package middleware
import (
"bytes"
"fmt"
"html/template"
"net/http"
"path"
)
// SwaggerUIOpts configures the Swaggerui middlewares
type SwaggerUIOpts struct {
// BasePath for the UI path, defaults to: /
BasePath string
// Path combines with BasePath for the full UI path, defaults to: docs
Path string
// SpecURL the url to find the spec for
SpecURL string
// The three components needed to embed swagger-ui
SwaggerURL string
SwaggerPresetURL string
SwaggerStylesURL string
Favicon32 string
Favicon16 string
// Title for the documentation site, default to: API documentation
Title string
}
// EnsureDefaults in case some options are missing
func (r *SwaggerUIOpts) EnsureDefaults() {
if r.BasePath == "" {
r.BasePath = "/"
}
if r.Path == "" {
r.Path = "docs"
}
if r.SpecURL == "" {
r.SpecURL = "/swagger.json"
}
if r.SwaggerURL == "" {
r.SwaggerURL = swaggerLatest
}
if r.SwaggerPresetURL == "" {
r.SwaggerPresetURL = swaggerPresetLatest
}
if r.SwaggerStylesURL == "" {
r.SwaggerStylesURL = swaggerStylesLatest
}
if r.Favicon16 == "" {
r.Favicon16 = swaggerFavicon16Latest
}
if r.Favicon32 == "" {
r.Favicon32 = swaggerFavicon32Latest
}
if r.Title == "" {
r.Title = "API documentation"
}
}
// SwaggerUI creates a middleware to serve a documentation site for a swagger spec.
// This allows for altering the spec before starting the http listener.
func SwaggerUI(opts SwaggerUIOpts, next http.Handler) http.Handler {
opts.EnsureDefaults()
pth := path.Join(opts.BasePath, opts.Path)
tmpl := template.Must(template.New("swaggerui").Parse(swaggeruiTemplate))
buf := bytes.NewBuffer(nil)
_ = tmpl.Execute(buf, &opts)
b := buf.Bytes()
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if r.URL.Path == pth {
rw.Header().Set("Content-Type", "text/html; charset=utf-8")
rw.WriteHeader(http.StatusOK)
_, _ = rw.Write(b)
return
}
if next == nil {
rw.Header().Set("Content-Type", "text/plain")
rw.WriteHeader(http.StatusNotFound)
_, _ = rw.Write([]byte(fmt.Sprintf("%q not found", pth)))
return
}
next.ServeHTTP(rw, r)
})
}
const (
swaggerLatest = "https://unpkg.com/swagger-ui-dist/swagger-ui-bundle.js"
swaggerPresetLatest = "https://unpkg.com/swagger-ui-dist/swagger-ui-standalone-preset.js"
swaggerStylesLatest = "https://unpkg.com/swagger-ui-dist/swagger-ui.css"
swaggerFavicon32Latest = "https://unpkg.com/swagger-ui-dist/favicon-32x32.png"
swaggerFavicon16Latest = "https://unpkg.com/swagger-ui-dist/favicon-16x16.png"
swaggeruiTemplate = `
{{ .Title }}
`
)