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

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

# rfc3339.py -- Implementation of the majority of RFC 3339 for python. 

# Copyright (c) 2008, 2009, 2010 LShift Ltd. <query@lshift.net> 

# 

# Permission is hereby granted, free of charge, to any person obtaining a copy 

# of this software and associated documentation files (the "Software"), to deal 

# in the Software without restriction, including without limitation the rights 

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 

# copies of the Software, and to permit persons to whom the Software is 

# furnished to do so, subject to the following conditions: 

# 

# The above copyright notice and this permission notice shall be included in 

# all copies or substantial portions of the Software. 

# 

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 

# THE SOFTWARE. 

 

""" 

Implementation of the majority of http://www.ietf.org/rfc/rfc3339.txt. 

 

Use datetime.datetime.isoformat() as an inverse of the various parsing 

routines in this module. 

 

Limitations, with respect to RFC 3339: 

 

- Section 4.3, "Unknown Local Offset Convention", is not implemented. 

 

- Section 5.6, "Internet Date/Time Format", is the ONLY supported format 

   implemented by the various parsers in this module. (Section 5.6 is 

   reproduced in its entirety below.) 

 

- Section 5.7, "Restrictions", is left to the datetime.datetime constructor 

   to implement, with the exception of limits on timezone 

   minutes-east-of-UTC magnitude. In particular, leap seconds are not 

   addressed by this module. (And it appears that they are not supported 

   by datetime, either.) 

 

Potential Improvements: 

 

- Support for leap seconds. (There's a table of them in RFC 3339 itself, 

   and http://tf.nist.gov/pubs/bulletin/leapsecond.htm updates monthly.) 

 

Here's an excerpt from RFC 3339 itself: 

 

5.6. Internet Date/Time Format 

 

   The following profile of ISO 8601 [ISO8601] dates SHOULD be used in 

   new protocols on the Internet.  This is specified using the syntax 

   description notation defined in [ABNF]. 

 

   date-fullyear   = 4DIGIT 

   date-month      = 2DIGIT  ; 01-12 

   date-mday       = 2DIGIT  ; 01-28, 01-29, 01-30, 01-31 based on 

                             ; month/year 

   time-hour       = 2DIGIT  ; 00-23 

   time-minute     = 2DIGIT  ; 00-59 

   time-second     = 2DIGIT  ; 00-58, 00-59, 00-60 based on leap second 

                             ; rules 

   time-secfrac    = "." 1*DIGIT 

   time-numoffset  = ("+" / "-") time-hour ":" time-minute 

   time-offset     = "Z" / time-numoffset 

 

   partial-time    = time-hour ":" time-minute ":" time-second 

                     [time-secfrac] 

   full-date       = date-fullyear "-" date-month "-" date-mday 

   full-time       = partial-time time-offset 

 

   date-time       = full-date "T" full-time 

 

      NOTE: Per [ABNF] and ISO8601, the "T" and "Z" characters in this 

      syntax may alternatively be lower case "t" or "z" respectively. 

 

      This date/time format may be used in some environments or contexts 

      that distinguish between the upper- and lower-case letters 'A'-'Z' 

      and 'a'-'z' (e.g. XML).  Specifications that use this format in 

      such environments MAY further limit the date/time syntax so that 

      the letters 'T' and 'Z' used in the date/time syntax must always 

      be upper case.  Applications that generate this format SHOULD use 

      upper case letters. 

 

      NOTE: ISO 8601 defines date and time separated by "T". 

      Applications using this syntax may choose, for the sake of 

      readability, to specify a full-date and full-time separated by 

      (say) a space character. 

""" 

 

import datetime, time, calendar 

import re 

 

__all__ = ["tzinfo", "UTC_TZ", "parse_date", "parse_datetime", "now", "utcfromtimestamp", "utctotimestamp", "datetimetostr", "timestamptostr", "strtotimestamp"] 

 

ZERO = datetime.timedelta(0) 

 

class tzinfo(datetime.tzinfo): 

    """ 

    Implementation of a fixed-offset tzinfo. 

