Source Code for Module cherrypy.lib.http

  1  """HTTP library functions.""" 
  2   
  3  # This module contains functions for building an HTTP application 
  4  # framework: any one, not just one whose name starts with "Ch". ;) If you 
  5  # reference any modules from some popular framework inside *this* module, 
  6  # FuManChu will personally hang you up by your thumbs and submit you 
  7  # to a public caning. 
  8   
  9  from BaseHTTPServer import BaseHTTPRequestHandler 
 10  response_codes = BaseHTTPRequestHandler.responses.copy() 
 11   
 12  # From http://www.cherrypy.org/ticket/361 
 13  response_codes[500] = ('Internal Server Error', 
 14                        'The server encountered an unexpected condition ' 
 15                        'which prevented it from fulfilling the request.') 
 16  response_codes[503] = ('Service Unavailable', 
 17                        'The server is currently unable to handle the ' 
 18                        'request due to a temporary overloading or ' 
 19                        'maintenance of the server.') 
 20   
 21   
 22  import cgi 
 23  from email.Header import Header, decode_header 
 24  import re 
 25  import rfc822 
 26  HTTPDate = rfc822.formatdate 
 27  import time 
 28   
 29   
 30 -def urljoin(*atoms): 
 31      url = "/".join(atoms) 
 32      while "//" in url: 
 33          url = url.replace("//", "/") 
 34      return url 
 35   
 36 -def protocol_from_http(protocol_str): 
 37      """Return a protocol tuple from the given 'HTTP/x.y' string.""" 
 38      return int(protocol_str[5]), int(protocol_str[7]) 
 39   
 40 -def get_ranges(headervalue, content_length): 
 41      """Return a list of (start, stop) indices from a Range header, or None. 
 42       
 43      Each (start, stop) tuple will be composed of two ints, which are suitable 
 44      for use in a slicing operation. That is, the header "Range: bytes=3-6", 
 45      if applied against a Python string, is requesting resource[3:7]. This 
 46      function will return the list [(3, 7)]. 
 47       
 48      If this function return an empty list, you should return HTTP 416. 
 49      """ 
 50       
 51      if not headervalue: 
 52          return None 
 53       
 54      result = [] 
 55      bytesunit, byteranges = headervalue.split("=", 1) 
 56      for brange in byteranges.split(","): 
 57          start, stop = [x.strip() for x in brange.split("-", 1)] 
 58          if start: 
 59              if not stop: 
 60                  stop = content_length - 1 
 61              start, stop = map(int, (start, stop)) 
 62              if start >= content_length: 
 63                  # From rfc 2616 sec 14.16: 
 64                  # "If the server receives a request (other than one 
 65                  # including an If-Range request-header field) with an 
 66                  # unsatisfiable Range request-header field (that is, 
 67                  # all of whose byte-range-spec values have a first-byte-pos 
 68                  # value greater than the current length of the selected 
 69                  # resource), it SHOULD return a response code of 416 
 70                  # (Requested range not satisfiable)." 
 71                  continue 
 72              if stop < start: 
 73                  # From rfc 2616 sec 14.16: 
 74                  # "If the server ignores a byte-range-spec because it 
 75                  # is syntactically invalid, the server SHOULD treat 
 76                  # the request as if the invalid Range header field 
 77                  # did not exist. (Normally, this means return a 200 
 78                  # response containing the full entity)." 
 79                  return None 
 80              result.append((start, stop + 1)) 
 81          else: 
 82              if not stop: 
 83                  # See rfc quote above. 
 84                  return None 
 85              # Negative subscript (last N bytes) 
 86              result.append((content_length - int(stop), content_length)) 
 87       
 88      return result 
 89   
 90   
 91 -class HeaderElement(object): 
 92      """An element (with parameters) from an HTTP header's element list.""" 
 93       
 94 -    def __init__(self, value, params=None): 
 95          self.value = value 
 96          if params is None: 
 97              params = {} 
 98          self.params = params 
 99       
100 -    def __unicode__(self): 
101          p = [";%s=%s" % (k, v) for k, v in self.params.iteritems()] 
102          return u"%s%s" % (self.value, "".join(p)) 
103       
104 -    def __str__(self): 
105          return str(self.__unicode__()) 
106       
107 -    def parse(elementstr): 
108          """Transform 'token;key=val' to ('token', {'key': 'val'}).""" 
