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This release introduces new features and some breaking changes. The codebase for Dependency Injection, Internationalization and localization and more have been simplified a lot (fewer LOCs and easier to read and follow up).

Fixes and Improvements

  • New iris.IsErrEmptyJSON(err) bool which reports whether the given “err” is caused by a Context.ReadJSON call when the request body didn't start with { (or it was totally empty).

Example Code:

func handler(ctx iris.Context) {
    var opts SearchOptions
    if err := ctx.ReadJSON(&opts); err != nil && !iris.IsErrEmptyJSON(err) {
        ctx.StopWithJSON(iris.StatusBadRequest, iris.Map{"message": "unable to parse body"})

    // [...continue with default values of "opts" struct if the client didn't provide some]

That means that the client can optionally set a JSON body.

  • New APIContainer.EnableStrictMode(bool) to disable automatic payload binding and panic on missing dependencies for exported struct'sfields or function's input parameters on MVC controller or hero function or PartyConfigurator.

  • New Party.PartyConfigure(relativePath string, partyReg ...PartyConfigurator) Party helper, registers a children Party like Party and PartyFunc but instead it accepts a structure value which may contain one or more of the dependencies registered by RegisterDependency or ConfigureContainer().RegisterDependency methods and fills the unset/zero exported struct's fields respectfully (useful when the api's dependencies amount are too much to pass on a function).

  • New feature: add the ability to set custom error handlers on path type parameters errors (existing or custom ones). Example Code:

app.Macros().Get("uuid").HandleError(func(ctx iris.Context, paramIndex int, err error) {

    param := ctx.Params().GetEntryAt(paramIndex)
        "error":     err.Error(),
        "message":   "invalid path parameter",
        "parameter": param.Key,
        "value":     param.ValueRaw,

app.Get("/users/{id:uuid}", getUser)
  • Improve the performance and fix :int, :int8, :int16, :int32, :int64, :uint, :uint8, :uint16, :uint32, :uint64 path type parameters couldn't accept a positive number written with the plus symbol or with a leading zeroes, e.g. +42 and 021.

  • The iris.WithEmptyFormError option is respected on context.ReadQuery method too, as requested at #1727. Example comments were updated.

  • New httptest.Strict option setter to enable the httpexpect.RequireReporter instead of the default `httpexpect.AssetReporter. Use that to enable complete test failure on the first error. As requested at: #1722.

  • New uuid builtin path parameter type. Example:

// +------------------------+
// | {param:uuid}           |
// +------------------------+
// UUIDv4 (and v1) path parameter validation.

// http://localhost:8080/user/bb4f33e4-dc08-40d8-9f2b-e8b2bb615c0e -> OK
// http://localhost:8080/user/dsadsa-invalid-uuid                  -> NOT FOUND
app.Get("/user/{id:uuid}", func(ctx iris.Context) {
    id := ctx.Params().Get("id")
  • New Configuration.KeepAlive and iris.WithKeepAlive(time.Duration) Configurator added as helpers to start the server using a tcp listener featured with keep-alive.

  • New DirOptions.ShowHidden bool is added by @tuhao1020 at PR #1717 to show or hide the hidden files when ShowList is set to true.

  • New Context.ReadJSONStream method and JSONReader options for Context.ReadJSON and Context.ReadJSONStream, see the example.

  • New FallbackView feature, per-party or per handler chain. Example can be found at: _examples/view/fallback.

    app.FallbackView(iris.FallbackViewFunc(func(ctx iris.Context, err iris.ErrViewNotExist) error {
        // err.Name is the previous template name.
        // err.IsLayout reports whether the failure came from the layout template.
        // err.Data is the template data provided to the previous View call.
        // [...custom logic e.g. ctx.View("fallback.html", err.Data)]
        return err
  • New versioning.Aliases middleware and up to 80% faster version resolve. Example Code:
app := iris.New()

api := app.Party("/api")
    versioning.Empty: "1", // when no version was provided by the client.
    "beta": "4.0.0",
    "stage": "5.0.0-alpha"

v1 := NewGroup(api, ">=1.0.0 <2.0.0")

v4 := NewGroup(api, ">=4.0.0 <5.0.0")

stage := NewGroup(api, "5.0.0-alpha")
  • New Basic Authentication middleware. Its Default function has not changed, however, the rest, e.g. New contains breaking changes as the new middleware features new functionalities.

  • Add iris.DirOptions.SPA bool field to allow Single Page Applications under a file server.

  • A generic User interface, see the Context.SetUser/User methods in the New Context Methods section for more. In-short, the basicauth middleware's stored user can now be retrieved through Context.User() which provides more information than the native ctx.Request().BasicAuth() method one. Third-party authentication middleware creators can benefit of these two methods, plus the Logout below.

  • A Context.Logout method is added, can be used to invalidate basicauth or jwt client credentials.

  • Add the ability to share functions between handlers chain and add an example on sharing Go structures (aka services).

  • Add the new Party.UseOnce method to the *Route

  • Add a new *Route.RemoveHandler(...interface{}) int and Party.RemoveHandler(...interface{}) Party methods, delete a handler based on its name or the handler pc function.

func middleware(ctx iris.Context) {
    // [...]

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

    // Register the middleware to all matched routes.

