Code Explainers

Go code explainers

go 
package middleware
 
import (
	"crypto/hmac"

Verifying signed URLs with Gin middleware

hmac middleware authentication
Intermediate 8 steps
go 
package dedup
 
import (
	"hash/fnv"

A rolling Bloom filter deduper in Go

bloom-filter deduplication concurrency
Advanced 7 steps
go 
package server
 
import (
	"net/http"

Rate limiting HTTP handlers with a token bucket

rate-limiting token-bucket middleware
Advanced 7 steps
go 
package middleware
 
import (
	"fmt"

How a panic-recovery middleware works in Gin

middleware panic-recovery error-reporting
Intermediate 8 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
go 
package handlers
 
type WebhookEvent struct {
	ID   string          `json:"id"`

Verifying and processing webhooks in Gin

webhooks hmac idempotency
Intermediate 9 steps
go 
package logparse
 
import (
	"bufio"

Splitting multi-line logs with a Scanner

parsing streaming bufio
Intermediate 9 steps
go 
package handlers
 
import (
	"net/http"

Custom validators and binding in Gin

validation struct-tags error-handling
Intermediate 8 steps
go 
package hashring
 
import (
	"hash/crc32"

How consistent hashing works in Go

consistent-hashing load-balancing concurrency
Intermediate 8 steps
go 
package middleware
 
import (
	"net/http"

Wrapping Gin requests in a DB transaction

middleware transactions error-handling
Intermediate 8 steps
go 
package handlers
 
import (
	"encoding/base64"

Cursor pagination in a Gin handler

pagination cursor rest-api
Intermediate 8 steps
go 
package metrics
 
import (
	"sync"

A thread-safe sliding-window average in Go

concurrency sliding-window running-average
Intermediate 8 steps
go 
package logging
 
import (
	"fmt"

Redacting secrets with Go reflection

reflection recursion struct-tags
Advanced 10 steps
go 
package middleware
 
import (
	"context"

Per-tenant daily rate limiting in Gin

rate-limiting middleware redis
Intermediate 8 steps
go 
func (h *ExportHandler) StreamExport(c *gin.Context) {
	datasetID := c.Param("id")
 
	ctx := c.Request.Context()

Streaming NDJSON progress with Gin

streaming goroutines channels
Advanced 8 steps
go 
package handler
 
type flightResult struct {
	status int

Deduping in-flight requests in Gin

middleware concurrency deduplication
Advanced 9 steps
go 
type CreateUserInput struct {
	Name     string `json:"name" binding:"required,min=2,max=64"`
	Email    string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required,min=8"`

Turning Gin validation errors into JSON

validation request-binding error-handling
Intermediate 9 steps
go 
package middleware
 
import (
	"net/http"

Per-IP write rate limiting in Gin

rate-limiting middleware concurrency
Intermediate 8 steps