summaryrefslogtreecommitdiff
path: root/examples/freebase-images-appengine/freebase/api/mqlkey.py
blob: d7dd01ba7084752f6306ad699cbd6a381a571a40 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
# ========================================================================
# Copyright (c) 2007, Metaweb Technologies, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY METAWEB TECHNOLOGIES AND CONTRIBUTORS
# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL METAWEB
# TECHNOLOGIES OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# ========================================================================

import string
import re

def quotekey(ustr):
    """
    quote a unicode string to turn it into a valid namespace key
    
    """
    valid_always = string.ascii_letters + string.digits
    valid_interior_only = valid_always + '_-'

    if isinstance(ustr, str):
        s = unicode(ustr,'utf-8')        
    elif isinstance(ustr, unicode):
        s = ustr
    else:
        raise ValueError, 'quotekey() expects utf-8 string or unicode'

    output = []
    if s[0] in valid_always:
        output.append(s[0])
    else:
        output.append('$%04X' % ord(s[0]))

    for c in s[1:-1]:
        if c in valid_interior_only:
            output.append(c)
        else:
            output.append('$%04X' % ord(c))

    if len(s) > 1:
        if s[-1] in valid_always:
            output.append(s[-1])
        else:
            output.append('$%04X' % ord(s[-1]))

    return str(''.join(output))


def unquotekey(key, encoding=None):
    """
    unquote a namespace key and turn it into a unicode string
    """

    valid_always = string.ascii_letters + string.digits

    output = []
    i = 0
    while i < len(key):
        if key[i] in valid_always:
            output.append(key[i])
            i += 1
        elif key[i] in '_-' and i != 0 and i != len(key):
            output.append(key[i])
            i += 1
        elif key[i] == '$' and i+4 < len(key):
            # may raise ValueError if there are invalid characters
            output.append(unichr(int(key[i+1:i+5],16)))
            i += 5
        else:
            raise ValueError, "unquote key saw invalid character '%s' at position %d" % (key[i], i)

    ustr = u''.join(output)
    
    if encoding is None:
        return ustr

    return ustr.encode(encoding)


# should this also include "'()" into safe?
def urlencode_pathseg(data):
    '''
    urlencode for placement between slashes in an url.
    '''
    if isinstance(data, unicode):
        data = data.encode('utf_8')
    return urllib.quote(data, "~:@$!*,;=&+")


def id_to_urlid(id):
    """
    convert a mql id to an id suitable for embedding in a url path.
    """

    segs = id.split('/')

    assert isinstance(id, str) and id != '', 'bad id "%s"' % id

    if id[0] == '~':
        assert len(segs) == 1
        # assume valid, should check
        return id

    if id[0] == '#':
        assert len(segs) == 1
        # assume valid, should check
        return '%23' + id[1:]

    if id[0] != '/':
        raise ValueError, 'unknown id format %s' % id

    # ok, we have a slash-path
    # requote components as keys and rejoin.
    # urlids do not have leading slashes!!!
    return '/'.join(urlencode_pathseg(unquotekey(seg)) for seg in segs[1:])