split a pdf based on outline

Question

i would like to use pyPdf to split a pdf file based on the outline where each destination in the outline refers to a different page within the pdf.

example outline:

main       --> points to page 1
  sect1    --> points to page 1
  sect2    --> points to page 15
  sect3    --> points to page 22

it is easy within pyPdf to iterate over each page of the document or each destination in the document's outline; however, i cannot figure out how to get the page number where the destination points.

does anybody know how to find the referencing page number for each destination in the outline?

Answer 1

I figured it out:

class Darrell(pyPdf.PdfFileReader):

    def getDestinationPageNumbers(self):
        def _setup_outline_page_ids(outline, _result=None):
            if _result is None:
                _result = {}
            for obj in outline:
                if isinstance(obj, pyPdf.pdf.Destination):
                    _result[(id(obj), obj.title)] = obj.page.idnum
                elif isinstance(obj, list):
                    _setup_outline_page_ids(obj, _result)
            return _result

        def _setup_page_id_to_num(pages=None, _result=None, _num_pages=None):
            if _result is None:
                _result = {}
            if pages is None:
                _num_pages = []
                pages = self.trailer["/Root"].getObject()["/Pages"].getObject()
            t = pages["/Type"]
            if t == "/Pages":
                for page in pages["/Kids"]:
                    _result[page.idnum] = len(_num_pages)
                    _setup_page_id_to_num(page.getObject(), _result, _num_pages)
            elif t == "/Page":
                _num_pages.append(1)
            return _result

        outline_page_ids = _setup_outline_page_ids(self.getOutlines())
        page_id_to_page_numbers = _setup_page_id_to_num()

        result = {}
        for (_, title), page_idnum in outline_page_ids.iteritems():
            result[title] = page_id_to_page_numbers.get(page_idnum, '???')
        return result

pdf = Darrell(open(PATH-TO-PDF, 'rb'))
template = '%-5s  %s'
print template % ('page', 'title')
for p,t in sorted([(v,k) for k,v in pdf.getDestinationPageNumbers().iteritems()]):
    print template % (p+1,t)