1 | # Copyright (C) 2007 STFC & NERC (Science and Technology Facilities Council). |
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2 | # This software may be distributed under the terms of the |
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3 | # Q Public License, version 1.0 or later. |
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4 | # http://ndg.nerc.ac.uk/public_docs/QPublic_license.txt |
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5 | """ |
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6 | Example WMS controller driven by CSML. |
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7 | |
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8 | @author: Stephen Pascoe |
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9 | |
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10 | """ |
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11 | from ows_server.lib.base import * |
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12 | from ows_server.lib.decorators import * |
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13 | from ows_server.lib import grid_util, render |
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14 | from ows_server.lib.csml_cache import csmlCache, extractCache |
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15 | import ows_server.lib.validators as V |
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16 | |
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17 | from elementtree import ElementTree as ET |
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18 | |
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19 | from ows_common import exceptions as OWS_E |
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20 | from ows_common.wms import * |
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21 | from ows_common.common import BoundingBox |
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22 | from ows_common.domain import ValuesUnit, PossibleValues |
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23 | |
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24 | import cdms |
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25 | import os, sys |
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26 | from cStringIO import StringIO |
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27 | import MA |
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28 | |
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29 | class CsmlWmsController(OwsController): |
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30 | |
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31 | _ows_parameters = { |
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32 | 'Format': make_domain(['text/xml']), |
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33 | 'ExceptionFormat': make_domain(['text/xml']), |
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34 | } |
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35 | |
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36 | #_ows_constraints = { |
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37 | # MaximumLayerLevels |
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38 | # MaximumWidth |
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39 | # MaximumWidth |
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40 | # } |
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41 | |
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42 | |
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43 | def _iterDimensions(self, feature): |
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44 | """ |
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45 | Retrieve the non-geospatial dimensions of a feature. |
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46 | |
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47 | @return: generator of dimension names |
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48 | |
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49 | """ |
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50 | # Waiting for this feature to be implemented |
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51 | #lat = feature.getLatitude() |
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52 | #lon = feature.getLongitude() |
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53 | lat = 'latitude'; lon = 'longitude' |
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54 | |
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55 | for axis_name in feature.getDomain(): |
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56 | if axis_name not in [lat, lon]: |
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57 | yield axis_name |
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58 | |
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59 | def _loadFeatureDimensions(self, feature): |
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60 | dims = {} |
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61 | domain = feature.getDomain() |
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62 | for axis_name in self._iterDimensions(feature): |
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63 | axis = domain[axis_name] |
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64 | dims[axis_name] = Dimension(possibleValues=PossibleValues.fromAllowedValues(axis), |
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65 | #!TODO: see ticket:770 for how to populate this |
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66 | valuesUnit=ValuesUnit(uoms=[''], |
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67 | referenceSystems=[''])) |
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68 | return dims |
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69 | |
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70 | def _loadFeatureSummary(self, feature): |
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71 | dims = self._loadFeatureDimensions(feature) |
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72 | |
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73 | return WmsDatasetSummary(identifier=feature.id, |
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74 | titles=[feature.description.CONTENT], |
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75 | boundingBoxes=[BoundingBox([-180,-90], [180,90], |
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76 | crs='CRS:84')], |
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77 | dimensions=dims, |
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78 | ) |
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79 | |
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80 | def _loadCapabilities(self): |
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81 | """ |
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82 | Overriding subclass to add layer capabilities |
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83 | |
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84 | """ |
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85 | # Get default capabilities from superclass |
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86 | sm = super(CsmlWmsController, self)._loadCapabilities() |
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87 | |
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88 | # For WMS 1.3.0 compatibility we need a single root DatasetSummary |
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89 | ds = WmsDatasetSummary(titles=['Root Dataset'], datasetSummaries=[], |
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90 | CRSs=['CRS:84']) |
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91 | # Add a DatasetSummary for each feature |
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92 | for f_n in c.dataset.getFeatureList(): |
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93 | feature_ds = self._loadFeatureSummary(c.dataset.getFeature(f_n)) |
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94 | ds.datasetSummaries.append(feature_ds) |
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95 | |
