1 """Generic MIME writer.

     2 

     3 This module defines the class MimeWriter.  The MimeWriter class implements

     4 a basic formatter for creating MIME multi-part files.  It doesn't seek around

     5 the output file nor does it use large amounts of buffer space. You must write

     6 the parts out in the order that they should occur in the final file.

     7 MimeWriter does buffer the headers you add, allowing you to rearrange their

     8 order.

     9 

    10 """

    11 

    12 

    13 import mimetools

    14 

    15 __all__ = ["MimeWriter"]

    16 

    17 import warnings

    18 

    19 warnings.warn("the MimeWriter module is deprecated; use the email package instead",

    20                 DeprecationWarning, 2)

    21 

    22 class MimeWriter:

    23 

    24     """Generic MIME writer.

    25 

    26     Methods:

    27 

    28     __init__()

    29     addheader()

    30     flushheaders()

    31     startbody()

    32     startmultipartbody()

    33     nextpart()

    34     lastpart()

    35 

    36     A MIME writer is much more primitive than a MIME parser.  It

    37     doesn't seek around on the output file, and it doesn't use large

    38     amounts of buffer space, so you have to write the parts in the

    39     order they should occur on the output file.  It does buffer the

    40     headers you add, allowing you to rearrange their order.

    41 

    42     General usage is:

    43 

    44     f = <open the output file>

    45     w = MimeWriter(f)

    46     ...call w.addheader(key, value) 0 or more times...

    47 

    48     followed by either:

    49 

    50     f = w.startbody(content_type)

    51     ...call f.write(data) for body data...

    52 

    53     or:

    54 

    55     w.startmultipartbody(subtype)

    56     for each part:

    57         subwriter = w.nextpart()

    58         ...use the subwriter's methods to create the subpart...

    59     w.lastpart()

    60 

    61     The subwriter is another MimeWriter instance, and should be

    62     treated in the same way as the toplevel MimeWriter.  This way,

    63     writing recursive body parts is easy.

    64 

    65     Warning: don't forget to call lastpart()!

    66 

    67     XXX There should be more state so calls made in the wrong order

    68     are detected.

    69 

    70     Some special cases:

    71 

    72     - startbody() just returns the file passed to the constructor;

    73       but don't use this knowledge, as it may be changed.

    74 

    75     - startmultipartbody() actually returns a file as well;

    76       this can be used to write the initial 'if you can read this your

    77       mailer is not MIME-aware' message.

    78 

    79     - If you call flushheaders(), the headers accumulated so far are

    80       written out (and forgotten); this is useful if you don't need a

    81       body part at all, e.g. for a subpart of type message/rfc822

    82       that's (mis)used to store some header-like information.

    83 

    84     - Passing a keyword argument 'prefix=<flag>' to addheader(),

    85       start*body() affects where the header is inserted; 0 means

    86       append at the end, 1 means insert at the start; default is

    87       append for addheader(), but insert for start*body(), which use

    88       it to determine where the Content-Type header goes.

    89 

    90     """

    91 

    92     def __init__(self, fp):

    93         self._fp = fp

    94         self._headers = []

    95 

    96     def addheader(self, key, value, prefix=0):

    97         """Add a header line to the MIME message.

    98 

    99         The key is the name of the header, where the value obviously provides

   100         the value of the header. The optional argument prefix determines

   101         where the header is inserted; 0 means append at the end, 1 means

   102         insert at the start. The default is to append.

   103 

   104         """

   105         lines = value.split("\n")

   106         while lines and not lines[-1]: del lines[-1]

   107         while lines and not lines[0]: del lines[0]

   108         for i in range(1, len(lines)):

   109             lines[i] = "    " + lines[i].strip()

   110         value = "\n".join(lines) + "\n"

   111         line = key + ": " + value

   112         if prefix:

   113             self._headers.insert(0, line)

   114         else:

   115             self._headers.append(line)

   116 

   117     def flushheaders(self):

   118         """Writes out and forgets all headers accumulated so far.

   119 

   120         This is useful if you don't need a body part at all; for example,

   121         for a subpart of type message/rfc822 that's (mis)used to store some

   122         header-like information.

   123 

   124         """

   125         self._fp.writelines(self._headers)

   126         self._headers = []

   127 

   128     def startbody(self, ctype, plist=[], prefix=1):

   129         """Returns a file-like object for writing the body of the message.

   130 

   131         The content-type is set to the provided ctype, and the optional

   132         parameter, plist, provides additional parameters for the

   133         content-type declaration.  The optional argument prefix determines

   134         where the header is inserted; 0 means append at the end, 1 means

   135         insert at the start. The default is to insert at the start.

   136 

   137         """

   138         for name, value in plist:

   139             ctype = ctype + ';\n %s=\"%s\"' % (name, value)

   140         self.addheader("Content-Type", ctype, prefix=prefix)

   141         self.flushheaders()

   142         self._fp.write("\n")

   143         return self._fp

   144 

   145     def startmultipartbody(self, subtype, boundary=None, plist=[], prefix=1):

   146         """Returns a file-like object for writing the body of the message.

   147 

   148         Additionally, this method initializes the multi-part code, where the

   149         subtype parameter provides the multipart subtype, the boundary

   150         parameter may provide a user-defined boundary specification, and the

   151         plist parameter provides optional parameters for the subtype.  The

   152         optional argument, prefix, determines where the header is inserted;

   153         0 means append at the end, 1 means insert at the start. The default

   154         is to insert at the start.  Subparts should be created using the

   155         nextpart() method.

   156 

   157         """

   158         self._boundary = boundary or mimetools.choose_boundary()

   159         return self.startbody("multipart/" + subtype,

   160                               [("boundary", self._boundary)] + plist,

   161                               prefix=prefix)

   162 

   163     def nextpart(self):

   164         """Returns a new instance of MimeWriter which represents an

   165         individual part in a multipart message.

   166 

   167         This may be used to write the part as well as used for creating

   168         recursively complex multipart messages. The message must first be

   169         initialized with the startmultipartbody() method before using the

   170         nextpart() method.

   171 

   172         """

   173         self._fp.write("\n--" + self._boundary + "\n")

   174         return self.__class__(self._fp)

   175 

   176     def lastpart(self):

   177         """This is used to designate the last part of a multipart message.

   178 

   179         It should always be used when writing multipart messages.

   180 

   181         """

   182         self._fp.write("\n--" + self._boundary + "--\n")

   183 

   184 

   185 if __name__ == '__main__':

   186     import test.test_MimeWriter