1. Periodically capture a screenshot of the current queue
2. Extract the queue time remaining from the screenshot
3. Send an alert when the queue reaches a certain time

Prerequisites

You'll need Python 3.6 or higher: you can find information on downloading and installing python here if needed.

You'll also need the python package manager pip for installing the libraries. If you need information on pip you can find it here.

Libraries

You will need to install the following two packages:

1. pytesseract: This is an optical character recognition (OCR) package which we will use to extract the queue time information from a screenshot of your WoW classic queue. To install pytesseract, first you'll need to install Tesseract which is the underlying engine. After you have Tesseract on your system, you can install the pytesseract package with the PIP command: pip install pytesseract

2. pillow: This is an image processing library which we will use to capture and prepare the screenshots. Install it using the PIP command: pip install pillow

Now, onto the fun part. We need to periodically capture an image of the current WoW Classic queue, and extract the information we want: the minutes left in the queue - i.e. the "199" below (full image not shown).

Capture a screenshot

We will use pillow's ImageGrab.grab() to screenshot every 5 seconds, and put the screenshot image in a variable called "img". The while True in line 2 means it will run indefinitely until it is told to stop.

from PIL import ImageGrab
while True:
    time.sleep(5)
    img = ImageGrab.grab()

Process the image

Next we need to process our screenshot ("img") to prepare it for image recognition. This code will crop the image (line 3), apply a threshold to increase contrast (line 4), remove the color (line 5) so that the image becomes black and white.

from PIL import ImageEnhance
width, height = img.size
img = img.crop((width*.3, height*.4, width*.7, height*.6))
img = img.point(lambda p: p > 128 and 255)
img = ImageEnhance.Color(img).enhance(0)

This processing makes it easier for the text recognition by removing shadows, gradiants and colors.

Extract the data

Now the image is ready we use pytesseract's image_to_data function to extract the data from the processed image. The image_to_data function returns a dictionary that includes the text, its location, and a confidence value.

We'll use a list comprehension (line 3) to filter to the text elements that have a reasonable degree of confidence (rendered in green below), then join those elements into a single string (line 3).

Finally we'll use regular expressions (regex) extract the numeric digits after the word "time", so that we can check how long is left in the queue.

import pytesseract
import re
imgdata = pytesseract.image_to_data(img, output_type=pytesseract.Output.DICT)
imgtext = ' '.join([x for i,x in enumerate(imgdata['text']) if int(imgdata['conf'][i]) >= 70])
imgtime = re.search(r'time[^\d+]*(\d+)', imgtext).group(1)

The image processing function

We will wrap the image processing steps into a single get_time_in_queue() function. This function will accept the screenshot image as a parameter called img, process it, and return the queue minutes as an integer, or a None value if it is unable to extract the data.

def get_time_in_queue(img):
    width, height = img.size
    img = img.crop((width*.3, height*.4, width*.7, height*.6))
    img = img.point(lambda p: p > 128 and 255)
    img = ImageEnhance.Color(img).enhance(0)
    imgdata = pytesseract.image_to_data(img, output_type=pytesseract.Output.DICT)
    imgtext = ' '.join([x for i,x in enumerate(imgdata['text']) if int(imgdata['conf'][i]) >= 70])
    imgtime = re.search(r'time[^\d+]*(\d+)', imgtext)
    if imgtime:
        return int(imgtime.group(1))

Ths simplest option is to sound a system alert. Here is a super simple way of playing a system alert tone on most systems:

print(chr(7))

This may not work in an integrated development environment or notebook, but it should work in your python console or in a python script executed from the console.

Recieving an email when the queue is ready can be convenient, especially if you get email notifications on your phone, and you aren't at your computer.

To do so, we need a few of Python's in-built libraries, and to configure the email login and send settings. We won't go into a huge amount of detail on setting up email notifications as there are plenty of resources out there already.

The following imports come packaged up with Python so all you need to do is add them to the list of imports at the top of your file.

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

The code to set up an email server is shown below, but don't forget to substitute your email provider's details. If you are using one of Microsoft's services, you're most likely good to go with the below.

emailserver = smtplib.SMTP(host='smtp-mail.outlook.com', port=587)
emailserver.starttls()
emailserver.login(EMAILADDRESS, PASSWORD)

NB: You will note that we haven't coded USERNAME or PASSWORD. These values are normally passed in as strings. We do NOT recommend hardcoding any credentials directly into a Python script! This is especially important if you are using version control that pushes to the cloud, for e.g. Github.

These credentials should be, at the very least, saved in another file and have some basic encryption.

One option is to save your details (e.g. as a class called outlook containing email and password attributes) as a python module, encrypt it, and import it like from mypymodule import outlook. You can then replace all instances of USERNAME and PASSWORD with outlook.email and outlook.password. Be careful though, anyone with a login to your computer can still potentially access your details.

Once the server is set up, we can create a message object, add some contents, and then use that emailserver to send the message.

msg = MIMEMultipart() 
msg['From'] = EMAILADDRESS
msg['To'] = EMAILADDRESS
msg['Subject'] = "Time to WoW!"
message = 'Your WoW queue is about to pop!'
msg.attach(MIMEText(message, 'plain'))
emailserver.send_message(msg)

And just because we can, here's how you can play a song from your computer for an extra special alarm. You'll probably want to update the file path to something a bit more interesting than this windows alarm!

songfile = 'C:\\Windows\\Media\\Alarm01.wav'
from playsound import playsound
playsound(songfile)