Inconsistent SignatureDoesNotMatch Amazon S3 with django-pipeline, s3boto and storages - python

I have 2 files compiled by django-pipeline along with s3boto: master.css and master.js. They are set to "Public" in my buckets. However, when I access them, sometimes master.css is served, sometimes it errs with SignatureDoesNotMatch. The same with master.js. This doesn't happen on Chrome. What could I be missing?
EDIT: It now happens on Chrome too.

Happened to me too...
Took a few hours to find, but I figured it out eventually.
Turns out that if the right signature is :
ssCNsAOxLf5vA80ldAI3M0CU2%2Bw=
Then AWS will NOT accept:
ssCNsAOxLf5vA80ldAI3M0CU2+w=
Where the only difference is the translation of %2B to '+'.
S3BotoStorage actually yields it correctly but the encoding happens on CachedFilesMixin in the final line of the url method (return unquote(final_url)).
To fix it, I derived a new CachedFilesMixin to undo the "damage" (I should mention that I don't know why this unquote exists in the first place, so undoing it might cause other problems)
class MyCachedFilesMixin(CachedFilesMixin):
def url(self, *a, **kw):
s = super(MyCachedFilesMixin, self).url(*a, **kw)
if isinstance(s, unicode):
s = s.encode('utf-8', 'ignore')
scheme, netloc, path, qs, anchor = urlparse.urlsplit(s)
path = urllib.quote(path, '/%')
qs = urllib.quote_plus(qs, ':&=')
return urlparse.urlunsplit((scheme, netloc, path, qs, anchor))
Where I used the code I found here.
Hope this helps...

I had a similar issue causing SignatureDoesNotMatch errors when downloading files using an S3 signed URL and the python requests HTTP library.
My problem ended up being a bad content-type. The documentation at AWS on Authenticating REST Requests helped me figure it out, and has examples in Python.

I was struggling with this for a while, and I didn't like the idea of messing up with CachedFilesMixin (seemed like an overkill to me).
Until a proper fix is issued to the django platform, I've found quoting the signature two times is a good option. I know it's not pretty, but it works and it's simple.
So you'll just have to do something like this:
signature = urllib.quote_plus(signature.strip())
signature = urllib.quote_plus(signature.strip())
Hope it helps!

This article on Flask is a good resource on getting your signatures right: https://devcenter.heroku.com/articles/s3-upload-python
#app.route('/sign_s3/')
def sign_s3():
AWS_ACCESS_KEY = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')
S3_BUCKET = os.environ.get('S3_BUCKET')
object_name = request.args.get('s3_object_name')
mime_type = request.args.get('s3_object_type')
expires = int(time.time()+10)
amz_headers = "x-amz-acl:public-read"
put_request = "PUT\n\n%s\n%d\n%s\n/%s/%s" % (mime_type, expires, amz_headers, S3_BUCKET, object_name)
signature = base64.encodestring(hmac.new(AWS_SECRET_KEY,put_request, sha).digest())
signature = urllib.quote_plus(signature.strip())
url = 'https://%s.s3.amazonaws.com/%s' % (S3_BUCKET, object_name)
return json.dumps({
'signed_request': '%s?AWSAccessKeyId=%s&Expires=%d&Signature=%s' % (url, AWS_ACCESS_KEY, expires, signature),
'url': url
})

Simple workaround for me was to generate a new access key with only alphanumeric characters (ie no special characters such as "/", "+", etc. which AWS sometimes adds to the keys).

