Response Recorder

Learn how to record and modify responses in Iris.

Basic Response Recording

package main

import "github.com/kataras/iris/v12"

func main() {
    app := iris.New()

    app.Get("/record", func(ctx iris.Context) {
        // Create recorder
        rec := ctx.Recorder()

        // Write response
        rec.Write([]byte("Hello World"))
        rec.Writef(" from %s", "Iris")

        // Get recorded body
        body := rec.Body()

        // Modify response
        modified := strings.ToUpper(string(body))

        // Write final response
        ctx.WriteString(modified)
    })

    app.Listen(":8080")
}

Recording with Middleware

func recordMiddleware(ctx iris.Context) {
    // Start recording
    rec := ctx.Recorder()

    // Continue to next handler
    ctx.Next()

    // Get recorded response
    body := rec.Body()
    status := rec.StatusCode()
    headers := rec.Headers()

    // Log response
    ctx.Application().Logger().Infof(
        "Response: Status=%d, Body=%s, Headers=%v",
        status,
        string(body),
        headers,
    )
}

app.Use(recordMiddleware)

Modifying Response

app.Get("/modify", func(ctx iris.Context) {
    rec := ctx.Recorder()

    // Write original response
    ctx.JSON(iris.Map{
        "message": "hello world",
    })

    // Get recorded response
    var data map[string]interface{}
    if err := json.Unmarshal(rec.Body(), &data); err != nil {
        ctx.StopWithError(iris.StatusInternalServerError, err)
        return
    }

    // Modify response
    data["modified"] = true
    data["timestamp"] = time.Now()

    // Write modified response
    ctx.JSON(data)
})

Best Practices

1. Implementation:

   • Record selectively
   • Handle large responses
   • Monitor memory
   • Clean resources
   • Handle errors

2. Performance:

   • Buffer appropriately
   • Monitor usage
   • Handle timeouts
   • Optimize recording
   • Regular cleanup

3. Security:

   • Validate modifications
   • Monitor changes
   • Handle sensitive data
   • Control access
   • Log modifications

4. Maintenance:

   • Monitor usage
   • Update handlers
   • Regular testing
   • Document changes
   • Review performance