Python I/O made easy with filehandlers

Reece Dunham — Fri, 27 Sep 2019 15:15:29 +0000

Hello everybody,
Today I am here to explain how my library, filehandlers, makes basic Python I/O easier for everyone.

Let me start off by saying that Python's open built-in function can be confusing. While it is well documented on 3rd party websites, integration in general can be difficult. The result of using the function is a io.TextIOWrapper object, which by itself does have documentation, but still can be hard for beginners and advanced Python developers alike.

(Before you can continue, filehandlers needs to be installed. You will need to install the filehandlers package with pip (guide), or add it to your requirements.txt.)

Creating Files

Let's start off with the bare minimum, creating a file in the working directory.

# import the library
# make sure you followed the steps in the parentheses above!
import filehandlers

# define a "file", even if said "file" doesn't yet exist
# this call just creates an instance, nothing too spooky going on here
myfile = filehandlers.AbstractFile("mycoolfile.txt")

# create the file on the disk
myfile.touch()

# note in the console what great work we have done
print("I created the file!")

Easy, right?

Writing to Files

Now, let's create a file, and write a hello world to it:

# same basic starter steps
import filehandlers

myfile = filehandlers.AbstractFile("mycoolfile.txt")

# create the file on the disk
myfile.touch()

print("I created the file!")

# create a manipulator object so we can change the file:
manipulator_of_myfile = filehandlers.FileManipulator(
    # we need to input the AbstractFile instance to this function:
    myfile
)

# now, we will write "hello world!" to the file:
manipulator_of_myfile.write_to_file("hello world!")

# and we are done
print("Mission complete.")

Now that we have created files and written to files, I think it's time we read files, so we can use existing data.

Reading Files

Alright, let's just get right into this:

# this time, we'll just import the modules we need
# so there is no need to fully type out the class names inline
from filehandlers import AbstractFile, FileManipulator

myfile = AbstractFile("data.cfg")

manipulator = FileManipulator(myfile)

# we just created the manipulator, so the file cache should be up to date
# if at any time you believe the file may have changed, you can run:
# my_manipulator_variable.refresh()

# get the file's line cache
# (this will be an array, each index will be the next line, so the_cache_element[0] will be the first line, the_cache_element[1] will be the second line, etc. etc.)

the_cache_element = manipulator.get_cache()

# print the first line of the file
print("Line 1: " + the_cache_element[0])

# print all of the lines:
for line in the_cache_element:
    print(line)

Super simple.

If you would like to do further reading, full docs can be found here.

Want to contribute? The library is open source and can be found here.

Setting up Python unittests with GitHub annotations

Reece Dunham — Fri, 27 Sep 2019 01:21:43 +0000

Hello!
This is my first post on DEV, so I'm going to try to make this quick and simple.

If you want inline examples of exactly where your code is failing, you can integrate Cirrus CI with GitHub annotations. This is super simple to do.

Start off by writing unittests. This is super simple.
Setup a basic CI pipeline (.cirrus.yml file). You will want to do something like this:

tests_task:
  # define Docker container
  container:
    image: python:latest

  # install project requirements and the annotation result builder
  install_script: |
    pip install -r ./some-requirements-file.txt
    pip install unittest-xml-reporting

  # normally, you would run unittests with the main command
  # we need to build XML reports, so use this command
  script: python3 -m xmlrunner tests
  # replace tests with the name of the module your unittests are in

  # (always) upload results - even if the tests fail
  always:
    unittest_results_artifacts:
      # where the outputted XML files are
      path: ./*.xml
      # required, even though it sounds wrong
      format: junit

And that is all you need to do!
You should then get annotations.

Have a nice day!

Forem: Reece Dunham

Python I/O made easy with filehandlers

Creating Files

Writing to Files

Reading Files

Setting up Python unittests with GitHub annotations