    """ 

    def __init__(self, minutesEast, name): 

        """ 

        minutesEast -> number of minutes east of UTC that this tzinfo represents. 

        name -> symbolic (but uninterpreted) name of this tzinfo. 

        """ 

        self.minutesEast = minutesEast 

        self.offset = datetime.timedelta(minutes = minutesEast) 

        self.name = name 

 

    def utcoffset(self, dt): 

        """Returns minutesEast from the constructor, as a datetime.timedelta.""" 

        return self.offset 

 

    def dst(self, dt): 

        """This is a fixed offset tzinfo, so always returns a zero timedelta.""" 

        return ZERO 

 

    def tzname(self, dt): 

        """Returns the name from the constructor.""" 

        return self.name 

 

    def __repr__(self): 

        """If minutesEast==0, prints specially as rfc3339.UTC_TZ.""" 

        if self.minutesEast == 0: 

            return "rfc3339.UTC_TZ" 

        else: 

            return "rfc3339.tzinfo(%s,%s)" % (self.minutesEast, repr(self.name)) 

 

UTC_TZ = tzinfo(0, 'Z') 

 

date_re_str = r'(\d\d\d\d)-(\d\d)-(\d\d)' 

time_re_str = r'(\d\d):(\d\d):(\d\d)(\.(\d+))?([zZ]|(([-+])(\d\d):(\d\d)))' 

 

def make_re(*parts): 

    return re.compile(r'^\s*' + ''.join(parts) + r'\s*$') 

 

date_re = make_re(date_re_str) 

datetime_re = make_re(date_re_str, r'[ tT]', time_re_str) 

 

def parse_date(s): 

    """ 

    Given a string matching the 'full-date' production above, returns 

    a datetime.date instance. Any deviation from the allowed format 

    will produce a raised ValueError. 

 

    >>> parse_date("2008-08-24") 

    datetime.date(2008, 8, 24) 

    >>> parse_date("   2008-08-24       ") 

    datetime.date(2008, 8, 24) 

    >>> parse_date("2008-08-00") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 134, in parse_date 

        return datetime.date(int(y), int(m), int(d)) 

    ValueError: day is out of range for month 

    >>> parse_date("2008-06-31") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 134, in parse_date 

        return datetime.date(int(y), int(m), int(d)) 

    ValueError: day is out of range for month 

    >>> parse_date("2008-13-01") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 134, in parse_date 

        return datetime.date(int(y), int(m), int(d)) 

    ValueError: month must be in 1..12 

    >>> parse_date("22008-01-01") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 136, in parse_date 

        raise ValueError('Invalid RFC 3339 date string', s) 

    ValueError: ('Invalid RFC 3339 date string', '22008-01-01') 

    >>> parse_date("2008-08-24").isoformat() 

    '2008-08-24' 

    """ 

    m = date_re.match(s) 

    if m: 

        (y, m, d) = m.groups() 

        return datetime.date(int(y), int(m), int(d)) 

    else: 

        raise ValueError('Invalid RFC 3339 date string', s) 

 

def parse_datetime(s): 

    """ 

    Given a string matching the 'date-time' production above, returns 

    a datetime.datetime instance. Any deviation from the allowed 

    format will produce a raised ValueError. 

 

    >>> parse_datetime("2008-08-24T00:00:00Z") 

    datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) 

    >>> parse_datetime("   2008-08-24T00:00:00Z ") 

    datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) 

    >>> parse_datetime("2008-08-24T00:00:00") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 208, in parse_datetime 

        raise ValueError('Invalid RFC 3339 datetime string', s) 

    ValueError: ('Invalid RFC 3339 datetime string', '2008-08-24T00:00:00') 

    >>> parse_datetime("2008-08-24T00:00:00+00:00") 

    datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) 

    >>> parse_datetime("2008-08-24T00:00:00+01:00") 

    datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.tzinfo(60,'+01:00')) 

    >>> parse_datetime("2008-08-24T00:00:00-01:00") 

    datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.tzinfo(-60,'-01:00')) 

