fix

web/web.go

@@ -6,11 +6,12 @@ import (
 	"encoding/json"
 	"io/fs"
 	"net/http"
+	"os"
 	"sort"
 	"strings"
 
-	"wh/docs"
-	"wh/examples"
+	"halcyon/docs"
+	"halcyon/examples"
 )
 
 //go:embed static
@@ -18,15 +19,18 @@ var static embed.FS
 
 // Handler serves the site. Mount it as the catch-all route; more specific API
 // routes registered on the same mux take precedence.
-func Handler() http.Handler {
+//
+// manualPath is the rendered PDF manual; it is opened on every request, so a
+// new render is served as soon as it is renamed into place, without a restart.
+func Handler(manualPath string) http.Handler {
 	sub, _ := fs.Sub(static, "static")
 	files := http.FileServerFS(sub)
 
 	mux := http.NewServeMux()
 	mux.Handle("GET /", files)
-	mux.HandleFunc("GET /manual.txt", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
-		w.Write(docs.Manual)
+	mux.HandleFunc("GET /manual.md", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/markdown; charset=utf-8")
+		w.Write(docs.Markdown)
 	})
 	mux.HandleFunc("GET /examples/index.json", func(w http.ResponseWriter, r *http.Request) {
 		entries, _ := fs.ReadDir(examples.FS, ".")
@@ -41,7 +45,34 @@ func Handler() http.Handler {
 		json.NewEncoder(w).Encode(names)
 	})
 	mux.Handle("GET /examples/", http.StripPrefix("/examples/", http.FileServerFS(examples.FS)))
-	return secure(mux)
+
+	top := http.NewServeMux()
+	top.HandleFunc("GET /manual.pdf", manualPDF(manualPath)) // not under the site's CSP: PDF viewers need their own resources
+	top.Handle("/", secure(mux))
+	return top
+}
+
+// manualPDF serves the manual rendered separately from the app.
+func manualPDF(path string) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		f, err := os.Open(path)
+		if err != nil {
+			http.Error(w, "The PDF manual has not been rendered yet (run scripts/render-manual.sh). "+
+				"The Markdown source is at /manual.md.", http.StatusNotFound)
+			return
+		}
+		defer f.Close()
+		st, err := f.Stat()
+		if err != nil {
+			http.Error(w, "cannot read the PDF manual", http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/pdf")
+		w.Header().Set("Content-Disposition", `inline; filename="halcyon-hc33-manual.pdf"`)
+		w.Header().Set("X-Content-Type-Options", "nosniff")
+		w.Header().Set("Cache-Control", "no-cache")            // revalidate, so a fresh render shows up
+		http.ServeContent(w, r, "manual.pdf", st.ModTime(), f) // ranges and If-Modified-Since
+	}
 }
 
 // secure adds headers appropriate to a page that loads only its own assets.