Related

How do I Authenticate my FTX_Client in Python

I have looked through the FTX api documentation found here: https://docs.ftx.us/#overview
And I've looked at example code found in this repo: https://github.com/ftexchange/ftx/tree/master/rest
I can't 'get' or 'post' anything that requires the Authentication. I am using the api key on my account that has 'full trade permissions', and when I look at: print(request.headers) the headers look like they are in the right format.
I've tried: using google colab instead of vs code, updating all my libraries, generating a new api key, restarting kernel and computer. I can pull something like 'markets' because it doesn't need the Authentication.
Let me know if you need any more information, below is a portion of the code I have that isolates the problem and returns {'success': False, 'error': 'Not logged in'}
import time
import urllib.parse
from typing import Optional, Dict, Any, List
from requests import Request, Session, Response
import hmac
ep = 'https://ftx.us/api/wallet/balances'
ts = int(time.time() * 1000)
s = Session()
request = Request('GET', ep)
prepared = request.prepare()
signature_payload = f'{ts}{prepared.method}{prepared.path_url}'.encode()
if prepared.body:
signature_payload += prepared.body
signature = hmac.new(secret.encode(), signature_payload, 'sha256').hexdigest()
request.headers['FTX-KEY'] = key
request.headers['FTX-SIGN'] = signature
request.headers['FTX-TS'] = str(ts)
response = s.send(prepared)
data = response.json()
print(data)
I've faced with the same problem.
You need to change this part:
prepared.headers['FTX-KEY'] = key
prepared.headers['FTX-SIGN'] = signature
prepared.headers['FTX-TS'] = str(ts)
PS. I believe that the FTX needs to fix their API documentation
PSS. I've checked the a part of https://github.com/ftexchange/ftx/tree/master/rest code. I beleave FTX guys just do a copy-paste into docs this code but originally it belongs to more a sophisticated object oriented solution that will work correctly because they pass into method an already created request and use a prepared variable just to calculate path_url and method
For ftx.us, you need to use different headers:
prepared.headers['FTXUS-KEY'] = key
prepared.headers['FTXUS-TS'] = str(ts)
prepared.headers['FTXUS-SIGN'] = signature

Pythonic/efficient way to check organisation of public IP addresses

I have a DataFrame common_ips containing IPs as shown below.
I need to achieve two basic tasks:
Identify private and public IPs.
Check organisation for public IPs.
Here is what I am doing:
import json
import urllib
import re
baseurl = 'http://ipinfo.io/' # no HTTPS supported (at least: not without a plan)
def isIPpublic(ipaddress):
return not isIPprivate(ipaddress)
def isIPprivate(ipaddress):
if ipaddress.startswith("::ffff:"):
ipaddress=ipaddress.replace("::ffff:", "")
# IPv4 Regexp from https://stackoverflow.com/questions/30674845/
if re.search(r"^(?:10|127|172\.(?:1[6-9]|2[0-9]|3[01])|192\.168)\..*", ipaddress):
# Yes, so match, so a local or RFC1918 IPv4 address
return True
if ipaddress == "::1":
# Yes, IPv6 localhost
return True
return False
def getipInfo(ipaddress):
url = '%s%s/json' % (baseurl, ipaddress)
try:
urlresult = urllib.request.urlopen(url)
jsonresult = urlresult.read() # get the JSON
parsedjson = json.loads(jsonresult) # put parsed JSON into dictionary
return parsedjson
except:
return None
def checkIP(ipaddress):
if (isIPpublic(ipaddress)):
if bool(getipInfo(ipaddress)):
if 'bogon' in getipInfo(ipaddress).keys():
return 'Private IP'
elif bool(getipInfo(ipaddress).get('org')):
return getipInfo(ipaddress)['org']
else:
return 'No organization data'
else:
return 'No data available'
else:
return 'Private IP'
And applying it to my common_ips DataFrame with
common_ips['Info'] = common_ips.IP.apply(checkIP)
But it's taking longer than I expected. And for some IPs, it's giving incorrect Info.
For instance:
where it should have been AS19902 Department of Administrative Services as I cross-checked it by
and
What am I missing here ? And how can I achieve these tasks in a more Pythonic way ?
A blanket except: is basically always a bug. You are returning None instead of handling any anomalous or error response from the server, and of course the rest of your code has no way to recover.
As a first debugging step, simply take out the try/except handling. Maybe then you can find a way to put back a somewhat more detailed error handler for some cases which you know how to recover from.
def getipInfo(ipaddress):
url = '%s%s/json' % (baseurl, ipaddress)
urlresult = urllib.request.urlopen(url)
jsonresult = urlresult.read() # get the JSON
parsedjson = json.loads(jsonresult) # put parsed JSON into dictionary
return parsedjson
Perhaps the calling code in checkIP should have a try/except instead, and e.g. retry after sleeping for a bit if the server indicates that you are going too fast.
(In the absence of an authorization token, it looks like you are using the free version of this service, which is probably not in any way guaranteed anyway. Also maybe look at using their recommended library -- I haven't looked at it in more detail, but I would imagine it at the very least knows better how to behave in the case of a server-side error. It's almost certainly also more Pythonic, at least in the sense that you should not reinvent things which already exist.)

