new ArrayList<>();
+            for (String item : listToValidate) {
+                if (!exclude.contains(item)) {
+                    filteredList.add(item);
+                }
+            }
+
+            if (filteredList.isEmpty()) {
+                return false;
+            }
+
+            return validateFileTypes(fileBytes, filteredList);
+
+        } catch (IOException e) {
+            logger.severe("An error occurred while reading the file: " + e.getMessage());
+            return false;
+        }
+    }
+
+    private static boolean isPng(byte[] fileBytes) {
+        return fileBytes[0] == (byte) 0x89 && fileBytes[1] == 0x50 && fileBytes[2] == 0x4E && fileBytes[3] == 0x47;
+    }
+
+    private static boolean isJpeg(byte[] fileBytes) {
+        return fileBytes[0] == (byte) 0xFF && fileBytes[1] == (byte) 0xD8 && fileBytes[2] == (byte) 0xFF;
+    }
+
+    private static boolean isGif(byte[] fileBytes) {
+        return fileBytes[0] == 0x47 && fileBytes[1] == 0x49 && fileBytes[2] == 0x46 && fileBytes[3] == 0x38;
+    }
+
+    private static boolean isIco(byte[] fileBytes) {
+        return fileBytes[0] == 0x00 && fileBytes[1] == 0x00 && fileBytes[2] == 0x01;
+    }
+
+    private static boolean validateFileTypes(byte[] fileBytes, List<String> filteredList) {
+        boolean isGifValid = filteredList.contains("gif") && isGif(fileBytes);
+        boolean isIcoValid = filteredList.contains("ico") && isIco(fileBytes);
+        boolean isJpegValid = filteredList.contains("jpeg") && isJpeg(fileBytes);
+        boolean isPngValid = filteredList.contains("png") && isPng(fileBytes);
+
+        return isGifValid || isIcoValid || isJpegValid || isPngValid;
+    }
+}

.idea/sonarlint/issuestore/3/c/3c8842d6f65bc0f21cf2bfc030702ffe7e82d70d

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+import io.github.multiform_validator.FileValidator;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class FileValidatorTest {
+    final String basePath = "src/test/java/assets/isValidImage/";
+
+    @Test
+    void testValidateImage() {
+        File file = new File(basePath + "/valid/valid.jpg");
+        assertTrue(FileValidator.validateImage(file));
+    }
+
+    @Test
+    void testValidateImageWithExclusion() {
+        File file = new File(basePath + "/valid/valid.jpg");
+        List<String> exclude = Arrays.asList("gif", "ico", "png");
+        assertTrue(FileValidator.validateImage(file, exclude));
+    }
+
+    @Test
+    void testValidateImageWithInvalidImage() {
+        File file = new File(basePath + "/invalid/invalid.png");
+        assertFalse(FileValidator.validateImage(file));
+    }
+
+    @Test
+    void testValidateImageWithValidImageAndValidExclusion() {
+        File file = new File(basePath + "/valid/valid.png");
+        List<String> exclude = Arrays.asList("gif", "ico", "png");
+        assertFalse(FileValidator.validateImage(file, exclude));
+    }
+
+    @Test
+    void testValidateImageWithValidImageAndInvalidExclusion() {
+        File file = new File(basePath + "/valid/valid.png");
+        List<String> exclude = Arrays.asList("gif", "ico");
+        assertTrue(FileValidator.validateImage(file, exclude));
+    }
+
+    @Test
+    void testValidateImageWithNullFile() {
+        assertThrows(IllegalArgumentException.class, () -> FileValidator.validateImage(null));
+    }
+}

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.idea/sonarlint/issuestore/index.pb

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