Configurable index template and static files

Iterating on riotbib's Pull Request #45, it is now possible to overwrite
the index.html template file during startup. Furthermore, static files
are now also supported, e.g., for stylesheets.

CHANGELOG.md

@@ -23,14 +23,14 @@ Types of changes:
 - Add goshy as bash script and NixOS program, [@riotbib](https://github.com/riotbib) in [#27](https://github.com/oxzi/gosh/pull/27).
 - Created Store RPC working on Unix domain sockets to allow a `fork`+`exec`ed daemon.
 - Configuration through YAML configuration file.
+- Configurable index template and static files, partially by [@riotbib](https://github.com/riotbib) in [#45](https://github.com/oxzi/gosh/pull/45).
 
 ### Changed
 - Dependency version bumps.
 - Great structural refactoring.
 - `goshd` became `gosh`.
 - Made `gosh` a `chroot`ed, privilege dropped, `fork`+`exec`ed daemon.
 - OpenBSD installation changed due to structural program changes.
-- Extract web template into a more editable file, [@riotbib](https://github.com/riotbib) in [#45](https://github.com/oxzi/gosh/pull/45).
 - Bumped required Go version from 1.19 to 1.21.
 - Replaced logrus logging with Go's new `log/slog` and do wrapping for child processes.
 

gosh.go

@@ -11,6 +11,14 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+// StaticFileConfig describes a static_files from the YAML and holds its data.
+type StaticFileConfig struct {
+	Path string `yaml:"path"`
+	Mime string `yaml:"mime"`
+
+	data []byte
+}
+
 // Config is the struct representation of gosh's YAML configuration file.
 //
 // For each field's meaning, please consider the gosh.yml file in this
@@ -40,6 +48,10 @@ type Config struct {
 
 		UrlPrefix string `yaml:"url_prefix"`
 
+		CustomIndex string `yaml:"custom_index"`
+
+		StaticFiles map[string]StaticFileConfig `yaml:"static_files"`
+
 		ItemConfig struct {
 			MaxSize     string        `yaml:"max_size"`
 			MaxLifetime time.Duration `yaml:"max_lifetime"`

gosh.yml

@@ -39,6 +39,20 @@ webserver:
   # url_prefix is an optional prefix in URL to be used, e.g., "/gosh"
   url_prefix: ""
 
+  # custom_index will be used instead of the compiled in index.html template.
+  # For starters, copy the index.html from the repository somewhere nice.
+  custom_index: "/path/to/alternative/index.html"
+
+  # static_files to be read during startup and returned instead of being passed
+  # against the store's database. This might be used for custom resources.
+  static_files:
+    "/favicon.ico":
+      path: "/path/to/favicon.ico"
+      mime: "image/vnd.microsoft.icon"
+    "/custom.css":
+      path: "/path/to/custom.css"
+      mime: "text/css"
+
   # item_config sets restrictions for new items, e.g., their max_size, in bytes
   # or suffixed with a unit, and max_lifetime, as a Go duration. Furthermore,
   # some MIME types might be dropped by mime_drop or rewritten with mime_map.

gosh_webserver.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"io"
 	"io/fs"
 	"log/slog"
 	"net"
@@ -95,6 +96,43 @@ func mainWebserver(conf Config) {
 
 	storeClient := NewStoreRpcClient(rpcConn, fdConn)
 
+	indexTpl := ""
+	if conf.Webserver.CustomIndex != "" {
+		f, err := os.Open(conf.Webserver.CustomIndex)
+		if err != nil {
+			slog.Error("Failed to open custom index file", slog.Any("error", err))
+			os.Exit(1)
+		}
+
+		indexTplRaw, err := io.ReadAll(f)
+		if err != nil {
+			slog.Error("Failed to read custom index file", slog.Any("error", err))
+			os.Exit(1)
+		}
+		_ = f.Close()
+
+		indexTpl = string(indexTplRaw)
+	}
+
+	for k, sfc := range conf.Webserver.StaticFiles {
+		f, err := os.Open(sfc.Path)
+		if err != nil {
+			slog.Error("Failed to open static file",
+				slog.String("file", sfc.Path), slog.Any("error", err))
+			os.Exit(1)
+		}
+
+		sfc.data, err = io.ReadAll(f)
+		if err != nil {
+			slog.Error("Failed to read static file",
+				slog.String("file", sfc.Path), slog.Any("error", err))
+			os.Exit(1)
+		}
+		_ = f.Close()
+
+		conf.Webserver.StaticFiles[k] = sfc
+	}
+
 	maxFilesize, err := ParseBytesize(conf.Webserver.ItemConfig.MaxSize)
 	if err != nil {
 		slog.Error("Failed to parse byte size", slog.Any("error", err))
@@ -159,11 +197,15 @@ func mainWebserver(conf Config) {
 