109          # Split the element into a value and parameters. The 'value' may 
110          # be of the form, "token=token", but we don't split that here. 
111          atoms = [x.strip() for x in elementstr.split(";")] 
112          initial_value = atoms.pop(0).strip() 
113          params = {} 
114          for atom in atoms: 
115              atom = [x.strip() for x in atom.split("=", 1) if x.strip()] 
116              key = atom.pop(0) 
117              if atom: 
118                  val = atom[0] 
119              else: 
120                  val = "" 
121              params[key] = val 
122          return initial_value, params 
123      parse = staticmethod(parse) 
124       
125 -    def from_str(cls, elementstr): 
126          """Construct an instance from a string of the form 'token;key=val'.""" 
127          ival, params = cls.parse(elementstr) 
128          return cls(ival, params) 
129      from_str = classmethod(from_str) 
130   
131   
132  q_separator = re.compile(r'; *q *=') 
133   
134 -class AcceptElement(HeaderElement): 
135      """An element (with parameters) from an Accept-* header's element list.""" 
136       
137 -    def from_str(cls, elementstr): 
138          qvalue = None 
139          # The first "q" parameter (if any) separates the initial 
140          # parameter(s) (if any) from the accept-params. 
141          atoms = q_separator.split(elementstr, 1) 
142          initial_value = atoms.pop(0).strip() 
143          if atoms: 
144              # The qvalue for an Accept header can have extensions. The other 
145              # headers cannot, but it's easier to parse them as if they did. 
146              qvalue = HeaderElement.from_str(atoms[0].strip()) 
147           
148          ival, params = cls.parse(initial_value) 
149          if qvalue is not None: 
150              params["q"] = qvalue 
151          return cls(ival, params) 
152      from_str = classmethod(from_str) 
153       
154 -    def qvalue(self): 
155          val = self.params.get("q", "1") 
156          if isinstance(val, HeaderElement): 
157              val = val.value 
158          return float(val) 
159      qvalue = property(qvalue, doc="The qvalue, or priority, of this value.") 
160       
161 -    def __cmp__(self, other): 
162          # If you sort a list of AcceptElement objects, they will be listed 
163          # in priority order; the most preferred value will be first. 
164          diff = cmp(other.qvalue, self.qvalue) 
165          if diff == 0: 
166              diff = cmp(str(other), str(self)) 
167          return diff 
168   
169   
170 -def header_elements(fieldname, fieldvalue): 
171      """Return a HeaderElement list from a comma-separated header str.""" 
172       
173      if not fieldvalue: 
174          return None 
175      headername = fieldname.lower() 
176       
177      result = [] 
178      for element in fieldvalue.split(","): 
179          if headername.startswith("accept") or headername == 'te': 
180              hv = AcceptElement.from_str(element) 
181          else: 
182              hv = HeaderElement.from_str(element) 
183          result.append(hv) 
184       
185      result.sort() 
186      return result 
187   
188 -def decode_TEXT(value): 
189      """Decode RFC-2047 TEXT (e.g. "=?utf-8?q?f=C3=BCr?=" -> u"f\xfcr").""" 
190      atoms = decode_header(value) 
191      decodedvalue = "" 
192      for atom, charset in atoms: 
193          if charset is not None: 
194              atom = atom.decode(charset) 
195          decodedvalue += atom 
196      return decodedvalue 
197   
198 -def valid_status(status): 
199      """Return legal HTTP status Code, Reason-phrase and Message. 
200       
201      The status arg must be an int, or a str that begins with an int. 
202       
203      If status is an int, or a str and  no reason-phrase is supplied, 
204      a default reason-phrase will be provided. 
205      """ 
206       
207      if not status: 
208          status = 200 
209       
210      status = str(status) 
211      parts = status.split(" ", 1) 
212      if len(parts) == 1: 
213          # No reason supplied. 
