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ruoyi-common/src/main/java/com/ruoyi/common/utils/file/FileTypeUtils.java

@@ -0,0 +1,76 @@
+package com.ruoyi.common.utils.file;
+
+import java.io.File;
+import org.apache.commons.lang3.StringUtils;
+
+/**
+ * 文件类型工具类
+ *
+ * @author ruoyi
+ */
+public class FileTypeUtils
+{
+    /**
+     * 获取文件类型
+     * <p>
+     * 例如: ruoyi.txt, 返回: txt
+     * 
+     * @param file 文件名
+     * @return 后缀（不含".")
+     */
+    public static String getFileType(File file)
+    {
+        if (null == file)
+        {
+            return StringUtils.EMPTY;
+        }
+        return getFileType(file.getName());
+    }
+
+    /**
+     * 获取文件类型
+     * <p>
+     * 例如: ruoyi.txt, 返回: txt
+     *
+     * @param fileName 文件名
+     * @return 后缀（不含".")
+     */
+    public static String getFileType(String fileName)
+    {
+        int separatorIndex = fileName.lastIndexOf(".");
+        if (separatorIndex < 0)
+        {
+            return "";
+        }
+        return fileName.substring(separatorIndex + 1).toLowerCase();
+    }
+
+    /**
+     * 获取文件类型
+     * 
+     * @param photoByte 文件字节码
+     * @return 后缀（不含".")
+     */
+    public static String getFileExtendName(byte[] photoByte)
+    {
+        String strFileExtendName = "JPG";
+        if ((photoByte[0] == 71) && (photoByte[1] == 73) && (photoByte[2] == 70) && (photoByte[3] == 56)
+                && ((photoByte[4] == 55) || (photoByte[4] == 57)) && (photoByte[5] == 97))
+        {
+            strFileExtendName = "GIF";
+        }
+        else if ((photoByte[6] == 74) && (photoByte[7] == 70) && (photoByte[8] == 73) && (photoByte[9] == 70))
+        {
+            strFileExtendName = "JPG";
+        }
+        else if ((photoByte[0] == 66) && (photoByte[1] == 77))
+        {
+            strFileExtendName = "BMP";
+        }
+        else if ((photoByte[1] == 80) && (photoByte[2] == 78) && (photoByte[3] == 71))
+        {
+            strFileExtendName = "PNG";
+        }
+        return strFileExtendName;
+    }
+}

ruoyi-common/src/main/java/com/ruoyi/common/utils/file/FileUploadUtils.java

@@ -0,0 +1,260 @@
+package com.ruoyi.common.utils.file;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.Objects;
+import org.apache.commons.io.FilenameUtils;
+import org.springframework.web.multipart.MultipartFile;
+import com.ruoyi.common.config.RuoYiConfig;
+import com.ruoyi.common.constant.Constants;
+import com.ruoyi.common.exception.file.FileNameLengthLimitExceededException;
+import com.ruoyi.common.exception.file.FileSizeLimitExceededException;
+import com.ruoyi.common.exception.file.InvalidExtensionException;
+import com.ruoyi.common.utils.DateUtils;
+import com.ruoyi.common.utils.StringUtils;
+import com.ruoyi.common.utils.uuid.IdUtils;
+import com.ruoyi.common.utils.uuid.Seq;
+
+/**
+ * 文件上传工具类
+ * 
+ * @author ruoyi
+ */
+public class FileUploadUtils
+{
+    /**
+     * 默认大小 50M
+     */
+    public static final long DEFAULT_MAX_SIZE = 50 * 1024 * 1024L;
+
+    /**
+     * 默认的文件名最大长度 100
+     */
+    public static final int DEFAULT_FILE_NAME_LENGTH = 100;
+
+    /**
+     * 默认上传的地址
+     */
+    private static String defaultBaseDir = RuoYiConfig.getProfile();
+
+    public static void setDefaultBaseDir(String defaultBaseDir)
+    {
+        FileUploadUtils.defaultBaseDir = defaultBaseDir;
+    }
+
+    public static String getDefaultBaseDir()
+    {
+        return defaultBaseDir;
+    }
+
+    /**
+     * 以默认配置进行文件上传
+     *
+     * @param file 上传的文件
+     * @return 文件名称