    // Handlers = middleware, other
    app.Get("/", index)

    // Handlers = other
    app.Get("/other", other).RemoveHandler(middleware)
  • Redis Driver is now based on the go-redis module. Radix and redigo removed entirely. Sessions are now stored in hashes which fixes issue #1610. The only breaking change on default configuration is that the redis.Config.Delim option was removed. The redis sessions database driver is now defaults to the &redis.GoRedisDriver{}. End-developers can implement their own implementations too. The Database#Close is now automatically called on interrupt signals, no need to register it by yourself.

  • Add builtin support for i18n pluralization. Please check out the following yaml locale example to see an overview of the supported formats.

  • Fix #1650

  • Fix #1649

  • Fix #1648

  • Fix #1641

  • Add Party.SetRoutesNoLog(disable bool) Party to disable (the new) verbose logging of next routes.

  • Add mvc.Application.SetControllersNoLog(disable bool) *mvc.Application to disable (the new) verbose logging of next controllers. As requested at #1630.

  • Fix #1621 and add a new cache.WithKey to customize the cached entry key.

  • Add a Response() *http.Response to the Response Recorder.

  • Fix Response Recorder Flush when transfer-encoding is chunked.

  • Fix Response Recorder Clone concurrent access afterwards.

  • Add a ParseTemplate method on view engines to manually parse and add a template from a text as requested. Examples.

  • Full http.FileSystem interface support for all view engines as requested. The first argument of the functions(HTML, Blocks, Pug, Amber, Ace, Jet, Django, Handlebars) can now be either a directory of string type (like before) or a value which completes the http.FileSystem interface. The .Binary method of all view engines was removed: pass the go-bindata's latest version AssetFile() exported function as the first argument instead of string.

  • Add Route.ExcludeSitemap() *Route to exclude a route from sitemap as requested in chat, also offline routes are excluded automatically now.

  • Improved tracing (with app.Logger().SetLevel("debug")) for routes. Screens:

DBUG Routes (1)

DBUG routes 1

DBUG Routes (2)

DBUG routes 2

DBUG Routes (3)

DBUG routes with Controllers

  # Redirects /seo/* to /*
  - 301 /seo/(.*) /$1

  # Redirects /docs/v12* to /docs
  - 301 /docs/v12(.*) /docs

  # Redirects /old(.*) to /
  - 301 /old(.*) /

  # Redirects http or https://test.* to http or https://newtest.*
  - 301 ^(http|https)://test.(.*) $1://newtest.$2

  # Handles /*.json or .xml as *?format=json or xml,
  # without redirect. See /users route.
  # When Code is 0 then it does not redirect the request,
  # instead it changes the request URL
  # and leaves a route handle the request.
  - 0 /(.*).(json|xml) /$1?format=$2

# Redirects root domain to www.
# Creation of a www subdomain inside the Application is unnecessary,
# all requests are handled by the root Application itself.
PrimarySubdomain: www
  • New TraceRoute bool on middleware/logger middleware. Displays information about the executed route. Also marks the handlers executed. Screenshot:

apps image example

  • Fix AutoTLS when used with iris.TLSNoRedirect *. The AutoTLS runner can be customized through the new iris.AutoTLSNoRedirect instead, read its go documentation. Example of having both TLS and non-TLS versions of the same application without conflicts with letsencrypt ./well-known path:

package main

import (


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

	app.Get("/", func(ctx iris.Context) {
			"time": time.Now().Unix(),
			"tls":  ctx.Request().TLS != nil,

	var fallbackServer = func(acme func(http.Handler) http.Handler) *http.Server {
		srv := &http.Server{Handler: acme(app)}
		go srv.ListenAndServe()
		return srv

	app.Run(iris.AutoTLS(":443", "", "",
  • iris.Minify middleware to minify responses based on their media/content-type.

  • Context.OnCloseErr and Context.OnConnectionCloseErr - to call a function of func() error instead of an iris.Handler when request is closed or manually canceled.

  • Party.UseError(...Handler) - to register handlers to run before any http errors (e.g. before OnErrorCode/OnAnyErrorCode or default error codes when no handler is responsible to handle a specific http status code).

  • Party.UseRouter(...Handler) and Party.ResetRouterFilters() - to register handlers before the main router, useful on handlers that should control whether the router itself should ran or not. Independently of the incoming request's method and path values. These handlers will be executed ALWAYS against ALL incoming matched requests. Example of use-case: CORS.

  • *versioning.Group type is a full Party now.

  • Party.UseOnce - either inserts a middleware, or on the basis of the middleware already existing, replace that existing middleware instead.

  • Ability to register a view engine per group of routes or for the current chain of handlers through Party.RegisterView and Context.ViewEngine respectfully.

  • Add Blocks template engine.

  • Add Ace template parser to the view engine and other minor improvements.

  • Fix huge repo size of 55.7MB, which slows down the overall Iris installation experience. Now, go-get performs ~3 times faster. I ‘ve managed it using the bfg-repo-cleaner tool - an alternative to git-filter-branch command. Watch the small gif below to learn how:

  • gRPC features:

    • New Router Wrapper.
    • New MVC .Handle(ctrl, mvc.GRPC{...}) option which allows to register gRPC services per-party (without the requirement of a full wrapper) and optionally strict access to gRPC clients only, see the example here.
  • Add Configuration.RemoteAddrHeadersForce bool to force Context.RemoteAddr() string to return the first entry of request headers as a fallback instead of the Request.RemoteAddr one, as requested at: 1567#issuecomment-663972620.

  • Fix #1569#issuecomment-663739177.

  • Fix #1564.

  • Fix #1553.

