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fiber/docs/api/ctx.md

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---
id: ctx
title: 🧠 Ctx
description: >-
The Ctx interface represents the Context which hold the HTTP request and
response. It has methods for the request query string, parameters, body, HTTP
headers, and so on.
sidebar_position: 3
---
## Accepts
Checks, if the specified **extensions** or **content** **types** are acceptable.
:::info
Based on the request’s [Accept](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept) HTTP header.
:::
```go title="Signature"
func (c Ctx) Accepts(offers ...string) string
func (c Ctx) AcceptsCharsets(offers ...string) string
func (c Ctx) AcceptsEncodings(offers ...string) string
func (c Ctx) AcceptsLanguages(offers ...string) string
```
```go title="Example"
// Accept: text/html, application/json; q=0.8, text/plain; q=0.5; charset="utf-8"
app.Get("/", func(c fiber.Ctx) error {
c.Accepts("html") // "html"
c.Accepts("text/html") // "text/html"
c.Accepts("json", "text") // "json"
c.Accepts("application/json") // "application/json"
c.Accepts("text/plain", "application/json") // "application/json", due to quality
c.Accepts("image/png") // ""
c.Accepts("png") // ""
// ...
})
```
```go title="Example 2"
// Accept: text/html, text/*, application/json, */*; q=0
app.Get("/", func(c fiber.Ctx) error {
c.Accepts("text/plain", "application/json") // "application/json", due to specificity
c.Accepts("application/json", "text/html") // "text/html", due to first match
c.Accepts("image/png") // "", due to */* without q factor 0 is Not Acceptable
// ...
})
```
Media-Type parameters are supported.
```go title="Example 3"
// Accept: text/plain, application/json; version=1; foo=bar
app.Get("/", func(c fiber.Ctx) error {
// Extra parameters in the accept are ignored
c.Accepts("text/plain;format=flowed") // "text/plain;format=flowed"
// An offer must contain all parameters present in the Accept type
c.Accepts("application/json") // ""
// Parameter order and capitalization does not matter. Quotes on values are stripped.
c.Accepts(`application/json;foo="bar";VERSION=1`) // "application/json;foo="bar";VERSION=1"
})
```
```go title="Example 4"
// Accept: text/plain;format=flowed;q=0.9, text/plain
// i.e., "I prefer text/plain;format=flowed less than other forms of text/plain"
app.Get("/", func(c fiber.Ctx) error {
// Beware: the order in which offers are listed matters.
// Although the client specified they prefer not to receive format=flowed,
// the text/plain Accept matches with "text/plain;format=flowed" first, so it is returned.
c.Accepts("text/plain;format=flowed", "text/plain") // "text/plain;format=flowed"
// Here, things behave as expected:
c.Accepts("text/plain", "text/plain;format=flowed") // "text/plain"
})
```
Fiber provides similar functions for the other accept headers.
```go
// Accept-Charset: utf-8, iso-8859-1;q=0.2
// Accept-Encoding: gzip, compress;q=0.2
// Accept-Language: en;q=0.8, nl, ru
app.Get("/", func(c fiber.Ctx) error {
c.AcceptsCharsets("utf-16", "iso-8859-1")
// "iso-8859-1"
c.AcceptsEncodings("compress", "br")
// "compress"
c.AcceptsLanguages("pt", "nl", "ru")
// "nl"
// ...
})
```
## App
Returns the [\*App](ctx.md) reference so you could easily access all application settings.
```go title="Signature"
func (c Ctx) App() *App
```
```go title="Example"
app.Get("/stack", func(c fiber.Ctx) error {
return c.JSON(c.App().Stack())
})
```
## Append
Appends the specified **value** to the HTTP response header field.
:::caution
If the header is **not** already set, it creates the header with the specified value.
:::
```go title="Signature"
func (c Ctx) Append(field string, values ...string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Append("Link", "http://google.com", "http://localhost")
// => Link: http://localhost, http://google.com
c.Append("Link", "Test")
// => Link: http://localhost, http://google.com, Test
// ...
})
```
## Attachment
Sets the HTTP response [Content-Disposition](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition) header field to `attachment`.
```go title="Signature"
func (c Ctx) Attachment(filename ...string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Attachment()
// => Content-Disposition: attachment
c.Attachment("./upload/images/logo.png")
// => Content-Disposition: attachment; filename="logo.png"
// => Content-Type: image/png
// ...
})
```
## AutoFormat
Performs content-negotiation on the [Accept](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept) HTTP header. It uses [Accepts](ctx.md#accepts) to select a proper format.
The supported content types are `text/html`, `text/plain`, `application/json`, and `application/xml`.
For more flexible content negotiation, use [Format](ctx.md#format).
:::info
If the header is **not** specified or there is **no** proper format, **text/plain** is used.
:::
```go title="Signature"
func (c Ctx) AutoFormat(body any) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// Accept: text/plain
c.AutoFormat("Hello, World!")
// => Hello, World!
// Accept: text/html
c.AutoFormat("Hello, World!")
// => <p>Hello, World!</p>
type User struct {
Name string
}
user := User{"John Doe"}
// Accept: application/json
c.AutoFormat(user)
// => {"Name":"John Doe"}
// Accept: application/xml
c.AutoFormat(user)
// => <User><Name>John Doe</Name></User>
// ..
})
```
## BaseURL
Returns the base URL \(**protocol** + **host**\) as a `string`.
```go title="Signature"
func (c Ctx) BaseURL() string
```
```go title="Example"
// GET https://example.com/page#chapter-1
app.Get("/", func(c fiber.Ctx) error {
c.BaseURL() // https://example.com
// ...
})
```
## Bind
Bind is a method that support supports bindings for the request/response body, query parameters, URL parameters, cookies and much more.
It returns a pointer to the [Bind](./bind.md) struct which contains all the methods to bind the request/response data.
For detailed information check the [Bind](./bind.md) documentation.
```go title="Signature"
func (c Ctx) Bind() *Bind
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
user := new(User)
// Bind the request body to a struct:
return c.Bind().Body(user)
})
```
## Body
As per the header `Content-Encoding`, this method will try to perform a file decompression from the **body** bytes. In case no `Content-Encoding` header is sent, it will perform as [BodyRaw](#bodyraw).
