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Posts Tagged ‘python

Automate build and load of Hugo sites to Amazon S3 using Rclone with Python

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This was the build and load flow for my Hugo site before I gave up on Hugo and moved back to WordPress. The site was generated using Hugo and pushed to Amazon s3 using rclone.

The code assumes the hugo and rclone executables, and the hugo root directory are in the same folder.

In this example the hugo directory is called codepearls.xyzio.com.


import os, shutil

# s3 auth info
s3SecretAccessKey = 's3_secret_key'
s3AccessKeyId = 's3_access_key'

# Hugo folder and bucket name.  sitepath is path to the hugo public folder.
path = 'codepearls.xyzio.com'
sitepath = os.path.join(path, 'public')

#Remove the files from the previous build by deleting the public folder
if os.path.exists(sitepath):
   shutil.rmtree(sitepath)

# Run hugo from root directory
cmd = 'hugo.exe -s ' + path
os.system(cmd)

# Run rclone from root directory to sync /public to s3 and the appropriate args to encrypt the files and enable public read
cmd = 'rclone.exe sync ' + sitepath + ' s3:' + path
cmd += ' -v --s3-secret-access-key ' + s3SecretAccessKey
cmd += ' --s3-access-key-id ' + s3AccessKeyId
cmd += ' --s3-acl public-read'
cmd += ' --s3-server-side-encryption AES256'
cmd += ' --s3-provider AWS'
cmd += ' --s3-region us-west-2'

os.system(cmd)

Written by M Kapoor

December 24, 2019 at 3:26 am

Posted in python

Tagged with , ,

Open a zip archive and iterate through its files with Python

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Open a file compressed as .zip and iterate through its files line by line with Python.


import zipfile

#Path to the zip file
zipfilepath = 'path_to_zip_file'

#Read in zip file
zip = zipfile.ZipFile(zipfilepath)

#Iterate through files in zip file
for zipfilename in zip.filelist:
    
    #Read contents of the file
    filecontents = zip.read(zipfilename)
    
    #Break up contents into list and process
    for line in filecontents.replace('\r\n', '\n').split('\n'):
        print line

Written by M Kapoor

December 24, 2019 at 3:09 am

Posted in Programming

Tagged with ,

Open and print a .gz.bz2 file with Python

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Open and print a file that is compressed with gzip and then with bzip2, i.e a gz.bz2 file, with Python.


import sys
import bz2
import gzip
from cStringIO import StringIO

# .gz.bz2 File is given as commandline argument
filename = sys.argv[1]

gzbzfilename = filename

#Read in the bz2 data
o = open(gzbzfilename, 'rb')
gzbzdata = o.read()

#Decompress the bz2 data
gzdata = bz2.decompress(gzbzdata)

#Next, gunzip the gzip file and read out the file pointer
f = gzip.GzipFile(fileobj=StringIO(gzdata))
file_content = f.read()
f.close()

#Print out the file contents
print file_content

Written by M Kapoor

December 24, 2019 at 3:04 am

Posted in Programming

Tagged with , , ,

Convert magnet link to torrent file with Python and add additional trackers

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With rtorrent it is easier to have it pick up torrent files from a directory. This code converts a magnet link into a torrent file with Python and then inserts additional trackers to the torrent file.


import urllib
import HTMLParser

#This is the magnet link to modify
magnetLink = 'magnet:?xt=urn:btih:b54a3ba68fd398ed019e21290beecc9dda64a858&dn=wikipedia_en_all_novid_2018-06.zim&tr=udp%3a%2f%2ftracker.mg64.net'

#Here is a list of trackers to insert into the torrent
trackers = {'list','of','trackers'}

#Convert HTML special characters to escaped normal characters
magnetLink = urllib.unquote(magnetLink).decode('utf8')
magnetLink = HTMLParser.HTMLParser().unescape(magnetLink)

#Split out the trackers from the magnet link and save for later
magnetsplit = magnetLink.split('&tr=')
base = magnetsplit[0]
magnetTrackers = magnetsplit[1::]

#Add the trackers from the magnet link to our list of trackers
for magnetTracker in magnetTrackers:
    trackers.add(magnetTracker)

#Add the trackers
magnetLink = base
for tracker in trackers:
    magnetLink += '&tr=' + tracker

#Create the torrent file name - it is named after the magnet hash
magnetName = magnetLink[magnetLink.find("btih:") + 1:magnetLink.find("&")]
magnetName = magnetName.replace('tih:','')
torrentfilename = 'meta-' + magnetName + '.torrent'

#Write the magnet link to the torrent file
with open(torrentfilename, 'w') as o:
    linkstr = u'd10:magnet-uri' + str(len(magnetLink)) + u':' + magnetLink + u'e'
    linkstr = linkstr.encode('utf8')
    o.write(linkstr)


Written by M Kapoor

December 23, 2019 at 11:48 pm

Posted in Programming

Tagged with ,

Authenticate with BackBlaze B2 and list buckets with Python

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Authenticate with BackBlaze B2 and list buckets with Python.

