| 1 | #! /usr/bin/env python |
| 2 | |
| 3 | """Conversions to/from quoted-printable transport encoding as per RFC 1521.""" |
| 4 | |
| 5 | # (Dec 1991 version). |
| 6 | |
| 7 | __all__ = ["encode", "decode", "encodestring", "decodestring"] |
| 8 | |
| 9 | ESCAPE = '=' |
| 10 | MAXLINESIZE = 76 |
| 11 | HEX = '0123456789ABCDEF' |
| 12 | EMPTYSTRING = '' |
| 13 | |
| 14 | try: |
| 15 | from binascii import a2b_qp, b2a_qp |
| 16 | except ImportError: |
| 17 | a2b_qp = None |
| 18 | b2a_qp = None |
| 19 | |
| 20 | |
| 21 | def needsquoting(c, quotetabs, header): |
| 22 | """Decide whether a particular character needs to be quoted. |
| 23 | |
| 24 | The 'quotetabs' flag indicates whether embedded tabs and spaces should be |
| 25 | quoted. Note that line-ending tabs and spaces are always encoded, as per |
| 26 | RFC 1521. |
| 27 | """ |
| 28 | if c in ' \t': |
| 29 | return quotetabs |
| 30 | # if header, we have to escape _ because _ is used to escape space |
| 31 | if c == '_': |
| 32 | return header |
| 33 | return c == ESCAPE or not (' ' <= c <= '~') |
| 34 | |
| 35 | def quote(c): |
| 36 | """Quote a single character.""" |
| 37 | i = ord(c) |
| 38 | return ESCAPE + HEX[i//16] + HEX[i%16] |
| 39 | |
| 40 | |
| 41 | |
| 42 | def encode(input, output, quotetabs, header = 0): |
| 43 | """Read 'input', apply quoted-printable encoding, and write to 'output'. |
| 44 | |
| 45 | 'input' and 'output' are files with readline() and write() methods. |
| 46 | The 'quotetabs' flag indicates whether embedded tabs and spaces should be |
| 47 | quoted. Note that line-ending tabs and spaces are always encoded, as per |
| 48 | RFC 1521. |
| 49 | The 'header' flag indicates whether we are encoding spaces as _ as per |
| 50 | RFC 1522. |
| 51 | """ |
| 52 | |
| 53 | if b2a_qp is not None: |
| 54 | data = input.read() |
| 55 | odata = b2a_qp(data, quotetabs = quotetabs, header = header) |
| 56 | output.write(odata) |
| 57 | return |
| 58 | |
| 59 | def write(s, output=output, lineEnd='\n'): |
| 60 | # RFC 1521 requires that the line ending in a space or tab must have |
| 61 | # that trailing character encoded. |
| 62 | if s and s[-1:] in ' \t': |
| 63 | output.write(s[:-1] + quote(s[-1]) + lineEnd) |
| 64 | elif s == '.': |
| 65 | output.write(quote(s) + lineEnd) |
| 66 | else: |
| 67 | output.write(s + lineEnd) |
| 68 | |
| 69 | prevline = None |
| 70 | while 1: |
| 71 | line = input.readline() |
| 72 | if not line: |
| 73 | break |
| 74 | outline = [] |
| 75 | # Strip off any readline induced trailing newline |
| 76 | stripped = '' |
| 77 | if line[-1:] == '\n': |
| 78 | line = line[:-1] |
| 79 | stripped = '\n' |
| 80 | # Calculate the un-length-limited encoded line |
| 81 | for c in line: |
| 82 | if needsquoting(c, quotetabs, header): |
| 83 | c = quote(c) |
| 84 | if header and c == ' ': |
| 85 | outline.append('_') |
| 86 | else: |
| 87 | outline.append(c) |
| 88 | # First, write out the previous line |
| 89 | if prevline is not None: |
| 90 | write(prevline) |
| 91 | # Now see if we need any soft line breaks because of RFC-imposed |
| 92 | # length limitations. Then do the thisline->prevline dance. |
| 93 | thisline = EMPTYSTRING.join(outline) |
| 94 | while len(thisline) > MAXLINESIZE: |
| 95 | # Don't forget to include the soft line break `=' sign in the |
| 96 | # length calculation! |
| 97 | write(thisline[:MAXLINESIZE-1], lineEnd='=\n') |
| 98 | thisline = thisline[MAXLINESIZE-1:] |
| 99 | # Write out the current line |
| 100 | prevline = thisline |
| 101 | # Write out the last line, without a trailing newline |
| 102 | if prevline is not None: |
| 103 | write(prevline, lineEnd=stripped) |
| 104 | |
| 105 | def encodestring(s, quotetabs = 0, header = 0): |
| 106 | if b2a_qp is not None: |
| 107 | return b2a_qp(s, quotetabs = quotetabs, header = header) |
| 108 | from cStringIO import StringIO |