```go title="Signature"
func (c Ctx) Body() []byte
```
```go title="Example"
// echo 'user=john' | gzip | curl -v -i --data-binary @- -H "Content-Encoding: gzip" http://localhost:8080
app.Post("/", func(c fiber.Ctx) error {
// Decompress body from POST request based on the Content-Encoding and return the raw content:
return c.Send(c.Body()) // []byte("user=john")
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## BodyRaw
Returns the raw request **body**.
```go title="Signature"
func (c Ctx) BodyRaw() []byte
```
```go title="Example"
// curl -X POST http://localhost:8080 -d user=john
app.Post("/", func(c fiber.Ctx) error {
// Get raw body from POST request:
return c.Send(c.BodyRaw()) // []byte("user=john")
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## ClearCookie
Expire a client cookie \(_or all cookies if left empty\)_
```go title="Signature"
func (c Ctx) ClearCookie(key ...string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// Clears all cookies:
c.ClearCookie()
// Expire specific cookie by name:
c.ClearCookie("user")
// Expire multiple cookies by names:
c.ClearCookie("token", "session", "track_id", "version")
// ...
})
```
:::caution
Web browsers and other compliant clients will only clear the cookie if the given options are identical to those when creating the cookie, excluding expires and maxAge. ClearCookie will not set these values for you - a technique similar to the one shown below should be used to ensure your cookie is deleted.
:::
```go title="Example"
app.Get("/set", func(c fiber.Ctx) error {
c.Cookie(&fiber.Cookie{
Name: "token",
Value: "randomvalue",
Expires: time.Now().Add(24 * time.Hour),
HTTPOnly: true,
SameSite: "lax",
})
// ...
})
app.Get("/delete", func(c fiber.Ctx) error {
c.Cookie(&fiber.Cookie{
Name: "token",
// Set expiry date to the past
Expires: time.Now().Add(-(time.Hour * 2)),
HTTPOnly: true,
SameSite: "lax",
})
// ...
})
```
## ClientHelloInfo
ClientHelloInfo contains information from a ClientHello message in order to guide application logic in the GetCertificate and GetConfigForClient callbacks.
You can refer to the [ClientHelloInfo](https://golang.org/pkg/crypto/tls/#ClientHelloInfo) struct documentation for more information on the returned struct.
```go title="Signature"
func (c Ctx) ClientHelloInfo() *tls.ClientHelloInfo
```
```go title="Example"
// GET http://example.com/hello
app.Get("/hello", func(c fiber.Ctx) error {
chi := c.ClientHelloInfo()
// ...
})
```
## Context
Returns [\*fasthttp.RequestCtx](https://godoc.org/github.com/valyala/fasthttp#RequestCtx) that is compatible with the context.Context interface that requires a deadline, a cancellation signal, and other values across API boundaries.
```go title="Signature"
func (c Ctx) Context() *fasthttp.RequestCtx
```
:::info
Please read the [Fasthttp Documentation](https://pkg.go.dev/github.com/valyala/fasthttp?tab=doc) for more information.
:::
## Cookie
Set cookie
```go title="Signature"
func (c Ctx) Cookie(cookie *Cookie)
```
```go
type Cookie struct {
Name string `json:"name"` // The name of the cookie
Value string `json:"value"` // The value of the cookie
Path string `json:"path"` // Specifies a URL path which is allowed to receive the cookie
Domain string `json:"domain"` // Specifies the domain which is allowed to receive the cookie
MaxAge int `json:"max_age"` // The maximum age (in seconds) of the cookie
Expires time.Time `json:"expires"` // The expiration date of the cookie
Secure bool `json:"secure"` // Indicates that the cookie should only be transmitted over a secure HTTPS connection
HTTPOnly bool `json:"http_only"` // Indicates that the cookie is accessible only through the HTTP protocol
SameSite string `json:"same_site"` // Controls whether or not a cookie is sent with cross-site requests
Partitioned bool `json:"partitioned"` // Indicates if the cookie is stored in a partitioned cookie jar
SessionOnly bool `json:"session_only"` // Indicates if the cookie is a session-only cookie
}
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// Create cookie
cookie := new(fiber.Cookie)
cookie.Name = "john"
cookie.Value = "doe"
cookie.Expires = time.Now().Add(24 * time.Hour)
// Set cookie
c.Cookie(cookie)
// ...
})
```
:::info
Partitioned cookies allow partitioning the cookie jar by top-level site, enhancing user privacy by preventing cookies from being shared across different sites. This feature is particularly useful in scenarios where a user interacts with embedded third-party services that should not have access to the main site's cookies. You can check out [CHIPS](https://developers.google.com/privacy-sandbox/3pcd/chips) for more information.
:::
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// Create a new partitioned cookie
cookie := new(fiber.Cookie)
cookie.Name = "user_session"
cookie.Value = "abc123"
cookie.Partitioned = true // This cookie will be stored in a separate jar when it's embeded into another website
// Set the cookie in the response
c.Cookie(cookie)
return c.SendString("Partitioned cookie set")
})
```
## Cookies
Get cookie value by key, you could pass an optional default value that will be returned if the cookie key does not exist.
```go title="Signature"
func (c Ctx) Cookies(key string, defaultValue ...string) string
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// Get cookie by key:
c.Cookies("name") // "john"
c.Cookies("empty", "doe") // "doe"
// ...
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## Download
Transfers the file from path as an `attachment`.
Typically, browsers will prompt the user to download. By default, the [Content-Disposition](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition) header `filename=` parameter is the file path \(_this typically appears in the browser dialog_\).
Override this default with the **filename** parameter.
```go title="Signature"
func (c Ctx) Download(file string, filename ...string) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.Download("./files/report-12345.pdf");
// => Download report-12345.pdf
return c.Download("./files/report-12345.pdf", "report.pdf");
// => Download report.pdf
})
```
## Format
Performs content-negotiation on the [Accept](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept) HTTP header. It uses [Accepts](ctx.md#accepts) to select a proper format from the supplied offers. A default handler can be provided by setting the `MediaType` to `"default"`. If no offers match and no default is provided, a 406 (Not Acceptable) response is sent. The Content-Type is automatically set when a handler is selected.
:::info
If the Accept header is **not** specified, the first handler will be used.