Zendesk: Authenticating using Python 3.2.2 'requests' module and API token

I've been asked to deal with an external REST API (Zendesk's, in fact) whose credentials need to be formatted as {email}/token:{security_token} -- a single value rather than the usual username/password pair. I'm trying to use the Python requests module for this task, since it's Pythonic and doesn't hurt my brain too badly, but I'm not sure how to format the authentication credentials. The Zendesk documentation only gives access examples using curl, which I'm unfamiliar with.
Here's how I currently have requests.auth.AuthBase subclassed:
class ZDTokenAuth(requests.auth.AuthBase):
def __init__(self,username,token):
self.username = username
self.token = token
def __call__(self,r):
auth_string = self.username + "/token:" + self.token
auth_string = auth_string.encode('utf-8')
r.headers['Authorization'] = base64.b64encode(auth_string)
return r
I'm not sure that the various encodings are required, but that's how someone did it on github (https://github.com/skipjac/Zendesk-python-api/blob/master/zendesk-ticket-delete.py) so why not. I've tried it without the encoding too, of course - same result.
Here's the class and methods I'm using to test this:
class ZDStats(object):
api_base = "https://mycompany.zendesk.com/api/v2/"
def __init__(self,zd_auth):
self.zd_auth = zd_auth # this is assumed to be a ZDTokenAuth object
def testCredentials(self):
zd_users_url = self.api_base + "users.json"
zdreq = requests.get(zd_users_url, auth=self.zdauth)
return zdreq
This is called with:
credentials = ZDTokenAuth(zd_username,zd_apitoken)
zd = ZDStats(credentials)
users = zd.testCredentials()
print(users.status_code)
print(users.text)
The status code I'm getting back is a 401, and the text is simply {"error":"Couldn't authenticate you."}. Clearly I'm doing something wrong here, but I don't think I know enough to know what it is I'm doing wrong, if that makes sense. Any ideas?
What you're missing is the auth type. Your Authorization header should be created like this:
r.headers['Authorization'] = b"Basic " + base64.b64encode(auth_string)
You can also achieve the same passing by a tuple as auth parameter with:
requests.get(url, auth=(username+"/token", token))

