Add config option SignaturePrefix

config.json

@@ -7,7 +7,8 @@
           "AppendPayload": true
       },
       "Secret": "THISISVERYSECRET",
-      "SignatureHeader": "X-Gitea-Signature",
+      "SignatureHeader": "X-Hub-Signature",
+      "SignaturePrefix": "sha256=",
       "Tests": [
         {
           "Program": "echo",

config/config.go

@@ -10,6 +10,7 @@ type Config struct {
 	Services      map[string]struct {
 		Script          Command
 		Secret          string
+		SignaturePrefix string
 		SignatureHeader string
 		Tests           []Command
 	}

main.go

@@ -63,7 +63,7 @@ func webhookHandler(w http.ResponseWriter, r *http.Request) {
 
 	// Verify that signature provided matches signature calculated using secretsss
 	signature := r.Header.Get(service.SignatureHeader)
-	calculatedSignature := getSha256HMACSignature([]byte(service.Secret), payload)
+	calculatedSignature := fmt.Sprintf("%v%v", service.SignaturePrefix, getSha256HMACSignature([]byte(service.Secret), payload))
 	fmt.Printf("signature = %v\n", signature)
 	fmt.Printf("calcuatedSignature = %v\n", signature)
 	if signature != calculatedSignature && checkSignature {

readme.md

@@ -22,6 +22,9 @@ You **must** set which HTTP header gohookr will receive a signature from using t
 key for each service.
 You should also specify a shared secret in the `Secret` key.
 
+You may also need to specify a `SignaturePrefix`.
+For GitHub it would be `sha256=`.
+
 ### Disable Signature Verification
 
 You can disable signature verification altogether by setting environment variable
@@ -61,7 +64,8 @@ An example config file can be found [here](./config.json) but also below:
           "AppendPayload": true
       },
       "Secret": "THISISVERYSECRET",
-      "SignatureHeader": "X-Gitea-Signature",
+      "SignatureHeader": "X-Hub-Signature",
+      "SignaturePrefix": "sha256=",
       "Tests": [
         {
           "Program": "echo",