Added instructions on how to run the example

.gitignore

@@ -1,2 +1,6 @@
 coverage.html
-coverage.out
+coverage.out
+/examples/*.pem
+/examples/go.mod
+/examples/go.sum
+/.idea/

README.md

@@ -92,4 +92,12 @@ go build -tags static -ldflags '-s -extldflags "-static"' -o /bin/xmldsig-static
 
 Running `ldd` on the output should produce `not a dynamic executable`.
 
+# Running the example
 
+After cloning this repository, change your current directory to the `examples` one, then run:
+```
+openssl req -x509 -nodes -newkey rsa:4096 -sha512 -keyout key.pem -out crt.pem -days 1095
+go mod init example
+go mod tidy
+go run xmldsig.go -s -k key.pem -x example.xml
+```

examples/example.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+XML Security Library example: Simple signature template file for sign1 example.
+See https://www.aleksey.com/xmlsec/api/xmlsec-examples-sign-template-file.html#xmlsec-example-sign1-tmpl
+-->
+<Envelope xmlns="urn:envelope">
+  <Data>
+    Hello, World!
+  </Data>
+  <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
+    <SignedInfo>
+      <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
+      <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
+      <Reference URI="">
+        <Transforms>
+          <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
+        </Transforms>
+        <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
+        <DigestValue></DigestValue>
+      </Reference>
+    </SignedInfo>
+    <SignatureValue/>
+    <KeyInfo>
+      <KeyName/>
+    </KeyInfo>
+  </Signature>
+</Envelope>

examples/xmldsig.go

@@ -13,6 +13,7 @@ func main() {
 	doVerify := flag.Bool("v", false, "verify the document")
 	doSign := flag.Bool("s", false, "sign the document")
 	keyPath := flag.String("k", "", "the path to the key")
+	xmlFile := flag.String("x", "", "the path to the xml file")
 	flag.Parse()
 
 	if !*doVerify && !*doSign {
@@ -30,7 +31,12 @@ func main() {
 		os.Exit(1)
 	}
 
-	buf, err := ioutil.ReadAll(os.Stdin)
+	buf, err := readXml(xmlFile)
+
+	if err != nil {
+		fmt.Printf("%s\n", err)
+		os.Exit(1)
+	}
 
 	if *doSign {
 		signedBuf, err := xmlsec.Sign(key, buf, xmlsec.SignatureOptions{})
@@ -54,3 +60,11 @@ func main() {
 		fmt.Println("signature is correct")
 	}
 }
+
+func readXml(xmlFileName *string) ([]byte, error) {
+	if *xmlFileName == "" {
+		return ioutil.ReadAll(os.Stdin)
+	} else {
+		return ioutil.ReadFile(*xmlFileName)
+	}
+}