mimetypes —- Map filenames to MIME types

Source code:Lib/mimetypes.py

The mimetypes module converts between a filename or URL and the MIME typeassociated with the filename extension. Conversions are provided from filenameto MIME type and from MIME type to filename extension; encodings are notsupported for the latter conversion.

The module provides one class and a number of convenience functions. Thefunctions are the normal interface to this module, but some applications may beinterested in the class as well.

The functions described below provide the primary interface for this module. Ifthe module has not been initialized, they will call init() if they rely onthe information init() sets up.

  • mimetypes.guesstype(_url, strict=True)
  • Guess the type of a file based on its filename or URL, given by url. Thereturn value is a tuple (type, encoding) where type is None if thetype can't be guessed (missing or unknown suffix) or a string of the form'type/subtype', usable for a MIME content-type header.

encoding is None for no encoding or the name of the program used to encode(e.g. compress or gzip). The encoding is suitable for useas a Content-Encoding header, not as aContent-Transfer-Encoding header. The mappings are table driven.Encoding suffixes are case sensitive; type suffixes are first tried casesensitively, then case insensitively.

The optional strict argument is a flag specifying whether the list of known MIME typesis limited to only the official types registered with IANA.When strict is True (the default), only the IANA types are supported; whenstrict is False, some additional non-standard but commonly used MIME typesare also recognized.

  • mimetypes.guessall_extensions(_type, strict=True)
  • Guess the extensions for a file based on its MIME type, given by type. Thereturn value is a list of strings giving all possible filename extensions,including the leading dot ('.'). The extensions are not guaranteed to havebeen associated with any particular data stream, but would be mapped to the MIMEtype type by guess_type().

The optional strict argument has the same meaning as with the guess_type() function.

  • mimetypes.guessextension(_type, strict=True)
  • Guess the extension for a file based on its MIME type, given by type. Thereturn value is a string giving a filename extension, including the leading dot('.'). The extension is not guaranteed to have been associated with anyparticular data stream, but would be mapped to the MIME type type byguess_type(). If no extension can be guessed for type, None isreturned.

The optional strict argument has the same meaning as with the guess_type() function.

Some additional functions and data items are available for controlling thebehavior of the module.

  • mimetypes.init(files=None)
  • Initialize the internal data structures. If given, files must be a sequenceof file names which should be used to augment the default type map. If omitted,the file names to use are taken from knownfiles; on Windows, thecurrent registry settings are loaded. Each file named in files orknownfiles takes precedence over those named before it. Callinginit() repeatedly is allowed.

Specifying an empty list for files will prevent the system defaults frombeing applied: only the well-known values will be present from a built-in list.

If files is None the internal data structure is completely rebuilt to itsinitial default value. This is a stable operation and will produce the same resultswhen called multiple times.

在 3.2 版更改: Previously, Windows registry settings were ignored.

  • mimetypes.readmime_types(_filename)
  • Load the type map given in the file filename, if it exists. The type map isreturned as a dictionary mapping filename extensions, including the leading dot('.'), to strings of the form 'type/subtype'. If the file _filename_does not exist or cannot be read, None is returned.
  • mimetypes.addtype(_type, ext, strict=True)
  • Add a mapping from the MIME type type to the extension ext. When theextension is already known, the new type will replace the old one. When the typeis already known the extension will be added to the list of known extensions.

When strict is True (the default), the mapping will be added to theofficial MIME types, otherwise to the non-standard ones.

  • mimetypes.inited
  • Flag indicating whether or not the global data structures have been initialized.This is set to True by init().
  • mimetypes.knownfiles
  • List of type map file names commonly installed. These files are typically namedmime.types and are installed in different locations by differentpackages.
  • mimetypes.suffix_map
  • Dictionary mapping suffixes to suffixes. This is used to allow recognition ofencoded files for which the encoding and the type are indicated by the sameextension. For example, the .tgz extension is mapped to .tar.gzto allow the encoding and type to be recognized separately.
  • mimetypes.encodings_map
  • Dictionary mapping filename extensions to encoding types.
  • mimetypes.types_map
  • Dictionary mapping filename extensions to MIME types.
  • mimetypes.common_types
  • Dictionary mapping filename extensions to non-standard, but commonly found MIMEtypes.

An example usage of the module:

  1. >>> import mimetypes
  2. >>> mimetypes.init()
  3. >>> mimetypes.knownfiles
  4. ['/etc/mime.types', '/etc/httpd/mime.types', ... ]
  5. >>> mimetypes.suffix_map['.tgz']
  6. '.tar.gz'
  7. >>> mimetypes.encodings_map['.gz']
  8. 'gzip'
  9. >>> mimetypes.types_map['.tgz']
  10. 'application/x-tar-gz'

MimeTypes Objects

The MimeTypes class may be useful for applications which may want morethan one MIME-type database; it provides an interface similar to the one of themimetypes module.

  • class mimetypes.MimeTypes(filenames=(), strict=True)
  • This class represents a MIME-types database. By default, it provides access tothe same database as the rest of this module. The initial database is a copy ofthat provided by the module, and may be extended by loading additionalmime.types-style files into the database using the read() orreadfp() methods. The mapping dictionaries may also be cleared beforeloading additional data if the default data is not desired.

The optional filenames parameter can be used to cause additional files to beloaded "on top" of the default database.

  • suffix_map

  • Dictionary mapping suffixes to suffixes. This is used to allow recognition ofencoded files for which the encoding and the type are indicated by the sameextension. For example, the .tgz extension is mapped to .tar.gzto allow the encoding and type to be recognized separately. This is initially acopy of the global suffix_map defined in the module.

  • encodings_map

  • Dictionary mapping filename extensions to encoding types. This is initially acopy of the global encodings_map defined in the module.

  • types_map

  • Tuple containing two dictionaries, mapping filename extensions to MIME types:the first dictionary is for the non-standards types and the second one is forthe standard types. They are initialized by common_types andtypes_map.

  • types_map_inv

  • Tuple containing two dictionaries, mapping MIME types to a list of filenameextensions: the first dictionary is for the non-standards types and thesecond one is for the standard types. They are initialized bycommon_types and types_map.

  • guessextension(_type, strict=True)

  • Similar to the guess_extension() function, using the tables stored as partof the object.

  • guesstype(_url, strict=True)

  • Similar to the guess_type() function, using the tables stored as part ofthe object.

  • guessall_extensions(_type, strict=True)

  • Similar to the guess_all_extensions() function, using the tables storedas part of the object.

  • read(filename, strict=True)

  • Load MIME information from a file named filename. This uses readfp() toparse the file.

If strict is True, information will be added to list of standard types,else to the list of non-standard types.

  • readfp(fp, strict=True)
  • Load MIME type information from an open file fp. The file must have the format ofthe standard mime.types files.

If strict is True, information will be added to the list of standardtypes, else to the list of non-standard types.

  • readwindows_registry(_strict=True)
  • Load MIME type information from the Windows registry.

可用性: Windows。

If strict is True, information will be added to the list of standardtypes, else to the list of non-standard types.

3.2 新版功能.