69 lines
2.2 KiB
Python
69 lines
2.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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pdfparanoia.eraser
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~~~~~~~~~~~~~~~
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Tools to erase things from pdfs by direct manipulation of the pdf format.
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"""
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def manipulate_pdf(content, objid, callback, *args):
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"""
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Iterates through a pdf looking for the object with the objid id. When the
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object is found, callback is called with a reference to the current list of
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output lines.
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"""
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outlines = []
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content = content.replace("\r\n", "\n")
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lines = content.split("\n")
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last_line = None
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skip_mode = False
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for line in lines:
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if line == "":
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outlines.append("")
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continue
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if not skip_mode:
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if last_line in ["endobj", "endobj ", None]:
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if line[-3:] == "obj" or line[-4:] == "obj " or " obj <<" in line[0:50] or " obj<<" in line[0:50]:
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if line.startswith(str(objid) + " "):
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skip_mode = True
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last_line = line
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callback(outlines, *args)
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continue
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outlines.append(line)
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elif skip_mode:
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if line == "endobj" or line == "endobj ":
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skip_mode = False
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last_line = line
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output = "\n".join(outlines)
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return output
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def remove_object_by_id(content, objid):
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"""
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Deletes an object from a pdf. Mostly streams and FlateDecode stuff.
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"""
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def _remove_object(outlines): pass
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output = manipulate_pdf(content, objid, _remove_object)
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return output
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def replace_object_with(content, objid, replacement):
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"""
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Replaces an object from a pdf. Mostly streams. This is useful for replacing
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an encoded object with a plaintext object.
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"""
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def _replace_object_with(outlines, details):
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objid = details["objid"]
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replacement = details["replacement"]
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output = str(objid) + " 0 obj\n"
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output += "<</Length " + str(len(replacement)+2) + ">>stream\n"
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output += replacement
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output += "\nendstream\nendobj\n"
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for line in output.split("\n"):
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outlines.append(line)
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output = manipulate_pdf(content, objid, _replace_object_with, {"objid": objid, "replacement": replacement})
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return output
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