""" magic is a wrapper around the libmagic file identification library. Usage: >>> import magic >>> magic.from_file("testdata/test.pdf") 'PDF document, version 1.2' >>> magic.from_file("testdata/test.pdf", mime=True) 'application/pdf' >>> magic.from_buffer(open("testdata/test.pdf").read(1024)) 'PDF document, version 1.2' >>> """ import sys import os.path class MagicException(Exception): pass class Magic: """ Magic is a wrapper around the libmagic C library. """ def __init__(self, mime=False, magic_file=None, mime_encoding=False): """ Create a new libmagic wrapper. mime - if True, mimetypes are returned instead of textual descriptions mime_encoding - if True, codec is returned magic_file - use a mime database other than the system default """ flags = MAGIC_NONE if mime: flags |= MAGIC_MIME elif mime_encoding: flags |= MAGIC_MIME_ENCODING self.cookie = magic_open(flags) magic_load(self.cookie, magic_file) def from_buffer(self, buf): """ Identify the contents of `buf` """ return magic_buffer(self.cookie, buf) def from_file(self, filename): """ Identify the contents of file `filename` raises IOError if the file does not exist """ if not os.path.exists(filename): raise IOError("File does not exist: " + filename) return magic_file(self.cookie, filename) def __del__(self): # 析构函数，确保在对象被垃圾回收时关闭 libmagic cookie if self.cookie and magic_close: magic_close(self.cookie) self.cookie = None # 全局变量，用于保存默认和MIME magic对象 _magic_mime = None _magic = None # 获取默认和MIME magic对象的函数 def _get_magic_mime(): global _magic_mime if not _magic_mime: _magic_mime = Magic(mime=True) return _magic_mime def _get_magic(): global _magic if not _magic: _magic = Magic() return _magic def _get_magic_type(mime): if mime: return _get_magic_mime() else: return _get_magic() # 公共函数，用于识别文件和缓冲区 def from_file(filename, mime=False): m = _get_magic_type(mime) return m.from_file(filename) def from_buffer(buffer, mime=False): m = _get_magic_type(mime) return m.from_buffer(buffer) # 使用 ctypes 导入 libmagic 库 try: libmagic = None import ctypes import ctypes.util from ctypes import c_char_p, c_int, c_size_t, c_void_p # 尝试找到 libmagic 库 dll = ctypes.util.find_library('magic') or ctypes.util.find_library('magic1') # This is necessary because find_library returns None if it doesn't find the library if dll: try: libmagic = ctypes.CDLL(dll) except WindowsError: pass # 如果没有找到，尝试平台特定的路径 if not libmagic or not libmagic._name: platform_to_lib = {'darwin': ['/opt/local/lib/libmagic.dylib', '/usr/local/lib/libmagic.dylib', '/usr/local/Cellar/libmagic/5.10/lib/libmagic.dylib'], 'win32': ['magic1.dll']} for dll in platform_to_lib.get(sys.platform, []): try: libmagic = ctypes.CDLL(dll) except OSError: pass # 如果仍然没有找到，抛出 ImportError if not libmagic or not libmagic._name: # It is better to raise an ImportError since we are importing magic module raise ImportError('failed to find libmagic. Check your installation') # 定义 magic_t 类型和错误检查函数 magic_t = ctypes.c_void_p def errorcheck(result, func, args): err = magic_error(args[0]) if err is not None: raise MagicException(err) else: return result def coerce_filename(filename): if filename is None: return None return filename.encode(sys.getfilesystemencoding()) # 使用 ctypes 定义 libmagic 函数 magic_open = libmagic.magic_open magic_open.restype = magic_t magic_open.argtypes = [c_int] magic_close = libmagic.magic_close magic_close.restype = None magic_close.argtypes = [magic_t] magic_error = libmagic.magic_error magic_error.restype = c_char_p magic_error.argtypes = [magic_t] magic_errno = libmagic.magic_errno magic_errno.restype = c_int magic_errno.argtypes = [magic_t] _magic_file = libmagic.magic_file _magic_file.restype = c_char_p _magic_file.argtypes = [magic_t, c_char_p] _magic_file.errcheck = errorcheck def magic_file(cookie, filename): return _magic_file(cookie, coerce_filename(filename)) _magic_buffer = libmagic.magic_buffer _magic_buffer.restype = c_char_p _magic_buffer.argtypes = [magic_t, c_void_p, c_size_t] _magic_buffer.errcheck = errorcheck def magic_buffer(cookie, buf): return _magic_buffer(cookie, buf, len(buf)) _magic_load = libmagic.magic_load _magic_load.restype = c_int _magic_load.argtypes = [magic_t, c_char_p] _magic_load.errcheck = errorcheck def magic_load(cookie, filename): return _magic_load(cookie, coerce_filename(filename)) magic_setflags = libmagic.magic_setflags magic_setflags.restype = c_int magic_setflags.argtypes = [magic_t, c_int] magic_check = libmagic.magic_check magic_check.restype = c_int magic_check.argtypes = [magic_t, c_char_p] magic_compile = libmagic.magic_compile magic_compile.restype = c_int magic_compile.argtypes = [magic_t, c_char_p] # 如果 libmagic 无法导入，定义回退函数 except (ImportError, OSError): from_file = from_buffer = lambda *args, **kwargs: MAGIC_UNKNOWN_FILETYPE # 定义 libmagic 标志常量 MAGIC_NONE = 0x000000 # 无标志 MAGIC_DEBUG = 0x000001 # 打开调试 MAGIC_SYMLINK = 0x000002 # 跟随符号链接 MAGIC_COMPRESS = 0x000004 # 检查压缩文件内部 MAGIC_DEVICES = 0x000008 # 查看设备内容 MAGIC_MIME = 0x000010 # 返回 MIME 字符串 MAGIC_MIME_ENCODING = 0x000400 # 返回 MIME 编码 MAGIC_CONTINUE = 0x000020 # 返回所有匹配项 MAGIC_CHECK = 0x000040 # 打印警告到标准错误 MAGIC_PRESERVE_ATIME = 0x000080 # 退出时恢复访问时间 MAGIC_RAW = 0x000100 # 不转换不可打印字符 MAGIC_ERROR = 0x000200 # 将 ENOENT 等视为真实错误 MAGIC_NO_CHECK_COMPRESS = 0x001000 # 不检查压缩文件 MAGIC_NO_CHECK_TAR = 0x002000 # 不检查 tar 文件 MAGIC_NO_CHECK_SOFT = 0x004000 # 不检查 magic 条目 MAGIC_NO_CHECK_APPTYPE = 0x008000 # 不检查应用程序类型 MAGIC_NO_CHECK_ELF = 0x010000 # 不检查 elf 详细信息 MAGIC_NO_CHECK_ASCII = 0x020000 # 不检查 ascii 文件 MAGIC_NO_CHECK_TROFF = 0x040000 # 不检查 ascii/troff MAGIC_NO_CHECK_FORTRAN = 0x080000 # 不检查 ascii/fortran MAGIC_NO_CHECK_TOKENS = 0x100000 # 不检查 ascii/tokens MAGIC_UNKNOWN_FILETYPE = b"unknown"