gin

gin

Fast Go HTTP framework with zero-allocation router and minimal memory footprint.

Core Concepts

• Fast routing: radix tree-based router with gin.Default() for logger and recovery middleware
• Middleware chains: r.Use() for global middleware, group-level chains for scoped behavior
• JSON/XML binding: c.ShouldBindJSON() with struct tags for automatic request validation
• Route grouping: v1 := r.Group("/api/v1") with shared middleware and URL prefixes

Common Patterns

• File uploads: c.FormFile("file") with c.SaveUploadedFile() for multipart form handling
• Custom middleware: func() gin.HandlerFunc closure pattern for request-scoped data injection
• Error handling: c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()}) for structured errors
• Testing: httptest.NewRecorder() with r.ServeHTTP() for integration tests without server

Best Practices

• Use ShouldBindJSON for strict validation, ShouldBindBodyWith for content-type negotiation
• Validate structs with binding tags (required, min, max, oneof) rather than manual checks
• Group routes by version and domain for maintainable API organization
• Use c.Set()/c.Get() for request-scoped values like user identity from auth middleware

Common Code Patterns

• r.GET("/ping", func(c *gin.Context) { c.JSON(200, gin.H{"message": "pong"}) })
• authorized := r.Group("/", AuthRequired()); authorized.POST("/items", createItem)