(Go) Create XML Signature using Java KeyStore (.jks)

Demonstrates how to create an XML digital signature using a certificate and private key from a Java KeyStore (.jks)

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    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The SOAP XML to be signed in this example contains the following:

    // <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
    // <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
    //     <SOAP-ENV:Header>
    //         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
    //     </SOAP-ENV:Header>
    //     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
    //         <z:FooBar xmlns:z="http://example.com" />
    //     </SOAP-ENV:Body>
    // </SOAP-ENV:Envelope>
    // 

    // Build the XML to sign.
    // Use this online tool to generate the code from sample XML: 
    // Generate Code to Create XML

    xml := chilkat.NewXml()
    xml.SetTag("SOAP-ENV:Envelope")
    xml.AddAttribute("xmlns:SOAP-ENV","http://schemas.xmlsoap.org/soap/envelope/")
    xml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",true,"xmlns:wsse","http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")
    xml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",true,"SOAP-ENV:mustUnderstand","1")
    xml.UpdateAttrAt("SOAP-ENV:Body",true,"xmlns:SOAP-SEC","http://schemas.xmlsoap.org/soap/security/2000-12")
    xml.UpdateAttrAt("SOAP-ENV:Body",true,"SOAP-SEC:id","Body")
    xml.UpdateAttrAt("SOAP-ENV:Body|z:FooBar",true,"xmlns:z","http://example.com")

    // Load a JavaKeyStore file containing the certificate + private key.
    jks := chilkat.NewJavaKeyStore()
    password := "secret"
    success := jks.LoadFile(password,"qa_data/jks/test_secret.jks")
    if success != true {
        fmt.Println(jks.LastErrorText())
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        return
    }

    // Make sure we have a private key.
    if jks.NumPrivateKeys() < 1 {
        fmt.Println("No private key available.")
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        return
    }

    // -------------------------------------------------------------------------
    // Get the certificate chain associated with the 1st (and probably only) private key in the JKS.
    chain := jks.GetCertChain(0)
    if jks.LastMethodSuccess() != true {
        fmt.Println(jks.LastErrorText())
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        return
    }

    cert := chain.GetCert(0)
    if chain.LastMethodSuccess() != true {
        fmt.Println(chain.LastErrorText())
        chain.DisposeCertChain()
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        return
    }

    chain.DisposeCertChain()

    // Verify again that this cert has a private key.
    if cert.HasPrivateKey() != true {
        fmt.Println("Certificate has no associated private key.")
        cert.DisposeCert()
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        return
    }

    // Prepare for signing...
    // Use this online tool to generate the following code from an already-signed XML sample: 
    // Generate Code to Create an XML Signature
    gen := chilkat.NewXmlDSigGen()

    // Indicate where the Signature will be inserted.
    gen.SetSigLocation("SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security")

    // Add a reference to the fragment of the XML to be signed.
    gen.AddSameDocRef("Body","sha1","EXCL_C14N","","")

    // (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
    gen.SetSignedInfoPrefixList("wsse SOAP-ENV")

    // Provide the private key for signing via the certificate, and indicate that
    // we want the base64 of the certificate embedded in the KeyInfo.
    gen.SetKeyInfoType("X509Data")
    gen.SetX509Type("Certificate")

    // Note: Because our certificate was loaded from a JKS which also contained the private key,
    // Chilkat automatically knows and has the private key associated with the certificate.
    // We set bUsePrivateKey to tell the SetX509Cert method to automatically use the private key
    // associated with the certificate for signing.
    bUsePrivateKey := true
    success = gen.SetX509Cert(cert,bUsePrivateKey)
    if success != true {
        fmt.Println(gen.LastErrorText())
        cert.DisposeCert()
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        gen.DisposeXmlDSigGen()
        return
    }

    cert.DisposeCert()

    // Everything's specified.  Now create and insert the Signature
    sbXml := chilkat.NewStringBuilder()
    xml.GetXmlSb(sbXml)
    success = gen.CreateXmlDSigSb(sbXml)
    if success != true {
        fmt.Println(gen.LastErrorText())
        xml.DisposeXml()
        jks.DisposeJavaKeyStore()
        gen.DisposeXmlDSigGen()
        sbXml.DisposeStringBuilder()
        return
    }

    // Examine the XML with the digital signature inserted
    fmt.Println(*sbXml.GetAsString())

    xml.DisposeXml()
    jks.DisposeJavaKeyStore()
    gen.DisposeXmlDSigGen()
    sbXml.DisposeStringBuilder()