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Complex Request Validation in FastAPI with Pydantic

Complex Request Validation in FastAPI with Pydantic
Why should you care? 🤔 Pydantic + FastAPI gets along very well, and provide easy to code, type-annotation based basic validations for atomic types and complex types (created from atomic types). What happens when these basic validations aren’t sufficient for you and you would like to do much more complex? 😲 We use @validator decorator in Pydantic to perform complex validation per request parameter. Let’s dive in.. 🤿 Here’s how we’ll go about this, we are gonna construct a simple API endpoint for printing the date given the day number of the present year.

Python - How traverse filesystem directory

Python - How traverse filesystem directory
Every so often you will find yourself needing to write code that traverse a directory. They tend to be one-off scripts or clean up scripts that run in cron in my experience. Anyway, Python provides a very useful methods of walking a directory structure. We cover best of them. Testing directory structure Here is my testing filesystem tree. Root is in /test ~] tree -a /test /test ├── A │ ├── AA │ │ └── aa.

Python map and starmap functions

Python map and starmap functions
python map function python map function map(function, iterable, ...) Python map function Return an iterator that applies function to every item of iterable, yielding the results. If additional iterable arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. For cases where the function inputs are already arranged into argument tuples, see itertools.

Python reduce and accumulate total guide

Python reduce and accumulate total guide
Python reduce function Python’s reduce() implements a mathematical technique commonly known as folding or reduction. You’re doing a fold or reduction when you reduce a list of items to a single cumulative value. Python’s reduce() operates on any iterable (not just lists) and performs the following steps: Apply a function (or callable) to the first two items (default) in an iterable and generate a partial result. Use that partial result, together with the third item in the iterable, to generate another partial result.

Python case|match - structural pattern matching

Python case|match - structural pattern matching
After many proposals to add a switch/case like syntax to Python failed, a recent proposal by Python language creator Guido van Rossum and a number of other contributors has been accepted for Python 3.10: structural pattern matching . Structural pattern matching not only makes it possible to perform simple switch/case style matches, but also supports a broader range of use cases. Python structural pattern matching Structural pattern matching introduces the match/case statement and the pattern syntax to Python.

Python Multiprocessing - Right Way

Python Multiprocessing - Right Way
We will not write about what multiprocessing is. You can find many articles about what is multiprocessing . Although cumbersome at first sight, multiprocessing does have several advantages. Keeping processes separated in their own virtual memory "cages" can actually help in debugging and avoids confusion. Once you sort out the intercommunication problem in a systematic way and avoid some common pitfalls, programming with python multiprocesses becomes a joy. One frequent error is to mix multithreading and multiprocessing together, creating a crashy/leaky program and then conclude that python sucks.

Awk BuiltIn Variables

Awk BuiltIn Variables
The following is a list of variables that awk sets automatically on certain occasions in order to provide information to your program. The variables that are specific to gawk are marked with a pound sign (#). These variables are gawk extensions. In other awk implementations or if gawk is in compatibility mode (see section Command-Line Options ), they are not special. VARIABLE NAME DESCRIPTION FS input field separator variable OFS Output Field Separator RS Input Record Separator variable ORS Output Record Separator Variable NR Number of Records NF Number of Fields in a record FILENAME Name of the current input file FNR Number of Records relative to the current input file RLENGTH length of the substring matched by the match() function RSTART first position in the string matched by match() function FS - input field separator variable It represents the (input) field separator and its default value is space.

Awk If Statement

Awk If Statement
In this awk tutorial, let us review awk conditional if statements with practical examples. Normally conditional statement checks the condition, before performing any action. If the condition is true action(s) are performed. Similarly action can be performed if the condition is false. Conditional statement starts with the keyword called "if". Awk supports three different kind of if statement. Awk Simple If statement Awk If-Else statement Awk If-Else-If statement awk If Statement Single Action: Simple If statement is used to check the conditions, if the condition returns true, it performs its corresponding action(s).

FastAPI language translations I18n Step by Step

FastAPI language translations I18n Step by Step
Since the beginning of 2020, FastAPI has been gaining momentum as one of the potential alternatives to Flask server for RESTful API. If you are an existing FastAPI user, you should be aware that it does not come with built-in internationalization, and that will likely not change soon, because internationalization strategies are application-dependent. The following tutorial focuses on server-side i18n . This tutorial will show you how to i18n your FastAPI web application easily using the following Python libraries:
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