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Getting decoding error from server database [duplicate]

as3:~/ngokevin-site# nano content/blog/20140114_test-chinese.mkd
as3:~/ngokevin-site# wok
Traceback (most recent call last):
File "/usr/local/bin/wok", line 4, in
Engine()
File "/usr/local/lib/python2.7/site-packages/wok/engine.py", line 104, in init
self.load_pages()
File "/usr/local/lib/python2.7/site-packages/wok/engine.py", line 238, in load_pages
p = Page.from_file(os.path.join(root, f), self.options, self, renderer)
File "/usr/local/lib/python2.7/site-packages/wok/page.py", line 111, in from_file
page.meta['content'] = page.renderer.render(page.original)
File "/usr/local/lib/python2.7/site-packages/wok/renderers.py", line 46, in render
return markdown(plain, Markdown.plugins)
File "/usr/local/lib/python2.7/site-packages/markdown/init.py", line 419, in markdown
return md.convert(text)
File "/usr/local/lib/python2.7/site-packages/markdown/init.py", line 281, in convert
source = unicode(source)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe8 in position 1: ordinal not in range(128). -- Note: Markdown only accepts unicode input!
How to fix it?
In some other python-based static blog apps, Chinese post can be published successfully.
Such as this app: http://github.com/vrypan/bucket3. In my site http://bc3.brite.biz/, Chinese post can be published successfully.

tl;dr / quick fix
Don't decode/encode willy nilly
Don't assume your strings are UTF-8 encoded
Try to convert strings to Unicode strings as soon as possible in your code
Fix your locale: How to solve UnicodeDecodeError in Python 3.6?
Don't be tempted to use quick reload hacks
Unicode Zen in Python 2.x - The Long Version
Without seeing the source it's difficult to know the root cause, so I'll have to speak generally.
UnicodeDecodeError: 'ascii' codec can't decode byte generally happens when you try to convert a Python 2.x str that contains non-ASCII to a Unicode string without specifying the encoding of the original string.
In brief, Unicode strings are an entirely separate type of Python string that does not contain any encoding. They only hold Unicode point codes and therefore can hold any Unicode point from across the entire spectrum. Strings contain encoded text, beit UTF-8, UTF-16, ISO-8895-1, GBK, Big5 etc. Strings are decoded to Unicode and Unicodes are encoded to strings. Files and text data are always transferred in encoded strings.
The Markdown module authors probably use unicode() (where the exception is thrown) as a quality gate to the rest of the code - it will convert ASCII or re-wrap existing Unicodes strings to a new Unicode string. The Markdown authors can't know the encoding of the incoming string so will rely on you to decode strings to Unicode strings before passing to Markdown.
Unicode strings can be declared in your code using the u prefix to strings. E.g.
>>> my_u = u'my ünicôdé strįng'
>>> type(my_u)
<type 'unicode'>
Unicode strings may also come from file, databases and network modules. When this happens, you don't need to worry about the encoding.
Gotchas
Conversion from str to Unicode can happen even when you don't explicitly call unicode().
The following scenarios cause UnicodeDecodeError exceptions:
# Explicit conversion without encoding
unicode('€')
# New style format string into Unicode string
# Python will try to convert value string to Unicode first
u"The currency is: {}".format('€')
# Old style format string into Unicode string
# Python will try to convert value string to Unicode first
u'The currency is: %s' % '€'
# Append string to Unicode
# Python will try to convert string to Unicode first
u'The currency is: ' + '€'
Examples
In the following diagram, you can see how the word café has been encoded in either "UTF-8" or "Cp1252" encoding depending on the terminal type. In both examples, caf is just regular ascii. In UTF-8, é is encoded using two bytes. In "Cp1252", é is 0xE9 (which is also happens to be the Unicode point value (it's no coincidence)). The correct decode() is invoked and conversion to a Python Unicode is successfull:
In this diagram, decode() is called with ascii (which is the same as calling unicode() without an encoding given). As ASCII can't contain bytes greater than 0x7F, this will throw a UnicodeDecodeError exception:
The Unicode Sandwich
It's good practice to form a Unicode sandwich in your code, where you decode all incoming data to Unicode strings, work with Unicodes, then encode to strs on the way out. This saves you from worrying about the encoding of strings in the middle of your code.
Input / Decode
Source code
If you need to bake non-ASCII into your source code, just create Unicode strings by prefixing the string with a u. E.g.
u'Zürich'
To allow Python to decode your source code, you will need to add an encoding header to match the actual encoding of your file. For example, if your file was encoded as 'UTF-8', you would use:
# encoding: utf-8
This is only necessary when you have non-ASCII in your source code.
Files
Usually non-ASCII data is received from a file. The io module provides a TextWrapper that decodes your file on the fly, using a given encoding. You must use the correct encoding for the file - it can't be easily guessed. For example, for a UTF-8 file:
import io
with io.open("my_utf8_file.txt", "r", encoding="utf-8") as my_file:
my_unicode_string = my_file.read()
my_unicode_string would then be suitable for passing to Markdown. If a UnicodeDecodeError from the read() line, then you've probably used the wrong encoding value.
CSV Files
The Python 2.7 CSV module does not support non-ASCII characters 😩. Help is at hand, however, with https://pypi.python.org/pypi/backports.csv.
Use it like above but pass the opened file to it:
from backports import csv
import io
with io.open("my_utf8_file.txt", "r", encoding="utf-8") as my_file:
for row in csv.reader(my_file):
yield row
Databases
Most Python database drivers can return data in Unicode, but usually require a little configuration. Always use Unicode strings for SQL queries.
MySQL
In the connection string add:
charset='utf8',
use_unicode=True
E.g.
>>> db = MySQLdb.connect(host="localhost", user='root', passwd='passwd', db='sandbox', use_unicode=True, charset="utf8")
PostgreSQL
Add:
psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
psycopg2.extensions.register_type(psycopg2.extensions.UNICODEARRAY)
HTTP
Web pages can be encoded in just about any encoding. The Content-type header should contain a charset field to hint at the encoding. The content can then be decoded manually against this value. Alternatively, Python-Requests returns Unicodes in response.text.
Manually
If you must decode strings manually, you can simply do my_string.decode(encoding), where encoding is the appropriate encoding. Python 2.x supported codecs are given here: Standard Encodings. Again, if you get UnicodeDecodeError then you've probably got the wrong encoding.
The meat of the sandwich
Work with Unicodes as you would normal strs.
Output
stdout / printing
print writes through the stdout stream. Python tries to configure an encoder on stdout so that Unicodes are encoded to the console's encoding. For example, if a Linux shell's locale is en_GB.UTF-8, the output will be encoded to UTF-8. On Windows, you will be limited to an 8bit code page.
An incorrectly configured console, such as corrupt locale, can lead to unexpected print errors. PYTHONIOENCODING environment variable can force the encoding for stdout.
Files
Just like input, io.open can be used to transparently convert Unicodes to encoded byte strings.
Database
The same configuration for reading will allow Unicodes to be written directly.
Python 3
Python 3 is no more Unicode capable than Python 2.x is, however it is slightly less confused on the topic. E.g the regular str is now a Unicode string and the old str is now bytes.
The default encoding is UTF-8, so if you .decode() a byte string without giving an encoding, Python 3 uses UTF-8 encoding. This probably fixes 50% of people's Unicode problems.
Further, open() operates in text mode by default, so returns decoded str (Unicode ones). The encoding is derived from your locale, which tends to be UTF-8 on Un*x systems or an 8-bit code page, such as windows-1251, on Windows boxes.
Why you shouldn't use sys.setdefaultencoding('utf8')
It's a nasty hack (there's a reason you have to use reload) that will only mask problems and hinder your migration to Python 3.x. Understand the problem, fix the root cause and enjoy Unicode zen.
See Why should we NOT use sys.setdefaultencoding("utf-8") in a py script? for further details

Finally I got it:
as3:/usr/local/lib/python2.7/site-packages# cat sitecustomize.py
# encoding=utf8
import sys
reload(sys)
sys.setdefaultencoding('utf8')
Let me check:
as3:~/ngokevin-site# python
Python 2.7.6 (default, Dec 6 2013, 14:49:02)
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> reload(sys)
<module 'sys' (built-in)>
>>> sys.getdefaultencoding()
'utf8'
>>>
The above shows the default encoding of python is utf8. Then the error is no more.

This is the classic "unicode issue". I believe that explaining this is beyond the scope of a StackOverflow answer to completely explain what is happening.
It is well explained here.
In very brief summary, you have passed something that is being interpreted as a string of bytes to something that needs to decode it into Unicode characters, but the default codec (ascii) is failing.
The presentation I pointed you to provides advice for avoiding this. Make your code a "unicode sandwich". In Python 2, the use of from __future__ import unicode_literals helps.
Update: how can the code be fixed:
OK - in your variable "source" you have some bytes. It is not clear from your question how they got in there - maybe you read them from a web form? In any case, they are not encoded with ascii, but python is trying to convert them to unicode assuming that they are. You need to explicitly tell it what the encoding is. This means that you need to know what the encoding is! That is not always easy, and it depends entirely on where this string came from. You could experiment with some common encodings - for example UTF-8. You tell unicode() the encoding as a second parameter:
source = unicode(source, 'utf-8')

In some cases, when you check your default encoding (print sys.getdefaultencoding()), it returns that you are using ASCII. If you change to UTF-8, it doesn't work, depending on the content of your variable.
I found another way:
import sys
reload(sys)
sys.setdefaultencoding('Cp1252')

I was searching to solve the following error message:
unicodedecodeerror: 'ascii' codec can't decode byte 0xe2 in position 5454: ordinal not in range(128)
I finally got it fixed by specifying 'encoding':
f = open('../glove/glove.6B.100d.txt', encoding="utf-8")
Wish it could help you too.

"UnicodeDecodeError: 'ascii' codec can't decode byte"
Cause of this error: input_string must be unicode but str was given
"TypeError: Decoding Unicode is not supported"
Cause of this error: trying to convert unicode input_string into unicode
So first check that your input_string is str and convert to unicode if necessary:
if isinstance(input_string, str):
input_string = unicode(input_string, 'utf-8')
Secondly, the above just changes the type but does not remove non ascii characters. If you want to remove non-ascii characters:
if isinstance(input_string, str):
input_string = input_string.decode('ascii', 'ignore').encode('ascii') #note: this removes the character and encodes back to string.
elif isinstance(input_string, unicode):
input_string = input_string.encode('ascii', 'ignore')

In order to resolve this on an operating system level in an Ubuntu installation check the following:
$ locale charmap
If you get
locale: Cannot set LC_CTYPE to default locale: No such file or directory
instead of
UTF-8
then set LC_CTYPE and LC_ALL like this:
$ export LC_ALL="en_US.UTF-8"
$ export LC_CTYPE="en_US.UTF-8"

I find the best is to always convert to unicode - but this is difficult to achieve because in practice you'd have to check and convert every argument to every function and method you ever write that includes some form of string processing.
So I came up with the following approach to either guarantee unicodes or byte strings, from either input. In short, include and use the following lambdas:
# guarantee unicode string
_u = lambda t: t.decode('UTF-8', 'replace') if isinstance(t, str) else t
_uu = lambda *tt: tuple(_u(t) for t in tt)
# guarantee byte string in UTF8 encoding
_u8 = lambda t: t.encode('UTF-8', 'replace') if isinstance(t, unicode) else t
_uu8 = lambda *tt: tuple(_u8(t) for t in tt)
Examples:
text='Some string with codes > 127, like Zürich'
utext=u'Some string with codes > 127, like Zürich'
print "==> with _u, _uu"
print _u(text), type(_u(text))
print _u(utext), type(_u(utext))
print _uu(text, utext), type(_uu(text, utext))
print "==> with u8, uu8"
print _u8(text), type(_u8(text))
print _u8(utext), type(_u8(utext))
print _uu8(text, utext), type(_uu8(text, utext))
# with % formatting, always use _u() and _uu()
print "Some unknown input %s" % _u(text)
print "Multiple inputs %s, %s" % _uu(text, text)
# but with string.format be sure to always work with unicode strings
print u"Also works with formats: {}".format(_u(text))
print u"Also works with formats: {},{}".format(*_uu(text, text))
# ... or use _u8 and _uu8, because string.format expects byte strings
print "Also works with formats: {}".format(_u8(text))
print "Also works with formats: {},{}".format(*_uu8(text, text))
Here's some more reasoning about this.

Got a same error and this solved my error. Thanks!
python 2 and python 3 differing in unicode handling is making pickled files quite incompatible to load. So Use python pickle's encoding argument. Link below helped me solve the similar problem when I was trying to open pickled data from my python 3.7, while my file was saved originally in python 2.x version.
https://blog.modest-destiny.com/posts/python-2-and-3-compatible-pickle-save-and-load/
I copy the load_pickle function in my script and called the load_pickle(pickle_file) while loading my input_data like this:
input_data = load_pickle("my_dataset.pkl")
The load_pickle function is here:
def load_pickle(pickle_file):
try:
with open(pickle_file, 'rb') as f:
pickle_data = pickle.load(f)
except UnicodeDecodeError as e:
with open(pickle_file, 'rb') as f:
pickle_data = pickle.load(f, encoding='latin1')
except Exception as e:
print('Unable to load data ', pickle_file, ':', e)
raise
return pickle_data

Encode converts a unicode object in to a string object. I think you are trying to encode a string object. first convert your result into unicode object and then encode that unicode object into 'utf-8'.
for example
result = yourFunction()
result.decode().encode('utf-8')

This worked for me:
file = open('docs/my_messy_doc.pdf', 'rb')

I had the same error, with URLs containing non-ascii chars (bytes with values > 128), my solution:
url = url.decode('utf8').encode('utf-8')
Note: utf-8, utf8 are simply aliases . Using only 'utf8' or 'utf-8' should work in the same way
In my case, worked for me, in Python 2.7, I suppose this assignment changed 'something' in the str internal representation--i.e., it forces the right decoding of the backed byte sequence in url and finally puts the string into a utf-8 str with all the magic in the right place.
Unicode in Python is black magic for me.
Hope useful

I had the same problem but it didn't work for Python 3. I followed this and it solved my problem:
enc = sys.getdefaultencoding()
file = open(menu, "r", encoding = enc)
You have to set the encoding when you are reading/writing the file.

I got the same problem with the string "Pastelería Mallorca" and I solved with:
unicode("Pastelería Mallorca", 'latin-1')

In short, to ensure proper unicode handling in Python 2:
use io.open for reading/writing files
use from __future__ import unicode_literals
configure other data inputs/outputs (e.g., databases, network) to use unicode
if you cannot configure outputs to utf-8, convert your output for them print(text.encode('ascii', 'replace').decode())
For explanations, see #Alastair McCormack's detailed answer.

In a Django (1.9.10)/Python 2.7.5 project I have frequent UnicodeDecodeError exceptions; mainly when I try to feed unicode strings to logging. I made a helper function for arbitrary objects to basically format to 8-bit ascii strings and replacing any characters not in the table to '?'. I think it's not the best solution but since the default encoding is ascii (and i don't want to change it) it will do:
def encode_for_logging(c, encoding='ascii'):
if isinstance(c, basestring):
return c.encode(encoding, 'replace')
elif isinstance(c, Iterable):
c_ = []
for v in c:
c_.append(encode_for_logging(v, encoding))
return c_
else:
return encode_for_logging(unicode(c))
`

This error occurs when there are some non ASCII characters in our string and we are performing any operations on that string without proper decoding.
This helped me solve my problem.
I am reading a CSV file with columns ID,Text and decoding characters in it as below:
train_df = pd.read_csv("Example.csv")
train_data = train_df.values
for i in train_data:
print("ID :" + i[0])
text = i[1].decode("utf-8",errors="ignore").strip().lower()
print("Text: " + text)

Here is my solution, just add the encoding.
with open(file, encoding='utf8') as f
And because reading glove file will take a long time, I recommend to the glove file to a numpy file. When netx time you read the embedding weights, it will save your time.
import numpy as np
from tqdm import tqdm
def load_glove(file):
"""Loads GloVe vectors in numpy array.
Args:
file (str): a path to a glove file.
Return:
dict: a dict of numpy arrays.
"""
embeddings_index = {}
with open(file, encoding='utf8') as f:
for i, line in tqdm(enumerate(f)):
values = line.split()
word = ''.join(values[:-300])
coefs = np.asarray(values[-300:], dtype='float32')
embeddings_index[word] = coefs
return embeddings_index
# EMBEDDING_PATH = '../embedding_weights/glove.840B.300d.txt'
EMBEDDING_PATH = 'glove.840B.300d.txt'
embeddings = load_glove(EMBEDDING_PATH)
np.save('glove_embeddings.npy', embeddings)
Gist link: https://gist.github.com/BrambleXu/634a844cdd3cd04bb2e3ba3c83aef227

Specify: # encoding= utf-8 at the top of your Python File, It should fix the issue

I experienced this error with Python2.7. It happened to me while trying to run many python programs, but I managed to reproduce it with this simple script:
#!/usr/bin/env python
import subprocess
import sys
result = subprocess.Popen([u'svn', u'info'])
if not callable(getattr(result, "__enter__", None)) and not callable(getattr(result, "__exit__", None)):
print("foo")
print("bar")
On success, it should print out 'foo' and 'bar', and probably an error message if you're not in a svn folder.
On failure, it should print 'UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 39: ordinal not in range(128)'.
After trying to regenerate my locales and many other solutions posted in this question, I learned the error was happening because I had a special character (ĺ) encoded in my PATH environment variable. After fixing the PATH in '~/.bashrc', and exiting my session and entering again, (apparently sourcing '~/.bashrc' didn't work), the issue was gone.

python - How to properly encode string in utf8 which is ISO8859-1 from xml

I'm using the following code in python 2.7 to retrieve an xmlFile containing some german umlauts like ä,ü,ö,ß:
.....
def getXML(self,url):
xmlFile=urllib2.urlopen(self.url)
xmlResponse=xmlFile.read()
xmlResponse=xmlResponse
xmlFile.close()
return xmlResponse
pass
def makeDict(self, xmlFile):
data = xmltodict.parse(xmlFile)
return data
def saveJSON(self, dictionary):
currentDayData=dictionary['speiseplan']['tag'][1]
file=open('data.json','w')
# Write the currentDay as JSON
file.write(json.dumps(currentDayData))
file.close()
return True
pass
# Execute
url="path/to/xml/"
App=GetMensaJSON(url)
xml=GetMensaJSON.getXML(App,url)
dictionary=GetMensaJSON.makeDict(App,xml)
GetMensaJSON.saveJSON(App,dictionary)
The problem is that the xml File claims in its <xml> tag that it is utf-8. It however isn't. By trying I found out that it is iso8859_1
So I wanted to reconvert from utf-8 to iso8859 and back to utf-8 to resolve the conflicts.
Is there an elegant way to resolve missing umlauts? In my code for example I have instead of ß\u00c3\u009f an instead of ü\u00c3\u00bc
I found this similar question but I can't get it to work How to parse an XML file with encoding declaration in Python?
Also I should add that I can't influence the way I get the xml.
The XML File Link can be found in the code.
The output from ´repr(xmlResponse)´ is
"<?xml version='1.0' encoding='utf-8'?>\n<speiseplan>\n<tag timestamp='1453676400'>\n<item language='de'>\n<category>Stammessen</category>\n<title>Gem\xc3\x83\xc2\xbcsebr\xc3\x83\xc2\xbche mit Backerbsen (25,28,31,33,34), paniertes H\xc3\x83\xc2\xa4hnchenbrustschnitzel (25) mit Paprikasauce (33,34), Pommes frites und Gem\xc3\x83\xc2\xbcse

You are trying to encode already encoded data. urllib2.urlopen() can only return you a bytestring, not unicode, so encoding makes little sense.
What happens instead is that Python is trying to be helpful here; if you insist on encoding bytes, then it'll decode those to unicode data first. And it'll use the default codec for that.
On top of that, XML documents are themselves responsible for documenting what codec should be used to decode. The default codec is UTF-8, don't manually re-code the data yourself, leave that to a XML parser.
If you have Mojibake data in your XML document, the best way to fix that is to do so after parsing. I recommend the ftfy package to do this for you.
You could manually 'fix' the encoding by first decoding as UTF-8, then encoding to Latin-1 again:
xmlResponse = xmlFile.read().decode('utf-8').encode('latin-1')
However, this makes the assumption that your data has been badly decoded as Latin-1 to begin with; this is not always a safe assumption. If it was decoded as Windows CP 1252, for example, then the best way to recover your data is to still use ftfy.
You could try using ftfy before parsing as XML, but this relies on the document not having used any non-ASCII elements outside of text and attribute content:
xmlResponse = ftfy.fix_text(
xmlFile.read().decode('utf-8'),
fix_entities=False, uncurl_quotes=False, fix_latin_ligatures=False).encode('utf-8')

Python ─ UTF-8 filename from HTML form via CherryPy

Python Header: # ! /usr/bin/env python
# -*- coding: utf-8 -*-
# image_upload.py
Cherrypy Config: cherrypy.config.update(
{'tools.encode.on': True,
'tools.encode.encoding': 'utf-8',
'tools.decode.on': True,
},)
HTML Header: <head><meta http-equiv="Content-Type"
content="text/html;charset=ISO-8859-1"></head>
""" Python 2.7.3
Cherrypy 3.2.2
Ubuntu 12.04
"""
With an HTML form, I'm uploading an image file to a database. That works so far without problems. However, if the filename ist not 100% in ASCII, there seems to be no way to retrieve it in UTF-8. This is weird, because with the HTML text input fields it works without problems, from saving until showing. Therefore I assume that it's an encoding or decoding problem with the web application framework CherryPy, because the upload is handeld by it, like here.
How it works:
The HTML form POSTs the uploaded file to another Python function, which receives the file in the standard dictionary **kwargs. From here you get the filename with extention, like this: filename = kwargs['file'].filename. But that's already with the wrong encoding. Until now the image hasn't been processed, stored or used in any way.
I'm asking for a solution, which would prevent it, to just parse the filename and change it back "manually". I guess the result already is in UTF-8, which makes it cumbersome to get it right. That's why getting CherryPy to do it, might be the best way. But maybe it's even an HTML issue, because the file comes from a form.
Here are the wrong decoded umlauts.
What I need is the input as result.
input → result input → result
ä → ä Ä → Ä
ö → ö Ö → Ö
ü → ü Ü → Ãœ
Following are the failed attempts to get the right result, which would be: "Würfel"
NOTE: img_file = kwargs['file']
original attempt:
result = img_file.filename.rsplit('.',1)[0]
result: "Würfel"
change system encoding:
reload(sys)
sys.setdefaultencoding('utf-8')
result: "Würfel"
encoding attempt 1:
result = img_file.filename.rsplit('.',1)[0].encode('utf-8')
result: "Würfel"
encoding attempt 2:
result = unicode(img_file.filename.rsplit('.',1)[0], 'urf-8')
Error Message:
TypeError: decoding Unicode is not supported
decoding attempt:
result = img_file.filename.rsplit('.',1)[0].decode('utf-8')
Error Message:
UnicodeEncodeError: 'ascii' codec can't encode characters in position 1-2: ordinal not in range(128)
cast attempt:
result = str(img_file.filename.rsplit('.',1)[0])
Error Message:
UnicodeEncodeError: 'ascii' codec can't encode characters in position 1-2: ordinal not in range(128)

Trying with your string it seems I can get the filename using latin1 encoding.
>>> s = u'W\xc3\xbcrfel.jpg'
>>> print s.encode('latin1')
Würfel.jpg
>>>
You simply need to use that .encode('latin1') before splitting.
But the problem here is broader. You really need to figure out why your web encoding is latin1 instead of utf8. I don't know cherrypy but try to ensure to use utf8 or you could get in other glitches when serving your application through a webserver like apache or nginx.

The problem is that you serve your HTML with charset ISO-8859-1; this makes the browsers confused and they use the charset also when sending to server. Serve all your HTML always with UTF-8, code in UTF-8, and set your terminal to UTF-8, and you shouldn't have problems.

UnicodeDammit: detwingle crashes on a website

I’m scraping websites and use BeautifulSoup4 to parse them. As the websits can have really random char sets, I use UnicodeDammit.detwingle to ensure that I feed proper data to BeautifulSoup. It worked fine... until it crashed. One website causes the code to break. The code to build "soup" looks like this:
u = bs.UnicodeDammit.detwingle( html_blob ) <--- here it crashes
u = bs.UnicodeDammit( u.decode('utf-8'),
smart_quotes_to='html',
is_html = True )
u = u.unicode_markup
soup = bs.BeautifulSoup( u )
And the error (standard Python-Unicode hell duo)
File ".../something.py", line 92, in load_bs_from_html_blob
u = bs.UnicodeDammit.detwingle( html_blob )
File ".../beautifulsoup4-4.1.3-py2.7.egg/bs4/dammit.py", line 802, in detwingle
return b''.join(byte_chunks)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 0:
ordinal not in range(128)
The offending website is this one
Question: How to make a proper and bulletproof website source decoding?

This website is not a special case in terms of character encoding at all, it's perfectly valid utf-8 with even the http header set correctly. It then follows that your code would have crashed on any website encoded in utf-8 with code points beyond ASCII.
It is also evident from the documentation, that UnicodeDammit.detwingle takes an unicode string. You are passing it html_blob, and the variable naming suggests that it's not a decoded unicode string. (Misunderstanding)
To handle any website encoding is not trivial in the case the http header or markup lies about the encoding or is not included at all. You need to perform various heuristics and even then you won't get it right. But this website is sending the charset header correctly and has been encoded correctly in that charset.
Interesting trivia. The only beyond ASCII text in the website are these javascript comments (after being decoded as utf-8):
image = new Array(4); //¶¨ÒåimageΪͼƬÊýÁ¿µÄÊý×é
image[0] = 'sample_BG_image01.png' //±³¾°Í¼ÏóµÄ·¾¶
If you then encode those to ISO-8859-1, and decode the result as GB2312, you get:
image = new Array(4); //定义image为图片数量的数组
image[0] = 'sample_BG_image01.png' //背景图象的路径
Which google chinese -> english, translates to:
image = new Array(4); //Defined image of the array of the number of images
image[0] = 'sample_BG_image01.png' //The path of the background image

How to open an ascii-encoded file as UTF8?

My files are in US-ASCII and a command like a = file( 'main.html') and a.read() loads them as an ASCII text. How do I get it to load as UTF8?
The problem I am tring to solve is:
UnicodeEncodeError: 'ascii' codec can't encode character u'\xae' in position 38: ordinal not in range(128)
I was using the content of the files for templating as in template_str.format(attrib=val). But the string to interpolate is of a superset of ASCII.
Our team's version control and text editors does not care about the encoding. So how do I handle it in the code?

You are trying to opening files without specifying an encoding, which means that python uses the default value (ASCII).
You need to decode the byte-string explicitly, using the .decode() function:
template_str = template_str.decode('utf8')
Your val variable you tried to interpolate into your template is itself a unicode value, and python wants to automatically convert your byte-string template (read from the file) into a unicode value too, so that it can combine both, and it'll use the default encoding to do so.
Did I mention already you should read Joel Spolsky's article on Unicode and the Python Unicode HOWTO? They'll help you understand what happened here.

A solution working in Python2:
import codecs
fo = codecs.open('filename.txt', 'r', 'ascii')
content = fo.read() ## returns unicode
assert type(content) == unicode
fo.close()
utf8_content = content.encode('utf-8')
assert type(utf8_content) == str

I suppose that you are sure that your files are encoded in ASCII. Are you? :) As ASCII is included in UTF-8, you can decode this data using UTF-8 without expecting problems. However, when you are sure that the data is just ASCII, you should decode the data using just ASCII and not UTF-8.
"How do I get it to load as UTF8?"
I believe you mean "How do I get it to load as unicode?". Just decode the data using the ASCII codec and, in Python 2.x, the resulting data will be of type unicode. In Python 3, the resulting data will be of type str.
You will have to read about this topic in order to learn how to perform this kind of decoding in Python. Once understood, it is very simple.