+     * @throws Exception
+     */
+    public static final String upload(MultipartFile file) throws IOException
+    {
+        try
+        {
+            return upload(getDefaultBaseDir(), file, MimeTypeUtils.DEFAULT_ALLOWED_EXTENSION);
+        }
+        catch (Exception e)
+        {
+            throw new IOException(e.getMessage(), e);
+        }
+    }
+
+    /**
+     * 根据文件路径上传
+     *
+     * @param baseDir 相对应用的基目录
+     * @param file 上传的文件
+     * @return 文件名称
+     * @throws IOException
+     */
+    public static final String upload(String baseDir, MultipartFile file) throws IOException
+    {
+        try
+        {
+            return upload(baseDir, file, MimeTypeUtils.DEFAULT_ALLOWED_EXTENSION);
+        }
+        catch (Exception e)
+        {
+            throw new IOException(e.getMessage(), e);
+        }
+    }
+
+    /**
+     * 文件上传
+     *
+     * @param baseDir 相对应用的基目录
+     * @param file 上传的文件
+     * @param allowedExtension 上传文件类型
+     * @return 返回上传成功的文件名
+     * @throws FileSizeLimitExceededException 如果超出最大大小
+     * @throws FileNameLengthLimitExceededException 文件名太长
+     * @throws IOException 比如读写文件出错时
+     * @throws InvalidExtensionException 文件校验异常
+     */
+    public static final String upload(String baseDir, MultipartFile file, String[] allowedExtension)
+            throws FileSizeLimitExceededException, IOException, FileNameLengthLimitExceededException,
+            InvalidExtensionException
+    {
+        return upload(baseDir, file, allowedExtension, false);
+    }
+    
+    /**
+     * 文件上传
+     *
+     * @param baseDir 相对应用的基目录
+     * @param file 上传的文件
+     * @param useCustomNaming 系统自定义文件名
+     * @param allowedExtension 上传文件类型
+     * @return 返回上传成功的文件名
+     * @throws FileSizeLimitExceededException 如果超出最大大小
+     * @throws FileNameLengthLimitExceededException 文件名太长
+     * @throws IOException 比如读写文件出错时
+     * @throws InvalidExtensionException 文件校验异常
+     */
+    public static final String upload(String baseDir, MultipartFile file, String[] allowedExtension, boolean useCustomNaming)
+            throws FileSizeLimitExceededException, IOException, FileNameLengthLimitExceededException,
+            InvalidExtensionException
+    {
+        int fileNameLength = Objects.requireNonNull(file.getOriginalFilename()).length();
+        if (fileNameLength > FileUploadUtils.DEFAULT_FILE_NAME_LENGTH)
+        {
+            throw new FileNameLengthLimitExceededException(FileUploadUtils.DEFAULT_FILE_NAME_LENGTH);
+        }
+
+        assertAllowed(file, allowedExtension);
+
+        String fileName = useCustomNaming ? uuidFilename(file) : extractFilename(file);
+
+        String absPath = getAbsoluteFile(baseDir, fileName).getAbsolutePath();
+        file.transferTo(Paths.get(absPath));
+        return getPathFileName(baseDir, fileName);
+    }
+
+    /**
+     * 编码文件名(日期格式目录 + 原文件名 + 序列值 + 后缀)
+     */
+    public static final String extractFilename(MultipartFile file)
+    {
+        return StringUtils.format("{}/{}_{}.{}", DateUtils.datePath(), FilenameUtils.getBaseName(file.getOriginalFilename()), Seq.getId(Seq.uploadSeqType), getExtension(file));
+    }
+
+    /**
+     * 编编码文件名(日期格式目录 + UUID + 后缀)
+     */
+    public static final String uuidFilename(MultipartFile file)
+    {
+        return StringUtils.format("{}/{}.{}", DateUtils.datePath(), IdUtils.fastSimpleUUID(), getExtension(file));
+    }
+
+    public static final File getAbsoluteFile(String uploadDir, String fileName) throws IOException
+    {
