PDF Comment extraction with Python and PDFMIner

extract_pdf_comments.py

from pdfminer.pdfparser import PDFParser
from pdfminer.pdfdocument import PDFDocument
from pdfminer.pdftypes import PDFObjectNotFound

pages = []

def extract(objid, obj):
    global pages
    if isinstance(obj, dict):
        # 'Type' is PDFObjRef type
        if obj.has_key('Type') and obj['Type'].name == 'Page':
            pages.append(objid)
        elif obj.has_key('C'):
            pr = obj['P']
            try:
                pi = pages.index(pr.objid)+1
            except:
                pi = -1
            print(objid,pi, obj['Subj'],obj['T'],obj['Contents'])


fp = file("y.pdf", 'rb')
parser = PDFParser(fp)
doc = PDFDocument(parser, "")
visited = set()
for xref in doc.xrefs:
    for objid in xref.get_objids():
        if objid in visited: continue
        visited.add(objid)
        try:
            obj = doc.getobj(objid)
            if obj is None: continue
            extract(objid,obj)
        except PDFObjectNotFound, e:
            print >>sys.stderr, 'not found: %r' % e

hi!
How to get the comment data of pdf files with python?
If you know that please help me.
Thank you!

@babytiger0929 Sorry, in don't know this off the top of my head.