:::
```go title="Signature"
func (c Ctx) Format(handlers ...ResFmt) error
```
```go title="Example"
// Accept: application/json => {"command":"eat","subject":"fruit"}
// Accept: text/plain => Eat Fruit!
// Accept: application/xml => Not Acceptable
app.Get("/no-default", func(c fiber.Ctx) error {
return c.Format(
fiber.ResFmt{"application/json", func(c fiber.Ctx) error {
return c.JSON(fiber.Map{
"command": "eat",
"subject": "fruit",
})
}},
fiber.ResFmt{"text/plain", func(c fiber.Ctx) error {
return c.SendString("Eat Fruit!")
}},
)
})
// Accept: application/json => {"command":"eat","subject":"fruit"}
// Accept: text/plain => Eat Fruit!
// Accept: application/xml => Eat Fruit!
app.Get("/default", func(c fiber.Ctx) error {
textHandler := func(c fiber.Ctx) error {
return c.SendString("Eat Fruit!")
}
handlers := []fiber.ResFmt{
{"application/json", func(c fiber.Ctx) error {
return c.JSON(fiber.Map{
"command": "eat",
"subject": "fruit",
})
}},
{"text/plain", textHandler},
{"default", textHandler},
}
return c.Format(handlers...)
})
```
## FormFile
MultipartForm files can be retrieved by name, the **first** file from the given key is returned.
```go title="Signature"
func (c Ctx) FormFile(key string) (*multipart.FileHeader, error)
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
// Get first file from form field "document":
file, err := c.FormFile("document")
// Save file to root directory:
return c.SaveFile(file, fmt.Sprintf("./%s", file.Filename))
})
```
## FormValue
Any form values can be retrieved by name, the **first** value from the given key is returned.
```go title="Signature"
func (c Ctx) FormValue(key string, defaultValue ...string) string
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
// Get first value from form field "name":
c.FormValue("name")
// => "john" or "" if not exist
// ..
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## Fresh
When the response is still **fresh** in the client's cache **true** is returned, otherwise **false** is returned to indicate that the client cache is now stale and the full response should be sent.
When a client sends the Cache-Control: no-cache request header to indicate an end-to-end reload request, `Fresh` will return false to make handling these requests transparent.
Read more on [https://expressjs.com/en/4x/api.html\#req.fresh](https://expressjs.com/en/4x/api.html#req.fresh)
```go title="Signature"
func (c Ctx) Fresh() bool
```
## Get
Returns the HTTP request header specified by the field.
:::tip
The match is **case-insensitive**.
:::
```go title="Signature"
func (c Ctx) Get(key string, defaultValue ...string) string
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Get("Content-Type") // "text/plain"
c.Get("CoNtEnT-TypE") // "text/plain"
c.Get("something", "john") // "john"
// ..
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## GetReqHeaders
Returns the HTTP request headers as a map. Since a header can be set multiple times in a single request, the values of the map are slices of strings containing all the different values of the header.
```go title="Signature"
func (c Ctx) GetReqHeaders() map[string][]string
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## GetRespHeader
Returns the HTTP response header specified by the field.
:::tip
The match is **case-insensitive**.
:::
```go title="Signature"
func (c Ctx) GetRespHeader(key string, defaultValue ...string) string
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.GetRespHeader("X-Request-Id") // "8d7ad5e3-aaf3-450b-a241-2beb887efd54"
c.GetRespHeader("Content-Type") // "text/plain"
c.GetRespHeader("something", "john") // "john"
// ..
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## GetRespHeaders
Returns the HTTP response headers as a map. Since a header can be set multiple times in a single request, the values of the map are slices of strings containing all the different values of the header.
```go title="Signature"
func (c Ctx) GetRespHeaders() map[string][]string
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## GetRouteURL
Generates URLs to named routes, with parameters. URLs are relative, for example: "/user/1831"
```go title="Signature"
func (c Ctx) GetRouteURL(routeName string, params Map) (string, error)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.SendString("Home page")
}).Name("home")
app.Get("/user/:id", func(c fiber.Ctx) error {
return c.SendString(c.Params("id"))
}).Name("user.show")
app.Get("/test", func(c fiber.Ctx) error {
location, _ := c.GetRouteURL("user.show", fiber.Map{"id": 1})
return c.SendString(location)
})
// /test returns "/user/1"
```
## Host
Returns the host derived from the [Host](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Host) HTTP header.
In a network context, [`Host`](#host) refers to the combination of a hostname and potentially a port number used for connecting, while [`Hostname`](#hostname) refers specifically to the name assigned to a device on a network, excluding any port information.
```go title="Signature"
func (c Ctx) Host() string
```
```go title="Example"
// GET http://google.com:8080/search
app.Get("/", func(c fiber.Ctx) error {
c.Host() // "google.com:8080"
c.Hostname() // "google.com"
// ...
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## Hostname
Returns the hostname derived from the [Host](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Host) HTTP header.
```go title="Signature"
func (c Ctx) Hostname() string
```
```go title="Example"
// GET http://google.com/search
app.Get("/", func(c fiber.Ctx) error {
c.Hostname() // "google.com"
// ...
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## IP
Returns the remote IP address of the request.
```go title="Signature"
func (c Ctx) IP() string
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.IP() // "127.0.0.1"
// ...
})
```
When registering the proxy request header in the fiber app, the ip address of the header is returned [(Fiber configuration)](fiber.md#proxyheader)
```go
app := fiber.New(fiber.Config{
ProxyHeader: fiber.HeaderXForwardedFor,
})
```
## IPs
Returns an array of IP addresses specified in the [X-Forwarded-For](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For) request header.
```go title="Signature"
func (c Ctx) IPs() []string
```
```go title="Example"
// X-Forwarded-For: proxy1, 127.0.0.1, proxy3
app.Get("/", func(c fiber.Ctx) error {
c.IPs() // ["proxy1", "127.0.0.1", "proxy3"]
// ...
})
```
:::caution
Improper use of the X-Forwarded-For header can be a security risk. For details, see the [Security and privacy concerns](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For#security_and_privacy_concerns) section.
:::
## Is
Returns the matching **content type**, if the incoming request’s [Content-Type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type) HTTP header field matches the [MIME type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types) specified by the type parameter.
:::info
If the request has **no** body, it returns **false**.
