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Is it possible for str.encode(encoding='utf-8', errors='strict') to raise UnicodeError?

I am writing some code that needs to work with both Py2.7 and Py3.7+.
I need to write text to a file using UTF-8 encoding. My code looks like this:
import six
...
content = ...
if isinstance(content, six.string_types):
content = content.encode(encoding='utf-8', errors='strict')
# write 'content' to file
Above, is it possible for content.encode() to raise UnicodeError from either Py2.7 or Py3.7+? I cannot think of a scenario where this is possible. I am not a Python expert, so I think there there must be an edge case.
Here is my reasoning why I think it will never raise UnicodeError:
six.string_types covers three types: Py2.7 str & unicode, Py3.7+ str
All of these types can always encode as UTF-8.

Yes, it's possible:
import six
content = ''.join(map(chr, range(0x110000)))
if isinstance(content, six.string_types):
content = content.encode(encoding='utf-8', errors='strict')
Result (Try it online!, using Python 3.7.4):
Traceback (most recent call last):
File ".code.tio", line 5, in <module>
content = content.encode(encoding='utf-8', errors='strict')
UnicodeEncodeError: 'utf-8' codec can't encode characters in position 55296-57343: surrogates not allowed
And UnicodeEncodeErrors are UnicodeErrors.

Encode error scraping

Scraping site with chineese simbols .
How do i scrap chineese simbolse ??
from urllib.request import urlopen
from urllib.parse import urljoin
from lxml.html import fromstring
URL = 'http://list.suning.com/0-258003-0.html'
ITEM_PATH = '.clearfix .product .border-out .border-in .wrap .res-info .sell-point'
def parse_items():
f = urlopen(URL)
list_html = f.read().decode('utf-8')
list_doc = fromstring(list_html)
for elem in list_doc.cssselect(ITEM_PATH):
a = elem.cssselect('a')[0]
href = a.get('href')
title = a.text
em = elem.cssselect('em')[0]
title2 = em.text
print(href, title, title2)
def main():
parse_items()
if __name__ == '__main__':
main()
Error looks like this.
Error looks like this
Error looks like this
Error looks like this
Error looks like this
http://product.suning.com/0000000000/146422477.html Traceback (most recent call last):
File "parser.py", line 27, in <module>
main()
File "parser.py", line 24, in main
parse_items()
File "parser.py", line 20, in parse_items
print(href, title, title2)
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-2: ordinal not in range(128)

From the print syntax and the imports, I assume that you use a Python3 version, since it can matter for unicode.
So, we can expect that href, title and title2 are all unicode strings (or Python 3 strings). But the print function will try to convert the strings to an encoding acceptable by the output system - for a reason I cannot know, you system uses by default ASCII, so the error.
How to fix:
the best way would be to make your system accept unicode. On Linux or other unixes, you can declare an UTF8 charset in LANG environment variable (export LANG=en_US.UTF-8), on Windows you can try chcp 65001 but this latter if far from being sure
if it does not work, or does not meet your needs, you can force an explicit encoding, or more exactly filter out offending characters, because Python3 natively uses unicode strings.
I would use:
import sys
def u_filter(s, encoding = sys.stdout.encoding):
return (s.encode(encoding, errors='replace').decode(encoding)
if isinstance(s, str) else s)
That means: if s is a unicode string encode it in the encoding used for stdout, replacing any non convertible character by a replacement char, and decode it back into a now clean string
and next:
def fprint(*args, **kwargs):
fargs = [ u_filter(arg) for arg in args ]
print(*fargs, **kwargs)
means: filter out any offending character from unicode strings and print the remaining unchanged.
With that you can safely replace your print throwing the exception with:
fprint(href, title, title2)

