Book Image

Modern Python Standard Library Cookbook

By : Alessandro Molina
Book Image

Modern Python Standard Library Cookbook

By: Alessandro Molina

Overview of this book

The Python 3 Standard Library is a vast array of modules that you can use for developing various kinds of applications. It contains an exhaustive list of libraries, and this book will help you choose the best one to address specific programming problems in Python. The Modern Python Standard Library Cookbook begins with recipes on containers and data structures and guides you in performing effective text management in Python. You will find Python recipes for command-line operations, networking, filesystems and directories, and concurrent execution. You will learn about Python security essentials in Python and get to grips with various development tools for debugging, benchmarking, inspection, error reporting, and tracing. The book includes recipes to help you create graphical user interfaces for your application. You will learn to work with multimedia components and perform mathematical operations on date and time. The recipes will also show you how to deploy different searching and sorting algorithms on your data. By the end of the book, you will have acquired the skills needed to write clean code in Python and develop applications that meet your needs.
Table of Contents (21 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Submitting forms to HTTP


Sometimes you have to interact with HTML forms or upload files. This usually requires handling the multipart/form-data encoding.

Forms can mix files and text data, and there can be multiple different fields within a form. Thus, it requires a way to express multiple fields in the same request and some of those fields can be binary files.

That's why encoding data in multipart can get tricky, but it's possible to roll out a basic recipe using only standard library tools that will work in most cases.

How to do it...

Here are the steps for this recipe:

  1. multipart itself requires tracking all the fields and files we want to encode and then performing the encoding itself.
  2. We will rely on io.BytesIO to store all the resulting bytes:
import io
import mimetypes
import uuid


class MultiPartForm:
    def __init__(self):
        self.fields = {}
        self.files = []

    def __setitem__(self, name, value):
        self.fields[name] = value

    def add_file(self, field, filename...