+        File desc = new File(uploadDir + File.separator + fileName);
+
+        if (!desc.exists())
+        {
+            if (!desc.getParentFile().exists())
+            {
+                desc.getParentFile().mkdirs();
+            }
+        }
+        return desc;
+    }
+
+    public static final String getPathFileName(String uploadDir, String fileName) throws IOException
+    {
+        int dirLastIndex = RuoYiConfig.getProfile().length() + 1;
+        String currentDir = StringUtils.substring(uploadDir, dirLastIndex);
+        return Constants.RESOURCE_PREFIX + "/" + currentDir + "/" + fileName;
+    }
+
+    /**
+     * 文件大小校验
+     *
+     * @param file 上传的文件
+     * @return
+     * @throws FileSizeLimitExceededException 如果超出最大大小
+     * @throws InvalidExtensionException
+     */
+    public static final void assertAllowed(MultipartFile file, String[] allowedExtension)
+            throws FileSizeLimitExceededException, InvalidExtensionException
+    {
+        long size = file.getSize();
+        if (size > DEFAULT_MAX_SIZE)
+        {
+            throw new FileSizeLimitExceededException(DEFAULT_MAX_SIZE / 1024 / 1024);
+        }
+
+        String fileName = file.getOriginalFilename();
+        String extension = getExtension(file);
+        if (allowedExtension != null && !isAllowedExtension(extension, allowedExtension))
+        {
+            if (allowedExtension == MimeTypeUtils.IMAGE_EXTENSION)
+            {
+                throw new InvalidExtensionException.InvalidImageExtensionException(allowedExtension, extension,
+                        fileName);
+            }
+            else if (allowedExtension == MimeTypeUtils.FLASH_EXTENSION)
+            {
+                throw new InvalidExtensionException.InvalidFlashExtensionException(allowedExtension, extension,
+                        fileName);
+            }
+            else if (allowedExtension == MimeTypeUtils.MEDIA_EXTENSION)
+            {
+                throw new InvalidExtensionException.InvalidMediaExtensionException(allowedExtension, extension,
+                        fileName);
+            }
+            else if (allowedExtension == MimeTypeUtils.VIDEO_EXTENSION)
+            {
+                throw new InvalidExtensionException.InvalidVideoExtensionException(allowedExtension, extension,
+                        fileName);
+            }
+            else
+            {
+                throw new InvalidExtensionException(allowedExtension, extension, fileName);
+            }
+        }
+    }
+
+    /**
+     * 判断MIME类型是否是允许的MIME类型
+     *
+     * @param extension
+     * @param allowedExtension
+     * @return
+     */
+    public static final boolean isAllowedExtension(String extension, String[] allowedExtension)
+    {
+        for (String str : allowedExtension)
+        {
+            if (str.equalsIgnoreCase(extension))
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * 获取文件名的后缀
+     * 
+     * @param file 表单文件
+     * @return 后缀名
+     */
+    public static final String getExtension(MultipartFile file)
+    {
+        String extension = FilenameUtils.getExtension(file.getOriginalFilename());
+        if (StringUtils.isEmpty(extension))
+        {
+            extension = MimeTypeUtils.getExtension(Objects.requireNonNull(file.getContentType()));
+        }
+        return extension;
+    }
+}

ruoyi-common/src/main/java/com/ruoyi/common/utils/file/FileUtils.java

@@ -0,0 +1,303 @@
+package com.ruoyi.common.utils.file;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.apache.commons.io.FilenameUtils;
