manifold/metadata.py

   1 import json
   2
   3 from manifold.manifoldresult import ManifoldResult
   4 from manifold.manifoldapi import ManifoldAPI
   5
   6 debug=False
   7 debug=True
   8
   9 # turn this on if you want to work offline
  10 work_offline=False
  11 #work_offline=True
  12
  13 class MetaData:
  14
  15     def __init__ (self, auth):
  16         self.auth=auth
  17         self.hash_by_subject={}
  18
  19     def fetch (self):
  20         offline_filename="offline-metadata.json"
  21         if work_offline:
  22             try:
  23                 with file(offline_metadata) as f:
  24                     self.hash_by_subject=json.loads(f.read())
  25                 return
  26             except:
  27                 print "metadata.work_offline: failed to decode %s"%offline_filename
  28         manifold_api = ManifoldAPI(self.auth)
  29         fields = ['table', 'column.column',
  30                   'column.description','column.header', 'column.title',
  31                   'column.unit', 'column.info_type',
  32                   'column.resource_type', 'column.value_type',
  33                   'column.allowed_values', 'column.platforms.platform',
  34                   'column.platforms.platform_url']
  35         rows_result = manifold_api.Get('metadata:table', [], [], fields)
  36         rows = rows_result.ok_value()
  37         if not rows:
  38             print "Failed to retrieve metadata",rows_result.error()
  39         self.hash_by_subject = dict ( [ (row['table'], row) for row in rows ] )
  40         # save for next time we use offline mode
  41         if debug:
  42             with file(offline_filename,'w') as f:
  43                 f.write(json.dumps(self.hash_by_subject))
  44
  45     def to_json(self):
  46         return json.dumps(self.hash_by_subject)
  47
  48     def details_by_subject (self, subject):
  49         return self.hash_by_subject[subject]
  50
  51     def sorted_fields_by_subject (self, subject):
  52         return self.hash_by_subject[subject]['columns'].sort()
  53