| Guido van Rossum | c75db0b | 1996-08-26 16:33:30 +0000 | [diff] [blame^] | 1 | """Generic MIME writer. |
| 2 | |
| 3 | Classes: |
| 4 | |
| 5 | MimeWriter - the only thing here. |
| 6 | |
| 7 | """ |
| 8 | |
| 9 | __version__ = '$Revision$' |
| 10 | # $Source$ |
| 11 | |
| 12 | |
| 13 | import string |
| 14 | import mimetools |
| 15 | |
| 16 | |
| 17 | class MimeWriter: |
| 18 | |
| 19 | """Generic MIME writer. |
| 20 | |
| 21 | Methods: |
| 22 | |
| 23 | __init__() |
| 24 | addheader() |
| 25 | flushheaders() |
| 26 | startbody() |
| 27 | startmultipartbody() |
| 28 | nextpart() |
| 29 | lastpart() |
| 30 | |
| 31 | A MIME writer is much more primitive than a MIME parser. It |
| 32 | doesn't seek around on the output file, and it doesn't use large |
| 33 | amounts of buffer space, so you have to write the parts in the |
| 34 | order they should occur on the output file. It does buffer the |
| 35 | headers you add, allowing you to rearrange their order. |
| 36 | |
| 37 | General usage is: |
| 38 | |
| 39 | f = <open the output file> |
| 40 | w = MimeWriter(f) |
| 41 | ...call w.addheader(key, value) 0 or more times... |
| 42 | |
| 43 | followed by either: |
| 44 | |
| 45 | f = w.startbody(content_type) |
| 46 | ...call f.write(data) for body data... |
| 47 | |
| 48 | or: |
| 49 | |
| 50 | w.startmultipartbody(subtype) |
| 51 | for each part: |
| 52 | subwriter = w.nextpart() |
| 53 | ...use the subwriter's methods to create the subpart... |
| 54 | w.lastpart() |
| 55 | |
| 56 | The subwriter is another MimeWriter instance, and should be |
| 57 | treated in the same way as the toplevel MimeWriter. This way, |
| 58 | writing recursive body parts is easy. |
| 59 | |
| 60 | Warning: don't forget to call lastpart()! |
| 61 | |
| 62 | XXX There should be more state so calls made in the wrong order |
| 63 | are detected. |
| 64 | |
| 65 | Some special cases: |
| 66 | |
| 67 | - startbody() just returns the file passed to the constructor; |
| 68 | but don't use this knowledge, as it may be changed. |
| 69 | |
| 70 | - startmultipartbody() actually returns a file as well; |
| 71 | this can be used to write the initial 'if you can read this your |
| 72 | mailer is not MIME-aware' message. |
| 73 | |
| 74 | - If you call flushheaders(), the headers accumulated so far are |
| 75 | written out (and forgotten); this is useful if you don't need a |
| 76 | body part at all, e.g. for a subpart of type message/rfc822 |
| 77 | that's (mis)used to store some header-like information. |
| 78 | |
| 79 | - Passing a keyword argument 'prefix=<flag>' to addheader(), |
| 80 | start*body() affects where the header is inserted; 0 means |
| 81 | append at the end, 1 means insert at the start; default is |
| 82 | append for addheader(), but insert for start*body(), which use |
| 83 | it to determine where the Content-Type header goes. |
| 84 | |
| 85 | """ |
| 86 | |
| 87 | def __init__(self, fp): |
| 88 | self._fp = fp |
| 89 | self._headers = [] |
| 90 | |
| 91 | def addheader(self, key, value, prefix=0): |
| 92 | lines = string.splitfields(value, "\n") |
| 93 | while lines and not lines[-1]: del lines[-1] |
| 94 | while lines and not lines[0]: del lines[0] |
| 95 | for i in range(1, len(lines)): |
| 96 | lines[i] = " " + string.strip(lines[i]) |
| 97 | value = string.joinfields(lines, "\n") + "\n" |
| 98 | line = key + ": " + value |
| 99 | if prefix: |
| 100 | self._headers.insert(0, line) |
| 101 | else: |
| 102 | self._headers.append(line) |
| 103 | |
| 104 | def flushheaders(self): |
| 105 | self._fp.writelines(self._headers) |
| 106 | self._headers = [] |
| 107 | |
| 108 | def startbody(self, ctype, plist=[], prefix=1): |
| 109 | for name, value in plist: |
| 110 | ctype = ctype + ';\n %s=\"%s\"' % (name, value) |
| 111 | self.addheader("Content-Type", ctype, prefix=prefix) |
| 112 | self.flushheaders() |
| 113 | self._fp.write("\n") |
| 114 | return self._fp |
| 115 | |
| 116 | def startmultipartbody(self, subtype, boundary=None, plist=[], prefix=1): |
| 117 | self._boundary = boundary or mimetools.choose_boundary() |
| 118 | return self.startbody("multipart/" + subtype, |
| 119 | [("boundary", self._boundary)] + plist, |
| 120 | prefix=prefix) |
| 121 | |
| 122 | def nextpart(self): |
| 123 | self._fp.write("\n--" + self._boundary + "\n") |
| 124 | return self.__class__(self._fp) |
| 125 | |
| 126 | def lastpart(self): |
| 127 | self._fp.write("\n--" + self._boundary + "--\n") |
| 128 | |
| 129 | |
| 130 | if __name__ == '__main__': |
| 131 | print "To test the MimeWriter module, run TestMimeWriter.py." |