How to use map in Python for reading files?

Question

I have the following Python code, that parses URL from each files from directory, I try to use function map to realize mulitiprocessing

import glob, os
import xmltodict
import mysql.connector
from multiprocessing import Pool


def get_xml_paths(folder):

    return (os.path.join(folder, f)
            for f in os.listdir(folder)
            if 'xml' in f)

def openXML(file):

    global i
    doc = xmltodict.parse(file.read())
    for i in range(0, len(doc['urlset']['url'])):

        if i > to:
            break

    ## Validation
        url = doc['urlset']['url'][i]['loc'];
        if "books" in url:
            c.execute("INSERT INTO apps (url) VALUES (%s)", [url])
            conn.commit()

    i = i + 1

if __name__ == '__main__':

    files = get_xml_paths("unzip/")

    pool = Pool()
    pool.map(openXML, files)
    pool.close()
    pool.join()
    c.close()

So, when I run this app, I get error list:

multiprocessing.pool.RemoteTraceback: 
"""
Traceback (most recent call last):
  File "C:\Users\O\AppData\Local\Programs\Python\Python35-32\lib\multiprocessing\pool.py", line 119, in worker
    result = (True, func(*args, **kwds))
  File "C:\Users\O\AppData\Local\Programs\Python\Python35-32\lib\multiprocessing\pool.py", line 44, in mapstar
    return list(map(*args))
  File "C:\Users\O\PycharmProjects\Grabber\grabber.py", line 28, in openXML
    doc = xmltodict.parse(file.read())
AttributeError: 'str' object has no attribute 'read'

How can I fix this? I don't see obvious reasons.

Answer 1

file in openXML is a string not a file object, therefore you have no read-method in strings. You have to open the file first:

import glob, os
import xmltodict
import mysql.connector
from multiprocessing import Pool

def open_xml(file):
    with open(file) as xml:
        doc = xmltodict.parse(xml.read())
    cursor = conn.cursor()
    for url in doc['urlset']['url']:
        url = url['loc'];
        if "books" in url:
            cursor.execute("INSERT INTO apps (url) VALUES (%s)", [url])
            conn.commit()

if __name__ == '__main__':
    files = glob.glob("unzip/*.xml")
    pool = Pool()
    pool.map(open_xml, files)