:::
```go title="Signature"
func (c Ctx) Is(extension string) bool
```
```go title="Example"
// Content-Type: text/html; charset=utf-8
app.Get("/", func(c fiber.Ctx) error {
c.Is("html") // true
c.Is(".html") // true
c.Is("json") // false
// ...
})
```
## IsFromLocal
Returns true if request came from localhost
```go title="Signature"
func (c Ctx) IsFromLocal() bool {
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
// If request came from localhost, return true else return false
c.IsFromLocal()
// ...
})
```
## IsProxyTrusted
Checks trustworthiness of remote ip.
If [`EnableTrustedProxyCheck`](fiber.md#enabletrustedproxycheck) false, it returns true
IsProxyTrusted can check remote ip by proxy ranges and ip map.
```go title="Signature"
func (c Ctx) IsProxyTrusted() bool
```
```go title="Example"
app := fiber.New(fiber.Config{
// EnableTrustedProxyCheck enables the trusted proxy check
EnableTrustedProxyCheck: true,
// TrustedProxies is a list of trusted proxy IP addresses
TrustedProxies: []string{"0.8.0.0", "0.8.0.1"},
})
app.Get("/", func(c fiber.Ctx) error {
// If request came from trusted proxy, return true else return false
c.IsProxyTrusted()
// ...
})
```
## JSON
Converts any **interface** or **string** to JSON using the [encoding/json](https://pkg.go.dev/encoding/json) package.
:::info
JSON also sets the content header to the `ctype` parameter. If no `ctype` is passed in, the header is set to `application/json`.
:::
```go title="Signature"
func (c Ctx) JSON(data any, ctype ...string) error
```
```go title="Example"
type SomeStruct struct {
Name string
Age uint8
}
app.Get("/json", func(c fiber.Ctx) error {
// Create data struct:
data := SomeStruct{
Name: "Grame",
Age: 20,
}
return c.JSON(data)
// => Content-Type: application/json
// => "{"Name": "Grame", "Age": 20}"
return c.JSON(fiber.Map{
"name": "Grame",
"age": 20,
})
// => Content-Type: application/json
// => "{"name": "Grame", "age": 20}"
return c.JSON(fiber.Map{
"type": "https://example.com/probs/out-of-credit",
"title": "You do not have enough credit.",
"status": 403,
"detail": "Your current balance is 30, but that costs 50.",
"instance": "/account/12345/msgs/abc",
}, "application/problem+json")
// => Content-Type: application/problem+json
// => "{
// => "type": "https://example.com/probs/out-of-credit",
// => "title": "You do not have enough credit.",
// => "status": 403,
// => "detail": "Your current balance is 30, but that costs 50.",
// => "instance": "/account/12345/msgs/abc",
// => }"
})
```
## JSONP
Sends a JSON response with JSONP support. This method is identical to [JSON](ctx.md#json), except that it opts-in to JSONP callback support. By default, the callback name is simply callback.
Override this by passing a **named string** in the method.
```go title="Signature"
func (c Ctx) JSONP(data any, callback ...string) error
```
```go title="Example"
type SomeStruct struct {
name string
age uint8
}
app.Get("/", func(c fiber.Ctx) error {
// Create data struct:
data := SomeStruct{
name: "Grame",
age: 20,
}
return c.JSONP(data)
// => callback({"name": "Grame", "age": 20})
return c.JSONP(data, "customFunc")
// => customFunc({"name": "Grame", "age": 20})
})
```
## Links
Joins the links followed by the property to populate the response’s [Link](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Link) HTTP header field.
```go title="Signature"
func (c Ctx) Links(link ...string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Links(
"http://api.example.com/users?page=2", "next",
"http://api.example.com/users?page=5", "last",
)
// Link: <http://api.example.com/users?page=2>; rel="next",
// <http://api.example.com/users?page=5>; rel="last"
// ...
})
```
## Locals
A method that stores variables scoped to the request and, therefore, are available only to the routes that match the request. The stored variables are removed after the request is handled. If any of the stored data implements the `io.Closer` interface, its `Close` method will be called before it's removed.
:::tip
This is useful if you want to pass some **specific** data to the next middleware. Remember to perform type assertions when retrieving the data to ensure it is of the expected type. You can also use a non-exported type as a key to avoid collisions.
:::
```go title="Signature"
func (c Ctx) Locals(key any, value ...any) any
```
```go title="Example"
// keyType is an unexported type for keys defined in this package.
// This prevents collisions with keys defined in other packages.
type keyType int
// userKey is the key for user.User values in Contexts. It is
// unexported; clients use user.NewContext and user.FromContext
// instead of using this key directly.
var userKey keyType
app.Use(func(c fiber.Ctx) error {
c.Locals(userKey, "admin") // Stores the string "admin" under a non-exported type key
return c.Next()
})
app.Get("/admin", func(c fiber.Ctx) error {
user, ok := c.Locals(userKey).(string) // Retrieves the data stored under the key and performs a type assertion
if ok && user == "admin" {
return c.Status(fiber.StatusOK).SendString("Welcome, admin!")
}
return c.SendStatus(fiber.StatusForbidden)
})
```
An alternative version of the Locals method that takes advantage of Go's generics feature is also available. This version
allows for the manipulation and retrieval of local values within a request's context with a more specific data type.
```go title="Signature"
func Locals[V any](c Ctx, key any, value ...V) V
```
```go title="Example"
app.Use(func(c Ctx) error {
fiber.Locals[string](c, "john", "doe")
fiber.Locals[int](c, "age", 18)
fiber.Locals[bool](c, "isHuman", true)
return c.Next()
})
app.Get("/test", func(c Ctx) error {
fiber.Locals[string](c, "john") // "doe"
fiber.Locals[int](c, "age") // 18
fiber.Locals[bool](c, "isHuman") // true
return nil
})
````
Make sure to understand and correctly implement the Locals method in both its standard and generic form for better control
over route-specific data within your application.
## Location
Sets the response [Location](https://developer.mozilla.org/ru/docs/Web/HTTP/Headers/Location) HTTP header to the specified path parameter.
```go title="Signature"
func (c Ctx) Location(path string)
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
c.Location("http://example.com")
c.Location("/foo/bar")
return nil
})
```
## Method
Returns a string corresponding to the HTTP method of the request: `GET`, `POST`, `PUT`, and so on.
Optionally, you could override the method by passing a string.
```go title="Signature"
func (c Ctx) Method(override ...string) string
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
c.Method() // "POST"
c.Method("GET")
c.Method() // GET
// ...
})
```
## MultipartForm
To access multipart form entries, you can parse the binary with `MultipartForm()`. This returns a `map[string][]string`, so given a key, the value will be a string slice.
```go title="Signature"
func (c Ctx) MultipartForm() (*multipart.Form, error)
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
// Parse the multipart form:
if form, err := c.MultipartForm(); err == nil {
// => *multipart.Form
if token := form.Value["token"]; len(token) > 0 {
// Get key value:
fmt.Println(token[0])
}
// Get all files from "documents" key:
files := form.File["documents"]
// => []*multipart.FileHeader
// Loop through files:
for _, file := range files {
fmt.Println(file.Filename, file.Size, file.Header["Content-Type"][0])
// => "tutorial.pdf" 360641 "application/pdf"
// Save the files to disk:
if err := c.SaveFile(file, fmt.Sprintf("./%s", file.Filename)); err != nil {
return err
}
}
}
return err
})
```
## Next
When **Next** is called, it executes the next method in the stack that matches the current route. You can pass an error struct within the method that will end the chaining and call the [error handler](https://docs.gofiber.io/guide/error-handling).
```go title="Signature"
func (c Ctx) Next() error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
fmt.Println("1st route!")
return c.Next()
})
app.Get("*", func(c fiber.Ctx) error {
fmt.Println("2nd route!")
return c.Next()
})
app.Get("/", func(c fiber.Ctx) error {
fmt.Println("3rd route!")
return c.SendString("Hello, World!")
})
```
## OriginalURL
Returns the original request URL.
```go title="Signature"
func (c Ctx) OriginalURL() string
```
```go title="Example"
// GET http://example.com/search?q=something
app.Get("/", func(c fiber.Ctx) error {
c.OriginalURL() // "/search?q=something"
// ...
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
## Params
Method can be used to get the route parameters, you could pass an optional default value that will be returned if the param key does not exist.
:::info
Defaults to empty string \(`""`\), if the param **doesn't** exist.
:::
```go title="Signature"
func (c Ctx) Params(key string, defaultValue ...string) string
```
```go title="Example"
// 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"
// ...
})
```
Unnamed route parameters\(\*, +\) can be fetched by the **character** and the **counter** in the route.
```go title="Example"
// ROUTE: /v1/*/shop/*
// GET: /v1/brand/4/shop/blue/xs
c.Params("*1") // "brand/4"
c.Params("*2") // "blue/xs"
```
For reasons of **downward compatibility**, the first parameter segment for the parameter character can also be accessed without the counter.
```go title="Example"
app.Get("/v1/*/shop/*", func(c fiber.Ctx) error {
c.Params("*") // outputs the values of the first wildcard segment
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
In certain scenarios, it can be useful to have an alternative approach to handle different types of parameters, not
just strings. This can be achieved using a generic Query function known as `Params[V GenericType](c Ctx, key string, defaultValue ...V) V`.
This function is capable of parsing a query string and returning a value of a type that is assumed and specified by `V GenericType`.
```go title="Signature"
func Params[v GenericType](c Ctx, key string, default value ...V) V
```
```go title="Example"
// Get http://example.com/user/114
app.Get("/user/:id", func(c fiber.Ctx) error{
fiber.Params[string](c, "id") // returns "114" as string.
fiber.Params[int](c, "id") // returns 114 as integer
fiber.Params[string](c, "number") // retunrs "" (default string type)
fiber.Params[int](c, "number") // returns 0 (default integer value type)
})
```
The generic Params function supports returning the following data types based on V GenericType:
- Integer: int, int8, int16, int32, int64
- Unsigned integer: uint, uint8, uint16, uint32, uint64
- Floating-point numbers: float32, float64
- Boolean: bool
- String: string
- Byte array: []byte
## Path
Contains the path part of the request URL. Optionally, you could override the path by passing a string. For internal redirects, you might want to call [RestartRouting](ctx.md#restartrouting) instead of [Next](ctx.md#next).
```go title="Signature"
func (c Ctx) Path(override ...string) string
```
```go title="Example"
// GET http://example.com/users?sort=desc
app.Get("/users", func(c fiber.Ctx) error {
c.Path() // "/users"
c.Path("/john")
c.Path() // "/john"
// ...
})
```
## Port
Returns the remote port of the request.
```go title="Signature"
func (c Ctx) Port() string
```
```go title="Example"
// GET http://example.com:8080
app.Get("/", func(c fiber.Ctx) error {
c.Port() // "8080"
// ...
})
```
## Protocol
Contains the request protocol string: `http` or `https` for **TLS** requests.
```go title="Signature"
func (c Ctx) Protocol() string
```
```go title="Example"
// GET http://example.com
app.Get("/", func(c fiber.Ctx) error {
c.Protocol() // "http"
// ...
})
```
## Queries
Queries is a function that returns an object containing a property for each query string parameter in the route.
```go title="Signature"
func (c Ctx) Queries() map[string]string
```
```go title="Example"
// 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"] // ""
// ...
})
```
```go title="Example"
// GET http://example.com/?field1=value1&field1=value2&field2=value3
app.Get("/", func (c fiber.Ctx) error {
m := c.Queries()
m["field1"] // "value2"
m["field2"] // value3
})
```
```go title="Example"
// GET http://example.com/?list_a=1&list_a=2&list_a=3&list_b[]=1&list_b[]=2&list_b[]=3&list_c=1,2,3
app.Get("/", func(c fiber.Ctx) error {
m := c.Queries()
m["list_a"] // "3"
m["list_b[]"] // "3"
m["list_c"] // "1,2,3"
})
```
```go title="Example"
// GET /api/posts?filters.author.name=John&filters.category.name=Technology
app.Get("/", func(c fiber.Ctx) error {
m := c.Queries()
m["filters.author.name"] // John
m["filters.category.name"] // Technology
})
```
```go title="Example"
// GET /api/posts?tags=apple,orange,banana&filters[tags]=apple,orange,banana&filters[category][name]=fruits&filters.tags=apple,orange,banana&filters.category.name=fruits
app.Get("/", func(c fiber.Ctx) error {
m := c.Queries()
m["tags"] // apple,orange,banana
m["filters[tags]"] // apple,orange,banana
m["filters[category][name]"] // fruits
m["filters.tags"] // apple,orange,banana
m["filters.category.name"] // fruits
})
```
## Query
This property is an object containing a property for each query string parameter in the route, you could pass an optional default value that will be returned if the query key does not exist.
:::info
If there is **no** query string, it returns an **empty string**.
:::
```go title="Signature"
func (c Ctx) Query(key string, defaultValue ...string) string
```
```go title="Example"
// GET http://example.com/?order=desc&brand=nike
app.Get("/", func(c fiber.Ctx) error {
c.Query("order") // "desc"
c.Query("brand") // "nike"
c.Query("empty", "nike") // "nike"
// ...
})
```
:::info
Returned value is only valid within the handler. Do not store any references.
Make copies or use the [**`Immutable`**](./ctx.md) setting instead. [Read more...](../#zero-allocation)
:::
In certain scenarios, it can be useful to have an alternative approach to handle different types of query parameters, not
just strings. This can be achieved using a generic Query function known as `Query[V GenericType](c Ctx, key string, defaultValue ...V) V`.
This function is capable of parsing a query string and returning a value of a type that is assumed and specified by `V GenericType`.
Here is the signature for the generic Query function:
```go title="Signature"
func Query[V GenericType](c Ctx, key string, defaultValue ...V) V
```
Consider this example:
```go title="Example"
// GET http://example.com/?page=1&brand=nike&new=true
app.Get("/", func(c fiber.Ctx) error {
fiber.Query[int](c, "page") // 1
fiber.Query[string](c, "brand") // "nike"
fiber.Query[bool](c, "new") // true
// ...
})
```
In this case, `Query[V GenericType](c Ctx, key string, defaultValue ...V) V` can retrieve 'page' as an integer, 'brand'
as a string, and 'new' as a boolean. The function uses the appropriate parsing function for each specified type to ensure
the correct type is returned. This simplifies the retrieval process of different types of query parameters, making your
controller actions cleaner.
The generic Query function supports returning the following data types based on V GenericType:
- Integer: int, int8, int16, int32, int64
- Unsigned integer: uint, uint8, uint16, uint32, uint64
- Floating-point numbers: float32, float64
- Boolean: bool
- String: string
- Byte array: []byte
## Range
A struct containing the type and a slice of ranges will be returned.
```go title="Signature"
func (c Ctx) Range(size int) (Range, error)
```
```go title="Example"
// Range: bytes=500-700, 700-900
app.Get("/", func(c fiber.Ctx) error {
b := c.Range(1000)
if b.Type == "bytes" {
for r := range r.Ranges {
fmt.Println(r)
// [500, 700]
}
}
})
```
## Redirect
Returns the Redirect reference.
For detailed information check the [Redirect](./redirect.md) documentation.
```go title="Signature"
func (c Ctx) Redirect() *Redirect
```
```go title="Example"
app.Get("/coffee", func(c fiber.Ctx) error {
return c.Redirect().To("/teapot")
})
app.Get("/teapot", func(c fiber.Ctx) error {
return c.Status(fiber.StatusTeapot).Send("🍵 short and stout 🍵")
})
```
## Render
Renders a view with data and sends a `text/html` response. By default `Render` uses the default [**Go Template engine**](https://pkg.go.dev/html/template/). If you want to use another View engine, please take a look at our [**Template middleware**](https://docs.gofiber.io/template).
```go title="Signature"
func (c Ctx) Render(name string, bind Map, layouts ...string) error
```
## Request
Request return the [\*fasthttp.Request](https://godoc.org/github.com/valyala/fasthttp#Request) pointer
```go title="Signature"
func (c Ctx) Request() *fasthttp.Request
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Request().Header.Method()
// => []byte("GET")
})
```
## Response
Response return the [\*fasthttp.Response](https://godoc.org/github.com/valyala/fasthttp#Response) pointer
```go title="Signature"
func (c Ctx) Response() *fasthttp.Response
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Response().BodyWriter().Write([]byte("Hello, World!"))
// => "Hello, World!"
return nil
})
```
## Reset
Reset the context fields by given request when to use server handlers.
```go title="Signature"
func (c Ctx) Reset(fctx *fasthttp.RequestCtx)
```
It is used outside of the Fiber Handlers to reset the context for the next request.
## RestartRouting
Instead of executing the next method when calling [Next](ctx.md#next), **RestartRouting** restarts execution from the first method that matches the current route. This may be helpful after overriding the path, i. e. an internal redirect. Note that handlers might be executed again which could result in an infinite loop.
```go title="Signature"
func (c Ctx) RestartRouting() error
```
```go title="Example"
app.Get("/new", func(c fiber.Ctx) error {
return c.SendString("From /new")
})
app.Get("/old", func(c fiber.Ctx) error {
c.Path("/new")
return c.RestartRouting()
})
```
## Route
Returns the matched [Route](https://pkg.go.dev/github.com/gofiber/fiber?tab=doc#Route) struct.
```go title="Signature"
func (c Ctx) Route() *Route
```
```go title="Example"
// http://localhost:8080/hello
app.Get("/hello/:name", func(c fiber.Ctx) error {
r := c.Route()
fmt.Println(r.Method, r.Path, r.Params, r.Handlers)
// GET /hello/:name handler [name]
// ...
})
```
:::caution
Do not rely on `c.Route()` in middlewares **before** calling `c.Next()` - `c.Route()` returns the **last executed route**.
:::
```go title="Example"
func MyMiddleware() fiber.Handler {
return func(c fiber.Ctx) error {
beforeNext := c.Route().Path // Will be '/'
err := c.Next()
afterNext := c.Route().Path // Will be '/hello/:name'
return err
}
}
```
## SaveFile
Method is used to save **any** multipart file to disk.
```go title="Signature"
func (c Ctx) SaveFile(fh *multipart.FileHeader, path string) error
```
```go title="Example"
app.Post("/", func(c fiber.Ctx) error {
// Parse the multipart form:
if form, err := c.MultipartForm(); err == nil {
// => *multipart.Form
// Get all files from "documents" key:
files := form.File["documents"]
// => []*multipart.FileHeader
// Loop through files:
for _, file := range files {
fmt.Println(file.Filename, file.Size, file.Header["Content-Type"][0])
// => "tutorial.pdf" 360641 "application/pdf"
// Save the files to disk:
if err := c.SaveFile(file, fmt.Sprintf("./%s", file.Filename)); err != nil {
return err
}
}
return err
}
})
```
## SaveFileToStorage
Method is used to save **any** multipart file to an external storage system.
```go title="Signature"
func (c Ctx) SaveFileToStorage(fileheader *multipart.FileHeader, path string, storage Storage) error
```
```go title="Example"
storage := memory.New()
app.Post("/", func(c fiber.Ctx) error {
// Parse the multipart form:
if form, err := c.MultipartForm(); err == nil {
// => *multipart.Form
// Get all files from "documents" key:
files := form.File["documents"]
// => []*multipart.FileHeader
// Loop through files:
for _, file := range files {
fmt.Println(file.Filename, file.Size, file.Header["Content-Type"][0])
// => "tutorial.pdf" 360641 "application/pdf"
// Save the files to storage:
if err := c.SaveFileToStorage(file, fmt.Sprintf("./%s", file.Filename), storage); err != nil {
return err
}
}
return err
}
})
```
## Schema
Contains the request protocol string: http or https for TLS requests.
:::info
Please use [`Config.EnableTrustedProxyCheck`](fiber.md#enabletrustedproxycheck) to prevent header spoofing, in case when your app is behind the proxy.
:::
```go title="Signature"
func (c Ctx) Schema() string
```
```go title="Example"
// GET http://example.com
app.Get("/", func(c fiber.Ctx) error {
c.Schema() // "http"
// ...
})
```
## Secure
A boolean property that is `true` , if a **TLS** connection is established.
```go title="Signature"
func (c Ctx) Secure() bool
```
```go title="Example"
// Secure() method is equivalent to:
c.Protocol() == "https"
```
## Send
Sets the HTTP response body.
```go title="Signature"
func (c Ctx) Send(body []byte) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.Send([]byte("Hello, World!")) // => "Hello, World!"
})
```
Fiber also provides `SendString` and `SendStream` methods for raw inputs.
:::tip
Use this if you **don't need** type assertion, recommended for **faster** performance.
:::
```go title="Signature"
func (c Ctx) SendString(body string) error
func (c Ctx) SendStream(stream io.Reader, size ...int) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.SendString("Hello, World!")
// => "Hello, World!"
return c.SendStream(bytes.NewReader([]byte("Hello, World!")))
// => "Hello, World!"
})
```
## SendFile
Transfers the file from the given path. Sets the [Content-Type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type) response HTTP header field based on the **filenames** extension.
```go title="Config" title="Config"
// SendFile defines configuration options when to transfer file with SendFile.
type SendFile struct {
// FS is the file system to serve the static files from.
// You can use interfaces compatible with fs.FS like embed.FS, os.DirFS etc.
//
// Optional. Default: nil
FS fs.FS
// When set to true, the server tries minimizing CPU usage by caching compressed files.
// This works differently than the github.com/gofiber/compression middleware.
// You have to set Content-Encoding header to compress the file.
// Available compression methods are gzip, br, and zstd.
//
// Optional. Default value false
Compress bool `json:"compress"`
// When set to true, enables byte range requests.
//
// Optional. Default value false
ByteRange bool `json:"byte_range"`
// When set to true, enables direct download.
//
// Optional. Default: false.
Download bool `json:"download"`
// Expiration duration for inactive file handlers.
// Use a negative time.Duration to disable it.
//
// Optional. Default value 10 * time.Second.
CacheDuration time.Duration `json:"cache_duration"`
// The value for the Cache-Control HTTP-header
// that is set on the file response. MaxAge is defined in seconds.
//
// Optional. Default value 0.
MaxAge int `json:"max_age"`
}
```
```go title="Signature" title="Signature"
func (c Ctx) SendFile(file string, config ...SendFile) error
```
```go title="Example"
app.Get("/not-found", func(c fiber.Ctx) error {
return c.SendFile("./public/404.html");
// Disable compression
return c.SendFile("./static/index.html", SendFile{
Compress: false,
});
})
```
:::info
If the file contains an url specific character you have to escape it before passing the file path into the `sendFile` function.
:::
```go title="Example"
app.Get("/file-with-url-chars", func(c fiber.Ctx) error {
return c.SendFile(url.PathEscape("hash_sign_#.txt"))
})
```
:::info
You can set `CacheDuration` config property to `-1` to disable caching.
:::
```go title="Example"
app.Get("/file", func(c fiber.Ctx) error {
return c.SendFile("style.css", SendFile{
CacheDuration: -1,
})
})
```
:::info
You can use multiple SendFile with different configurations in single route. Fiber creates different filesystem handler per config.
:::
```go title="Example"
app.Get("/file", func(c fiber.Ctx) error {
switch c.Query("config") {
case "filesystem":
return c.SendFile("style.css", SendFile{
FS: os.DirFS(".")
})
case "filesystem-compress":
return c.SendFile("style.css", SendFile{
FS: os.DirFS("."),
Compress: true,
})
case "compress":
return c.SendFile("style.css", SendFile{
Compress: true,
})
default:
return c.SendFile("style.css")
}
return nil
})
```
:::info
For sending multiple files from embedded file system [this functionality](../middleware/static.md#serving-files-using-embedfs) can be used
:::
## SendStatus
Sets the status code and the correct status message in the body, if the response body is **empty**.
:::tip
You can find all used status codes and messages [here](https://github.com/gofiber/fiber/blob/dffab20bcdf4f3597d2c74633a7705a517d2c8c2/utils.go#L183-L244).
:::
```go title="Signature"
func (c Ctx) SendStatus(status int) error
```
```go title="Example"
app.Get("/not-found", func(c fiber.Ctx) error {
return c.SendStatus(415)
// => 415 "Unsupported Media Type"
c.SendString("Hello, World!")
return c.SendStatus(415)
// => 415 "Hello, World!"
})
```
## SendStream
Sets response body to a stream of data and add optional body size.
```go title="Signature"
func (c Ctx) SendStream(stream io.Reader, size ...int) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.SendStream(bytes.NewReader([]byte("Hello, World!")))
// => "Hello, World!"
})
```
## SendString
Sets the response body to a string.
```go title="Signature"
func (c Ctx) SendString(body string) error
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
return c.SendString("Hello, World!")
// => "Hello, World!"
})
```
## Set
Sets the response’s HTTP header field to the specified `key`, `value`.
```go title="Signature"
func (c Ctx) Set(key string, val string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Set("Content-Type", "text/plain")
// => "Content-type: text/plain"
// ...
})
```
## SetUserContext
Sets the user specified implementation for context interface.
```go title="Signature"
func (c Ctx) SetUserContext(ctx context.Context)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
ctx := context.Background()
c.SetUserContext(ctx)
// Here ctx could be any context implementation
// ...
})
```
## Stale
[https://expressjs.com/en/4x/api.html\#req.stale](https://expressjs.com/en/4x/api.html#req.stale)
```go title="Signature"
func (c Ctx) Stale() bool
```
## Status
Sets the HTTP status for the response.
:::info
Method is a **chainable**.
:::
```go title="Signature"
func (c Ctx) Status(status int) Ctx
```
```go title="Example"
app.Get("/fiber", func(c fiber.Ctx) error {
c.Status(fiber.StatusOK)
return nil
}
app.Get("/hello", func(c fiber.Ctx) error {
return c.Status(fiber.StatusBadRequest).SendString("Bad Request")
}
app.Get("/world", func(c fiber.Ctx) error {
return c.Status(fiber.StatusNotFound).SendFile("./public/gopher.png")
})
```
## String
Returns unique string representation of the ctx.
```go title="Signature"
func (c Ctx) String() string
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.String() // => "#0000000100000001 - 127.0.0.1:3000 <-> 127.0.0.1:61516 - GET http://localhost:3000/"
// ...
})
```
## Subdomains
Returns a string slice of subdomains in the domain name of the request.
The application property subdomain offset, which defaults to `2`, is used for determining the beginning of the subdomain segments.
```go title="Signature"
func (c Ctx) Subdomains(offset ...int) []string
```
```go title="Example"
// Host: "tobi.ferrets.example.com"
app.Get("/", func(c fiber.Ctx) error {
c.Subdomains() // ["ferrets", "tobi"]
c.Subdomains(1) // ["tobi"]
// ...
})
```
## Type
Sets the [Content-Type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type) HTTP header to the MIME type listed [here](https://github.com/nginx/nginx/blob/master/conf/mime.types) specified by the file **extension**.
:::info
Method is a **chainable**.
:::
```go title="Signature"
func (c Ctx) Type(ext string, charset ...string) Ctx
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Type(".html") // => "text/html"
c.Type("html") // => "text/html"
c.Type("png") // => "image/png"
c.Type("json", "utf-8") // => "application/json; charset=utf-8"
// ...
})
```
## UserContext
UserContext returns a context implementation that was set by user earlier
or returns a non-nil, empty context, if it was not set earlier.
```go title="Signature"
func (c Ctx) UserContext() context.Context
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
ctx := c.UserContext()
// ctx is context implementation set by user
// ...
})
```
## Vary
Adds the given header field to the [Vary](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Vary) response header. This will append the header, if not already listed, otherwise leaves it listed in the current location.
:::info
Multiple fields are **allowed**.
:::
```go title="Signature"
func (c Ctx) Vary(fields ...string)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Vary("Origin") // => Vary: Origin
c.Vary("User-Agent") // => Vary: Origin, User-Agent
// No duplicates
c.Vary("Origin") // => Vary: Origin, User-Agent
c.Vary("Accept-Encoding", "Accept")
// => Vary: Origin, User-Agent, Accept-Encoding, Accept
// ...
})
```
## ViewBind
Add vars to default view var map binding to template engine.
Variables are read by the Render method and may be overwritten.
```go title="Signature"
func (c Ctx) ViewBind(vars Map) error
```
```go title="Example"
app.Use(func(c fiber.Ctx) error {
c.ViewBind(fiber.Map{
"Title": "Hello, World!",
})
})
app.Get("/", func(c fiber.Ctx) error {
return c.Render("xxx.tmpl", fiber.Map{}) // Render will use Title variable
})
```
## Write
Write adopts the Writer interface
```go title="Signature"
func (c Ctx) Write(p []byte) (n int, err error)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.Write([]byte("Hello, World!")) // => "Hello, World!"
fmt.Fprintf(c, "%s\n", "Hello, World!") // "Hello, World!Hello, World!"
})
```
## Writef
Writef adopts the string with variables
```go title="Signature"
func (c Ctx) Writef(f string, a ...any) (n int, err error)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
world := "World!"
c.Writef("Hello, %s", world) // => "Hello, World!"
fmt.Fprintf(c, "%s\n", "Hello, World!") // "Hello, World!Hello, World!"
})
```
## WriteString
WriteString adopts the string
```go title="Signature"
func (c Ctx) WriteString(s string) (n int, err error)
```
```go title="Example"
app.Get("/", func(c fiber.Ctx) error {
c.WriteString("Hello, World!") // => "Hello, World!"
fmt.Fprintf(c, "%s\n", "Hello, World!") // "Hello, World!Hello, World!"
})
```
## XHR
A Boolean property, that is `true`, if the request’s [X-Requested-With](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers) header field is [XMLHttpRequest](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest), indicating that the request was issued by a client library \(such as [jQuery](https://api.jquery.com/jQuery.ajax/)\).
```go title="Signature"
func (c Ctx) XHR() bool
```
```go title="Example"
// X-Requested-With: XMLHttpRequest
app.Get("/", func(c fiber.Ctx) error {
c.XHR() // true
// ...
})
```
## XML
Converts any **interface** or **string** to XML using the standard `encoding/xml` package.
:::info
XML also sets the content header to **application/xml**.
:::
```go title="Signature"
func (c Ctx) XML(data any) error
```
```go title="Example"
type SomeStruct struct {
XMLName xml.Name `xml:"Fiber"`
Name string `xml:"Name"`
Age uint8 `xml:"Age"`
}
app.Get("/", func(c fiber.Ctx) error {
// Create data struct:
data := SomeStruct{
Name: "Grame",
Age: 20,
}
return c.XML(data)
// <Fiber>
// <Name>Grame</Name>
// <Age>20</Age>
// </Fiber>
})
```
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