--- /dev/null
+"""Mailcap file handling. See RFC 1524."""
+
+import os
+import warnings
+import re
+
+__all__ = ["getcaps","findmatch"]
+
+
+# _DEPRECATION_MSG = ('The {name} module is deprecated and will be removed in '
+# 'Python {remove}. See the mimetypes module for an '
+# 'alternative.')
+# warnings._deprecated(__name__, _DEPRECATION_MSG, remove=(3, 13))
+
+
+def lineno_sort_key(entry):
+ # Sort in ascending order, with unspecified entries at the end
+ if 'lineno' in entry:
+ return 0, entry['lineno']
+ else:
+ return 1, 0
+
+_find_unsafe = re.compile(r'[^\xa1-\U0010FFFF\w@+=:,./-]').search
+
+class UnsafeMailcapInput(Warning):
+ """Warning raised when refusing unsafe input"""
+
+
+# Part 1: top-level interface.
+
+def getcaps():
+ """Return a dictionary containing the mailcap database.
+
+ The dictionary maps a MIME type (in all lowercase, e.g. 'text/plain')
+ to a list of dictionaries corresponding to mailcap entries. The list
+ collects all the entries for that MIME type from all available mailcap
+ files. Each dictionary contains key-value pairs for that MIME type,
+ where the viewing command is stored with the key "view".
+
+ """
+ caps = {}
+ lineno = 0
+ for mailcap in listmailcapfiles():
+ try:
+ fp = open(mailcap, 'r')
+ except OSError:
+ continue
+ with fp:
+ morecaps, lineno = _readmailcapfile(fp, lineno)
+ for key, value in morecaps.items():
+ if not key in caps:
+ caps[key] = value
+ else:
+ caps[key] = caps[key] + value
+ return caps
+
+def listmailcapfiles():
+ """Return a list of all mailcap files found on the system."""
+ # This is mostly a Unix thing, but we use the OS path separator anyway
+ if 'MAILCAPS' in os.environ:
+ pathstr = os.environ['MAILCAPS']
+ mailcaps = pathstr.split(os.pathsep)
+ else:
+ if 'HOME' in os.environ:
+ home = os.environ['HOME']
+ else:
+ # Don't bother with getpwuid()
+ home = '.' # Last resort
+ mailcaps = [home + '/.mailcap', '/etc/mailcap',
+ '/usr/etc/mailcap', '/usr/local/etc/mailcap']
+ return mailcaps
+
+
+# Part 2: the parser.
+def readmailcapfile(fp):
+ """Read a mailcap file and return a dictionary keyed by MIME type."""
+ warnings.warn('readmailcapfile is deprecated, use getcaps instead',
+ DeprecationWarning, 2)
+ caps, _ = _readmailcapfile(fp, None)
+ return caps
+
+
+def _readmailcapfile(fp, lineno):
+ """Read a mailcap file and return a dictionary keyed by MIME type.
+
+ Each MIME type is mapped to an entry consisting of a list of
+ dictionaries; the list will contain more than one such dictionary
+ if a given MIME type appears more than once in the mailcap file.
+ Each dictionary contains key-value pairs for that MIME type, where
+ the viewing command is stored with the key "view".
+ """
+ caps = {}
+ while line := fp.readline():
+ # Ignore comments and blank lines
+ if line[0] == '#' or line.strip() == '':
+ continue
+ nextline = line
+ # Join continuation lines
+ while nextline[-2:] == '\\\n':
+ nextline = fp.readline()
+ if not nextline: nextline = '\n'
+ line = line[:-2] + nextline
+ # Parse the line
+ key, fields = parseline(line)
+ if not (key and fields):
+ continue
+ if lineno is not None:
+ fields['lineno'] = lineno
+ lineno += 1
+ # Normalize the key
+ types = key.split('/')
+ for j in range(len(types)):
+ types[j] = types[j].strip()
+ key = '/'.join(types).lower()
+ # Update the database
+ if key in caps:
+ caps[key].append(fields)
+ else:
+ caps[key] = [fields]
+ return caps, lineno
+
+def parseline(line):
+ """Parse one entry in a mailcap file and return a dictionary.
+
+ The viewing command is stored as the value with the key "view",
+ and the rest of the fields produce key-value pairs in the dict.
+ """
+ fields = []
+ i, n = 0, len(line)
+ while i < n:
+ field, i = parsefield(line, i, n)
+ fields.append(field)
+ i = i+1 # Skip semicolon
+ if len(fields) < 2:
+ return None, None
+ key, view, rest = fields[0], fields[1], fields[2:]
+ fields = {'view': view}
+ for field in rest:
+ i = field.find('=')
+ if i < 0:
+ fkey = field
+ fvalue = ""
+ else:
+ fkey = field[:i].strip()
+ fvalue = field[i+1:].strip()
+ if fkey in fields:
+ # Ignore it
+ pass
+ else:
+ fields[fkey] = fvalue
+ return key, fields
+
+def parsefield(line, i, n):
+ """Separate one key-value pair in a mailcap entry."""
