From aa816a646e43e44a43579e45228b28ad4ac92f57 Mon Sep 17 00:00:00 2001
From: vin <git@vineetk.net>
Date: Wed, 8 Nov 2023 10:20:26 -0500
Subject: [PATCH] fix "LTI signature verification failed" message

Some of the form values being sent in the POST request had HTML
entities that needed to be unescaped.
---
 aplus.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/aplus.go b/aplus.go
index e2ec53b..ae5e054 100644
--- a/aplus.go
+++ b/aplus.go
@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"html"
 	"io"
 	"net/http"
 	"net/url"
@@ -41,7 +42,7 @@ func parse_form(form_html string) url.Values {
 	for _, input := range inputs {
 		// Extract field name and value
 		name := extract_attribute(input, "name")
-		value := extract_attribute(input, "value")
+		value := html.UnescapeString(extract_attribute(input, "value"))
 
 		if name != "" {
 			form_values.Add(name, value)