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96 | sm.contents = Contents(datasetSummaries=[ds]) |
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97 | return sm |
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98 | |
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99 | |
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100 | @operation |
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101 | @parameter('Format', possibleValues=['text/xml']) |
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102 | @parameter('Service', possibleValues=['WMS'], required=True) |
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103 | @parameter('Version', possibleValues=['1.3.0']) |
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104 | def GetCapabilities(self, file, service=None, version=None): |
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105 | """ |
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106 | @note: format and updatesequence parameters are not supported |
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107 | by this WMS. |
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108 | |
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109 | """ |
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110 | # Populate the context object with information required by the template |
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111 | c.dataset = csmlCache[file] |
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112 | |
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113 | return self._renderCapabilities('ows/wms_capabilities') |
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114 | |
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115 | |
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116 | @operation |
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117 | @parameter('Version', possibleValues=['1.3.0'], required=True) |
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118 | @parameter('Layers', required=True, validator=V.single_layer) |
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119 | @parameter('Styles', required=True) |
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120 | @parameter('CRS', possibleValues=['CRS:84'], required=True) |
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121 | @parameter('Bbox', required=True, validator=V.bbox_2d) |
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122 | @parameter('Width', required=True, validator=V.integer('Width')) |
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123 | @parameter('Height', required=True, validator=V.integer('Height')) |
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124 | @parameter('Format', required=True) |
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125 | @parameter('Transparent', validator=V.boolean('Transparent')) |
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126 | @parameter('Bgcolor') |
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127 | @parameter('Exceptions') |
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128 | # Dimension parameters Time, Elevation, etc. are handled separately |
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129 | def GetMap(self, file, version, layers, styles, crs, bbox, width, height, format, |
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130 | transparent=False, bgcolor=None, exceptions=None): |
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131 | |
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132 | # Retrieve dataset and selected feature |
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133 | dataset = csmlCache[file] |
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134 | feature = dataset.getFeature(layers) |
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135 | if feature is None: |
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136 | raise OWS_E.InvalidParameterValue('Layer not found', 'layers') |
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137 | |
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138 | # Clean up bbox. Openlayers can request some very strange bboxes. It is trimmed |
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139 | # here and the implications for the image's aspect ratio is calculated in |
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140 | # render.render_variable() |
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141 | #!TODO: This could be done better. |
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142 | #x1 = max(-180., min(180., bbox[0])) |
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143 | #x2 = max(-180., min(180., bbox[2])) |
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144 | #y1 = max(-90., min(90., bbox[1])) |
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145 | #y2 = max(-90., min(90., bbox[3])) |
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146 | |
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147 | # Define the extraction selector |
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148 | #sel = dict(latitude=(y1, y2), longitude=(x1, x2)) |
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149 | |
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150 | # Parse dimensions. |
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151 | sel = {} |
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152 | for dim in self._iterDimensions(feature): |
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153 | # For the moment hard-code time in. We don't support any other dimension yet. |
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154 | if dim.lower() != 'time': |
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155 | raise ValueError('Only lat, lon and time are supported domain axes') |
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156 | |
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157 | try: |
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158 | sel[dim] = self.ows_params[dim] |
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159 | except KeyError: |
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160 | raise OWS_E.MissingParameterValue('%s dimension not specified' % dim, dim) |
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161 | |
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162 | # Get the entire lat/lon slice from the extractCache |
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163 | var = extractCache[feature, sel] |
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164 | |
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165 | # Do geographical subsetting in cdms |
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166 | var = var(latitude=(bbox[1], bbox[3]), longitude=(bbox[0], bbox[2]), squeeze=1) |
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167 | |
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168 | # Deduce min and max |
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169 | #!TODO: How do we get the min/max? |
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170 | #varmin = MA.minimum(var, None) |
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171 | #varmax = MA.maximum(var, None) |
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172 | varmin=0; varmax=100 |
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173 | |
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174 | # Render variable to a PIL image |
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175 | img = render.render_variable(var, bbox, width, height, varmin, varmax) |
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176 | |
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177 | # Serialise it to PNG |
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178 | buf = StringIO() |
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179 | img.save(buf, 'PNG') |
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180 | |
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181 | return Response(content=buf.getvalue(), mimetype='image/png') |
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