  • New DirOptions.Cache to cache assets in-memory among with their compressed contents (in order to be ready to served if client ask). Learn more about this feature by reading all #1556 comments. Usage:

var dirOpts = DirOptions{
    // [...other options]
    Cache: DirCacheOptions{
        Enable: true,
        // Don't compress files smaller than 300 bytes.
        CompressMinSize: 300,
        // Ignore compress already compressed file types
        // (some images and pdf).
        CompressIgnore: iris.MatchImagesAssets,
        // Gzip, deflate, br(brotli), snappy.
        Encodings: []string{"gzip", "deflate", "br", "snappy"},
        // Log to the stdout the total reduced file size.
        Verbose: 1,
  • New DirOptions.PushTargets and PushTargetsRegexp to push index’ assets to the client without additional requests. Inspirated by issue #1562. Example matching all .js, .css and .ico files (recursively):
var dirOpts = iris.DirOptions{
    // [...other options]
    IndexName: "/index.html",
    PushTargetsRegexp: map[string]*regexp.Regexp{
        "/": regexp.MustCompile("((.*).js|(.*).css|(.*).ico)$"),
        // OR:
        // "/": iris.MatchCommonAssets,
    Compress: true,
  • Update jet parser to v5.0.2, closes #1551. It contains two breaking changes by its author:

    • Relative paths on extends, import, include... tmpl functions, e.g. {{extends "../layouts/application.jet"}} instead of layouts/application.jet
    • the new jet.Ranger interface now requires a ProvidesIndex() bool method too
    • Example has been updated
  • Fix #1552.

  • Proper listing of root directories on Party.HandleDir when its DirOptions.ShowList was set to true.

    • Customize the file/directory listing page through views, see example.
  • Socket Sharding as requested at #1544. New iris.WithSocketSharding Configurator and SocketSharding bool setting.

  • Versioned Controllers feature through the new mvc.Version option. See _examples/mvc/versioned-controller.

  • Fix #1539.

  • New rollbar example.

  • New builtin requestid middleware.

  • New builtin JWT middleware based on the fastest JWT implementation; kataras/jwt featured with optional wire encryption to set claims with sensitive data when necessary.

  • New iris.RouteOverlap route registration rule. Party.SetRegisterRule(iris.RouteOverlap) to allow overlapping across multiple routes for the same request subdomain, method, path. See 1536#issuecomment-643719922. This allows two or more MVC Controllers to listen on the same path based on one or more registered dependencies (see _examples/mvc/authenticated-controller).

  • Context.ReadForm now can return an iris.ErrEmptyForm instead of nil when the new Configuration.FireEmptyFormError is true (when iris.WithEmptyFormError is set) on missing form body to read from.

  • Configuration.EnablePathIntelligence | iris.WithPathIntelligence to enable path intelligence automatic path redirection on the most closest path (if any), [example]((

  • Enhanced cookie security and management through new Context.AddCookieOptions method and new cookie options (look on New Package-level functions section below), securecookie example has been updated.

  • Context.RemoveCookie removes also the Request's specific cookie of the same request lifecycle when iris.CookieAllowReclaim is set to cookie options, example.

  • iris.TLS can now accept certificates in form of raw []byte contents too.

  • iris.TLS registers a secondary http server which redirects “http://” to their “https://” equivalent requests, unless the new iris.TLSNoRedirect host Configurator is provided on iris.TLS, e.g. app.Run(iris.TLS("", "mycert.cert", "mykey.key", iris.TLSNoRedirect)). There is iris.AutoTLSNoRedirect option for AutoTLS too.

  • Fix an issue about i18n loading from path which contains potential language code.

  • Server will not return neither log the ErrServerClosed error if app.Shutdown was called manually via interrupt signal(CTRL/CMD+C), note that if the server closed by any other reason the error will be fired as previously (unless iris.WithoutServerError(iris.ErrServerClosed)).

  • Finally, Log level's and Route debug information colorization is respected across outputs. Previously if the application used more than one output destination (e.g. a file through app.Logger().AddOutput) the color support was automatically disabled from all, including the terminal one, this problem is fixed now. Developers can now see colors in their terminals while log files are kept with clear text.

  • New iris.WithLowercaseRouting option which forces all routes’ paths to be lowercase and converts request paths to their lowercase for matching.

  • New app.Validator { Struct(interface{}) error } field and app.Validate method were added. The app.Validator = can be used to integrate a 3rd-party package such as go-playground/validator. If set-ed then Iris Context's ReadJSON, ReadXML, ReadMsgPack, ReadYAML, ReadForm, ReadQuery, ReadBody methods will return the validation error on data validation failures. The read-json-struct-validation example was updated.

  • A result of can implement the new hero.PreflightResult interface which contains a single method of Preflight(iris.Context) error. If this method exists on a custom struct value which is returned from a handler then it will fire that Preflight first and if not errored then it will cotninue by sending the struct value as JSON(by-default) response body.

  • ctx.JSON, JSONP, XML: if iris.WithOptimizations is NOT passed on app.Run/Listen then the indentation defaults to " " (four spaces) and " " respectfully otherwise it is empty or the provided value.

  • Hero Handlers (and app.ConfigureContainer().Handle) do not have to require iris.Context just to call ctx.Next() anymore, this is done automatically now.

  • Improve Remote Address parsing as requested at: #1453. Add Configuration.RemoteAddrPrivateSubnets to exclude those addresses when fetched by Configuration.RemoteAddrHeaders through context.RemoteAddr() string.

  • Fix #1487.

  • Fix #1473.

