Code Explainers

Go code explainers

go 
package fetch
 
import (
	"context"

Concurrent API fetches with errgroup in Go

concurrency goroutines error-handling
Intermediate 8 steps
go 
func UploadFiles(c *gin.Context) {
	form, err := c.MultipartForm()
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid multipart form"})

Handling multi-file uploads in Gin

file-upload multipart validation
Intermediate 8 steps
go 
package pipeline
 
import (
	"context"

A cancelable worker pool in Go

concurrency channels worker-pool
Advanced 8 steps
go 
package auth
 
import (
	"net/http"

Building a JWT auth middleware in Gin

middleware jwt authentication
Intermediate 7 steps
go 
func RecoveryHandler(logger *zap.Logger) gin.HandlerFunc {
	return gin.CustomRecovery(func(c *gin.Context, recovered any) {
		var brokenPipe bool
		if ne, ok := recovered.(*net.OpError); ok {

A panic-recovery middleware in Gin

middleware panic-recovery structured-logging
Intermediate 6 steps
go 
package server
 
import (
	"context"

Composing HTTP middleware in Go

middleware http-handlers closures
Intermediate 8 steps
go 
package config
 
import (
	"encoding/json"

Parsing untyped JSON config in Go

json parsing type assertions error handling
Intermediate 7 steps
go 
package main
 
import (
	"net/http"

How route groups nest in Gin

routing middleware api versioning
Intermediate 6 steps
go 
package main
 
import (
	"errors"

Parsing and validating CLI flags in Go

cli-parsing validation error-handling
Intermediate 8 steps
go 
package cache
 
import (
	"container/list"

Building a generic LRU cache in Go

lru-cache generics linked-list
Intermediate 8 steps
go 
package model
 
import (
	"encoding/json"

Custom JSON marshaling in Go

json serialization interfaces
Intermediate 5 steps
go 
func (h *TransactionHandler) ExportCSV(c *gin.Context) {
	ctx := c.Request.Context()
	filters := parseTransactionFilters(c)
 

Streaming a CSV export in Gin

streaming csv-export database-cursor
Intermediate 8 steps
go 
package store
 
import (
	"database/sql"

Wrapping and inspecting errors in Go

error-handling error-wrapping sentinel-errors
Intermediate 8 steps
go 
package main
 
import (
	"context"

Graceful HTTP shutdown in Go

graceful-shutdown signals goroutines
Intermediate 8 steps
go 
package handlers
 
type SignupRequest struct {
	Email           string `json:"email" binding:"required,email"`

Validated signup handler in Gin

request validation error handling http status codes
Intermediate 7 steps
go 
package handlers
 
import (
	"net/http"

Cookie-based sessions in Gin

authentication cookies middleware
Intermediate 7 steps
go 
package validators
 
import (
	"regexp"

Custom validators in Gin

validation sync.once regexp
Intermediate 5 steps
go 
package logfmt
 
import (
	"bytes"

Pooling buffers for logfmt encoding in Go

object-pooling memory-reuse serialization
Intermediate 8 steps