1 | #============================================================================ |
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2 | # This library is free software; you can redistribute it and/or |
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3 | # modify it under the terms of version 2.1 of the GNU Lesser General Public |
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4 | # License as published by the Free Software Foundation. |
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5 | # |
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6 | # This library is distributed in the hope that it will be useful, |
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7 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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8 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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9 | # Lesser General Public License for more details. |
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10 | # |
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11 | # You should have received a copy of the GNU Lesser General Public |
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12 | # License along with this library; if not, write to the Free Software |
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13 | # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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14 | #============================================================================ |
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15 | # Copyright (C) 2004, 2005 Mike Wray <mike.wray@hp.com> |
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16 | #============================================================================ |
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17 | |
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18 | import types |
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19 | import StringIO |
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20 | |
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21 | from xen.xend import sxp |
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22 | |
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23 | class ArgError(StandardError): |
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24 | pass |
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25 | |
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26 | class Args: |
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27 | """Argument encoding support for HTTP. |
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28 | """ |
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29 | |
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30 | def __init__(self, paramspec, keyspec): |
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31 | self.arg_ord = [] |
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32 | self.arg_dict = {} |
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33 | self.key_ord = [] |
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34 | self.key_dict = {} |
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35 | for (name, typ) in paramspec: |
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36 | self.arg_ord.append(name) |
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37 | self.arg_dict[name] = typ |
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38 | for (name, typ) in keyspec: |
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39 | self.key_ord.append(name) |
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40 | self.key_dict[name] = typ |
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41 | |
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42 | def get_args(self, d, xargs=None): |
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43 | args = {} |
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44 | keys = {} |
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45 | params = [] |
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46 | if xargs: |
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47 | self.split_args(xargs, args, keys) |
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48 | self.split_args(d, args, keys) |
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49 | for a in self.arg_ord: |
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50 | if a in args: |
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51 | params.append(args[a]) |
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52 | else: |
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53 | raise ArgError('Missing parameter: %s' % a) |
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54 | return (params, keys) |
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55 | |
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56 | def split_args(self, d, args, keys): |
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57 | for (k, v) in d.items(): |
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58 | if k in self.arg_dict: |
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59 | typ = self.arg_dict[k] |
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60 | val = self.coerce(typ, v) |
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61 | args[k] = val |
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62 | elif k in self.key_dict: |
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63 | typ = self.key_dict[k] |
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64 | val = self.coerce(typ, v) |
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65 | keys[k] = val |
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66 | else: |
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67 | raise ArgError('Invalid parameter: %s' % k) |
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68 | |
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69 | def get_form_args(self, f, xargs=None): |
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70 | d = {} |
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71 | for (k, v) in f.items(): |
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72 | if ((k not in self.arg_dict) and |
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73 | (k not in self.key_dict)): |
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74 | continue |
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75 | if isinstance(v, types.ListType): |
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76 | n = len(v) |
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77 | if n == 0: |
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78 | continue |
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79 | elif n == 1: |
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80 | val = v[0] |
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81 | else: |
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82 | raise ArgError('Too many values for %s' % k) |
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83 | else: |
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84 | val = v |
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85 | d[k] = val |
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86 | return self.get_args(d, xargs=xargs) |
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87 | |
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88 | def coerce(self, typ, v): |
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89 | try: |
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90 | if typ == 'int': |
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91 | val = int(v) |
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92 | elif typ == 'long': |
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93 | val = long(v) |
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94 | elif typ == 'str': |
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95 | val = str(v) |
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96 | elif typ == 'sxpr': |
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97 | val = self.sxpr(v) |
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98 | elif typ == 'bool': |
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99 | val = self.bool(v) |
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100 | else: |
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101 | raise ArgError('invalid type:' + str(typ)) |
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102 | return val |
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103 | except ArgError: |
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104 | raise |
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105 | except StandardError, ex: |
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106 | raise ArgError(str(ex)) |
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107 | |
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108 | def bool(self, v): |
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109 | return (v.lower() in ['on', 'yes', '1', 'true']) |
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110 | |
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111 | def sxpr(self, v): |
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112 | if isinstance(v, types.ListType): |
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113 | val = v |
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114 | elif isinstance(v, types.FileType) or hasattr(v, 'readline'): |
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115 | val = self.sxpr_file(v) |
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116 | elif isinstance(v, types.StringType): |
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117 | val = self.sxpr_file(StringIO.StringIO(v)) |
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118 | else: |
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119 | val = str(v) |
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120 | return val |
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121 | |
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122 | def sxpr_file(self, fin): |
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123 | try: |
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124 | vals = sxp.parse(fin) |
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125 | except: |
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126 | raise ArgError('Coercion to sxpr failed') |
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127 | if len(vals) == 1: |
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128 | return vals[0] |
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129 | else: |
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130 | raise ArgError('Too many sxprs') |
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131 | |
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132 | def call_with_args(self, fn, args, xargs=None): |
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133 | (params, keys) = self.get_args(args, xargs=xargs) |
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134 | return fn(*params, **keys) |
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135 | |
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136 | def call_with_form_args(self, fn, fargs, xargs=None): |
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137 | (params, keys) = self.get_form_args(fargs, xargs=xargs) |
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138 | return fn(*params, **keys) |
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139 | |
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140 | class ArgFn(Args): |
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141 | """Represent a remote HTTP operation as a function. |
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142 | Used on the client. |
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143 | """ |
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144 | |
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145 | def __init__(self, fn, paramspec, keyspec = None): |
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146 | if keyspec == None: |
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147 | keyspec = {} |
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148 | Args.__init__(self, paramspec, keyspec) |
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149 | self.fn = fn |
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150 | |
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151 | def __call__(self, fargs, xargs=None): |
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152 | return self.call_with_args(self.fn, fargs, xargs=xargs) |
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153 | |
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154 | class FormFn(Args): |
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155 | """Represent an operation as a function over a form. |
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156 | Used in the HTTP server. |
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157 | """ |
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158 | |
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159 | def __init__(self, fn, paramspec, keyspec = None): |
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160 | if keyspec == None: |
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161 | keyspec = {} |
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162 | Args.__init__(self, paramspec, keyspec) |
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163 | self.fn = fn |
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164 | |
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165 | def __call__(self, fargs, xargs=None): |
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166 | return self.call_with_form_args(self.fn, fargs, xargs=xargs) |
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