New Package-level Variables

  • iris.DirListRichOptions to pass on iris.DirListRich method.
  • iris.DirListRich to override the default look and feel if the DirOptions.ShowList was set to true, can be passed to DirOptions.DirList field.
  • DirOptions.PushTargets for http/2 push on index *.
  • iris.Compression middleware to compress responses and decode compressed request data respectfully.
  • iris.B, KB, MB, GB, TB, PB, EB for byte units.
  • TLSNoRedirect to disable automatic “http://” to “https://” redirections (see below)
  • CookieAllowReclaim, CookieAllowSubdomains, CookieSameSite, CookieSecure and CookieEncoding to bring previously sessions-only features to all cookies in the request.

New Context Methods

  • Context.FormFiles(key string, before ...func(*Context, *multipart.FileHeader) bool) (files []multipart.File, headers []*multipart.FileHeader, err error) method.
  • Context.ReadURL(ptr interface{}) error shortcut of ReadParams and ReadQuery. Binds URL dynamic path parameters and URL query parameters to the given “ptr” pointer of a struct value.
  • Context.SetUser(User) and Context.User() User to store and retrieve an authenticated client. Read more here.
  • Context.SetLogoutFunc(fn interface{}, persistenceArgs ...interface{}) and Logout(args ...interface{}) error methods to allow different kind of auth middlewares to be able to set a “logout” a user/client feature with a single function, the route handler may not be aware of the implementation of the authentication used.
  • Context.SetFunc(name string, fn interface{}, persistenceArgs ...interface{}) and Context.CallFunc(name string, args ...interface{}) ([]reflect.Value, error) to allow middlewares to share functions dynamically when the type of the function is not predictable, see the example for more.
  • Context.TextYAML(interface{}) error same as Context.YAML but with set the Content-Type to text/yaml instead (Google Chrome renders it as text).
  • Context.IsDebug() bool reports whether the application is running under debug/development mode. It is a shortcut of Application.Logger().Level >= golog.DebugLevel.
  • Context.IsRecovered() bool reports whether the current request was recovered from the recover middleware. Also the Context.GetErrPublic() (bool, error), Context.SetErrPrivate(err error) methods and iris.ErrPrivate interface have been introduced.
  • Context.RecordRequestBody(bool) same as the Application's DisableBodyConsumptionOnUnmarshal configuration field but registers per chain of handlers. It makes the request body readable more than once.
  • Context.IsRecordingBody() bool reports whether the request body can be readen multiple times.
  • Context.ReadHeaders(ptr interface{}) error binds request headers to “ptr”. Example.
  • Context.ReadParams(ptr interface{}) error binds dynamic path parameters to “ptr”. Example.
  • Context.SaveFormFile(fh *multipart.FileHeader, dest string) (int64, error) previously unexported. Accepts a result file of Context.FormFile and saves it to the disk.
  • Context.URLParamSlice(name string) []string is a a shortcut of ctx.Request().URL.Query()[name]. Like URLParam but it returns all values as a string slice instead of a single string separated by commas.
  • Context.PostValueMany(name string) (string, error) returns the post data of a given key. The returned value is a single string separated by commas on multiple values. It also reports whether the form was empty or when the “name” does not exist or whether the available values are empty. It strips any empty key-values from the slice before return. See ErrEmptyForm, ErrNotFound and ErrEmptyFormField respectfully. The PostValueInt, PostValueInt64, PostValueFloat64 and PostValueBool now respect the above errors too (the PostValues method now returns a second output argument of error too, see breaking changes below).
  • Context.URLParamsSorted() []memstore.StringEntry returns a sorted (by key) slice of key-value entries of the URL Query parameters.
  • Context.ViewEngine(ViewEngine) to set a view engine on-fly for the current chain of handlers, responsible to render templates through ctx.View. Example.
  • Context.SetErr(error) and Context.GetErr() error helpers.
  • Context.CompressWriter(bool) error and Context.CompressReader(bool) error.
  • Context.Clone() Context returns a copy of the Context safe for concurrent access.
  • Context.IsCanceled() bool reports whether the request has been canceled by the client.
  • Context.IsSSL() bool reports whether the request is under HTTPS SSL (New Configuration.SSLProxyHeaders and HostProxyHeaders fields too).
  • Context.CompressReader(enable bool) method and iris.CompressReader middleware to enable future request read body calls to decompress data, example.
  • Context.RegisterDependency(v interface{}) and Context.UnregisterDependency(typ reflect.Type) to register/remove struct dependencies on serve-time through a middleware.
  • Context.SetID(id interface{}) and Context.GetID() interface{} added to register a custom unique indetifier to the Context, if necessary.
  • Context.Scheme() string returns the full scheme of the request URL.
  • Context.SubdomainFull() string returns the full subdomain(s) part of the host (host[0:rootLevelDomain]).
  • Context.Domain() string returns the root level domain.
  • Context.AddCookieOptions(...CookieOption) adds options for SetCookie, SetCookieKV, UpsertCookie and RemoveCookie methods for the current request.
  • Context.ClearCookieOptions() clears any cookie options registered through AddCookieOptions.
  • Context.SetLanguage(langCode string) force-sets a language code from inside a middleare, similar to the app.I18n.ExtractFunc
  • Context.ServeContentWithRate, ServeFileWithRate and SendFileWithRate methods to throttle the “download” speed of the client
  • Context.IsHTTP2() bool reports whether the protocol version for incoming request was HTTP/2
  • Context.IsGRPC() bool reports whether the request came from a gRPC client
  • Context.UpsertCookie(*http.Cookie, cookieOptions ...context.CookieOption) upserts a cookie, fixes #1485 too
  • Context.StopWithStatus(int) stops the handlers chain and writes the status code
  • StopWithText(statusCode int, format string, args ...interface{}) stops the handlers chain, writes thre status code and a plain text message
  • Context.StopWithError(int, error) stops the handlers chain, writes thre status code and the error's message
  • Context.StopWithJSON(int, interface{}) stops the handlers chain, writes the status code and sends a JSON response
  • Context.StopWithProblem(int, iris.Problem) stops the handlers, writes the status code and sends an application/problem+json response
  • Context.Protobuf(proto.Message) sends protobuf to the client (note that the Context.JSON is able to send protobuf as JSON)
  • Context.MsgPack(interface{}) sends msgpack format data to the client
  • Context.ReadProtobuf(ptr) binds request body to a proto message
  • Context.ReadJSONProtobuf(ptr, ...options) binds JSON request body to a proto message
  • Context.ReadMsgPack(ptr) binds request body of a msgpack format to a struct
  • Context.ReadBody(ptr) binds the request body to the “ptr” depending on the request's Method and Content-Type
  • Context.ReflectValue() []reflect.Value stores and returns the []reflect.ValueOf(ctx)
  • Context.Controller() reflect.Value returns the current MVC Controller value.

