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When a request comes in, your handler receives a *mizu.Ctx that provides access to everything sent by the client. You can read data from the URL, query string, headers, forms, cookies, or JSON body using clear helper methods.

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Path parameters

Use {name} in the route to mark a variable part of the path. Read it with c.Param(). 
func showUser(c *mizu.Ctx) error {
	id := c.Param("id")
	return c.Text(200, "User "+id)
}

func main() {
	app := mizu.New()
	app.Get("/users/{id}", showUser)
	app.Listen(":3000")
}

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Query parameters

Query strings appear after a ? in the URL, such as /search?q=go. Read them with c.Query(). 
func search(c *mizu.Ctx) error {
	q := c.Query("q")
	return c.Text(200, "Search for "+q)
}

func main() {
	app := mizu.New()
	app.Get("/search", search)
	app.Listen(":3000")
}
If you need multiple query values, use c.QueryValues(). 
params := c.QueryValues()
page := params.Get("page")
sort := params.Get("sort")

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Headers

Request headers contain metadata such as content type or authorization. You can read them from the request object. 
ua := c.Request().Header.Get("User-Agent")
auth := c.Request().Header.Get("Authorization")

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Forms

When a request sends form data, you can read it using c.Form(). 
form, err := c.Form()
if err != nil {
	return c.Text(400, "Invalid form")
}
name := form.Get("name")
email := form.Get("email")

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File uploads

To receive uploaded files, use c.MultipartForm() for multipart data. 
form, cleanup, err := c.MultipartForm(32 << 20)
if err != nil {
	return c.Text(400, "Bad upload")
}
defer cleanup()

file, hdr, err := c.Request().FormFile("upload")
if err != nil {
	return c.Text(400, "Missing file")
}
return c.Text(200, "Uploaded "+hdr.Filename)

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Cookies

You can read and set cookies directly. 
ck, err := c.Cookie("session")
if err == nil {
	c.Logger().Info("session", "value", ck.Value)
}

c.SetCookie(&http.Cookie{
	Name:  "lang",
	Value: "en",
	Path:  "/",
})

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JSON body

You can decode a JSON body into a struct with BindJSON(). It validates the data and rejects unknown fields. 
var input struct {
	Name string `json:"name"`
}
if err := c.BindJSON(&input, 1<<20); err != nil {
	return c.Text(400, err.Error())
}
return c.JSON(200, map[string]string{"hello": input.Name})

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Client IP

Get the IP address of the client that sent the request. 
ip := c.ClientIP()
c.Logger().Info("client", "ip", ip)

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Context

Use the request context to detect cancellation or timeouts. 
select {
case <-c.Context().Done():
	return c.Context().Err()
default:
}

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Summary

MethodPurpose
c.Param(name)Path parameter
c.Query(name)Query string value
c.QueryValues()All query parameters
c.Request().Header.Get(name)Request header
c.Form()Form data
c.MultipartForm(limit)Multipart form with files
c.Cookie(name)Read cookie
c.SetCookie(cookie)Set cookie
c.BindJSON(v, limit)Parse JSON body
c.ClientIP()Client IP address
c.Context()Request context

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Next steps

Response

Learn how to send responses.

Context

Full context reference.