Code Explainers

Code explainers tagged #error-handling

ruby 
require "nokogiri"
require "open-uri"
require "set"
 

Extracting and normalizing links in Ruby

web-scraping url-parsing html-parsing
Intermediate 8 steps
go 
package handlers
 
import (
	"context"

A custom Gin validator backed by Redis

validation redis struct-tags
Intermediate 8 steps
rust 
use std::collections::BTreeSet;
 
#[derive(Debug)]
pub enum FieldError {

Parsing a cron field in Rust

parsing error-handling enums
Intermediate 7 steps
rust 
use hmac::{Hmac, Mac};
use sha2::Sha256;
use subtle::ConstantTimeEq;
 

HMAC signing and constant-time verify in Rust

hmac cryptography constant-time
Intermediate 7 steps
ruby 
class WeatherLookup
  Result = Struct.new(:temperature, :conditions, keyword_init: true)
 
  class TimeoutError < StandardError; end

A resilient weather API service object in Rails

service-object http-client error-handling
Intermediate 7 steps
ruby 
namespace :active_storage do
  desc "Purge blobs that have been unattached for more than 48 hours"
  task purge_stale: :environment do
    cutoff = 48.hours.ago

A Rake task to purge stale Active Storage blobs in Rails

rake active-storage batch-processing
Intermediate 8 steps
javascript 
class ProblemError extends Error {
  constructor(status, title, detail, extensions = {}) {
    super(detail || title);
    this.status = status;

RFC 7807 problem details in Express

error-handling middleware http-api
Intermediate 8 steps
go 
type Warning struct {
	Field   string `json:"field"`
	Code    string `json:"code"`
	Message string `json:"message"`

Partial-success responses in Gin

error-handling input-validation http-status
Intermediate 8 steps
php 
<?php
 
namespace App\Http\Controllers;
 

Building a health check endpoint in Laravel

health-check invokable-controller error-handling
Intermediate 8 steps
typescript 
type RetryableRequest<T> = () => Promise<T>;
 
interface RetryOptions {
  maxAttempts?: number;

Retrying HTTP requests with backoff

retry exponential-backoff error-handling
Intermediate 8 steps
javascript 
const express = require('express');
const createError = require('http-errors');
const { Article } = require('../models');
 

Sharing route logic with router.param in Express

middleware authorization dry
Intermediate 10 steps
python 
from fastapi import APIRouter, status
from fastapi.responses import JSONResponse
from sqlalchemy import text
from sqlalchemy.exc import SQLAlchemyError

Liveness vs readiness health checks in FastAPI

health-checks dependency-injection async
Intermediate 6 steps
typescript 
import { Component, inject } from '@angular/core';
import { FormBuilder, ReactiveFormsModule, Validators } from '@angular/forms';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { finalize } from 'rxjs';

A reactive signup form in Angular

reactive-forms validation dependency-injection
Intermediate 10 steps
go 
package config
 
import (
	"bufio"

Parsing INI files in Go

parsing state-machine error-handling
Intermediate 7 steps
rust 
use axum::{
    async_trait,
    extract::FromRequestParts,
    http::{header::HeaderName, request::Parts, StatusCode},

A custom tenant extractor in Axum

extractors middleware error-handling
Intermediate 7 steps
rust 
use axum::{
    extract::{FromRef, FromRequestParts},
    http::{header, request::Parts, StatusCode},
    RequestPartsExt,

How a JWT extractor works in Axum

jwt authentication extractors
Intermediate 8 steps
rust 
#[derive(Deserialize)]
pub struct CreateArticle {
    title: String,
    body: String,

Building a create endpoint in Axum

extractors json-deserialization sqlx
Intermediate 7 steps
go 
func UploadDocument(c *gin.Context) {
	fileHeader, err := c.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "file is required"})

Handling multipart uploads in Gin

multipart-upload validation error-handling
Intermediate 9 steps