214          code, = parts 
215          reason = None 
216      else: 
217          code, reason = parts 
218          reason = reason.strip() 
219       
220      try: 
221          code = int(code) 
222      except ValueError: 
223          raise ValueError("Illegal response status from server " 
224                           "(%s is non-numeric)." % repr(code)) 
225       
226      if code < 100 or code > 599: 
227          raise ValueError("Illegal response status from server " 
228                           "(%s is out of range)." % repr(code)) 
229       
230      if code not in response_codes: 
231          # code is unknown but not illegal 
232          default_reason, message = "", "" 
233      else: 
234          default_reason, message = response_codes[code] 
235       
236      if reason is None: 
237          reason = default_reason 
238       
239      return code, reason, message 
240   
241   
242  image_map_pattern = re.compile(r"[0-9]+,[0-9]+") 
243   
244 -def parse_query_string(query_string, keep_blank_values=True): 
245      """Build a params dictionary from a query_string.""" 
246      if image_map_pattern.match(query_string): 
247          # Server-side image map. Map the coords to 'x' and 'y' 
248          # (like CGI::Request does). 
249          pm = query_string.split(",") 
250          pm = {'x': int(pm[0]), 'y': int(pm[1])} 
251      else: 
252          pm = cgi.parse_qs(query_string, keep_blank_values) 
253          for key, val in pm.items(): 
254              if len(val) == 1: 
255                  pm[key] = val[0] 
256      return pm 
257   
258 -def params_from_CGI_form(form): 
259      params = {} 
260      for key in form.keys(): 
261          value_list = form[key] 
262          if isinstance(value_list, list): 
263              params[key] = [] 
264              for item in value_list: 
265                  if item.filename is not None: 
266                      value = item # It's a file upload 
267                  else: 
268                      value = item.value # It's a regular field 
269                  params[key].append(value) 
270          else: 
271              if value_list.filename is not None: 
272                  value = value_list # It's a file upload 
273              else: 
274                  value = value_list.value # It's a regular field 
275              params[key] = value 
276      return params 
277   
278   
279 -class CaseInsensitiveDict(dict): 
280      """A case-insensitive dict subclass. 
281       
282      Each key is changed on entry to str(key).title(). 
283      """ 
284       
285 -    def __getitem__(self, key): 
286          return dict.__getitem__(self, str(key).title()) 
287       
288 -    def __setitem__(self, key, value): 
289          dict.__setitem__(self, str(key).title(), value) 
290       
291 -    def __delitem__(self, key): 
292          dict.__delitem__(self, str(key).title()) 
293       
294 -    def __contains__(self, key): 
295          return dict.__contains__(self, str(key).title()) 
296       
297 -    def get(self, key, default=None): 
298          return dict.get(self, str(key).title(), default) 
299       
300 -    def has_key(self, key): 
301          return dict.has_key(self, str(key).title()) 
302       
303 -    def update(self, E): 
304          for k in E.keys(): 
305              self[str(k).title()] = E[k] 
306       
307 -    def fromkeys(cls, seq, value=None): 
308          newdict = cls() 
309          for k in seq: 
310              newdict[str(k).title()] = value 
311          return newdict 
312      fromkeys = classmethod(fromkeys) 
313       
314 -    def setdefault(self, key, x=None): 
315          key = str(key).title() 
316          try: 
317              return self[key] 
318          except KeyError: 
319              self[key] = x 
320              return x 
321       
322 -    def pop(self, key, default): 
323          return dict.pop(self, str(key).title(), default) 
324   
325   
326 -class HeaderMap(CaseInsensitiveDict): 
327      """A dict subclass for HTTP request and response headers. 
328       
329      Each key is changed on entry to str(key).title(). This allows headers 
330      to be case-insensitive and avoid duplicates. 
331       
332      Values are header values (decoded according to RFC 2047 if necessary). 
333      """ 
334       
335 -    def elements(self, key): 
336          """Return a list of HeaderElements for the given header (or None).""" 
337          key = str(key).title() 
338          h = self.get(key) 
339          if h is None: 
340              return [] 
341          return header_elements(key, h) 
342       
343 -    def output(self, protocol=(1, 1)): 
344          """Transform self into a list of (name, value) tuples.""" 
345          header_list = [] 
346          for key, v in self.iteritems(): 
347              if isinstance(v, unicode): 
348                  # HTTP/1.0 says, "Words of *TEXT may contain octets 
349                  # from character sets other than US-ASCII." and 
350                  # "Recipients of header field TEXT containing octets 
351                  # outside the US-ASCII character set may assume that 
352                  # they represent ISO-8859-1 characters." 
353                  try: 
354                      v = v.encode("iso-8859-1") 
355                  except UnicodeEncodeError: 
356                      if protocol