Strange UnicodeEncodeError/AttributeError in my script

Currently I am writing a script in Python 2.7 that works fine except for after running it for a few seconds it runs into an error:
Enter Shopify website URL (without HTTP): store.highsnobiety.com
Scraping! Check log file # z:\shopify_output.txt to see output.
!!! Also make sure to clear file every hour or so !!!
Copper Bracelet - 3mm - Polished ['3723603267']
Traceback (most recent call last):
File "shopify_sitemap_scraper.py", line 38, in <module>
print(prod, variants).encode('utf-8')
AttributeError: 'NoneType' object has no attribute 'encode'
The script is to get data from a Shopify website and then print it to console. Code here:
# -*- coding: utf-8 -*-
from __future__ import print_function
from lxml.html import fromstring
import requests
import time
import sys
reload(sys)
sys.setdefaultencoding('utf-8')
# Log file location, change "z://shopify_output.txt" to your location.
logFileLocation = "z:\shopify_output.txt"
log = open(logFileLocation, "w")
# URL of Shopify website from user input (for testing, just use store.highsnobiety.com during input)
url = 'http://' + raw_input("Enter Shopify website URL (without HTTP): ") + '/sitemap_products_1.xml'
print ('Scraping! Check log file # ' + logFileLocation + ' to see output.')
print ("!!! Also make sure to clear file every hour or so !!!")
while True :
page = requests.get(url)
tree = fromstring(page.content)
# skip first url tag with no image:title
url_tags = tree.xpath("//url[position() > 1]")
data = [(e.xpath("./image/title//text()")[0],e.xpath("./loc/text()")[0]) for e in url_tags]
for prod, url in data:
# add xml extension to url
page = requests.get(url + ".xml")
tree = fromstring(page.content)
variants = tree.xpath("//variants[#type='array']//id[#type='integer']//text()")
print(prod, variants).encode('utf-8')
The most crazy part about it is that when I take out the .encode('utf-8') it gives me a UnicodeEncodeError seen here:
Enter Shopify website URL (without HTTP): store.highsnobiety.com
Scraping! Check log file # z:\shopify_output.txt to see output.
!!! Also make sure to clear file every hour or so !!!
Copper Bracelet - 3mm - Polished ['3723603267']
Copper Bracelet - 5mm - Brushed ['3726247811']
Copper Bracelet - 7mm - Polished ['3726253635']
Highsnobiety x EARLY - Leather Pouch ['14541472963', '14541473027', '14541473091']
Traceback (most recent call last):
File "shopify_sitemap_scraper.py", line 38, in <module>
print(prod, variants)
File "C:\Python27\lib\encodings\cp437.py", line 12, in encode
return codecs.charmap_encode(input,errors,encoding_map)
UnicodeEncodeError: 'charmap' codec can't encode character u'\xae' in position 13: character maps to <undefined>'
Any ideas? Have no idea what else to try after hours of googling.

snakecharmerb almost got it, but missed the cause of your first error. Your code
print(prod, variants).encode('utf-8')
means you print the values of the prod and variants variables, then try to run the encode() function on the output of print. Unfortunately, print() (as a function in Python 2 and always in Python 3) returns None. To fix it, use the following instead:
print(prod.encode("utf-8"), variants)

Your console has a default encoding of cp437, and cp437 is unable to represent the character u'\xae'.
>>> print (u'\xae')
®
>>> print (u'\xae'.encode('utf-8'))
b'\xc2\xae'
>>> print (u'\xae'.encode('cp437'))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.5/encodings/cp437.py", line 12, in encode
return codecs.charmap_encode(input,errors,encoding_map)
UnicodeEncodeError: 'charmap' codec can't encode character '\xae' in position 0: character maps to <undefined>
You can see that it's trying to convert to cp437 in the traceback:
File "C:\Python27\lib\encodings\cp437.py", line 12, in encode
(I reproduced the problem in Python3.5, but it's the same issue in both versions of Python)

Python3 and hmac . How to handle string not being binary

I had a script in Python2 that was working great.
def _generate_signature(data):
return hmac.new('key', data, hashlib.sha256).hexdigest()
Where data was the output of json.dumps.
Now, if I try to run the same kind of code in Python 3, I get the following:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.4/hmac.py", line 144, in new
return HMAC(key, msg, digestmod)
File "/usr/lib/python3.4/hmac.py", line 42, in __init__
raise TypeError("key: expected bytes or bytearray, but got %r" %type(key).__name__)
TypeError: key: expected bytes or bytearray, but got 'str'
If I try something like transforming the key to bytes like so:
bytes('key')
I get
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: string argument without an encoding
I'm still struggling to understand the encodings in Python 3.

