migrations/extract-views.py

   1 #!/usr/bin/env python3
   2
   3 import sys
   4 import re
   5
   6 class Schema:
   7
   8     def __init__ (self,input,output=None):
   9         self.input=input
  10         self.output=output
  11
  12     # left part is non-greedy
  13     comment = re.compile("(.*?)--.*")
  14     spaces = re.compile("^\s+(\S.*)")
  15     view = re.compile("(?i)\s*create\s+(or\s+replace)?\s+view.*")
  16
  17     def parse (self):
  18         if self.output:
  19             outfile = open(self.output, "a")
  20         else:
  21             outfile = sys.stdout
  22         with open(self.input) as feed:
  23             contents = feed.read()
  24         parts = contents.split(";")
  25         for part in parts:
  26             # normalize: remove comments, linebreaks, trailing spaces..
  27             normalized=''
  28             lines=part.split('\n');
  29             out_lines = []
  30             for line in lines:
  31                 # remove comment
  32                 match = Schema.comment.match(line)
  33                 if match:
  34                     line = match.group(1)
  35                 out_lines.append(line)
  36             # get them together
  37             out_line = " ".join(out_lines)
  38             # remove trailing spaces
  39             match = Schema.spaces.match(out_line)
  40             if match:
  41                 out_line = match.group(1)
  42             match = Schema.view.match(out_line)
  43             if match:
  44                 outfile.write("{};\n".format(out_line))
  45         if outfile != sys.stdout:
  46             outfile.close()
  47
  48 if __name__ == '__main__':
  49     if len(sys.argv) not in [2, 3]:
  50         print('Usage:', sys.argv[0], 'input [output]')
  51         sys.exit(1)
  52     input = sys.argv[1]
  53     try:
  54         output = sys.argv[2]
  55     except:
  56         output = None
  57     Schema(input, output).parse()
  58