Question

Following this example, I can list all elements into a pdf file

import pyPdf pdf = pyPdf.PdfFileReader(open('pdffile.pdf')) list(pdf.pages) # Process all the objects. print pdf.resolvedObjects 

now, I need to extract a non-standard object from the pdf file.

My object is the one named MYOBJECT and it is a string.

The piece printed by the python script that concernes me is:

{'/MYOBJECT': IndirectObject(584, 0)} 

The pdf file is this:

558 0 obj <</Contents 583 0 R/CropBox[0 0 595.22 842]/MediaBox[0 0 595.22 842]/Parent 29 0 R/Resources   <</ColorSpace <</CS0 563 0 R>>     /ExtGState <</GS0 568 0 R>>     /Font<</TT0 559 0 R/TT1 560 0 R/TT2 561 0 R/TT3 562 0 R>>     /ProcSet[/PDF/Text/ImageC]     /Properties<</MC0<</MYOBJECT 584 0 R>>/MC1<</SubKey 582 0 R>> >>     /XObject<</Im0 578 0 R>>>>   /Rotate 0/StructParents 0/Type/Page>> endobj ... ... ... 584 0 obj <</Length 8>>stream  1_22_4_1     --->>>>  this is the string I need to extract from the object  endstream endobj 

How can I follow the 584 value in order to refer to my string (under pyPdf of course)??

Answer 1

each element in pdf.pages is a dictionary, so assuming it’s on page 1, pdf.pages[0]['/MYOBJECT'] should be the element you want.

You can try to print that individually or poke at it with help and dir in a python prompt for more about how to get the string you want

Edit:

after receiving a copy of the pdf, i found the object at pdf.resolvedObjects[0][558]['/Resources']['/Properties']['/MC0']['/MYOBJECT'] and the value can be retrieved via getData()

the following function gives a more generic way to solve this by recursively looking for the key in question

import types import pyPdf pdf = pyPdf.PdfFileReader(open('file.pdf')) pages = list(pdf.pages)  def findInDict(needle,haystack):     for key in haystack.keys():         try:             value = haystack[key]         except:             continue         if key == needle:             return value         if type(value) == types.DictType or isinstance(value,pyPdf.generic.DictionaryObject):               x = findInDict(needle,value)             if x is not None:                 return x  answer = findInDict('/MYOBJECT',pdf.resolvedObjects).getData()