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.ArrayUtils;
+import com.ruoyi.common.config.RuoYiConfig;
+import com.ruoyi.common.constant.Constants;
+import com.ruoyi.common.utils.DateUtils;
+import com.ruoyi.common.utils.StringUtils;
+import com.ruoyi.common.utils.uuid.IdUtils;
+
+/**
+ * 文件处理工具类
+ * 
+ * @author ruoyi
+ */
+public class FileUtils
+{
+    public static String FILENAME_PATTERN = "[a-zA-Z0-9_\\-\\|\\.\\u4e00-\\u9fa5]+";
+
+    /**
+     * 输出指定文件的byte数组
+     * 
+     * @param filePath 文件路径
+     * @param os 输出流
+     * @return
+     */
+    public static void writeBytes(String filePath, OutputStream os) throws IOException
+    {
+        FileInputStream fis = null;
+        try
+        {
+            File file = new File(filePath);
+            if (!file.exists())
+            {
+                throw new FileNotFoundException(filePath);
+            }
+            fis = new FileInputStream(file);
+            byte[] b = new byte[1024];
+            int length;
+            while ((length = fis.read(b)) > 0)
+            {
+                os.write(b, 0, length);
+            }
+        }
+        catch (IOException e)
+        {
+            throw e;
+        }
+        finally
+        {
+            IOUtils.close(os);
+            IOUtils.close(fis);
+        }
+    }
+
+    /**
+     * 写数据到文件中
+     *
+     * @param data 数据
+     * @return 目标文件
+     * @throws IOException IO异常
+     */
+    public static String writeImportBytes(byte[] data) throws IOException
+    {
+        return writeBytes(data, RuoYiConfig.getImportPath());
+    }
+
+    /**
+     * 写数据到文件中
+     *
+     * @param data 数据
+     * @param uploadDir 目标文件
+     * @return 目标文件
+     * @throws IOException IO异常
+     */
+    public static String writeBytes(byte[] data, String uploadDir) throws IOException
+    {
+        FileOutputStream fos = null;
+        String pathName = "";
+        try
+        {
+            String extension = getFileExtendName(data);
+            pathName = DateUtils.datePath() + "/" + IdUtils.fastUUID() + "." + extension;
+            File file = FileUploadUtils.getAbsoluteFile(uploadDir, pathName);
+            fos = new FileOutputStream(file);
+            fos.write(data);
+        }
+        finally
+        {
+            IOUtils.close(fos);
+        }
+        return FileUploadUtils.getPathFileName(uploadDir, pathName);
+    }
+
+    /**
+     * 移除路径中的请求前缀片段
+     * 
+     * @param filePath 文件路径
+     * @return 移除后的文件路径
+     */
+    public static String stripPrefix(String filePath)
+    {
+        return StringUtils.substringAfter(filePath, Constants.RESOURCE_PREFIX);
+    }
+
+    /**
+     * 删除文件
+     * 
+     * @param filePath 文件
+     * @return
+     */
+    public static boolean deleteFile(String filePath)
+    {
+        boolean flag = false;
+        File file = new File(filePath);
+        // 路径为文件且不为空则进行删除
+        if (file.isFile() && file.exists())
+        {
+            flag = file.delete();
+        }
+        return flag;
+    }
+
+    /**
+     * 文件名称验证
+     * 
+     * @param filename 文件名称
+     * @return true 正常 false 非法
+     */
+    public static boolean isValidFilename(String filename)
+    {
+        return filename.matches(FILENAME_PATTERN);
+    }
+
+    /**
+     * 检查文件是否可下载
+     * 
+     * @param resource 需要下载的文件
+     * @return true 正常 false 非法
+     */
+    public static boolean checkAllowDownload(String resource)
+    {
+        // 禁止目录上跳级别
+        if (StringUtils.contains(resource, ".."))
