Read XML with multiple top-level elements using Python ElementTree?

Question

How can I read an XML file using Python ElementTree if XML has multiple top-level elements?

I have an XML file that I would like to read using Python ElementTree.

Unfortunately, it has several top-level tags. I would wrap it <doc>...</doc>around XML, but I have to put tags <doc> after <?xml> and <!DOCTYPE>. But figuring out where it <!DOCTYPE>ends is nontrivial.

What I have:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE FOO BAR "foo.dtd" [
<!ENTITY ...>
<!ENTITY ...>
<!ENTITY ...>
]>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>

What I want:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE FOO BAR "foo.dtd" [
<!ENTITY ...>
<!ENTITY ...>
<!ENTITY ...>
]>
<DOC>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
</DOC>

NB the tag name ARTICLE may change, so I cannot grep for it.

Can someone suggest me how can I add a trailing <doc>...</doc>XML after the header or suggest another workaround?

Answer 1

, toplevel XML. Python . myelementtree.add_toplevel_tag

import re
xmlprocre = re.compile("(\s*<[\?\!])")
def add_toplevel_tag(string):
    """
After all the XML processing instructions, add an enclosing top-level <DOC> tag, and return it.
e.g.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE FOO BAR "foo.dtd" [ <!ENTITY ...> <!ENTITY ...> <!ENTITY ...> ]> <ARTICLE> ...
</ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE>
=>
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE FOO BAR "foo.dtd" [ <!ENTITY ...> <!ENTITY ...> <!ENTITY ...> ]><DOC> <ARTICLE> ...
</ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE></DOC>
"""
    def _advance_proc(string, idx):
        # If possible, advance over whitespace and one processing
        # instruction starting at string index idx, and return its index.
        # If not possible, return None
        # Find the beginning of the processing instruction
        m = xmlprocre.match(string[idx:])
        if m is None: return None
        #print "Group", m.group(1)
        idx = idx + len(m.group(1))
        #print "Remain", string[idx:]

        # Find closing > bracket
        bracketdebt = 1
        while bracketdebt > 0:
            if string[idx] == "<": bracketdebt += 1
            elif string[idx] == ">": bracketdebt -= 1
            idx += 1
        #print "Remain", string[idx:]
        return idx
    loc = 0
    while 1:
        # Advance one processing instruction
        newloc = _advance_proc(string, loc)
        if newloc is None: break
        else: loc = newloc
    return string[:loc] + "<DOC>" + string[loc:] + "</DOC>"