From 1e8b533d45ad6c810d9a569625c1938aaa1d013d Mon Sep 17 00:00:00 2001
From: Kailash Nadh <kailash@nadh.in>
Date: Sun, 8 Nov 2020 18:36:25 +0530
Subject: [PATCH] Fix echo's URI routing race condition that caused random
 404s.

---
 cmd/campaigns.go |  6 +++---
 cmd/handlers.go  | 20 ++++++++++++++++++++
 cmd/lists.go     |  6 +++---
 cmd/templates.go |  6 +++---
 4 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/cmd/campaigns.go b/cmd/campaigns.go
index 55d9742..b3b66be 100644
--- a/cmd/campaigns.go
+++ b/cmd/campaigns.go
@@ -267,9 +267,9 @@ func handleCreateCampaign(c echo.Context) error {
 	}
 
 	// Hand over to the GET handler to return the last insertion.
-	c.SetParamNames("id")
-	c.SetParamValues(fmt.Sprintf("%d", newID))
-	return handleGetCampaigns(c)
+	return handleGetCampaigns(copyEchoCtx(c, map[string]string{
+		"id": fmt.Sprintf("%d", newID),
+	}))
 }
 
 // handleUpdateCampaign handles campaign modification.
diff --git a/cmd/handlers.go b/cmd/handlers.go
index e46dd9e..b699854 100644
--- a/cmd/handlers.go
+++ b/cmd/handlers.go
@@ -238,3 +238,23 @@ func getPagination(q url.Values, perPage, maxPerPage int) pagination {
 		Limit:   perPage,
 	}
 }
+
+// copyEchoCtx returns a copy of the the current echo.Context in a request
+// with the given params set for the active handler to proxy the request
+// to another handler without mutating its context.
+func copyEchoCtx(c echo.Context, params map[string]string) echo.Context {
+	var (
+		keys = make([]string, 0, len(params))
+		vals = make([]string, 0, len(params))
+	)
+	for k, v := range params {
+		keys = append(keys, k)
+		vals = append(vals, v)
+	}
+
+	b := c.Echo().NewContext(c.Request(), c.Response())
+	b.Set("app", c.Get("app").(*App))
+	b.SetParamNames(keys...)
+	b.SetParamValues(vals...)
+	return b
+}
diff --git a/cmd/lists.go b/cmd/lists.go
index ad5639d..9c3c20a 100644
--- a/cmd/lists.go
+++ b/cmd/lists.go
@@ -118,9 +118,9 @@ func handleCreateList(c echo.Context) error {
 	}
 
 	// Hand over to the GET handler to return the last insertion.
-	c.SetParamNames("id")
-	c.SetParamValues(fmt.Sprintf("%d", newID))
-	return handleGetLists(c)
+	return handleGetLists(copyEchoCtx(c, map[string]string{
+		"id": fmt.Sprintf("%d", newID),
+	}))
 }
 
 // handleUpdateList handles list modification.
diff --git a/cmd/templates.go b/cmd/templates.go
index c0b24b9..b31aa27 100644
--- a/cmd/templates.go
+++ b/cmd/templates.go
@@ -147,9 +147,9 @@ func handleCreateTemplate(c echo.Context) error {
 	}
 
 	// Hand over to the GET handler to return the last insertion.
-	c.SetParamNames("id")
-	c.SetParamValues(fmt.Sprintf("%d", newID))
-	return handleGetTemplates(c)
+	return handleGetTemplates(copyEchoCtx(c, map[string]string{
+		"id": fmt.Sprintf("%d", newID),
+	}))
 }
 
 // handleUpdateTemplate handles template modification.