| 109 | infp = StringIO(s) |
| 110 | outfp = StringIO() |
| 111 | encode(infp, outfp, quotetabs, header) |
| 112 | return outfp.getvalue() |
| 113 | |
| 114 | |
| 115 | |
| 116 | def decode(input, output, header = 0): |
| 117 | """Read 'input', apply quoted-printable decoding, and write to 'output'. |
| 118 | 'input' and 'output' are files with readline() and write() methods. |
| 119 | If 'header' is true, decode underscore as space (per RFC 1522).""" |
| 120 | |
| 121 | if a2b_qp is not None: |
| 122 | data = input.read() |
| 123 | odata = a2b_qp(data, header = header) |
| 124 | output.write(odata) |
| 125 | return |
| 126 | |
| 127 | new = '' |
| 128 | while 1: |
| 129 | line = input.readline() |
| 130 | if not line: break |
| 131 | i, n = 0, len(line) |
| 132 | if n > 0 and line[n-1] == '\n': |
| 133 | partial = 0; n = n-1 |
| 134 | # Strip trailing whitespace |
| 135 | while n > 0 and line[n-1] in " \t\r": |
| 136 | n = n-1 |
| 137 | else: |
| 138 | partial = 1 |
| 139 | while i < n: |
| 140 | c = line[i] |
| 141 | if c == '_' and header: |
| 142 | new = new + ' '; i = i+1 |
| 143 | elif c != ESCAPE: |
| 144 | new = new + c; i = i+1 |
| 145 | elif i+1 == n and not partial: |
| 146 | partial = 1; break |
| 147 | elif i+1 < n and line[i+1] == ESCAPE: |
| 148 | new = new + ESCAPE; i = i+2 |
| 149 | elif i+2 < n and ishex(line[i+1]) and ishex(line[i+2]): |
| 150 | new = new + chr(unhex(line[i+1:i+3])); i = i+3 |
| 151 | else: # Bad escape sequence -- leave it in |
| 152 | new = new + c; i = i+1 |
| 153 | if not partial: |
| 154 | output.write(new + '\n') |
| 155 | new = '' |
| 156 | if new: |
| 157 | output.write(new) |
| 158 | |
| 159 | def decodestring(s, header = 0): |
| 160 | if a2b_qp is not None: |
| 161 | return a2b_qp(s, header = header) |
| 162 | from cStringIO import StringIO |
| 163 | infp = StringIO(s) |
| 164 | outfp = StringIO() |
| 165 | decode(infp, outfp, header = header) |
| 166 | return outfp.getvalue() |
| 167 | |
| 168 | |
| 169 | |
| 170 | # Other helper functions |
| 171 | def ishex(c): |
| 172 | """Return true if the character 'c' is a hexadecimal digit.""" |
| 173 | return '0' <= c <= '9' or 'a' <= c <= 'f' or 'A' <= c <= 'F' |
| 174 | |
| 175 | def unhex(s): |
| 176 | """Get the integer value of a hexadecimal number.""" |
| 177 | bits = 0 |
| 178 | for c in s: |
| 179 | if '0' <= c <= '9': |
| 180 | i = ord('0') |
| 181 | elif 'a' <= c <= 'f': |
| 182 | i = ord('a')-10 |
| 183 | elif 'A' <= c <= 'F': |
| 184 | i = ord('A')-10 |
| 185 | else: |
| 186 | break |
| 187 | bits = bits*16 + (ord(c) - i) |
| 188 | return bits |
| 189 | |
| 190 | |
| 191 | |
| 192 | def main(): |
| 193 | import sys |
| 194 | import getopt |
| 195 | try: |
| 196 | opts, args = getopt.getopt(sys.argv[1:], 'td') |
| 197 | except getopt.error, msg: |
| 198 | sys.stdout = sys.stderr |
| 199 | print msg |
| 200 | print "usage: quopri [-t | -d] [file] ..." |
| 201 | print "-t: quote tabs" |
| 202 | print "-d: decode; default encode" |
| 203 | sys.exit(2) |
| 204 | deco = 0 |
| 205 | tabs = 0 |
| 206 | for o, a in opts: |
| 207 | if o == '-t': tabs = 1 |
| 208 | if o == '-d': deco = 1 |
| 209 | if tabs and deco: |
| 210 | sys.stdout = sys.stderr |
| 211 | print "-t and -d are mutually exclusive" |
| 212 | sys.exit(2) |
| 213 | if not args: args = ['-'] |
| 214 | sts = 0 |
| 215 | for file in args: |
| 216 | if file == '-': |
| 217 | fp = sys.stdin |
| 218 | else: |
| 219 | try: |
| 220 | fp = open(file) |
| 221 | except IOError, msg: |
| 222 | sys.stderr.write("%s: can't open (%s)\n" % (file, msg)) |
| 223 | sts = 1 |
| 224 | continue |
| 225 | if deco: |
| 226 | decode(fp, sys.stdout) |
| 227 | else: |
| 228 | encode(fp, sys.stdout, tabs) |
| 229 | if fp is not sys.stdin: |
| 230 | fp.close() |
| 231 | if sts: |
| 232 | sys.exit(sts) |
| 233 | |
| 234 | |
| 235 | |
| 236 | if __name__ == '__main__': |
| 237 | main() |