+        {
+            return false;
+        }
+
+        // 检查允许下载的文件规则
+        if (ArrayUtils.contains(MimeTypeUtils.DEFAULT_ALLOWED_EXTENSION, FileTypeUtils.getFileType(resource)))
+        {
+            return true;
+        }
+
+        // 不在允许下载的文件规则
+        return false;
+    }
+
+    /**
+     * 下载文件名重新编码
+     * 
+     * @param request 请求对象
+     * @param fileName 文件名
+     * @return 编码后的文件名
+     */
+    public static String setFileDownloadHeader(HttpServletRequest request, String fileName) throws UnsupportedEncodingException
+    {
+        final String agent = request.getHeader("USER-AGENT");
+        String filename = fileName;
+        if (agent.contains("MSIE"))
+        {
+            // IE浏览器
+            filename = URLEncoder.encode(filename, "utf-8");
+            filename = filename.replace("+", " ");
+        }
+        else if (agent.contains("Firefox"))
+        {
+            // 火狐浏览器
+            filename = new String(fileName.getBytes(), "ISO8859-1");
+        }
+        else if (agent.contains("Chrome"))
+        {
+            // google浏览器
+            filename = URLEncoder.encode(filename, "utf-8");
+        }
+        else
+        {
+            // 其它浏览器
+            filename = URLEncoder.encode(filename, "utf-8");
+        }
+        return filename;
+    }
+
+    /**
+     * 下载文件名重新编码
+     *
+     * @param response 响应对象
+     * @param realFileName 真实文件名
+     */
+    public static void setAttachmentResponseHeader(HttpServletResponse response, String realFileName) throws UnsupportedEncodingException
+    {
+        String percentEncodedFileName = percentEncode(realFileName);
+
+        StringBuilder contentDispositionValue = new StringBuilder();
+        contentDispositionValue.append("attachment; filename=")
+                .append(percentEncodedFileName)
+                .append(";")
+                .append("filename*=")
+                .append("utf-8''")
+                .append(percentEncodedFileName);
+
+        response.addHeader("Access-Control-Expose-Headers", "Content-Disposition,download-filename");
+        response.setHeader("Content-disposition", contentDispositionValue.toString());
+        response.setHeader("download-filename", percentEncodedFileName);
+    }
+
+    /**
+     * 百分号编码工具方法
+     *
+     * @param s 需要百分号编码的字符串
+     * @return 百分号编码后的字符串
+     */
+    public static String percentEncode(String s) throws UnsupportedEncodingException
+    {
+        String encode = URLEncoder.encode(s, StandardCharsets.UTF_8.toString());
+        return encode.replaceAll("\\+", "%20");
+    }
+
+    /**
+     * 获取图像后缀
+     * 
+     * @param photoByte 图像数据
+     * @return 后缀名
+     */
+    public static String getFileExtendName(byte[] photoByte)
+    {
+        String strFileExtendName = "jpg";
+        if ((photoByte[0] == 71) && (photoByte[1] == 73) && (photoByte[2] == 70) && (photoByte[3] == 56)
+                && ((photoByte[4] == 55) || (photoByte[4] == 57)) && (photoByte[5] == 97))
+        {
+            strFileExtendName = "gif";
+        }
+        else if ((photoByte[6] == 74) && (photoByte[7] == 70) && (photoByte[8] == 73) && (photoByte[9] == 70))
+        {
+            strFileExtendName = "jpg";
+        }
+        else if ((photoByte[0] == 66) && (photoByte[1] == 77))
+        {
+            strFileExtendName = "bmp";
+        }
+        else if ((photoByte[1] == 80) && (photoByte[2] == 78) && (photoByte[3] == 71))
+        {
+            strFileExtendName = "png";
+        }
+        return strFileExtendName;
+    }
+
+    /**
+     * 获取文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi.png
+     * 
+     * @param fileName 路径名称
+     * @return 没有文件路径的名称
+     */
+    public static String getName(String fileName)
+    {
+        if (fileName == null)
+        {
+            return null;
+        }
+        int lastUnixPos = fileName.lastIndexOf('/');
+        int lastWindowsPos = fileName.lastIndexOf('\\');
+        int index = Math.max(lastUnixPos, lastWindowsPos);
+        return fileName.substring(index + 1);
+    }
+
+    /**
+     * 获取不带后缀文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi
+     * 
+     * @param fileName 路径名称
+     * @return 没有文件路径和后缀的名称
+     */
+    public static String getNameNotSuffix(String fileName)
+    {
+        if (fileName == null)
+        {
+            return null;
+        }
+        String baseName = FilenameUtils.getBaseName(fileName);
+        return baseName;
+    }
+}

ruoyi-common/src/main/java/com/ruoyi/common/utils/file/ImageUtils.java

@@ -0,0 +1,98 @@
+package com.ruoyi.common.utils.file;
+
+import java.io.ByteArrayInputStream;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.Arrays;
+import org.apache.poi.util.IOUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import com.ruoyi.common.config.RuoYiConfig;
+import com.ruoyi.common.constant.Constants;
+import com.ruoyi.common.utils.StringUtils;
+
+/**
+ * 图片处理工具类
+ *
+ * @author ruoyi
+ */
+public class ImageUtils
+{
+    private static final Logger log = LoggerFactory.getLogger(ImageUtils.class);
+
+    public static byte[] getImage(String imagePath)
+    {
+        InputStream is = getFile(imagePath);
+        try
+        {
+            return IOUtils.toByteArray(is);
+        }
+        catch (Exception e)
+        {
+            log.error("图片加载异常 {}", e);
+            return null;
+        }
+        finally
+        {
+            IOUtils.closeQuietly(is);
+        }
+    }
+
+    public static InputStream getFile(String imagePath)
+    {
+        try
+        {
+            byte[] result = readFile(imagePath);
+            result = Arrays.copyOf(result, result.length);
+            return new ByteArrayInputStream(result);
+        }
+        catch (Exception e)
+        {
+            log.error("获取图片异常 {}", e);
+        }
+        return null;
+    }
+
+    /**
+     * 读取文件为字节数据
+     * 
+     * @param url 地址
+     * @return 字节数据
+     */
+    public static byte[] readFile(String url)
+    {
+        InputStream in = null;
+        try
+        {
+            if (url.startsWith("http"))
+            {
+                // 网络地址
+                URL urlObj = new URL(url);
+                URLConnection urlConnection = urlObj.openConnection();
+                urlConnection.setConnectTimeout(30 * 1000);
+                urlConnection.setReadTimeout(60 * 1000);
+                urlConnection.setDoInput(true);
+                in = urlConnection.getInputStream();
+            }
+            else
+            {
+                // 本机地址
+                String localPath = RuoYiConfig.getProfile();
+                String downloadPath = localPath + StringUtils.substringAfter(url, Constants.RESOURCE_PREFIX);
+                in = new FileInputStream(downloadPath);
+            }
+            return IOUtils.toByteArray(in);
+        }
+        catch (Exception e)
+        {
+            log.error("获取文件路径异常 {}", e);
+            return null;
+        }
+        finally
+        {
+            IOUtils.closeQuietly(in);
+        }
+    }
+}

ruoyi-common/src/main/java/com/ruoyi/common/utils/file/MimeTypeUtils.java

@@ -0,0 +1,59 @@
+package com.ruoyi.common.utils.file;
+
+/**
+ * 媒体类型工具类
+ * 
+ * @author ruoyi
+ */
+public class MimeTypeUtils
+{
+    public static final String IMAGE_PNG = "image/png";
+
+    public static final String IMAGE_JPG = "image/jpg";
+
+    public static final String IMAGE_JPEG = "image/jpeg";
+
+    public static final String IMAGE_BMP = "image/bmp";
+
+    public static final String IMAGE_GIF = "image/gif";
+    
+    public static final String[] IMAGE_EXTENSION = { "bmp", "gif", "jpg", "jpeg", "png" };
+
+    public static final String[] FLASH_EXTENSION = { "swf", "flv" };
+
+    public static final String[] MEDIA_EXTENSION = { "swf", "flv", "mp3", "wav", "wma", "wmv", "mid", "avi", "mpg",
+            "asf", "rm", "rmvb" };
+
+    public static final String[] VIDEO_EXTENSION = { "mp4", "avi", "rmvb" };
+
+    public static final String[] DEFAULT_ALLOWED_EXTENSION = {
+            // 图片
+            "bmp", "gif", "jpg", "jpeg", "png",
+            // word excel powerpoint
+            "doc", "docx", "xls", "xlsx", "ppt", "pptx", "html", "htm", "txt",
+            // 压缩文件
+            "rar", "zip", "gz", "bz2",
+            // 视频格式
+            "mp4", "avi", "rmvb",
+            // pdf
+            "pdf" };
+
+    public static String getExtension(String prefix)
+    {
+        switch (prefix)
+        {
+            case IMAGE_PNG:
+                return "png";
+            case IMAGE_JPG:
+                return "jpg";
+            case IMAGE_JPEG:
+                return "jpeg";
+            case IMAGE_BMP:
+                return "bmp";
+            case IMAGE_GIF:
+                return "gif";
+            default:
+                return "";
+        }
+    }
+}