chore: import clean Agent Desk snapshot (2/7)

internal/pkg/ginx/static.go

@@ -0,0 +1,188 @@
+package ginx
+
+import (
+	"io/fs"
+	"log/slog"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+type noDirFS struct {
+	fs http.FileSystem
+}
+
+type DirOptions struct {
+	ShowList  bool
+	SPA       bool
+	IndexName string
+}
+
+type SPAOptions struct {
+	Root             string
+	EmbeddedFS       fs.FS
+	EmbeddedRoot     string
+	DirOptions       DirOptions
+	NotFoundPrefixes []string
+	NotFoundHandler  gin.HandlerFunc
+	// RootRedirect, when set, answers "/" with a redirect instead of serving
+	// the SPA. The static export has no index.html at the root, so without this
+	// the site origin answers 404.
+	RootRedirect string
+}
+
+func StaticFiles(root string) http.FileSystem {
+	return noDirFS{fs: http.Dir(root)}
+}
+
+func (n noDirFS) Open(name string) (http.File, error) {
+	file, err := n.fs.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	info, err := file.Stat()
+	if err != nil {
+		_ = file.Close()
+		return nil, err
+	}
+	if info.IsDir() {
+		_ = file.Close()
+		return nil, os.ErrNotExist
+	}
+	return file, nil
+}
+
+func HandleSPA(engine *gin.Engine, options SPAOptions) gin.HandlerFunc {
+	handler := NewSPAHandler(options.Root, options.EmbeddedFS, options.EmbeddedRoot, options.DirOptions)
+	rootHandler := handler
+	if options.RootRedirect != "" {
+		target := options.RootRedirect
+		rootHandler = func(ctx *gin.Context) {
+			ctx.Redirect(http.StatusFound, target)
+		}
+	}
+	engine.GET("/", rootHandler)
+	engine.HEAD("/", rootHandler)
+	engine.NoRoute(func(ctx *gin.Context) {
+		for _, prefix := range options.NotFoundPrefixes {
+			if strings.HasPrefix(ctx.Request.URL.Path, prefix) {
+				if options.NotFoundHandler != nil {
+					options.NotFoundHandler(ctx)
+					return
+				}
+				ctx.AbortWithStatus(http.StatusNotFound)
+				return
+			}
+		}
+		handler(ctx)
+	})
+	return handler
+}
+
+func NewSPAHandler(root string, embeddedFS fs.FS, embeddedRoot string, options DirOptions) gin.HandlerFunc {
+	if _, err := os.Stat(path.Join(root, options.IndexName)); err == nil {
+		return DirHandler(http.Dir(root), options)
+	}
+
+	spaFS, err := fs.Sub(embeddedFS, embeddedRoot)
+	if err != nil {
+		slog.Error("failed to load embedded SPA files", slog.Any("err", err))
+		return func(ctx *gin.Context) {
+			ctx.AbortWithStatus(http.StatusInternalServerError)
+		}
+	}
+	return DirHandler(http.FS(spaFS), options)
+}
+
+func tryOpenFile(fileSystem http.FileSystem, filePath string) (http.File, os.FileInfo, bool) {
+	file, err := fileSystem.Open(filePath)
+	if err != nil {
+		return nil, nil, false
+	}
+	info, err := file.Stat()
+	if err != nil || info.IsDir() {
+		_ = file.Close()
+		return nil, nil, false
+	}
+	return file, info, true
+}
+
+func DirHandler(fileSystem http.FileSystem, options DirOptions) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		name := path.Clean(ctx.Request.URL.Path)
+		if name == "." || name == "/" {
+			name = "/" + options.IndexName
+		}
+
+		file, err := fileSystem.Open(name)
+		if err == nil {
+			defer file.Close()
+			info, err := file.Stat()
+			if err != nil {
+				ctx.AbortWithStatus(http.StatusInternalServerError)
+				return
+			}
+			if info.IsDir() {
+				if options.IndexName != "" {
+					indexName := path.Join(name, options.IndexName)
+					if indexFile, indexInfo, ok := tryOpenFile(fileSystem, indexName); ok {
+						defer indexFile.Close()
+						serveFile(ctx, indexName, indexFile, indexInfo)
+						return
+					}
+				}
+				// Support Next.js static export where directory name matches page html (e.g. /dashboard -> /dashboard.html)
+				htmlName := strings.TrimRight(name, "/") + ".html"
+				if htmlFile, htmlInfo, ok := tryOpenFile(fileSystem, htmlName); ok {
+					defer htmlFile.Close()
+					serveFile(ctx, htmlName, htmlFile, htmlInfo)
+					return
+				}
+				if !options.ShowList {
+					if options.SPA && options.IndexName != "" {
+						indexName := "/" + options.IndexName
+						if indexFile, indexInfo, ok := tryOpenFile(fileSystem, indexName); ok {
+							defer indexFile.Close()
+							serveFile(ctx, indexName, indexFile, indexInfo)
+							return
+						}
+					}
+					ctx.AbortWithStatus(http.StatusNotFound)
+					return
+				}
+			} else {
+				serveFile(ctx, name, file, info)
+				return
+			}
+		} else if !os.IsNotExist(err) {
+			ctx.AbortWithStatus(http.StatusInternalServerError)
+			return
+		}
+
+		// Try name.html (for sub-routes like /dashboard/login -> /dashboard/login.html)
+		htmlName := strings.TrimRight(name, "/") + ".html"
+		if htmlFile, htmlInfo, ok := tryOpenFile(fileSystem, htmlName); ok {
+			defer htmlFile.Close()
+			serveFile(ctx, htmlName, htmlFile, htmlInfo)
+			return
+		}
+
+		if options.SPA && options.IndexName != "" {
+			indexName := "/" + options.IndexName
+			if indexFile, indexInfo, ok := tryOpenFile(fileSystem, indexName); ok {
+				defer indexFile.Close()
+				serveFile(ctx, indexName, indexFile, indexInfo)
+				return
+			}
+		}
+
+		ctx.AbortWithStatus(http.StatusNotFound)
+	}
+}
+
+func serveFile(ctx *gin.Context, name string, file http.File, info os.FileInfo) {
+	http.ServeContent(ctx.Writer, ctx.Request, name, info.ModTime(), file)
+}