imgurl.py

#!/usr/bin/python3

###############################################################
# Imports
###############################################################
import random
import subprocess
import urllib.request
import os
import sys


###############################################################
#  Variables
###############################################################

# Base URL used for downloads
imgUrl = 'http://i.imgur.com/'

# output dir for images
dlPath = './output/'

# sha256sum of placeholder image from imgur.com
shaSum = '9b5936f4006146e4e1e9025b474c02863c0b5614132ad40db4b925a10e8bfbb9'

# Number of tries used to fetch an image
tries = 1

# Get number of images to download from user input (make this a static value to force download specific number of images when run)
numOfPics = int(input('How many pictures to download? '))


###############################################################
# Functions
###############################################################
def randomnes():	# Function to generate random url to images on imgur.com
    ext = '.jpg'
    chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'

    r1 = random.choice(chars)
    r2 = random.choice(chars)
    r3 = random.choice(chars)
    r4 = random.choice(chars)
    r5 = random.choice(chars)

    rT = r1 + r2 + r3 + r4 + r5
    rTE = rT + ext
    rTFull = imgUrl + rTE

    return (rTFull, rTE)


def downloadImages(rTFull, dlPath, filename):	# Download random generatet image url to ./output folder
    local_file_name = dlPath + filename

    with open(local_file_name, 'wb') as f:
        r = urllib.request.urlopen(rTFull).read()
        f.write(r)
        f.close()

    return local_file_name


def check_sha256sum(f, shaSum, numOfPics, tries):	# Check sha256sum of downloaded image, check if dead image placeholder downloadet, if so download a replacement image.
    file_name = f

    output = subprocess.check_output(['sha256sum', file_name])

    newShaSum = output[:64]	# grap 64 chars of the shasum
    newShaSum = newShaSum.decode('utf-8')	# converting it to a string to compare to shaSum


    # check if new file is a placeholder
    if newShaSum == shaSum:
        print ('Try number:', tries, '- dead image placeholder downloaded...')
        tries += 1

        # Delete image
        os.remove(file_name)
        shortFileName = file_name[9:]
        print ('deleting file', shortFileName, 'and downloading new image...\n')

        # Fetch new image
        rTFull = randomnes()
        local_file_name = downloadImages(rTFull[0], dlPath, rTFull[1])
        check_sha256sum(local_file_name, shaSum, numOfPics, tries)

    else:
        print ('Try number:', tries, '- done!\n\n')

        return


def check_output_dir(f):
    outputDir = os.path.dirname(f)
    print ('Checking if output folder exist...')
    if not os.path.exists(outputDir):
        print ('Output dir not found, making one...\n')
        os.makedirs(outputDir)
    else:
        print ('output folder exists...\n')


###############################################################
# Main
###############################################################
check_output_dir(dlPath)

print ('Need to download', numOfPics, 'images...\n')

for i in range(numOfPics):
    rTFull = randomnes()
    local_file_name = downloadImages(rTFull[0], dlPath, rTFull[1])
    check_sha256sum(local_file_name, shaSum, numOfPics, tries)