Code Explainers

Go code explainers

go 
package middleware
 
import (
	"net/http"

A content-type guard middleware in Gin

middleware closures http
Intermediate 7 steps
go 
package api
 
import (
	"errors"

Turning Gin validation errors into JSON

validation error-handling http-handlers
Intermediate 9 steps
go 
package breaker
 
import (
	"errors"

How a circuit breaker works in Go

circuit-breaker state-machine concurrency
Intermediate 8 steps
go 
package middleware
 
import (
	"net/http"

Role-based access control middleware in Gin

middleware authorization closures
Intermediate 7 steps
go 
func UserDashboardCache(rdb *redis.Client, ttl time.Duration) gin.HandlerFunc {
	return func(c *gin.Context) {
		claims, ok := c.Get("claims")
		if !ok {

Per-user response caching in Gin with Redis

middleware caching redis
Advanced 9 steps
go 
package middleware
 
import (
	"compress/gzip"

How gzip HTTP middleware works in Go

middleware compression object-pooling
Intermediate 7 steps
go 
package events
 
import (
	"net/http"

Two-pass JSON dispatch in Gin

polymorphic-json request-binding validation
Intermediate 8 steps
go 
package handlers
 
type ListFilters struct {
	Status    string `form:"status" binding:"omitempty,oneof=active archived all"`

Cross-field query validation in Gin

validation struct-tags query-binding
Intermediate 9 steps
go 
package editor
 
import (
	"context"

How a debouncer coalesces bursts in Go

debounce concurrency timers
Intermediate 8 steps
go 
package humanize
 
import (
	"fmt"

Parsing human-readable byte sizes in Go

parsing regex lookup-table
Intermediate 8 steps
go 
package handlers
 
import (
	"net/http"

Serving embedded static meta files in Gin

embedding static assets http caching
Intermediate 6 steps
go 
package config
 
import (
	"fmt"

A thread-safe config singleton in Go

singleton concurrency environment-variables
Intermediate 7 steps
go 
package scheduler
 
import (
	"container/heap"

A priority job queue with Go's container/heap

priority-queue heap interfaces
Intermediate 9 steps
go 
func UploadChunk(c *gin.Context) {
	uploadID := c.Param("uploadID")
	if !validUploadID.MatchString(uploadID) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid upload id"})

Resumable chunked uploads in Gin

file-upload content-range streaming
Advanced 9 steps
go 
func (h *ArticleHandler) Create(c *gin.Context) {
	var req struct {
		Title   string `json:"title" binding:"required"`
		Body    string `json:"body" binding:"required"`

Handling a POST request in Gin

request binding validation http status codes
Intermediate 7 steps
go 
package cache
 
import (
	"sync"

A thread-safe TTL cache in Go

concurrency mutex caching
Intermediate 9 steps
go 
package handlers
 
import (
	"net/http"

Sparse fieldsets in a Gin handler

sparse-fieldsets query-parsing json-serialization
Intermediate 9 steps
go 
package sse
 
import (
	"encoding/json"

Server-Sent Events streaming in Go

server-sent-events channels http-streaming
Intermediate 8 steps