Create message while sending Image through Asmack

Question

There is an issue that I am facing while sending Images through XMPP.Below is the code snippet that i have done. I don\'t know what is wrong with the code .

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Answer 1

You can use any name and namespace for your custom packets, but XML stream of your outgoing packets should be valid and well-formed XML document. In your example I see unbound ftpurl, httpurl, imageName nodes. Any good XML/XMPP parser will throw error, because your stream is not well-formed. Common practice is - wrap all you custom nodes in one top-level node and define namespace, like this:

 http://my.image.jpg
 ftp://my/image.jpg

This will cause XML parser to treat all your custom XML nodes as they come from "my:image:transfer" namespace and XML stream will be valid.

In the context of your "Image transfer extension" - you are trying to reinvent "Out-of-Band" XMPP File Transfer, which has well-known XMPP Extension - http://xmpp.org/extensions/xep-0066.html

Packets with OOB extension look like that:

  Yeah, but do you have a license to Jabber?
  
    http://www.jabber.org/images/psa-license.jpg
    Jabber license
  

Smack PacketExtension for this type of payload should look like:

public class OutOfBandData implements PacketExtension {

    String description;
    String url;

    @Override
    public String getElementName() {
        return "x";
    }

    @Override
    public String getNamespace() {
        return "jabber:x:oob";
    }

    @Override
    public String toXML() {
    StringBuilder builder = new StringBuilder();
    builder.("<" + getElementName() + " xmlns=\"" + getNamespace() + "\">");
    if (url != null) {
        builder.append("").append(url).append("");
    }
    if (description != null) {
        builder.append("").append(description).append("");
    }
    builder.append("");
    return builder.toString();
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String imageUrl) {
        this.url = imageUrl;
    }

This is not far from your implementation, but chances where other XMPP clients understand your "Image Transfer" are growing.