Getting started with secure AWS CloudFront streaming with Python

I have created a S3 bucket, uploaded a video, created a streaming distribution in CloudFront. Tested it with a static HTML player and it works. I have created a keypair through the account settings. I have the private key file sitting on my desktop at the moment. That's where I am.
My aim is to get to a point where my Django/Python site creates secure URLs and people can't access the videos unless they've come from one of my pages. The problem is I'm allergic to the way Amazon have laid things out and I'm just getting more and more confused.
I realise this isn't going to be the best question on StackOverflow but I'm certain I can't be the only fool out here that can't make heads or tails out of how to set up a secure CloudFront/S3 situation. I would really appreciate your help and am willing (once two days has passed) give a 500pt bounty to the best answer.
I have several questions that, once answered, should fit into one explanation of how to accomplish what I'm after:
In the documentation (there's an example in the next point) there's lots of XML lying around telling me I need to POST things to various places. Is there an online console for doing this? Or do I literally have to force this up via cURL (et al)?
How do I create a Origin Access Identity for CloudFront and bind it to my distribution? I've read this document but, per the first point, don't know what to do with it. How does my keypair fit into this?
Once that's done, how do I limit the S3 bucket to only allow people to download things through that identity? If this is another XML jobby rather than clicking around the web UI, please tell me where and how I'm supposed to get this into my account.
In Python, what's the easiest way of generating an expiring URL for a file. I have boto installed but I don't see how to get a file from a streaming distribution.
Are there are any applications or scripts that can take the difficulty of setting this garb up? I use Ubuntu (Linux) but I have XP in a VM if it's Windows-only. I've already looked at CloudBerry S3 Explorer Pro - but it makes about as much sense as the online UI.
You're right, it takes a lot of API work to get this set up. I hope they get it in the AWS Console soon!
UPDATE: I have submitted this code to boto - as of boto v2.1 (released 2011-10-27) this gets much easier. For boto < 2.1, use the instructions here. For boto 2.1 or greater, get the updated instructions on my blog: http://www.secretmike.com/2011/10/aws-cloudfront-secure-streaming.html Once boto v2.1 gets packaged by more distros I'll update the answer here.
To accomplish what you want you need to perform the following steps which I will detail below:
Create your s3 bucket and upload some objects (you've already done this)
Create a Cloudfront "Origin Access Identity" (basically an AWS account to allow cloudfront to access your s3 bucket)
Modify the ACLs on your objects so that only your Cloudfront Origin Access Identity is allowed to read them (this prevents people from bypassing Cloudfront and going direct to s3)
Create a cloudfront distribution with basic URLs and one which requires signed URLs
Test that you can download objects from basic cloudfront distribution but not from s3 or the signed cloudfront distribution
Create a key pair for signing URLs
Generate some URLs using Python
Test that the signed URLs work
1 - Create Bucket and upload object
The easiest way to do this is through the AWS Console but for completeness I'll show how using boto. Boto code is shown here:
import boto
#credentials stored in environment AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
s3 = boto.connect_s3()
#bucket name MUST follow dns guidelines
new_bucket_name = "stream.example.com"
bucket = s3.create_bucket(new_bucket_name)
object_name = "video.mp4"
key = bucket.new_key(object_name)
key.set_contents_from_filename(object_name)
2 - Create a Cloudfront "Origin Access Identity"
For now, this step can only be performed using the API. Boto code is here:
import boto
#credentials stored in environment AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
cf = boto.connect_cloudfront()
oai = cf.create_origin_access_identity(comment='New identity for secure videos')
#We need the following two values for later steps:
print("Origin Access Identity ID: %s" % oai.id)
print("Origin Access Identity S3CanonicalUserId: %s" % oai.s3_user_id)
3 - Modify the ACLs on your objects
Now that we've got our special S3 user account (the S3CanonicalUserId we created above) we need to give it access to our s3 objects. We can do this easily using the AWS Console by opening the object's (not the bucket's!) Permissions tab, click the "Add more permissions" button, and pasting the very long S3CanonicalUserId we got above into the "Grantee" field of a new. Make sure you give the new permission "Open/Download" rights.
You can also do this in code using the following boto script:
import boto