MVC & Dependency Injection

The new release contains a fresh new and awesome feature....a function dependency can accept previous registered dependencies and update or return a new value of any type.

The new implementation is faster on both design and serve-time.

The most common scenario from a route to handle is to:

  • accept one or more path parameters and request data, a payload
  • send back a response, a payload (JSON, XML,...)

The new Iris Dependency Injection feature is about 33.2% faster than its predecessor on the above case. This drops down even more the performance cost between native handlers and dynamic handlers with dependencies. This reason itself brings us, with safety and performance-wise, to the new Party.ConfigureContainer(builder ...func(*iris.APIContainer)) *APIContainer method which returns methods such as Handle(method, relativePath string, handlersFn ...interface{}) *Route and RegisterDependency.

Look how clean your codebase can be when using Iris’:

package main

import ""

type (
    testInput struct {
        Email string `json:"email"`

    testOutput struct {
        ID   int    `json:"id"`
        Name string `json:"name"`

func handler(id int, in testInput) testOutput {
    return testOutput{
        ID:   id,
        Name: in.Email,

func main() {
    app := iris.New()
    app.ConfigureContainer(func(api *iris.APIContainer) {
        api.Post("/{id:int}", handler)
    app.Listen(":5000", iris.WithOptimizations)

Your eyes don't lie you. You read well, no ctx.ReadJSON(&v) and ctx.JSON(send) neither error handling are presented. It is a huge relief but if you ever need, you still have the control over those, even errors from dependencies. Here is a quick list of the new Party.ConfigureContainer()‘s fields and methods:

// Container holds the DI Container of this Party featured Dependency Injection.
// Use it to manually convert functions or structs(controllers) to a Handler.
Container *hero.Container
// OnError adds an error handler for this Party's DI Hero Container and its handlers (or controllers).
// The "errorHandler" handles any error may occurred and returned
// during dependencies injection of the Party's hero handlers or from the handlers themselves.
OnError(errorHandler func(iris.Context, error))
// RegisterDependency adds a dependency.
// The value can be a single struct value or a function.
// Follow the rules:
// * <T> {structValue}
// * func(accepts <T>)                                 returns <D> or (<D>, error)
// * func(accepts iris.Context)                        returns <D> or (<D>, error)
// A Dependency can accept a previous registered dependency and return a new one or the same updated.
// * func(accepts1 <D>, accepts2 <T>)                  returns <E> or (<E>, error) or error
// * func(acceptsPathParameter1 string, id uint64)     returns <T> or (<T>, error)
// Usage:
// - RegisterDependency(loggerService{prefix: "dev"})
// - RegisterDependency(func(ctx iris.Context) User {...})
// - RegisterDependency(func(User) OtherResponse {...})
RegisterDependency(dependency interface{})

// UseResultHandler adds a result handler to the Container.
// A result handler can be used to inject the returned struct value
// from a request handler or to replace the default renderer.
UseResultHandler(handler func(next iris.ResultHandler) iris.ResultHandler)
type ResultHandler func(ctx iris.Context, v interface{}) error
// Use same as a common Party's "Use" but it accepts dynamic functions as its "handlersFn" input.
Use(handlersFn ...interface{})
// Done same as a common Party's but it accepts dynamic functions as its "handlersFn" input.
Done(handlersFn ...interface{})
// Handle same as a common Party's `Handle` but it accepts one or more "handlersFn" functions which each one of them
// can accept any input arguments that match with the Party's registered Container's `Dependencies` and
// any output result; like custom structs <T>, string, []byte, int, error,
// a combination of the above, hero.Result(hero.View | hero.Response) and more.
// It's common from a hero handler to not even need to accept a `Context`, for that reason,
// the "handlersFn" will call `ctx.Next()` automatically when not called manually.
// To stop the execution and not continue to the next "handlersFn"
// the end-developer should output an error and return `iris.ErrStopExecution`.
Handle(method, relativePath string, handlersFn ...interface{}) *Route

// Get registers a GET route, same as `Handle("GET", relativePath, handlersFn....)`.
Get(relativePath string, handlersFn ...interface{}) *Route
// and so on...

