Updated getKeyInfo function with actual implementation (#249)

* Updated getKeyInfo function with actual implementation

* Update lib/signed-xml.js

Co-authored-by: LoneRifle <LoneRifle@users.noreply.github.com>

* fix(key-info): ensure backcompat with `signingKey`

---------

Co-authored-by: Ganesh Kshirsagar <ganesh.kshirsagar@nice.com>
Co-authored-by: Chris Barth <chrisjbarth@hotmail.com>
Co-authored-by: LoneRifle <LoneRifle@users.noreply.github.com>

lib/signed-xml.js

@@ -18,9 +18,17 @@ function FileKeyInfo(file) {
   this.file = file
 
   this.getKeyInfo = function(key, prefix) {
-    prefix = prefix || ''
-    prefix = prefix ? prefix + ':' : prefix
-    return "<" + prefix + "X509Data></" + prefix + "X509Data>"
+    var currentPrefix = prefix || ''
+    currentPrefix = currentPrefix ? currentPrefix + ':' : currentPrefix
+    var signingCert = '';
+    if (key) {
+      var certArray = [].concat(key);
+      for(var i = 0; i < certArray.length; ++i) {
+        var cert = certArray[i]
+        signingCert += "<" + currentPrefix + "X509Certificate>" + cert + "</" + currentPrefix + "X509Certificate>"
+      }
+    }
+    return "<" + currentPrefix + "X509Data>" + signingCert + "</" + currentPrefix + "X509Data>"
   }
 
   this.getKey = function(keyInfo) {
@@ -298,6 +306,7 @@ function SignedXml(idMode, options) {
   this.references = []
   this.id = 0
   this.signingKey = null
+  this.signingCert = null
   this.signatureAlgorithm = this.options.signatureAlgorithm || "http://www.w3.org/2000/09/xmldsig#rsa-sha1";
   this.keyInfoProvider = null
   this.canonicalizationAlgorithm = this.options.canonicalizationAlgorithm || "http://www.w3.org/2001/10/xml-exc-c14n#"
@@ -861,7 +870,7 @@ SignedXml.prototype.getKeyInfo = function(prefix) {
 
   if (this.keyInfoProvider) {
     res += "<" + currentPrefix + "KeyInfo>"
-    res += this.keyInfoProvider.getKeyInfo(this.signingKey, prefix)
+    res += this.keyInfoProvider.getKeyInfo(this.signingCert || this.signingKey, prefix)
     res += "</" + currentPrefix + "KeyInfo>"
   }
   return res