Handling Various Request Parameters in Go Fiber Framework

Simple Example

All request parameters in the Fiber framework are obtained through the context object Ctx.

app.Get("/user/:name?", func(c *fiber.Ctx) error {
    // Obtain parameters through the Ctx parameter of the route function and call the appropriate method
    // Here, the name parameter is obtained through Params
    return c.SendString(c.Params("name"))
})

Obtaining Route Parameters

Obtaining parameters from the URL path

// GET http://example.com/user/fenny
app.Get("/user/:name", func(c *fiber.Ctx) error {
  c.Params("name") // "fenny"

  // ...
})

// GET http://example.com/user/fenny/123
app.Get("/user/*", func(c *fiber.Ctx) error {
  c.Params("*")  // "fenny/123"
  c.Params("*1") // "fenny/123"
  
  c.Params("*", "default value")  // Default value can be set with the second parameter
})

Obtaining Int type route parameters

// GET http://example.com/user/123
app.Get("/user/:id", func(c *fiber.Ctx) error {
  id, err := c.ParamsInt("id") // int 123 and no error

  // ...
})

Obtaining GET Request Query Parameters

// GET http://example.com/?order=desc&brand=nike
app.Get("/", func(c *fiber.Ctx) error {
  c.Query("order")         // "desc"
  c.Query("brand")         // "nike"
  // Second parameter can be used to set a default value, which will be returned if the parameter does not exist
  c.Query("empty", "nike") // "nike"

  // ...
})

Returning all query parameters

// GET http://example.com/?name=alex&want_pizza=false&id=
app.Get("/", func(c *fiber.Ctx) error {
    m := c.Queries()
    m["name"]        // "alex"
    m["want_pizza"]  // "false"
    m["id"]          // ""
    // ...
})

Binding query parameters to a struct object

// Define a struct to receive parameters
// Use query tag to specify the parameter names to be bound
type Person struct {
    Name     string     `query:"name"`
    Pass     string     `query:"pass"`
    Products []string   `query:"products"`
}

app.Get("/", func(c *fiber.Ctx) error {
        // Define a struct variable to receive parameters
        p := new(Person)

        // Use QueryParser to bind query parameters to variable p
        if err := c.QueryParser(p); err != nil {
            return err
        }

        log.Println(p.Name)     // john
        log.Println(p.Pass)     // doe
        log.Println(p.Products) // [shoe, hat]

        // ...
})
// Execute the following curl command to test
// curl "http://localhost:3000/?name=john&pass=doe&products=shoe,hat"

Obtaining POST Request Form Parameters

app.Post("/", func(c *fiber.Ctx) error {
  // Get the first value from the form field "name":
  c.FormValue("name")
  // => "john" or "" if it does not exist

  // ...
})

Handling Body Parameters

It is mainly used for processing POST/PUT requests and supports JSON, XML, and form parameters.

// Define the struct to receive parameters, and define the parameter field names you want to receive through the json, xml, and form tags
// json, xml, form can be selected as needed; it's not necessary to include all of them
type Person struct {
    Name string `json:"name" xml:"name" form:"name"`
    Pass string `json:"pass" xml:"pass" form:"pass"`
}

app.Post("/", func(c *fiber.Ctx) error {
    // Define the struct variable to receive parameters
    p := new(Person)

    // Use BodyParser to bind the body parameters to the variable p
    if err := c.BodyParser(p); err != nil {
        return err
    }

    log.Println(p.Name) // john
    log.Println(p.Pass) // doe

    // ...
})

// Examples of various types of requests; for JSON format parameter requests, remember to set Content-Type: application/json

// curl -X POST -H "Content-Type: application/json" --data "{\"name\":\"john\",\"pass\":\"doe\"}" localhost:3000

// curl -X POST -H "Content-Type: application/xml" --data "<login><name>john</name><pass>doe</pass></login>" localhost:3000

// curl -X POST -H "Content-Type: application/x-www-form-urlencoded" --data "name=john&pass=doe" localhost:3000

// curl -X POST -F name=john -F pass=doe http://localhost:3000

// curl -X POST "http://localhost:3000/?name=john&pass=doe"

How to retrieve the original body data is as follows:

// curl -X POST http://localhost:8080 -d user=john

app.Post("/", func(c *fiber.Ctx) error {
  // Use BodyRaw to return the raw body data
  return c.Send(c.BodyRaw()) // []byte("user=john")
})

Retrieving Request Headers

app.Get("/", func(c *fiber.Ctx) error {
  c.Get("Content-Type")       // "text/plain"
  c.Get("CoNtEnT-TypE")       // "text/plain"
  c.Get("something", "john")  // "john"
  // ...
})

Retrieving Client IP

app.Get("/", func(c *fiber.Ctx) error {
  c.IP() // "127.0.0.1"

  // ...
})

If you are deployed on a server using a proxy or load balancer, you need to retrieve the client's IP through the x-forwarded-for header by setting as follows:

app := fiber.New(fiber.Config{
  ProxyHeader: fiber.HeaderXForwardedFor,
})

Reading Cookies

app.Get("/", func(c *fiber.Ctx) error {
  // Get cookie by key:
  c.Cookies("name")         // "john"
  c.Cookies("empty", "doe") // "doe"
  // ...
})