From ff2183087d9e2f6bde0bcdd8588574718161df8f Mon Sep 17 00:00:00 2001
From: Ben Visness <bvisness@gmail.com>
Date: Tue, 9 Nov 2021 20:51:28 -0800
Subject: [PATCH] Preserve path when redirecting between official/personal
 projects

---
 src/hmnurl/hmnurl.go           |  6 ++++++
 src/website/requesthandling.go |  1 -
 src/website/routes.go          | 18 ++++++++----------
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/hmnurl/hmnurl.go b/src/hmnurl/hmnurl.go
index be701d9..c5103b7 100644
--- a/src/hmnurl/hmnurl.go
+++ b/src/hmnurl/hmnurl.go
@@ -84,6 +84,12 @@ func UrlWithFragment(path string, query []Q, fragment string) string {
 	return HMNProjectContext.UrlWithFragment(path, query, fragment)
 }
 
+func (c *UrlContext) RewriteProjectUrl(u *url.URL) string {
+	// we need to strip anything matching the personal project regex to get the base path
+	match := RegexPersonalProject.FindString(u.Path)
+	return c.Url(u.Path[len(match):], QFromURL(u))
+}
+
 func trim(path string) string {
 	if len(path) > 0 && path[0] == '/' {
 		return path[1:]
diff --git a/src/website/requesthandling.go b/src/website/requesthandling.go
index eec5729..0818a0c 100644
--- a/src/website/requesthandling.go
+++ b/src/website/requesthandling.go
@@ -93,7 +93,6 @@ nextroute:
 
 		var params map[string]string
 		for _, regex := range route.Regexes {
-
 			match := regex.FindStringSubmatch(currentPath)
 			if len(match) == 0 {
 				continue nextroute
diff --git a/src/website/routes.go b/src/website/routes.go
index d080d35..a16864f 100644
--- a/src/website/routes.go
+++ b/src/website/routes.go
@@ -8,6 +8,7 @@ import (
 	"math/rand"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -278,25 +279,23 @@ func NewWebsiteRoutes(longRequestContext context.Context, conn *pgxpool.Pool, pe
 					}
 				}
 
+				c.CurrentProject = &p.Project
+				c.UrlContext = UrlContextForProject(c.CurrentProject)
+
 				if !p.Project.Personal {
-					// TODO: Redirect to the same page on the other prefix
-					return c.Redirect(UrlContextForProject(&p.Project).BuildHomepage(), http.StatusSeeOther)
+					return c.Redirect(c.UrlContext.RewriteProjectUrl(c.URL()), http.StatusSeeOther)
 				}
 
 				if c.PathParams["slug"] != models.GeneratePersonalProjectSlug(p.Project.Name) {
-					// TODO: Redirect to the same page on the other path
-					return c.Redirect(hmnurl.BuildPersonalProject(p.Project.ID, models.GeneratePersonalProjectSlug(p.Project.Name)), http.StatusSeeOther)
+					return c.Redirect(c.UrlContext.RewriteProjectUrl(c.URL()), http.StatusSeeOther)
 				}
 
-				c.CurrentProject = &p.Project
-				c.UrlContext = UrlContextForProject(c.CurrentProject)
-
 				return h(c)
 			})
 		}
 		attachProjectRoutes(rb)
 	})
-	anyProject.Group(hmnurl.RegexHomepage, func(rb *RouteBuilder) {
+	anyProject.Group(regexp.MustCompile("^"), func(rb *RouteBuilder) {
 		rb.Middleware = func(h Handler) Handler {
 			return anyProject.Middleware(func(c *RequestContext) ResponseData {
 				// We could be on any project's subdomain.
@@ -304,8 +303,7 @@ func NewWebsiteRoutes(longRequestContext context.Context, conn *pgxpool.Pool, pe
 				// Check if the current project (matched by subdomain) is actually no longer official
 				// and therefore needs to be redirected to the personal project version of the route.
 				if c.CurrentProject.Personal {
-					// TODO: Redirect to the same page on the other prefix
-					return c.Redirect(hmnurl.BuildPersonalProject(c.CurrentProject.ID, c.CurrentProject.Slug), http.StatusSeeOther)
+					return c.Redirect(c.UrlContext.RewriteProjectUrl(c.URL()), http.StatusSeeOther)
 				}
 
 				return h(c)