Prior to this version the iris.Context was the only one dependency that has been automatically binded to the handler's input or a controller's fields and methods, read below to see what types are automatically binded:

Type Maps To
*mvc.Application Current MVC Application
iris.Context Current Iris Context
*sessions.Session Current Iris Session
context.Context ctx.Request().Context()
*http.Request ctx.Request()
http.ResponseWriter ctx.ResponseWriter()
http.Header ctx.Request().Header
time.Time time.Now()
*golog.Logger Iris Logger
net.IP net.ParseIP(ctx.RemoteAddr())
mvc.Code ctx.GetStatusCode() int
mvc.Err ctx.GetErr() error
iris/context.User ctx.User()
int, int8, int16, int32, int64,
uint, uint8, uint16, uint32, uint64,
float, float32, float64,
slice Path Parameter
Struct Request Body of JSON, XML, YAML, Form, URL Query, Protobuf, MsgPack

Here is a preview of what the new Hero handlers look like:

Request & Response & Path Parameters

1. Declare Go types for client's request body and a server's response.

type (
	request struct {
		Firstname string `json:"firstname"`
		Lastname  string `json:"lastname"`

	response struct {
		ID      uint64 `json:"id"`
		Message string `json:"message"`

2. Create the route handler.

Path parameters and request body are binded automatically.

  • id uint64 binds to “id:uint64”
  • input request binds to client request data such as JSON
func updateUser(id uint64, input request) response {
	return response{
		ID:      id,
		Message: "User updated successfully",

3. Configure the container per group and register the route.


func container(api *iris.APIContainer) {
    api.Put("/{id:uint64}", updateUser)

4. Simulate a client request which sends data to the server and displays the response.

curl --request PUT -d '{"firstanme":"John","lastname":"Doe"}' http://localhost:8080/user/42
    "id": 42,
    "message": "User updated successfully"

Custom Preflight

Before we continue to the next section, register dependencies, you may want to learn how a response can be customized through the iris.Context right before sent to the client.

The server will automatically execute the Preflight(iris.Context) error method of a function's output struct value right before send the response to the client.

Take for example that you want to fire different HTTP status codes depending on the custom logic inside your handler and also modify the value(response body) itself before sent to the client. Your response type should contain a Preflight method like below.

type response struct {
    ID      uint64 `json:"id,omitempty"`
    Message string `json:"message"`
    Code    int    `json:"code"`
    Timestamp int64 `json:"timestamp,omitempty"`

func (r *response) Preflight(ctx iris.Context) error {
    if r.ID > 0 {
        r.Timestamp = time.Now().Unix()

    if r.Code > 0 {

    return nil

Now, each handler that returns a *response value will call the response.Preflight method automatically.

func deleteUser(db *sql.DB, id uint64) *response {
    // [...custom logic]

    return &response{
        Message: "User has been marked for deletion",
        Code: iris.StatusAccepted,

If you register the route and fire a request you should see an output like this, the timestamp is filled and the HTTP status code of the response that the client will receive is 202 (Status Accepted).

  "message": "User has been marked for deletion",
  "code": 202,
  "timestamp": 1583313026

Register Dependencies

1. Import packages to interact with a database. The go-sqlite3 package is a database driver for SQLite.

import "database/sql"
import _ ""

2. Configure the container (see above), register your dependencies. Handler expects an *sql.DB instance.

localDB, _ := sql.Open("sqlite3", "./foo.db")

3. Register a route to create a user.

api.Post("/{id:uint64}", createUser)

4. The create user Handler.

The handler accepts a database and some client request data such as JSON, Protobuf, Form, URL Query and e.t.c. It Returns a response.

func createUser(db *sql.DB, user request) *response {
    // [custom logic using the db]
    userID, err := db.CreateUser(user)
    if err != nil {
        return &response{
            Message: err.Error(),
            Code: iris.StatusInternalServerError,

	return &response{
		ID:      userID,
		Message: "User created",
		Code:    iris.StatusCreated,

5. Simulate a client to create a user.

curl --request POST -d '{"firstname":"John","lastname":"Doe"}' \
--header 'Content-Type: application/json' \
# Form (multipart)
curl --request POST 'http://localhost:8080/users' \
--header 'Content-Type: multipart/form-data' \
--form 'firstname=John' \
--form 'lastname=Doe'
# Form (URL-encoded)
curl --request POST 'http://localhost:8080/users' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'firstname=John' \
--data-urlencode 'lastname=Doe'
# URL Query
curl --request POST 'http://localhost:8080/users?firstname=John&lastname=Doe'


    "id": 42,
    "message": "User created",
    "code": 201,
    "timestamp": 1583313026