    >>> parse_datetime("2008-08-24T24:00:00Z") 

    Traceback (most recent call last): 

      File "<stdin>", line 1, in <module> 

      File "rfc3339.py", line 206, in parse_datetime 

        tz) 

    ValueError: hour must be in 0..23 

    >>> midnightUTC = parse_datetime("2008-08-24T00:00:00Z") 

    >>> oneamBST = parse_datetime("2008-08-24T01:00:00+01:00") 

    >>> midnightUTC == oneamBST 

    True 

    >>> elevenpmUTC = parse_datetime("2008-08-23T23:00:00Z") 

    >>> midnightBST = parse_datetime("2008-08-24T00:00:00+01:00") 

    >>> midnightBST == elevenpmUTC 

    True 

    >>> elevenpmUTC.isoformat() 

    '2008-08-23T23:00:00+00:00' 

    >>> oneamBST.isoformat() 

    '2008-08-24T01:00:00+01:00' 

    >>> parse_datetime("2008-08-24T00:00:00.123Z").isoformat() 

    '2008-08-24T00:00:00.123000+00:00' 

    """ 

    m = datetime_re.match(s) 

    if m: 

        (y, m, d, hour, min, sec, ignore1, frac_sec, wholetz, ignore2, tzsign, tzhour, tzmin) = \ 

            m.groups() 

 

        if frac_sec: 

            frac_sec = float("0." + frac_sec) 

        else: 

            frac_sec = 0 

        microsec = int((frac_sec * 1000000) + 0.5) 

 

        if wholetz == 'z' or wholetz == 'Z': 

            tz = UTC_TZ 

        else: 

            tzhour = int(tzhour) 

            tzmin = int(tzmin) 

            offset = tzhour * 60 + tzmin 

            if offset == 0: 

                tz = UTC_TZ 

            else: 

                if tzhour > 24 or tzmin > 60 or offset > 1439: ## see tzinfo docs for the 1439 part 

                    raise ValueError('Invalid timezone offset', s, wholetz) 

 

                if tzsign == '-': 

                    offset = -offset 

                tz = tzinfo(offset, wholetz) 

 

        return datetime.datetime(int(y), int(m), int(d), 

                                 int(hour), int(min), int(sec), microsec, 

                                 tz) 

    else: 

        raise ValueError('Invalid RFC 3339 datetime string', s) 

 

def now(): 

    """Return a timezone-aware datetime.datetime object in 

    rfc3339.UTC_TZ timezone, representing the current moment 

    (time.time()). Useful as a replacement for the (timezone-unaware) 

    datetime.datetime.now() method.""" 

    return utcfromtimestamp(time.time()) 

 

def utcfromtimestamp(unix_epoch_timestamp): 

    """Interprets its argument as a count of seconds elapsed since the 

    Unix epoch, and returns a datetime.datetime in rfc3339.UTC_TZ 

    timezone.""" 

    (y, m, d, hour, min, sec) = time.gmtime(unix_epoch_timestamp)[:6] 

    return datetime.datetime(y, m, d, hour, min, sec, 0, UTC_TZ) 

 

def utctotimestamp(dt): 

    """Returns a count of the elapsed seconds between the Unix epoch 

    and the passed-in datetime.datetime object.""" 

    return calendar.timegm(dt.utctimetuple()) 

 

def datetimetostr(dt): 

    """Return a RFC3339 date-time string corresponding to the given 

    datetime object.""" 

    if dt.utcoffset() is not None: 

        return dt.isoformat() 

    else: 

        return "%sZ" % dt.isoformat() 

 

def timestamptostr(ts): 

    """Return a RFC3339 date-time string corresponding to the given 

    Unix-epoch timestamp.""" 

    return datetimetostr(utcfromtimestamp(ts)) 

 

def strtotimestamp(s): 

    """Return the Unix-epoch timestamp corresponding to the given RFC3339 

    date-time string.""" 

    return utctotimestamp(parse_datetime(s))