Golang Iris Middleware

Middleware is a mechanism that allows code to run before or after the main handling code in the lifecycle of an HTTP request. It can be understood as a hook in the framework intercepting all requests and responses.

Using Middleware in iris

You can register middleware to routes through the Use method in iris.

package main

// Import the package
import "github.com/kataras/iris/v12"

func main() {
  // Define the iris instance
  app := iris.New()
  // Use the gzip compression middleware
  app.Use(iris.Compression)

  // Route settings
  app.Get("/", func(ctx iris.Context) {
    ctx.HTML("Hello <strong>%s</strong>!", "World")
  })

  // Listen on port
  app.Listen(":8080")
}

Custom Middleware in iris

// Custom middleware function signature
func Logger() iris.Handler {
    // Return the handler through closure
    return func(ctx iris.Context) {
        t := time.Now()

        // Set parameters
        ctx.Values().Set("framework", "iris")

        // Logic before the request

        ctx.Next()

        // Logic after the request
        latency := time.Since(t)
        log.Print(latency)

        // Access the status being sent
        status := ctx.GetStatusCode()
        log.Println(status)
    }
}

func main() {
    app := iris.New()
    // Register the custom middleware
    app.Use(Logger())

    app.Get("/test", func(ctx iris.Context) {
        // Read the parameter set by the middleware
        framework := ctx.Values().GetString("framework")

        // It would print: "iris"
        log.Println(framework)
    })

    app.Listen(":8080")
}