Breaking Changes

  • The versioning.NewMatcher has been removed entirely in favor of NewGroup. Strict versions format on versioning.NewGroup is required. E.g. "1" is not valid anymore, you have to specify "1.0.0". Example: NewGroup(api, ">=1.0.0 <2.0.0"). The routing/versioning examples have been updated.
  • Now that RegisterView can be used to register different view engines per-Party, there is no need to support registering multiple engines under the same Party. The app.RegisterView now upserts the given Engine instead of append. You can now render templates without file extension, e.g. index instead of index.ace, both forms are valid now.
  • The Context.ContentType does not accept filenames to resolve the mime type anymore (caused issues with vendor-specific(vnd) MIME types).
  • The Configuration.RemoteAddrPrivateSubnets.IPRange.Start and End are now type of string instead of net.IP. The WithRemoteAddrPrivateSubnet option remains as it is, already accepts strings.
  • The i18n#LoaderConfig.FuncMap template.FuncMap field was replaced with Funcs func(iris.Locale) template.FuncMap in order to give current locale access to the template functions. A new app.I18n.Loader was introduced too, in order to make it easier for end-developers to customize the translation key values.
  • Request Logger's Columns bool field has been removed. Use the new accesslog middleware instead.
  • The .Binary method of all view engines was removed: pass the go-bindata's latest version AssetFile() exported function as the first argument instead of string. All examples updated.
  • ContextUploadFormFiles(destDirectory string, before ...func(*Context, *multipart.FileHeader) bool) (uploaded []*multipart.FileHeader, n int64, err error) now returns the total files uploaded too (as its first parameter) and the “before” variadic option should return a boolean, if false then the specific file is skipped.
  • Context.PostValues(name string) ([]string, error) now returns a second output argument of error type too, which reports ErrEmptyForm or ErrNotFound or ErrEmptyFormField. The single post value getters now returns the last value if multiple was given instead of the first one (this allows clients to append values on flow updates).
  • Party.GetReporter() removed. The Application.Build returns the first error now and the API's errors are logged, this allows the server to run even if some of the routes are invalid but not fatal to the entire application (it was a request from a company).
  • versioning.NewGroup(string) now accepts a Party as its first input argument: NewGroup(Party, string).
  • versioning.RegisterGroups is removed as it is no longer necessary.
  • Configuration.RemoteAddrHeaders from map[string]bool to []string. If you used With(out)RemoteAddrHeader then you are ready to proceed without any code changes for that one.
  • ctx.Gzip(boolean) replaced with ctx.CompressWriter(boolean) error.
  • ctx.GzipReader(boolean) error replaced with ctx.CompressReader(boolean) error.
  • iris.Gzip and iris.GzipReader replaced with iris.Compression (middleware).
  • ctx.ClientSupportsGzip() bool replaced with ctx.ClientSupportsEncoding("gzip", "br" ...) bool.
  • ctx.GzipResponseWriter() is removed.
  • Party.HandleDir/iris.FileServer now accepts both http.FileSystem and string and returns a list of []*Route (GET and HEAD) instead of GET only. You can write: both app.HandleDir("/", iris.Dir("./assets")) and app.HandleDir("/", "./assets") and DirOptions.Asset, AssetNames, AssetInfo removed, use go-bindata -fs [..] and app.HandleDir("/", AssetFile()) instead.
  • Context.OnClose and Context.OnCloseConnection now both accept an iris.Handler instead of a simple func() as their callback.
  • Context.StreamWriter(writer func(w io.Writer) bool) changed to StreamWriter(writer func(w io.Writer) error) error and it's now the Context.Request().Context().Done() channel that is used to receive any close connection/manual cancel signals, instead of the deprecated ResponseWriter().CloseNotify() one. Same for the Context.OnClose and Context.OnCloseConnection methods.
  • Fixed handler's error response not be respected when response recorder was used instead of the common writer. Fixes #1531. It contains a BREAKING CHANGE of: the new Configuration.ResetOnFireErrorCode field should be set to true in order to behave as it used before this update (to reset the contents on recorder).
  • Context.String() (rarely used by end-developers) it does not return a unique string anymore, to achieve the old representation you must call the new Context.SetID method first.
  • iris.CookieEncode and CookieDecode are replaced with the iris.CookieEncoding.
  • sessions#Config.Encode and Decode are removed in favor of (the existing) Encoding field.
  • versioning.GetVersion now returns an empty string if version wasn't found.
  • Change the MIME type of Javascript .js and JSONP as the HTML specification now recommends to "text/javascript" instead of the obselete "application/javascript". This change was pushed to the Go language itself as well. See
  • Remove the last input argument of enableGzipCompression in Context.ServeContent, ServeFile methods. This was deprecated a few versions ago. A middleware (app.Use(iris.CompressWriter)) or a prior call to Context.CompressWriter(true) will enable compression. Also these two methods and Context.SendFile one now support Content-Range and Accept-Ranges correctly out of the box (net/http had a bug, which is now fixed).
  • Context.ServeContent no longer returns an error, see ServeContentWithRate, ServeFileWithRate and SendFileWithRate new methods too.
  • route.Trace() string changed to route.Trace(w io.Writer), to achieve the same result just pass a bytes.Buffer
  • var mvc.AutoBinding removed as the default behavior now resolves such dependencies automatically (see [FEATURE REQUEST] MVC serving gRPC-compatible controller).
  • mvc#Application.SortByNumMethods() removed as the default behavior now binds the “thinnest” empty interface{} automatically (see MVC: service injecting fails).
  • mvc#BeforeActivation.Dependencies().Add should be replaced with mvc#BeforeActivation.Dependencies().Register instead
  • REMOVE the kataras/iris/v12/typescript package in favor of the new iris-cli. Also, the alm typescript online editor was removed as it is deprecated by its author, please consider using the designtsx instead.

Su, 16 February 2020 | v12.1.8

New Features:


New Examples:

Mo, 10 February 2020 | v12.1.7

Implement new SetRegisterRule(iris.RouteOverride, RouteSkip, RouteError) to resolve:

New Examples:

We, 05 February 2020 | v12.1.6


Su, 02 February 2020 | v12.1.5

Various improvements and linting.

Su, 29 December 2019 | v12.1.4

Minor fix on serving embedded files.

We, 25 December 2019 | v12.1.3

Fix [BUG] [iris.Default] RegisterView

Th, 19 December 2019 | v12.1.2

Fix [BUG]Session works incorrectly when meets the multi-level TLDs.