 	server, err := NewServer(
 		storeClient,
-		maxFilesize, conf.Webserver.ItemConfig.MaxLifetime,
+		maxFilesize,
+		conf.Webserver.ItemConfig.MaxLifetime,
 		conf.Webserver.Contact,
 		mimeDrop,
 		conf.Webserver.ItemConfig.MimeMap,
-		conf.Webserver.UrlPrefix)
+		conf.Webserver.UrlPrefix,
+		indexTpl,
+		conf.Webserver.StaticFiles,
+	)
 	if err != nil {
 		slog.Error("Failed to create webserver", slog.Any("error", err))
 		os.Exit(1)

webserver.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"html/template"
@@ -17,7 +18,7 @@ import (
 )
 
 //go:embed index.html
-var indexTpl string
+var defaultIndexTpl string
 
 const (
 	msgDeletionKeyWrong  = "Error: Deletion key is incorrect."
@@ -39,6 +40,8 @@ type Server struct {
 	mimeDrop    map[string]struct{}
 	mimeMap     map[string]string
 	urlPrefix   string
+	indexTpl    *template.Template
+	staticFiles map[string]StaticFileConfig
 }
 
 // NewServer creates a new Server with a given database directory, and
@@ -51,7 +54,19 @@ func NewServer(
 	mimeDrop map[string]struct{},
 	mimeMap map[string]string,
 	urlPrefix string,
+	indexTplRaw string,
+	staticFiles map[string]StaticFileConfig,
 ) (s *Server, err error) {
+	indexTpl := defaultIndexTpl
+	if indexTplRaw != "" {
+		indexTpl = indexTplRaw
+	}
+
+	t, err := template.New("index").Parse(indexTpl)
+	if err != nil {
+		return nil, err
+	}
+
 	s = &Server{
 		store:       store,
 		maxSize:     maxSize,
@@ -60,6 +75,8 @@ func NewServer(
 		mimeDrop:    mimeDrop,
 		mimeMap:     mimeMap,
 		urlPrefix:   urlPrefix,
+		indexTpl:    t,
+		staticFiles: staticFiles,
 	}
 	return
 }
@@ -98,6 +115,8 @@ func (serv *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		serv.handleRoot(w, r)
 	} else if strings.HasPrefix(reqPath, "/del/") {
 		serv.handleDeletion(w, r)
+	} else if stc, ok := serv.staticFiles[reqPath]; ok {
+		serv.handleStaticFile(w, r, stc)
 	} else {
 		serv.handleRequest(w, r)
 	}
@@ -119,14 +138,6 @@ func (serv *Server) handleRoot(w http.ResponseWriter, r *http.Request) {
 }
 
 func (serv *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
-	t, err := template.New("index").Parse(indexTpl)
-	if err != nil {
-		slog.Error("Failed to parse template", slog.Any("error", err))
-
-		http.Error(w, msgGenericError, http.StatusBadRequest)
-		return
-	}
-
 	data := struct {
 		Expires         string
 		Size            string
@@ -148,11 +159,32 @@ func (serv *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "text/html;charset=UTF-8")
 	w.WriteHeader(http.StatusOK)
 
-	if err := t.Execute(w, data); err != nil {
+	if err := serv.indexTpl.Execute(w, data); err != nil {
 		slog.Error("Failed to execute template", slog.Any("error", err))
 	}
 }
 
+func (serv *Server) handleStaticFile(w http.ResponseWriter, r *http.Request, sfc StaticFileConfig) {
+	if r.Method != http.MethodGet {
+		slog.Debug("Request with unsupported method", slog.String("method", r.Method))
+
+		http.Error(w, msgUnsupportedMethod, http.StatusMethodNotAllowed)
+		return
+	}
+
+	w.Header().Set("Content-Type", sfc.Mime)
+	w.WriteHeader(http.StatusOK)
+
+	staticReader := bytes.NewReader(sfc.data)
+	_, err := io.Copy(w, staticReader)
+	if err != nil {
+		slog.Error("Failed to write static file back to request", slog.Any("error", err))
+
+		http.Error(w, msgGenericError, http.StatusBadRequest)
+		return
+	}
+}
+
 func (serv *Server) handleUpload(w http.ResponseWriter, r *http.Request) {
 	item, f, err := NewItemFromRequest(r, serv.maxSize, serv.maxLifetime)
 	if err == ErrLifetimeTooLong {