appview: show error pages

Signed-off-by: Anirudh Oppiliappan <[e-mail]>

appview/middleware/middleware.go

···
 			f, err := mw.repoResolver.Resolve(r)
 			if err != nil {
 				log.Println("failed to fully resolve repo", err)
-				http.Error(w, "invalid repo url", http.StatusNotFound)
+				mw.pages.ErrorKnot404(w)
 				return
 			}
 
···
 			f, err := mw.repoResolver.Resolve(r)
 			if err != nil {
 				log.Println("failed to fully resolve repo", err)
-				http.Error(w, "invalid repo url", http.StatusNotFound)
+				mw.pages.ErrorKnot404(w)
 				return
 			}
 

appview/pages/pages.go

···
 	return p.execute("errors/404", w, nil)
 }
 
+func (p *Pages) ErrorKnot404(w io.Writer) error {
+	return p.execute("errors/knot404", w, nil)
+}
+
 func (p *Pages) Error503(w io.Writer) error {
 	return p.execute("errors/503", w, nil)
 }

appview/pages/templates/errors/knot404.html

···
+{{ define "title" }}404 · tangled{{ end }}
+
+{{ define "content" }}
+    <h1>404 &mdash; repository not found!</h1>
+    <p>
+        The repository you were looking for could not be found.
+        The knot serving the repository may be unavailable.
+    </p>
+{{ end }}

appview/repo/repo.go

···
 
 	repolog, err := us.Log(f.OwnerDid(), f.Name, ref, page)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
 
 	tagResult, err := us.Tags(f.OwnerDid(), f.Name)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	branchResult, err := us.Branches(f.OwnerDid(), f.Name)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	resp, err := http.Get(fmt.Sprintf("%s://%s/%s/%s/commit/%s", protocol, f.Knot, f.OwnerDid(), f.Repo.Name, ref))
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	resp, err := http.Get(fmt.Sprintf("%s://%s/%s/%s/tree/%s/%s", protocol, f.Knot, f.OwnerDid(), f.Repo.Name, ref, treePath))
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	result, err := us.Tags(f.OwnerDid(), f.Name)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	result, err := us.Branches(f.OwnerDid(), f.Name)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 	}
 	resp, err := http.Get(fmt.Sprintf("%s://%s/%s/%s/blob/%s/%s", protocol, f.Knot, f.OwnerDid(), f.Repo.Name, ref, filePath))
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}
···
 
 	result, err := us.Branches(f.OwnerDid(), f.Name)
 	if err != nil {
+		rp.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
 		return
 	}