Source Code for Module skytools.quoting

  1  # quoting.py 
  2   
  3  """Various helpers for string quoting/unquoting.""" 
  4   
  5  import psycopg, urllib, re 
  6   
  7  #  
  8  # SQL quoting 
  9  # 
 10   
 11 -def quote_literal(s): 
 12      """Quote a literal value for SQL. 
 13       
 14      Surronds it with single-quotes. 
 15      """ 
 16   
 17      if s == None: 
 18          return "null" 
 19      s = psycopg.QuotedString(str(s)) 
 20      return str(s) 
 21   
 22 -def quote_copy(s): 
 23      """Quoting for copy command.""" 
 24   
 25      if s == None: 
 26          return "\\N" 
 27      s = str(s) 
 28      s = s.replace("\\", "\\\\") 
 29      s = s.replace("\t", "\\t") 
 30      s = s.replace("\n", "\\n") 
 31      s = s.replace("\r", "\\r") 
 32      return s 
 33   
 34 -def quote_bytea_raw(s): 
 35      """Quoting for bytea parser.""" 
 36   
 37      if s == None: 
 38          return None 
 39      return s.replace("\\", "\\\\").replace("\0", "\\000") 
 40   
 41 -def quote_bytea_literal(s): 
 42      """Quote bytea for regular SQL.""" 
 43   
 44      return quote_literal(quote_bytea_raw(s)) 
 45   
 46 -def quote_bytea_copy(s): 
 47      """Quote bytea for COPY.""" 
 48   
 49      return quote_copy(quote_bytea_raw(s)) 
 50   
 51 -def quote_statement(sql, dict): 
 52      """Quote whose statement. 
 53   
 54      Data values are taken from dict. 
 55      """ 
 56      xdict = {} 
 57      for k, v in dict.items(): 
 58          xdict[k] = quote_literal(v) 
 59      return sql % xdict 
 60   
 61  # 
 62  # quoting for JSON strings 
 63  # 
 64   
 65  _jsre = re.compile(r'[\x00-\x1F\\/"]') 
 66  _jsmap = { "\b": "\\b", "\f": "\\f", "\n": "\\n", "\r": "\\r", 
 67      "\t": "\\t", "\\": "\\\\", '"': '\\"', 
 68      "/": "\\/",   # to avoid html attacks 
 69  } 
 70   
 71 -def _json_quote_char(m): 
 72      c = m.group(0) 
 73      try: 
 74          return _jsmap[c] 
 75      except KeyError: 
 76          return r"\u%04x" % ord(c) 
 77   
 78 -def quote_json(s): 
 79      """JSON style quoting.""" 
 80      if s is None: 
 81          return "null" 
 82      return '"%s"' % _jsre.sub(_json_quote_char, s) 
 83   
 84  # 
 85  # Database specific urlencode and urldecode. 
 86  # 
 87   
 88 -def db_urlencode(dict): 
 89      """Database specific urlencode. 
 90   
 91      Encode None as key without '='.  That means that in "foo&bar=", 
 92      foo is NULL and bar is empty string. 
 93      """ 
 94   
 95      elem_list = [] 
 96      for k, v in dict.items(): 
 97          if v is None: 
 98              elem = urllib.quote_plus(str(k)) 
 99          else: 
100              elem = urllib.quote_plus(str(k)) + '=' + urllib.quote_plus(str(v)) 
101          elem_list.append(elem) 
102      return '&'.join(elem_list) 
103   
104 -def db_urldecode(qs): 
105      """Database specific urldecode. 
106   
107      Decode key without '=' as None. 
108      This also does not support one key several times. 
109      """ 
110   
111      res = {} 
112      for elem in qs.split('&'): 
113          if not elem: 
114              continue 
115          pair = elem.split('=', 1) 
116          name = urllib.unquote_plus(pair[0]) 
117          if len(pair) == 1: 
118              res[name] = None 
119          else: 
120              res[name] = urllib.unquote_plus(pair[1]) 
121      return res 
122   
123  # 
124  # Remove C-like backslash escapes 
125  # 
126   
127  _esc_re = r"\\([0-7][0-7][0-7]|.)" 
128  _esc_rc = re.compile(_esc_re) 
129  _esc_map = { 
130      't': '\t', 
131      'n': '\n', 
132      'r': '\r', 
133      'a': '\a', 
134      'b': '\b', 
135      "'": "'", 
136      '"': '"', 
137      '\\': '\\', 
138  } 
139   
140 -def _sub_unescape(m): 
141      v = m.group(1) 
142      if len(v) == 1: 
143          return _esc_map[v] 
144      else: 
145          return chr(int(v, 8)) 
146   
147 -def unescape(val): 
148      """Removes C-style escapes from string.""" 
149      return _esc_rc.sub(_sub_unescape, val) 
150   
151 -def unescape_copy(val): 
152      """Removes C-style escapes, also converts "\N" to None.""" 
153      if val == r"\N": 
154          return None 
155      return unescape(val) 
156