127 lines
3.7 KiB
Go
127 lines
3.7 KiB
Go
package ui
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import (
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"embed"
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"fmt"
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"io/fs"
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"net/http"
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"regexp"
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"strings"
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)
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const (
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// Default page to load (upon a miss)
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DefaultPage = "index.html"
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// DefaultPageContentType is the content-type of the DefaultPage
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DefaultPageContentType = "text/html; charset=utf-8"
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)
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//go:embed build/*
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var embeddedFS embed.FS
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var buildDir fs.FS
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//go:embed package.json
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var packageJson string
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var version string
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// init initializes version and buildDir file system
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func init() {
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// parse version
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version = ""
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re := regexp.MustCompile(`"version"\s*:\s*"(.*)"`)
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if matches := re.FindStringSubmatch(packageJson); matches != nil {
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version = matches[1]
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}
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// initialize buildDir and default file
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var err error
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if buildDir, err = fs.Sub(embeddedFS, "build"); err != nil {
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panic("no ui/build directory found!")
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}
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}
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// BindataAssets serves embedded ui assets and also serves its index.html by default
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// in order to support single-page react-apps with its own router.
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type BindataAssets struct {
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}
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// fsImpl is a s imple fs.FS implementation that uses the supplied OpenFn function
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type fsImpl struct {
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openFn func(path string) (fs.File, error)
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}
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func (fs *fsImpl) Open(path string) (fs.File, error) {
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return fs.openFn(path)
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}
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// Handler returns HTTP handler that serves embedded data
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func (b *BindataAssets) Handler() http.Handler {
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return b
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}
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// addCacheHeaders requests an hour of Cache-Control and sets an ETag based on file size and modtime
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func addCacheHeaders(file fs.File, headers http.Header) error {
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fi, err := file.Stat()
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if err == nil {
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headers.Add("Cache-Control", "public, max-age=3600")
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headers.Add("X-Frame-Options", "SAMEORIGIN")
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headers.Add("X-XSS-Protection", "1; mode=block")
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headers.Add("X-Content-Type-Options", "nosniff")
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headers.Add("Content-Security-Policy", "script-src 'self'; object-src 'self'")
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hour, minute, second := fi.ModTime().Clock()
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etag := fmt.Sprintf(`"%d%d%d%d%d"`, fi.Size(), fi.ModTime().Day(), hour, minute, second)
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headers.Set("ETag", etag)
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}
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return err
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}
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// ServeHTTP wraps http.FileServer by returning a default asset if the asset
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// doesn't exist. This supports single-page react-apps with its own
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// built-in router. Additionally, we override the content-type if the
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// Default file is used.
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func (b *BindataAssets) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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// openFn wraps buidDir.Open in order to setup default HTTP headers
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// it also returns the default file if the file doesn't exist
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openFn := func(name string) (fs.File, error) {
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// If the named asset exists, then return it directly.
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file, err := buildDir.Open(name)
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if err != nil {
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// If this is at / then we just error out so we can return a Directory
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// This directory will then be redirected by go to the /index.html
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if name == "/" || name == "." {
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return nil, err
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}
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// If this is anything other than slash, we just return the default
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// asset. This default asset will handle the routing.
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// Additionally, because we know we are returning the default asset,
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// we need to set the default asset's content-type.
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w.Header().Set("Content-Type", DefaultPageContentType)
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defaultFile, err := buildDir.Open(DefaultPage)
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if err != nil {
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return nil, err
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}
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file = defaultFile
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}
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if err := addCacheHeaders(file, w.Header()); err != nil {
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return nil, err
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}
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// https://github.com/influxdata/chronograf/issues/5565
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// workaround wrong .js content-type on windows
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if strings.HasSuffix(name, ".js") {
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w.Header().Set("Content-Type", "text/javascript")
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}
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return file, nil
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}
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var fs fs.FS = &fsImpl{
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openFn: openFn,
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}
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http.FileServer(http.FS(fs)).ServeHTTP(w, r)
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}
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// GetVersion returns version of the packed assets
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func GetVersion() string {
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return version
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}
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