public async Task <ActionResult> Index()
{
// Instantiate the XmlElementSignatureStarter class, responsible for receiving the signature
// elements and start the signature process.
var signatureStarter = new FullXmlSignatureStarter(Util.GetRestPkiClient());
// Set the XML to be signed, a sample XML Document.
signatureStarter.SetXml(StorageMock.GetSampleXmlDocumentPath());
// Set the signature policy.
signatureStarter.SetSignaturePolicy(StandardXmlSignaturePolicies.XadesBes);
// Set the security context to be used to determine trust in the certificate chain. We have
// encapsulated the security context choice on Util.cs.
signatureStarter.SetSecurityContext(Util.GetSecurityContextId());
// Set the location on which to insert the signature node. If the location is not specified, the
// signature will appended to the root element (which is most usual with enveloped signatures).
var nsm = new NamespaceManager();
nsm.AddNamespace("ls", "http://www.lacunasoftware.com/sample");
signatureStarter.SetSignatureElementLocation("//ls:signaturePlaceholder", XmlInsertionOptions.AppendChild, nsm);
// Call the StartWithWebPki() method, which initiates the signature. This yields the token,
// a 43-character case-sensitive URL-safe string, which identifies this signature process. We'll
// use this value to call the signWithRestPki() method on the Web PKI component (see
// signature-form.js) and also to complete the signature on the POST action below (this should
// not be mistaken with the API access token).
var token = await signatureStarter.StartWithWebPkiAsync();
// The token acquired above can only be used for a single signature attempt. In order to retry
// the signature it is necessary to get a new token. This can be a problem if the user uses the
// back button of the browser, since the browser might show a cached page that we rendered
// previously, with a now stale token. To prevent this from happening, we call the method
// SetNoCacheHeaders() (in BaseController) which sets HTTP headers to prevent caching of the
// page.
base.SetNoCacheHeaders();
// Render the signature page with the token obtained from REST PKI.
return(View(new SignatureModel()
{
Token = token
}));
}