First to authenticate with BackBlaze B2:


import requests
from requests.auth import HTTPBasicAuth

#Credentials from BackBlaze B2 manager
key_id          = 'b2_key_id'
application_key = 'b2_application_key'

#Contact authorization server and check response
path   = 'https://api.backblazeb2.com/b2api/v1/b2_authorize_account'
result = requests.get(path, auth=HTTPBasicAuth(key_id, application_key))
if result.status_code != 200:
    print 'Error - Could not connect to BackBlaze B2'
    exit()

#Get results and add authorization token to headers
result_json = result.json()
account_id  = result_json['accountId']
auth_token  = result_json['authorizationToken']
api_url     = result_json['apiUrl'] + '/b2api/v1'
api_session = requests.Session()
api_session.headers.update({ 'Authorization': auth_token })

Now use api_session to interact with B2. For example, download the list of buckets like this:


#Construct the API url
url = api_url + '/b2_list_buckets'

#Use the api_session parameter to get a list of buckets
bucketInfo = api_session.post(url, json={'accountId': account_id})

#Convert datastream to json
jsonBucketInfo = bucketInfo.json()

#List id and name
for bucket in jsonBucketInfo['buckets']:
    bucketId = bucket['bucketId']
    bucketName = bucket['bucketName']

    print bucketId, bucketName

More details about tokens in the json are on BackBlaze’s list_buckets API page.

Written by M Kapoor

December 23, 2019 at 8:05 pm

Posted in Programming

Tagged with ,

Authenticate with BackBlaze B2 and get file URLs using Python

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Authenticate with BackBlaze B2 and get the URLs of files in a bucket.

First to authenticate with BackBlaze B2:


import requests
from requests.auth import HTTPBasicAuth

#Auth information from Backblaze
key_id = 'key_id'
application_key = 'application_key'

#Authenticate
path = 'https://api.backblazeb2.com/b2api/v1/b2_authorize_account'
result = requests.get(path, auth=HTTPBasicAuth(key_id, application_key))
if result.status_code != 200:
    print 'Error - Could not connect to BackBlaze B2'
    exit()

#Read response
result_json = result.json()
account_id = result_json['accountId']
auth_token = result_json['authorizationToken']
api_url    = result_json['apiUrl'] + '/b2api/v1'
download_url = result_json['downloadUrl'] + '/file/'
api_session = requests.Session()
api_session.headers.update({ 'Authorization': auth_token })

Now get bucket contents and assemble URL. Sample code for bucket ID and bucket name is here.


#Initialize
bucketId = 'bucket_id_from_b2'
bucketName = 'name_of_bucket'

params = {'bucketId': bucketId}
urls = set()

#Loop for as long as a nextFile exists
while True:
    #Construct api call, execute, and read back information
    url = api_url + '/' + 'b2_list_file_names'
    fileList =  api_session.post(url, json=params)
    jFileList = fileList.json()

    #Loop through files and construct url
    for file in jFileList['files']:
        urls.add(download_url + bucketName + '/' + file['filename'])

    #Check for next file and break if it doesn't exist
    startFileName = jFileList['nextFileName']
    if startFileName == None:
        break
    else:
        #continue If next file exists
        params['startFileName'] = startFileName
        

Written by M Kapoor

December 23, 2019 at 7:17 pm

Posted in Programming

Tagged with ,

Hacking Planet Atwood with Python and AWS

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Peter Atwood is a hobbyist who creates limited edition pocket tools and puts them up for sale on his site at Planet Pocket Tool.  His tools are fairly popular and being limited are hard to acquire.

Peter posts the sales randomly and the tools generally sell out within a few minutes of being listed.  The best way to capture a sale is to periodically check his site and get alerted when a sale is in progress.  This write-up is about automating the check and sending an alert via SMS and email using Python.

Blogspot publishes a RSS feed for their blogs.  I wrote a simple function to use feedparser to grab the datetime of the first item in the feed and compare it against the previous version.  I send out an alert if the datetime of the first item is different from the one I have saved.

