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.

1 files changed, 2 insertions, 1 deletions

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)