# 14.3. `netrc` — netrc file processing

Source code: Lib/netrc.py

The `netrc` class parses and encapsulates the netrc file format used by the Unix ftp program and other FTP clients.

class `netrc.``netrc`([file])

  A `netrc` instance or subclass instance encapsulates data from a netrc file. The initialization argument, if present, specifies the file to parse. If no argument is given, the file `.netrc` in the user’s home directory will be read. Parse errors will raise `NetrcParseError` with diagnostic information including the file name, line number, and terminating token. If no argument is specified on a POSIX system, the presence of passwords in the `.netrc` file will raise a `NetrcParseError` if the file ownership or permissions are insecure (owned by a user other than the user running the process, or accessible for read or write by any other user). This implements security behavior equivalent to that of ftp and other programs that use `.netrc`.

  3.4 版更變: Added the POSIX permission check.

exception `netrc.``NetrcParseError`

  Exception raised by the `netrc` class when syntactical errors are encountered in source text. Instances of this exception provide three interesting attributes: `msg` is a textual explanation of the error, `filename` is the name of the source file, and `lineno` gives the line number on which the error was found.

## 14.3.1. netrc Objects

A `netrc` instance has the following methods:

`netrc.``authenticators`(host)

  Return a 3-tuple `(login, account, password)` of authenticators for host. If the netrc file did not contain an entry for the given host, return the tuple associated with the 『default』 entry. If neither matching host nor default entry is available, return `None`.

`netrc.``__repr__`()

  Dump the class data as a string in the format of a netrc file. (This discards comments and may reorder the entries.)

Instances of `netrc` have public instance variables:

`netrc.``hosts`

  Dictionary mapping host names to `(login, account, password)` tuples. The 『default』 entry, if any, is represented as a pseudo-host by that name.

`netrc.``macros`

  Dictionary mapping macro names to string lists.

備註

Passwords are limited to a subset of the ASCII character set. All ASCII punctuation is allowed in passwords, however, note that whitespace and non-printable characters are not allowed in passwords. This is a limitation of the way the .netrc file is parsed and may be removed in the future.