#Get the blog entry
feed = feedparser.parse('http://atwoodknives.blogspot.com/feeds/posts/default')

#Figure out the publish time of the first entry
firstEntryPubTime = time.strftime('%Y%m%d%H%M%S', feed.entries[0].published_parsed)

#The newest post time did not match the previously saved post time
#We have a new post
if firstEntryPubTime != currentUpdateTime:

    #Save the new first blog entry time
    setCurrentUpdateTime(firstEntryPubTime)
    url = feed.entries[0].link
    subject = 'Atwood: ' + feed.entries[0].title
    body = url + feed.entries[0].summary

    #Send an alert
    send_alert(subject, body, url)

else:
    print "No Update"

Now, to send the alert we leverage Amazon Web Services and BOTO the AWS Python interface. Amazon has a service called Simple Notification Service or SNS. SNS is a push service that lets users push messages in various formats like SMS and email.

Getting started is simple. First create a topic to which people can subscribe using create_topic. Then subscribe your phone number, email address, and any other form of communication using subscribe. Now you are all set.

def send_alert(message_title, message_body, message_url):
    #Connect with boto using the AWS token and secret key
    c = boto.connect_sns('token','secret_key')
    topicarn = "arn:aws:sns:us-east-1:TopicName"
    #Publish or send out the URL of the blog post for quick clicking
    publication = c.publish(topicarn, url, subject=url[:110])
    #Close connection
    c.close()

I set up this script on a server at DigitalOcean and ran it periodically using cron. I was able to get to the buy link for most of Atwood’s sales with this methodology and eventually bought a Fancy Ti Atwrench. While nice and well made, it is definitely not worth what Peter Atwood charges for it.

Written by M Kapoor

June 10, 2015 at 11:58 pm

Driving Adafruit’s RGB Matrix with Python on the BeagleBone Black

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I wrote this code to drive the Adafruit 32×64 RGB Matrix using a Beaglebone Black and Adafruit’s IO Python library.  The code is super simple – it writes a static color background to the top and bottom halves of the display through the shift registers and triggers the latch.  It then iterates through the addresses so the LEDs for that row turn on and then goes to the next address.  This should create a background color through persistence of vision.

Along the way I discovered:

The Python Library isn’t fast enough to drive the RGB matrix to provide a persistent display.  There is flicker and when updating colors, you see each row turn on and off.  You literally see the delay.  There are ways to speed up the writes by using the PRU or direct IO writes.  But I should not have to do that on a 1GHz processor.

The RGB matrix doesn’t light up unless you continually change the address.  This was really annoying when I was figuring things out.  I did not find this documented anywhere on the web except on rayslogic’s RGB writeup.

It appears the BeagleBone Black’s IO pins cannot push enough current to turn on the input schmitt triggers.  I spent a lot of time being frustrated because I couldn’t get the green and blue LEDs to light up on my board.
Finally I noticed the green LEDs were barely on and had a brightness gradient from low to high address.  My guess is the address pin was barely turning on which meant 0 was the most common address – hence the higher brightness on the lower rows.  I got around this by plugging the G(reen) input directly into the 5V pin on the BeagleBone Black.  Of course this now meant the green LEDs are always on!

Adafruit charges too much for the RGB panels.  For example, the seller kbellenterprises on ebay has a 16×32 RGB matrix for $16 including shipping.  Adafruit has the same panel for $25 and you pay for shipping.

Adafruit charges too much for male-to-male jumper wires.  The seller funny-diy on ebay sells 40 for $1.80 with shipping while Adafruit charges $4+shipping for their so-called “premium” wires.  Adafruit needs to rename them to “premium-priced“.

My Python Code:
https://bitbucket.org/xyzio/rgbmatrix/src/master/bb_python/logic.py

Sources:
http://www.rayslogic.com/propeller/programming/AdafruitRGB/AdafruitRGB.htm
https://learn.adafruit.com/setting-up-io-python-library-on-beaglebone-black/overview

 

Written by M Kapoor

April 3, 2015 at 4:12 pm

Batch converting videos to play on the Nexus 7 using FFMPEG

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How to batch convert videos to play on the Nexus 7 using FFMPEG in Python.

mypath = r'path_to_video_files'

from os import listdir
from os.path import isfile, join
onlyfiles = [ f for f in listdir(mypath) if isfile(join(mypath,f)) ]

for file in onlyfiles:
    infile = '"' + mypath + file + '"'
    outfile = '"' + mypath + file + '.mp4' + '"'
    ffmpegpath = r'ffmpeg.exe'
    cmd = r' -i ' + infile + ' -acodec libmp3lame -vcodec libx264 -aspect 16:9 -s 800x480 -ab 128k -b 512k -f mp4 -strict experimental ' + outfile
    import os
    os.system(ffmpegpath + cmd)

Starting source:

http://stackoverflow.com/questions/8589976/how-to-convert-an-mkv-with-subtitles-to-something-nexus-one-friendly

Written by M Kapoor

September 29, 2014 at 3:01 pm

Posted in java

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