You can use bytes literal: b'key'
def _generate_signature(data):
return hmac.new(b'key', data, hashlib.sha256).hexdigest()
In addition to that, make sure data is also bytes. For example, if it is read from file, you need to use binary mode (rb) when opening the file.

Not to resurrect an old question but I did want to add something I feel is missing from this answer, to which I had trouble finding an appropriate explanation/example of anywhere else:
Aquiles Carattino was pretty close with his attempt at converting the string to bytes, but was missing the second argument, the encoding of the string to be converted to bytes.
If someone would like to convert a string to bytes through some other means than static assignment (such as reading from a config file or a DB), the following should work:
(Python 3+ only, not compatible with Python 2)
import hmac, hashlib
def _generate_signature(data):
key = 'key' # Defined as a simple string.
key_bytes= bytes(key , 'latin-1') # Commonly 'latin-1' or 'ascii'
data_bytes = bytes(data, 'latin-1') # Assumes `data` is also an ascii string.
return hmac.new(key_bytes, data_bytes , hashlib.sha256).hexdigest()
print(
_generate_signature('this is my string of data')
)

try
codecs.encode()
which can be used both in python2.7.12 and 3.5.2
import hashlib
import codecs
import hmac
a = "aaaaaaa"
b = "bbbbbbb"
hmac.new(codecs.encode(a), msg=codecs.encode(b), digestmod=hashlib.sha256).hexdigest()

for python3 this is how i solved it.
import codecs
import hmac
def _generate_signature(data):
return hmac.new(codecs.encode(key), codecs.encode(data), codecs.encode(hashlib.sha256)).hexdigest()

python odfpy AttributeError: Text instance has no attribute encode

I'm trying to read from an ods (Opendocument spreadsheet) document with the odfpy modules. So far I've been able to extract some data but whenever a cell contains non-standard input the script errors out with:
Traceback (most recent call last):
File "python/test.py", line 26, in <module>
print x.firstChild
File "/usr/lib/python2.7/site-packages/odf/element.py", line 247, in __str__
return self.data.encode()
UnicodeEncodeError: 'ascii' codec can't encode character u'\u0105' in position 4: ordinal not in range(128)
I tried to force an encoding on the output but apparently it does not go well with print:
Traceback (most recent call last):
File "python/test.py", line 27, in <module>
print x.firstChild.encode('utf-8', 'ignore')
AttributeError: Text instance has no attribute 'encode'
What is the problem here and how could it be solved without editing the module code (which I'd like to avoid at all cost)? Is there an alternative to running encode on output that could work?
Here is my code:
from odf.opendocument import Spreadsheet
from odf.opendocument import load
from odf.table import Table,TableRow,TableCell
from odf.text import P
import sys,codecs
doc = load(sys.argv[1])
d = doc.spreadsheet
tables = d.getElementsByType(Table)
for table in tables:
tName = table.attributes[(u'urn:oasis:names:tc:opendocument:xmlns:table:1.0', u'name')]
print tName
rows = table.getElementsByType(TableRow)
for row in rows[:2]:
cells = row.getElementsByType(TableCell)
for cell in cells:
tps = cell.getElementsByType(P)
if len(tps)>0:
for x in tps:
#print x.firstChild
print x.firstChild.encode('utf-8', 'ignore')

Maybe you are not using the latest odfpy, in the latest verion, the __str__ method of Text is implemented as:
def __str__(self):
return self.data
Update odfpy to the latest version, and modify your code as:
print x.firstChild.__str__().encode('utf-8', 'ignore')
UPDATE
This is another method for getting the raw unicode data for Text: __unicode__. So if you don't want to update odfpy, modify your code as:
print x.firstChild.__unicode__().encode('utf-8', 'ignore')

Seems like the library itself is calling encode() -
return self.data.encode()
This uses the system default encoding , which in your case seems to be ascii. you can check that by using -
import sys
sys.getdefaultencoding()
From the traceback, seems like the actual data exists in a variable called data.
Try doing the below instead -
print x.firstChild.data