Mo, 16 December 2019 | v12.1.1

Add Context.FindClosest(n int) []string

app := iris.New()
app.OnErrorCode(iris.StatusNotFound, notFound)
func notFound(ctx iris.Context) {
    suggestPaths := ctx.FindClosest(3)
    if len(suggestPaths) == 0 {
        ctx.WriteString("404 not found")

    ctx.HTML("Did you mean?<ul>")
    for _, s := range suggestPaths {
        ctx.HTML(`<li><a href="%s">%s</a></li>`, s, s)

Fr, 13 December 2019 | v12.1.0

Breaking Changes

Minor as many of you don't even use them but, indeed, they need to be covered here.

  • Old i18n middleware(iris/middleware/i18n) was replaced by the i18n sub-package which lives as field at your application: app.I18n.Load(globPathPattern string, languages ...string) (see below)
  • Community-driven i18n middleware(iris-contrib/middleware/go-i18n) has a NewLoader function which returns a loader which can be passed at app.I18n.Reset(loader i18n.Loader, languages ...string) to change the locales parser
  • The Configuration's TranslateFunctionContextKey was replaced by LocaleContextKey which Context store's value (if i18n is used) returns the current Locale which contains the translate function, the language code, the language tag and the index position of it
  • The context.Translate method was replaced by context.Tr as a shortcut for the new context.GetLocale().GetMessage(format, args...) method and it matches the view's function {{tr format args}} too
  • If you used Iris Django view engine with import _ you must change the import path to _ or add a go mod replace to your go.mod file, e.g. replace => v0.0.1.


All known issues.

  1. #1395
  2. #1369
  3. #1399 with PR #1400
  4. #1401
  5. #1406
  6. neffos/#20
  7. pio/#5

New Features

Internationalization and localization

Support for i18n is now a builtin feature and is being respected across your entire application, per say sitemap and views.

Refer to the wiki section: for details.


Iris generates and serves one or more sitemap.xml for your static routes.

Navigate through: for more.

New Examples

  1. _examples/i18n
  2. _examples/sitemap
  3. _examples/desktop/blink
  4. _examples/desktop/lorca
  5. _examples/desktop/webview

Sa, 26 October 2019 | v12.0.0

  • Add version suffix of the import path, learn why and see what people voted at issue #1370

  • All errors are now compatible with go1.13 errors.Is, errors.As and fmt.Errorf and a new core/errgroup package created
  • Fix #1383
  • Report whether system couldn't find the directory of view templates
  • Remove the Party#GetReport method, keep Party#GetReporter which is an error and an errgroup.Group.
  • Remove the router's deprecated methods such as StaticWeb and StaticEmbedded_XXX
  • The Context#CheckIfModifiedSince now returns an context.ErrPreconditionFailed type of error when client conditions are not met. Usage: if errors.Is(err, context.ErrPreconditionFailed) { ... }
  • Add SourceFileName and SourceLineNumber to the Route, reports the exact position of its registration inside your project's source code.
  • Fix a bug about the MVC package route binding, see PR #1364
  • Add mvc/Application#SortByNumMethods as requested at #1343
  • Add status code 103 Early Hints
  • Fix performance of session.UpdateExpiration on 200 thousands+ keys with new radix as reported at issue #1328
  • New redis session database configuration field: Driver: redis.Redigo() or redis.Radix(), see updated examples
  • Add Clusters support for redis:radix session database (Driver: redis:Radix()) as requested at issue #1339
  • Create Iranian README_FA translation with PR #1360
  • Create Korean README_KO translation with PR #1356
  • Create Spanish README_ES and HISTORY_ES translations with PR #1344.

The iris-contrib/middleare and examples are updated to use the new import path.

Fr, 16 August 2019 | v11.2.8

  • Set Cookie.SameSite to Lax when subdomains sessions share is enabled*
  • Add and update all experimental handlers
  • New XMLMap function which wraps a map[string]interface{} and converts it to a valid xml content to render through Context.XML method
  • Add new ProblemOptions.XML and RenderXML fields to render the Problem as XML(application/problem+xml) instead of JSON(“application/problem+json) and enrich the Negotiate to easily accept the application/problem+xml mime.

Commit log:

Th, 15 August 2019 | v11.2.7

This minor version contains improvements on the Problem Details for HTTP APIs implemented on v11.2.5.

Example and wikis updated.


Commit log:

We, 14 August 2019 | v11.2.6

Allow handle more than one route with the same paths and parameter types but different macro validation functions.

app.Get("/{alias:string regexp(^[a-z0-9]{1,10}\\.xml$)}", PanoXML)
app.Get("/{alias:string regexp(^[a-z0-9]{1,10}$)}", Tour)

Commit log:

Mo, 12 August 2019 | v11.2.5

Commit log:

Fr, 09 August 2019 | v11.2.4

Commit log:

Tu, 30 July 2019 | v11.2.3

We, 24 July 2019 | v11.2.2

Sessions as middleware:

import ""
// [...]

app := iris.New()
sess := sessions.New(sessions.Config{...})

app.Get("/path", func(ctx iris.Context){
    session := sessions.Get(ctx)
    // [work with session...]
  • Add Session.Len() int to return the total number of stored values/entries.
  • Make Context.HTML and Context.Text to accept an optional, variadic, args ...interface{} input arg(s) too.


Tu, 23 July 2019 | v11.2.0

Read about the new release at: