feat(staticweb): add path prefix stripping to all filesystem providers

Add PrefixStrippingProvider interface and implement it in all providers
(EmbedFSProvider, LocalFSProvider, ZipFSProvider) to support serving
files from subdirectories at the root level.

pkg/server/staticweb/interfaces.go

@@ -34,6 +34,29 @@ type ReloadableProvider interface {
 	Reload() error
 }
 
+// PrefixStrippingProvider is an optional interface that providers can implement
+// to support stripping path prefixes from requested paths.
+// This is useful when files are stored in a subdirectory but should be accessible
+// at the root level (e.g., files at "/dist/assets" accessible via "/assets").
+type PrefixStrippingProvider interface {
+	// WithStripPrefix sets the prefix to strip from requested paths.
+	// For example, WithStripPrefix("/dist") will make files at "/dist/assets"
+	// accessible via "/assets".
+	WithStripPrefix(prefix string)
+
+	// StripPrefix returns the configured strip prefix.
+	StripPrefix() string
+}
+
+// WithStripPrefix is a helper function that sets the strip prefix on a provider
+// if it implements PrefixStrippingProvider. Returns the provider for method chaining.
+func WithStripPrefix(provider FileSystemProvider, prefix string) FileSystemProvider {
+	if p, ok := provider.(PrefixStrippingProvider); ok {
+		p.WithStripPrefix(prefix)
+	}
+	return provider
+}
+
 // CachePolicy defines how files should be cached by browsers and proxies.
 // Implementations must be safe for concurrent use.
 type CachePolicy interface {

pkg/server/staticweb/providers/embed.go

@@ -142,12 +142,10 @@ func (p *EmbedFSProvider) ZipFile() string {
 // WithStripPrefix sets the prefix to strip from requested paths.
 // For example, WithStripPrefix("/dist") will make files at "/dist/assets"
 // accessible via "/assets".
-// Returns the provider for method chaining.
-func (p *EmbedFSProvider) WithStripPrefix(prefix string) *EmbedFSProvider {
+func (p *EmbedFSProvider) WithStripPrefix(prefix string) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
 	p.stripPrefix = prefix
-	return p
 }
 
 // StripPrefix returns the configured strip prefix.

pkg/server/staticweb/providers/local.go

@@ -4,13 +4,18 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
+	"path"
 	"path/filepath"
+	"strings"
+	"sync"
 )
 
 // LocalFSProvider serves files from a local directory.
 type LocalFSProvider struct {
-	path string
-	fs   fs.FS
+	path        string
+	stripPrefix string
+	fs          fs.FS
+	mu          sync.RWMutex
 }
 
 // NewLocalFSProvider creates a new LocalFSProvider for the given directory path.
@@ -39,8 +44,28 @@ func NewLocalFSProvider(path string) (*LocalFSProvider, error) {
 }
 
 // Open opens the named file from the local directory.
+// If a strip prefix is configured, it prepends the prefix to the requested path.
+// For example, with stripPrefix="/dist", requesting "/assets/style.css" will
+// open "/dist/assets/style.css" from the local filesystem.
 func (p *LocalFSProvider) Open(name string) (fs.File, error) {
-	return p.fs.Open(name)
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+
+	// Apply prefix stripping by prepending the prefix to the requested path
+	actualPath := name
+	if p.stripPrefix != "" {
+		// Clean the paths to handle leading/trailing slashes
+		prefix := strings.Trim(p.stripPrefix, "/")
+		cleanName := strings.TrimPrefix(name, "/")
+
+		if prefix != "" {
+			actualPath = path.Join(prefix, cleanName)
+		} else {
+			actualPath = cleanName
+		}
+	}
+
+	return p.fs.Open(actualPath)
 }
 
 // Close releases any resources held by the provider.
@@ -63,6 +88,9 @@ func (p *LocalFSProvider) Path() string {
 // For local directories, os.DirFS automatically picks up changes,
 // so this recreates the DirFS to ensure a fresh view.
 func (p *LocalFSProvider) Reload() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
 	// Verify the directory still exists
 	info, err := os.Stat(p.path)
 	if err != nil {
@@ -78,3 +106,19 @@ func (p *LocalFSProvider) Reload() error {
 
 	return nil
 }
+
+// WithStripPrefix sets the prefix to strip from requested paths.
+// For example, WithStripPrefix("/dist") will make files at "/dist/assets"
+// accessible via "/assets".
+func (p *LocalFSProvider) WithStripPrefix(prefix string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.stripPrefix = prefix
+}
+
+// StripPrefix returns the configured strip prefix.
+func (p *LocalFSProvider) StripPrefix() string {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return p.stripPrefix
+}

pkg/server/staticweb/providers/zip.go

@@ -4,7 +4,9 @@ import (
 	"archive/zip"
 	"fmt"
 	"io/fs"
+	"path"
 	"path/filepath"
+	"strings"
 	"sync"
 
 	"github.com/bitechdev/ResolveSpec/pkg/server/zipfs"
@@ -12,10 +14,11 @@ import (
 
 // ZipFSProvider serves files from a zip file.
 type ZipFSProvider struct {
-	zipPath   string
-	zipReader *zip.ReadCloser
-	zipFS     *zipfs.ZipFS
-	mu        sync.RWMutex
+	zipPath     string
+	stripPrefix string
+	zipReader   *zip.ReadCloser
+	zipFS       *zipfs.ZipFS
+	mu          sync.RWMutex
 }
 
 // NewZipFSProvider creates a new ZipFSProvider for the given zip file path.
@@ -40,6 +43,9 @@ func NewZipFSProvider(zipPath string) (*ZipFSProvider, error) {
 }
 
 // Open opens the named file from the zip archive.
+// If a strip prefix is configured, it prepends the prefix to the requested path.
+// For example, with stripPrefix="/dist", requesting "/assets/style.css" will
+// open "/dist/assets/style.css" from the zip filesystem.
 func (p *ZipFSProvider) Open(name string) (fs.File, error) {
 	p.mu.RLock()
 	defer p.mu.RUnlock()
@@ -48,7 +54,21 @@ func (p *ZipFSProvider) Open(name string) (fs.File, error) {
 		return nil, fmt.Errorf("zip filesystem is closed")
 	}
 
-	return p.zipFS.Open(name)
+	// Apply prefix stripping by prepending the prefix to the requested path
+	actualPath := name
+	if p.stripPrefix != "" {
+		// Clean the paths to handle leading/trailing slashes
+		prefix := strings.Trim(p.stripPrefix, "/")
+		cleanName := strings.TrimPrefix(name, "/")
+
+		if prefix != "" {
+			actualPath = path.Join(prefix, cleanName)
+		} else {
+			actualPath = cleanName
+		}
+	}
+
+	return p.zipFS.Open(actualPath)
 }
 
 // Close releases resources held by the zip reader.
@@ -100,3 +120,19 @@ func (p *ZipFSProvider) Reload() error {
 
 	return nil
 }
+
+// WithStripPrefix sets the prefix to strip from requested paths.
+// For example, WithStripPrefix("/dist") will make files at "/dist/assets"
+// accessible via "/assets".
+func (p *ZipFSProvider) WithStripPrefix(prefix string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.stripPrefix = prefix
+}
+
+// StripPrefix returns the configured strip prefix.
+func (p *ZipFSProvider) StripPrefix() string {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return p.stripPrefix
+}