Package com.axelor.common

Class MimeTypesUtils

java.lang.Object
com.axelor.common.MimeTypesUtils
public class MimeTypesUtils extends Object
This class defines static helper methods to deal with MIME types.

Security note: methods in this class fall into two categories:

  • Extension-based detection (getContentType(String), getExtensionContentType(String)): rely solely on the file name or extension. These must not be used for security validation, as a malicious user can rename any file to an allowed extension.
  • Content-based detection (getContentType(File, String), getContentType(InputStream, String)): inspect the file's magic bytes via Apache Tika. When a fileName is provided, it is used as a hint that may influence the result when content detection is ambiguous. To guarantee purely content-based detection (e.g. for security validation), pass null as fileName so that Tika relies exclusively on magic bytes.

  • Constructor Details

    • MimeTypesUtils

      public MimeTypesUtils()

  • Method Details

    • getContentType

      public static String getContentType(File file)
      Returns the content type from the file, using both its content (magic bytes) and its name as a hint.

      Security note: the file name is passed as a hint to Tika and may influence the result when content detection is ambiguous. For security validation, use getContentType(File, String) with null as the file name to rely solely on magic bytes.

      Parameters:
      file - the file
      Returns:
      detected content type if it is a supported format or "application/octet-stream" if it is an unsupported format

    • getContentType

      public static String getContentType(Path path)
      Returns the content type from the path, using both its content (magic bytes) and its name as a hint.

      Security note: the file name is passed as a hint to Tika and may influence the result when content detection is ambiguous. For security validation, use getContentType(File, String) with null as the file name to rely solely on magic bytes.

      Parameters:
      path - the path
      Returns:
      detected content type if it is a supported format or "application/octet-stream" if it is an unsupported format

    • getContentType

      public static String getContentType(String fileName)
      Detects the content type of the given file name. The type detection is based solely on known file name extensions, without inspecting file content.

      Security note: this method must not be used for security validation, as a malicious user can rename any file to an allowed extension.

      Parameters:
      fileName - the file name
      Returns:
      detected content type if it is a supported format or "application/octet-stream" if it is an unsupported format

    • getExtensionContentType

      public static String getExtensionContentType(String extension)
      Returns the content type from the file extension, without inspecting file content.

      Security note: this method must not be used for security validation, as a malicious user can rename any file to an allowed extension.

      Parameters:
      extension - the extension of the file (e.g., "doc")
      Returns:
      detected content type if it is a supported format or "application/octet-stream" if it is an unsupported format

    • getContentType

      public static String getContentType(File file, String fileName)
      Returns the content type from the file content (magic bytes), optionally using the file name as a hint.

      Security note: if fileName is non-null and non-blank, it is passed to Tika as a hint and may influence the result when content detection is ambiguous. To guarantee purely content-based detection (e.g. for security validation), pass null as fileName.

      Parameters:
      file - the file, can be null
      fileName - the file name hint (e.g., "doc"), or null for content-only detection
      Returns:
      detected content type if it is a supported format or "application/octet-stream" if it is an unsupported format

    • getContentType

      public static String getContentType(InputStream inputStream, String fileName)
      Detects the content type based on the input stream and an optional file name hint.

      This method is designed to be safe for all stream types. It guarantees that the provided InputStream is never consumed or corrupted.

      If the stream supports mark/reset (e.g., BufferedInputStream), this method will peek at the file header to determine the MIME type accurately, and then reset the stream to its original position.

      If the stream is null or does not support mark/reset (e.g., a raw FileInputStream), content inspection is skipped to avoid consuming data. In this case, detection relies solely on the provided fileName extension.

      Security note: if fileName is non-null and non-blank, it is passed to Tika as a hint and may influence the result when content detection is ambiguous. To guarantee purely content-based detection (e.g. for security validation), pass null as fileName and ensure the stream supports mark/reset (e.g. wrap it in a BufferedInputStream or use a ByteArrayInputStream).

      Parameters:
      inputStream - the input stream to inspect (can be null or raw)
      fileName - the file name hint (e.g., "doc"), or null for content-only detection
      Returns:
      the detected content type, or "application/octet-stream" if detection fails