+ start = i
+ while i < n:
+ c = line[i]
+ if c == ';':
+ break
+ elif c == '\\':
+ i = i+2
+ else:
+ i = i+1
+ return line[start:i].strip(), i
+
+
+# Part 3: using the database.
+
+def findmatch(caps, MIMEtype, key='view', filename="/dev/null", plist=[]):
+ """Find a match for a mailcap entry.
+
+ Return a tuple containing the command line, and the mailcap entry
+ used; (None, None) if no match is found. This may invoke the
+ 'test' command of several matching entries before deciding which
+ entry to use.
+
+ """
+ if _find_unsafe(filename):
+ msg = "Refusing to use mailcap with filename %r. Use a safe temporary filename." % (filename,)
+ warnings.warn(msg, UnsafeMailcapInput)
+ return None, None
+ entries = lookup(caps, MIMEtype, key)
+ # XXX This code should somehow check for the needsterminal flag.
+ for e in entries:
+ if 'test' in e:
+ test = subst(e['test'], filename, plist)
+ if test is None:
+ continue
+ if test and os.system(test) != 0:
+ continue
+ command = subst(e[key], MIMEtype, filename, plist)
+ if command is not None:
+ return command, e
+ return None, None
+
+def lookup(caps, MIMEtype, key=None):
+ entries = []
+ if MIMEtype in caps:
+ entries = entries + caps[MIMEtype]
+ MIMEtypes = MIMEtype.split('/')
+ MIMEtype = MIMEtypes[0] + '/*'
+ if MIMEtype in caps:
+ entries = entries + caps[MIMEtype]
+ if key is not None:
+ entries = [e for e in entries if key in e]
+ entries = sorted(entries, key=lineno_sort_key)
+ return entries
+
+def subst(field, MIMEtype, filename, plist=[]):
+ # XXX Actually, this is Unix-specific
+ res = ''
+ i, n = 0, len(field)
+ while i < n:
+ c = field[i]; i = i+1
+ if c != '%':
+ if c == '\\':
+ c = field[i:i+1]; i = i+1
+ res = res + c
+ else:
+ c = field[i]; i = i+1
+ if c == '%':
+ res = res + c
+ elif c == 's':
+ res = res + filename
+ elif c == 't':
+ if _find_unsafe(MIMEtype):
+ msg = "Refusing to substitute MIME type %r into a shell command." % (MIMEtype,)
+ warnings.warn(msg, UnsafeMailcapInput)
+ return None
+ res = res + MIMEtype
+ elif c == '{':
+ start = i
+ while i < n and field[i] != '}':
+ i = i+1
+ name = field[start:i]
+ i = i+1
+ param = findparam(name, plist)
+ if _find_unsafe(param):
+ msg = "Refusing to substitute parameter %r (%s) into a shell command" % (param, name)
+ warnings.warn(msg, UnsafeMailcapInput)
+ return None
+ res = res + param
+ # XXX To do:
+ # %n == number of parts if type is multipart/*
+ # %F == list of alternating type and filename for parts
+ else:
+ res = res + '%' + c
+ return res
+
+def findparam(name, plist):
+ name = name.lower() + '='
+ n = len(name)
+ for p in plist:
+ if p[:n].lower() == name:
+ return p[n:]
+ return ''
+
+
+# Part 4: test program.
+
+def test():
+ import sys
+ caps = getcaps()
+ if not sys.argv[1:]:
+ show(caps)
+ return
+ for i in range(1, len(sys.argv), 2):
+ args = sys.argv[i:i+2]
+ if len(args) < 2:
+ print("usage: mailcap [MIMEtype file] ...")
+ return
+ MIMEtype = args[0]
+ file = args[1]
+ command, e = findmatch(caps, MIMEtype, 'view', file)
+ if not command:
+ print("No viewer found for", type)
+ else:
+ print("Executing:", command)
+ sts = os.system(command)
+ sts = os.waitstatus_to_exitcode(sts)
+ if sts:
+ print("Exit status:", sts)
+
+def show(caps):
+ print("Mailcap files:")
+ for fn in listmailcapfiles(): print("\t" + fn)
+ print()
+ if not caps: caps = getcaps()
+ print("Mailcap entries:")
+ print()
+ ckeys = sorted(caps)
+ for type in ckeys:
+ print(type)
+ entries = caps[type]
+ for e in entries:
+ keys = sorted(e)
+ for k in keys:
+ print(" %-15s" % k, e[k])
+ print()
+
+if __name__ == '__main__':
+ test()
projects / mimedecode.git / commitdiff