refactor: move favicon.go to v1/favicon

internal/api/v1/favicon/favicon.go

@@ -0,0 +1,77 @@
+package favicon
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/yusing/go-proxy/internal/gperr"
+	"github.com/yusing/go-proxy/internal/homepage"
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/route/routes"
+)
+
+// GetFavIcon returns the favicon of the route
+//
+// Returns:
+//   - 200 OK: if icon found
+//   - 400 Bad Request: if alias is empty or route is not HTTPRoute
+//   - 404 Not Found: if route or icon not found
+//   - 500 Internal Server Error: if internal error
+//   - others: depends on route handler response
+func GetFavIcon(w http.ResponseWriter, req *http.Request) {
+	url, alias := req.FormValue("url"), req.FormValue("alias")
+	if url == "" && alias == "" {
+		gphttp.ClientError(w, gphttp.ErrMissingKey("url or alias"), http.StatusBadRequest)
+		return
+	}
+	if url != "" && alias != "" {
+		gphttp.ClientError(w, gperr.New("url and alias are mutually exclusive"), http.StatusBadRequest)
+		return
+	}
+
+	// try with url
+	if url != "" {
+		var iconURL homepage.IconURL
+		if err := iconURL.Parse(url); err != nil {
+			gphttp.ClientError(w, err, http.StatusBadRequest)
+			return
+		}
+		fetchResult := homepage.FetchFavIconFromURL(&iconURL)
+		if !fetchResult.OK() {
+			http.Error(w, fetchResult.ErrMsg, fetchResult.StatusCode)
+			return
+		}
+		w.Header().Set("Content-Type", fetchResult.ContentType())
+		gphttp.WriteBody(w, fetchResult.Icon)
+		return
+	}
+
+	// try with route.Icon
+	r, ok := routes.GetHTTPRoute(alias)
+	if !ok {
+		gphttp.ClientError(w, errors.New("no such route"), http.StatusNotFound)
+		return
+	}
+
+	var result *homepage.FetchResult
+	hp := r.HomepageItem()
+	if hp.Icon != nil {
+		if hp.Icon.IconSource == homepage.IconSourceRelative {
+			result = homepage.FindIcon(req.Context(), r, hp.Icon.Value)
+		} else {
+			result = homepage.FetchFavIconFromURL(hp.Icon)
+		}
+	} else {
+		// try extract from "link[rel=icon]"
+		result = homepage.FindIcon(req.Context(), r, "/")
+	}
+	if result.StatusCode == 0 {
+		result.StatusCode = http.StatusOK
+	}
+	if !result.OK() {
+		http.Error(w, result.ErrMsg, result.StatusCode)
+		return
+	}
+	w.Header().Set("Content-Type", result.ContentType())
+	gphttp.WriteBody(w, result.Icon)
+}