iris/versioning

Versioning

The versioning package provides semver versioning for your APIs. It implements all the suggestions written at api-guidelines and more.

The version comparison is done by the go-version package. It supports matching over patterns like ">= 1.0, < 3" and etc.

Features

• per route version matching, a normal iris handler with "switch" cases via Map for version => handler
• per group versioned routes and deprecation API
• version matching like ">= 1.0, < 2.0" or just "2.0.1" and etc.
• version not found handler (can be customized by simply adding the versioning.NotFound: customNotMatchVersionHandler on the Map)
• version is retrieved from the "Accept" and "Accept-Version" headers (can be customized via middleware)
• respond with "X-API-Version" header, if version found.
• deprecation options with customizable "X-API-Warn", "X-API-Deprecation-Date", "X-API-Deprecation-Info" headers via Deprecated wrapper.

Get version

Current request version is retrieved by versioning.GetVersion(ctx).

By default the GetVersion will try to read from:

• Accept header, i.e Accept: "application/json; version=1.0"
• Accept-Version header, i.e Accept-Version: "1.0"

You can also set a custom version for a handler via a middleware by using the context's store values. For example:

func(ctx iris.Context) {
    ctx.Values().Set(versioning.Key, ctx.URLParamDefault("version", "1.0"))
    ctx.Next()
}

Match version to handler

The versioning.NewMatcher(versioning.Map) iris.Handler creates a single handler which decides what handler need to be executed based on the requested version.

app := iris.New()

// middleware for all versions.
myMiddleware := func(ctx iris.Context) {
    // [...]
    ctx.Next()
}

myCustomNotVersionFound := func(ctx iris.Context) {
    ctx.StatusCode(404)
    ctx.Writef("%s version not found", versioning.GetVersion(ctx))
}

userAPI := app.Party("/api/user")
userAPI.Get("/", myMiddleware, versioning.NewMatcher(versioning.Map{
    "1.0":               sendHandler(v10Response),
    ">= 2, < 3":         sendHandler(v2Response),
    versioning.NotFound: myCustomNotVersionFound,
}))

Deprecation

Using the versioning.Deprecated(handler iris.Handler, options versioning.DeprecationOptions) iris.Handler function you can mark a specific handler version as deprecated.

v10Handler := versioning.Deprecated(sendHandler(v10Response), versioning.DeprecationOptions{
    // if empty defaults to: "WARNING! You are using a deprecated version of this API."
    WarnMessage string 
    DeprecationDate time.Time
    DeprecationInfo string
})

userAPI.Get("/", versioning.NewMatcher(versioning.Map{
    "1.0": v10Handler,
    // [...]
}))

This will make the handler to send these headers to the client:

• "X-API-Warn": options.WarnMessage
• "X-API-Deprecation-Date": context.FormatTime(ctx, options.DeprecationDate))
• "X-API-Deprecation-Info": options.DeprecationInfo

versioning.DefaultDeprecationOptions can be passed instead if you don't care about Date and Info.

Grouping routes by version

Grouping routes by version is possible as well.

Using the versioning.NewGroup(version string) *versioning.Group function you can create a group to register your versioned routes. The versioning.RegisterGroups(r iris.Party, groups ...*versioning.Group) must be called in the end in order to register the routes to a specific Party.

app := iris.New()

userAPI := app.Party("/api/user")
// [... static serving, middlewares and etc goes here].

userAPIV10 := versioning.NewGroup("1.0")
userAPIV10.Get("/", sendHandler(v10Response))

userAPIV2 := versioning.NewGroup(">= 2, < 3")
userAPIV2.Get("/", sendHandler(v2Response))
userAPIV2.Post("/", sendHandler(v2Response))
userAPIV2.Put("/other", sendHandler(v2Response))

versioning.RegisterGroups(userAPI, userAPIV10, userAPIV2)

Deprecation for Group

Just call the Deprecated(versioning.DeprecationOptions) on the group you want to notify your API consumers that this specific version is deprecated.

userAPIV10 := versioning.NewGroup("1.0").Deprecated(versioning.DefaultDeprecationOptions)

Version not found for Groups

In order to register a custom version not found handler you have to use the versioning.Concat first, which gives you the API to add a version not found handler.

versioning.Concat(userAPIV10, userAPIV2).NotFound(func(ctx iris.Context) {
    ctx.StatusCode(iris.StatusNotFound)
    ctx.Writef("unknown version %s", versioning.GetVersion(ctx))
}).For(userAPI)

Compare version manually from inside your handlers

// reports if the "version" is matching to the "is".
// the "is" can be a constraint like ">= 1, < 3".
If(version string, is string) bool

// same as `If` but expects a Context to read the requested version.
Match(ctx iris.Context, expectedVersion string) bool

app.Get("/api/user", func(ctx iris.Context) {
    if versioning.Match(ctx, ">= 2.2.3") {
        // [logic for >= 2.2.3 version of your handler goes here]
        return
    }
})