#credentials stored in environment AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
s3 = boto.connect_s3()
bucket_name = "stream.example.com"
bucket = s3.get_bucket(bucket_name)
object_name = "video.mp4"
key = bucket.get_key(object_name)
#Now add read permission to our new s3 account
s3_canonical_user_id = "<your S3CanonicalUserID from above>"
key.add_user_grant("READ", s3_canonical_user_id)
4 - Create a cloudfront distribution
Note that custom origins and private distributions are not fully supported in boto until version 2.0 which has not been formally released at time of writing. The code below pulls out some code from the boto 2.0 branch and hacks it together to get it going but it's not pretty. The 2.0 branch handles this much more elegantly - definitely use that if possible!
import boto
from boto.cloudfront.distribution import DistributionConfig
from boto.cloudfront.exception import CloudFrontServerError
import re
def get_domain_from_xml(xml):
results = re.findall("<DomainName>([^<]+)</DomainName>", xml)
return results[0]
#custom class to hack this until boto v2.0 is released
class HackedStreamingDistributionConfig(DistributionConfig):
def __init__(self, connection=None, origin='', enabled=False,
caller_reference='', cnames=None, comment='',
trusted_signers=None):
DistributionConfig.__init__(self, connection=connection,
origin=origin, enabled=enabled,
caller_reference=caller_reference,
cnames=cnames, comment=comment,
trusted_signers=trusted_signers)
#override the to_xml() function
def to_xml(self):
s = '<?xml version="1.0" encoding="UTF-8"?>\n'
s += '<StreamingDistributionConfig xmlns="http://cloudfront.amazonaws.com/doc/2010-07-15/">\n'
s += ' <S3Origin>\n'
s += ' <DNSName>%s</DNSName>\n' % self.origin
if self.origin_access_identity:
val = self.origin_access_identity
s += ' <OriginAccessIdentity>origin-access-identity/cloudfront/%s</OriginAccessIdentity>\n' % val
s += ' </S3Origin>\n'
s += ' <CallerReference>%s</CallerReference>\n' % self.caller_reference
for cname in self.cnames:
s += ' <CNAME>%s</CNAME>\n' % cname
if self.comment:
s += ' <Comment>%s</Comment>\n' % self.comment
s += ' <Enabled>'
if self.enabled:
s += 'true'
else:
s += 'false'
s += '</Enabled>\n'
if self.trusted_signers:
s += '<TrustedSigners>\n'
for signer in self.trusted_signers:
if signer == 'Self':
s += ' <Self/>\n'
else:
s += ' <AwsAccountNumber>%s</AwsAccountNumber>\n' % signer
s += '</TrustedSigners>\n'
if self.logging:
s += '<Logging>\n'
s += ' <Bucket>%s</Bucket>\n' % self.logging.bucket
s += ' <Prefix>%s</Prefix>\n' % self.logging.prefix
s += '</Logging>\n'
s += '</StreamingDistributionConfig>\n'
return s
def create(self):
response = self.connection.make_request('POST',
'/%s/%s' % ("2010-11-01", "streaming-distribution"),
{'Content-Type' : 'text/xml'},
data=self.to_xml())
body = response.read()
if response.status == 201:
return body
else:
raise CloudFrontServerError(response.status, response.reason, body)
cf = boto.connect_cloudfront()
s3_dns_name = "stream.example.com.s3.amazonaws.com"
comment = "example streaming distribution"
oai = "<OAI ID from step 2 above like E23KRHS6GDUF5L>"
#Create a distribution that does NOT need signed URLS
hsd = HackedStreamingDistributionConfig(connection=cf, origin=s3_dns_name, comment=comment, enabled=True)
hsd.origin_access_identity = oai
basic_dist = hsd.create()
print("Distribution with basic URLs: %s" % get_domain_from_xml(basic_dist))
#Create a distribution that DOES need signed URLS
hsd = HackedStreamingDistributionConfig(connection=cf, origin=s3_dns_name, comment=comment, enabled=True)
hsd.origin_access_identity = oai
#Add some required signers (Self means your own account)
hsd.trusted_signers = ['Self']
signed_dist = hsd.create()
print("Distribution with signed URLs: %s" % get_domain_from_xml(signed_dist))
5 - Test that you can download objects from cloudfront but not from s3
You should now be able to verify:
stream.example.com.s3.amazonaws.com/video.mp4 - should give AccessDenied
signed_distribution.cloudfront.net/video.mp4 - should give MissingKey (because the URL is not signed)
basic_distribution.cloudfront.net/video.mp4 - should work fine
The tests will have to be adjusted to work with your stream player, but the basic idea is that only the basic cloudfront url should work.
6 - Create a keypair for CloudFront
I think the only way to do this is through Amazon's web site. Go into your AWS "Account" page and click on the "Security Credentials" link. Click on the "Key Pairs" tab then click "Create a New Key Pair". This will generate a new key pair for you and automatically download a private key file (pk-xxxxxxxxx.pem). Keep the key file safe and private. Also note down the "Key Pair ID" from amazon as we will need it in the next step.
7 - Generate some URLs in Python
As of boto version 2.0 there does not seem to be any support for generating signed CloudFront URLs. Python does not include RSA encryption routines in the standard library so we will have to use an additional library. I've used M2Crypto in this example.
For a non-streaming distribution, you must use the full cloudfront URL as the resource, however for streaming we only use the object name of the video file. See the code below for a full example of generating a URL which only lasts for 5 minutes.
This code is based loosely on the PHP example code provided by Amazon in the CloudFront documentation.
from M2Crypto import EVP
import base64
import time
def aws_url_base64_encode(msg):
msg_base64 = base64.b64encode(msg)
msg_base64 = msg_base64.replace('+', '-')
msg_base64 = msg_base64.replace('=', '_')
msg_base64 = msg_base64.replace('/', '~')
return msg_base64
def sign_string(message, priv_key_string):
key = EVP.load_key_string(priv_key_string)
key.reset_context(md='sha1')
key.sign_init()
key.sign_update(str(message))
signature = key.sign_final()
return signature
def create_url(url, encoded_signature, key_pair_id, expires):
signed_url = "%(url)s?Expires=%(expires)s&Signature=%(encoded_signature)s&Key-Pair-Id=%(key_pair_id)s" % {
'url':url,
'expires':expires,
'encoded_signature':encoded_signature,
'key_pair_id':key_pair_id,
}
return signed_url
def get_canned_policy_url(url, priv_key_string, key_pair_id, expires):
#we manually construct this policy string to ensure formatting matches signature
canned_policy = '{"Statement":[{"Resource":"%(url)s","Condition":{"DateLessThan":{"AWS:EpochTime":%(expires)s}}}]}' % {'url':url, 'expires':expires}
#now base64 encode it (must be URL safe)
encoded_policy = aws_url_base64_encode(canned_policy)
#sign the non-encoded policy
signature = sign_string(canned_policy, priv_key_string)
#now base64 encode the signature (URL safe as well)
encoded_signature = aws_url_base64_encode(signature)
#combine these into a full url
signed_url = create_url(url, encoded_signature, key_pair_id, expires);
return signed_url
def encode_query_param(resource):
enc = resource
enc = enc.replace('?', '%3F')
enc = enc.replace('=', '%3D')
enc = enc.replace('&', '%26')
return enc
#Set parameters for URL
key_pair_id = "APKAIAZCZRKVIO4BQ" #from the AWS accounts page
priv_key_file = "cloudfront-pk.pem" #your private keypair file
resource = 'video.mp4' #your resource (just object name for streaming videos)
expires = int(time.time()) + 300 #5 min
#Create the signed URL
priv_key_string = open(priv_key_file).read()
signed_url = get_canned_policy_url(resource, priv_key_string, key_pair_id, expires)
#Flash player doesn't like query params so encode them
enc_url = encode_query_param(signed_url)
print(enc_url)
8 - Try out the URLs
Hopefully you should now have a working URL which looks something like this:
video.mp4%3FExpires%3D1309979985%26Signature%3DMUNF7pw1689FhMeSN6JzQmWNVxcaIE9mk1x~KOudJky7anTuX0oAgL~1GW-ON6Zh5NFLBoocX3fUhmC9FusAHtJUzWyJVZLzYT9iLyoyfWMsm2ylCDBqpy5IynFbi8CUajd~CjYdxZBWpxTsPO3yIFNJI~R2AFpWx8qp3fs38Yw_%26Key-Pair-Id%3DAPKAIAZRKVIO4BQ
Put this into your js and you should have something which looks like this (from the PHP example in Amazon's CloudFront documentation):
var so_canned = new SWFObject('http://location.domname.com/~jvngkhow/player.swf','mpl','640','360','9');
so_canned.addParam('allowfullscreen','true');
so_canned.addParam('allowscriptaccess','always');
so_canned.addParam('wmode','opaque');
so_canned.addVariable('file','video.mp4%3FExpires%3D1309979985%26Signature%3DMUNF7pw1689FhMeSN6JzQmWNVxcaIE9mk1x~KOudJky7anTuX0oAgL~1GW-ON6Zh5NFLBoocX3fUhmC9FusAHtJUzWyJVZLzYT9iLyoyfWMsm2ylCDBqpy5IynFbi8CUajd~CjYdxZBWpxTsPO3yIFNJI~R2AFpWx8qp3fs38Yw_%26Key-Pair-Id%3DAPKAIAZRKVIO4BQ');
so_canned.addVariable('streamer','rtmp://s3nzpoyjpct.cloudfront.net/cfx/st');
so_canned.write('canned');
Summary
As you can see, not very easy! boto v2 will help a lot setting up the distribution. I will find out if it's possible to get some URL generation code in there as well to improve this great library!
In Python, what's the easiest way of generating an expiring URL for a file. I have boto installed but I don't see how to get a file from a streaming distribution.
You can generate a expiring signed-URL for the resource. Boto3 documentation has a nice example solution for that:
import datetime
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import padding
from botocore.signers import CloudFrontSigner
def rsa_signer(message):
with open('path/to/key.pem', 'rb') as key_file:
private_key = serialization.load_pem_private_key(
key_file.read(),
password=None,
backend=default_backend()
)
signer = private_key.signer(padding.PKCS1v15(), hashes.SHA1())
signer.update(message)
return signer.finalize()
key_id = 'AKIAIOSFODNN7EXAMPLE'
url = 'http://d2949o5mkkp72v.cloudfront.net/hello.txt'
expire_date = datetime.datetime(2017, 1, 1)
cloudfront_signer = CloudFrontSigner(key_id, rsa_signer)
# Create a signed url that will be valid until the specfic expiry date
# provided using a canned policy.
signed_url = cloudfront_signer.generate_presigned_url(
url, date_less_than=expire_date)
print(signed_url)

Implementing a custom Python authentication handler

The answer to a previous question showed that Nexus implement a custom authentication helper called "NxBASIC".
How do I begin to implement a handler in python?
Update:
Implementing the handler per Alex's suggestion looks to be the right approach, but fails trying to extract the scheme and realm from the authreq.
The returned value for authreq is:
str: NxBASIC realm="Sonatype Nexus Repository Manager API""
AbstractBasicAuthHandler.rx.search(authreq) is only returning a single tuple:
tuple: ('NxBASIC', '"', 'Sonatype Nexus Repository Manager API')
so scheme,realm = mo.groups() fails. From my limited regex knowledge it looks like the standard regex from AbstractBasicAuthHandler should match scheme and realm, but it seems not to.
The regex is:
rx = re.compile('(?:.*,)*[ \t]*([^ \t]+)[ \t]+'
'realm=(["\'])(.*?)\\2', re.I)
Update 2:
From inspection of AbstractBasicAuthHandler, the default processing is to do:
scheme, quote, realm = mo.groups()
Changing to this works. I now just need to set the password against the correct realm. Thanks Alex!
If, as described, name and description are the only differences between this "NxBasic" and good old "Basic", then you could essentially copy-paste-edit some code from urllib2.py (which unfortunately doesn't expose the scheme name as easily overridable in itself), as follows (see urllib2.py's online sources):
import urllib2
class HTTPNxBasicAuthHandler(urllib2.HTTPBasicAuthHandler):
def http_error_auth_reqed(self, authreq, host, req, headers):
# host may be an authority (without userinfo) or a URL with an
# authority
# XXX could be multiple headers
authreq = headers.get(authreq, None)
if authreq:
mo = AbstractBasicAuthHandler.rx.search(authreq)
if mo:
scheme, realm = mo.groups()
if scheme.lower() == 'nxbasic':
return self.retry_http_basic_auth(host, req, realm)
def retry_http_basic_auth(self, host, req, realm):
user, pw = self.passwd.find_user_password(realm, host)
if pw is not None:
raw = "%s:%s" % (user, pw)
auth = 'NxBasic %s' % base64.b64encode(raw).strip()
if req.headers.get(self.auth_header, None) == auth:
return None
req.add_header(self.auth_header, auth)
return self.parent.open(req)
else:
return None
As you can see by inspection, I've just changed two strings from "Basic" to "NxBasic" (and the lowercase equivalents) from what's in urrlib2.py (in the abstract basic auth handler superclass of the http basic auth handler class).
Try using this version -- and if it's still not working, at least having it be your code can help you add print/logging statements, breakpoints, etc, to better understand what's breaking and how. Best of luck! (Sorry I can't help further but I don't have any Nexus around to experiment with).

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