MQTT Inside Sticker Engine

For a bit of fun round a project last year I created some Moo “MQTT Inside” stickers to put on the cases.

First sticker deployed

These became very popular around the office, with everybody wanting to label up their MQTT enabled projects and the first batch of 90 quickly disappeared.

Given demand was so high Andy Piper suggested it might be worth making it possible for others to order their own sets and pointed me at the Moo API.

The Moo API Doc is pretty good, but there aren’t any examples so it took a bit of trial and error. The API works by building up an object called a ‘pack‘. The Moo website uses the same API for the wizard you use to manually create any of their products and there is a very nice little Greasemonkey script called ‘Show API JSON’ which shows you the state of the pack object at each step. The API also lets you skip any steps in the process by just uploading a pack object already filled in. This meant I could reproduce the stickers by choosing to edit my original set and then using the script to save the pack.json file.

    "productVersion" : "1",
    "cards" : [
    "numCards" : 90,
    "extras" : [
            "value" : "blue",
            "key" : "pack_colour"
    "imageBasket" : {
        "name" : null,
        "immutable" : false,
        "items" : [
                "cacheId" : "partner_interface_uploader:e34bb9c2-637b-558545db-4e61502d-ff34.png",
                "imageBox" : null,
                "imageItems" : [
                        "rotation" : 0,
                        "height" : 297,
                        "resourceUri" : "",
                        "width" : 297,
                        "type" : "print"
                        "rotation" : 0,
                        "height" : 1024,
                        "resourceUri" : "",
                        "width" : 1024,
                        "type" : "preview"
                        "rotation" : 0,
                        "height" : 75,
                        "resourceUri" : "",
                        "width" : 75,
                        "type" : "thumbnail"
                "copyrightOwner" : null,
                "resourceUri" : "filestore://image_original/e34bb9c2-637b-558545db-4e61502d-ff34.png",
                "croppable" : true,
                "shouldEnhance" : false,
                "type" : "front",
                "removable" : true
        "type" : null
    "productCode" : "sticker",
    "sides" : [
            "type" : "image",
            "data" : [
                    "imageStoreFileId" : "e34bb9c2-637b-558545db-4e61502d-ff34",
                    "resourceUri" : "filestore://image_original/e34bb9c2-637b-558545db-4e61502d-ff34.png",
                    "linkId" : "variable_image_front",
                    "enhance" : false,
                    "imageBox" : {
                        "center" : {
                            "y" : 12,
                            "x" : 12
                        "height" : 20.88,
                        "width" : 20.88,
                        "angle" : 0
                    "type" : "imageData"
            "templateCode" : "sticker_image",
            "sideNum" : 1

Resubmitting this with the ‘moo.pack.createPack‘ method and then using the ‘finish’ Drop in point to direct the user to Moo checkout page to pay for their new stickers.

I used a little library called scrib to do the oAuth and the whole thing can be done with just these few lines:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	String authTokenString = request.getParameter("oauth_token");
	String authVerifyString = request.getParameter("oauth_verifier");
	Token authToken =;;
	Verifier verifier = new Verifier(authVerifyString);
	Token accessToken = service.getAccessToken(authToken, verifier);
	String createPack = rootURL + "method=moo.pack.createPack&product=sticker&pack=" + pack;
	createPack = createPack + "&friendlyName=" + URLEncoder.encode("MQTT Inside", "UTF-8");

	OAuthRequest oAuthRequest = new OAuthRequest(Verb.POST, createPack);
	service.signRequest(accessToken, oAuthRequest);
	Response oAuthResponse = oAuthRequest.send();
	if (oAuthResponse.getCode() == 200) {
		JSONTokener tok = new JSONTokener(oAuthResponse.getBody());
		try {
			JSONObject json = new JSONObject(tok);
			JSONObject dropings = json.getJSONObject("dropIns");
			String finishURL = dropings.getString("finish");
		} catch (JSONException e) {
	} else {

Andy is working to get a page set up on the site, but in the mean time you can click on the image bellow to order own set.


Andy has now added a Goodies page to the site that you can use to order stickers

8 thoughts on “MQTT Inside Sticker Engine”

  1. Marvellous. Now as well as llama-based business cards, I can celebrate various hard working devices about the house and the fine job they do :-)

  2. Hi Ben, I am trying to understand how the Moo API works, and came across your site. I don’t suppose you would be willing to share your coding in full so I can understand how to use the API? I am struggling with limited knowledge of API and can’t find any examples.

    1. Matt,

      All the code that actually does anything is in the article, but when I get five mins I’ll see if I can extract the rest. I would say the best thing you can do is get hold of the Grease Monkey script mentioned here and use it to capture the pack json for each step as you build up your striker/biz card/post card manually on the site.

      You can then work out what you would need to edit in the pack for your automated process and play it back.

      What is useful to know is that the pack holds all the information for a order, unless you are uploading different images every time then you can just build up the last pack json and send this to the last step in the API and it will jump to the right place.

  3. Hi, Thanks that would be great. I think this may be over my head as I have very limited knowledge but would love to be able to create a link to allow people to order some prints through moo and yours is the only one I can find that is doing this. How are you loading the api? is it through PHP?

    1. Matt,

      All my code is in Java. It consists of 3 servelets (equivalent to 3 PHP pages).

      I’ve zipped it up here basically sets up the OAuth and forwards the user to’s page is the point that redirects back to once the user has authorised the app. It sends the pack details back to and then sends a redirect to the checkout page. is a endpoint that is call by when an order is placed so I know how many people actually bought something

  4. Hi Ben, Thanks very much for sharing your code, I was so hopeful that I would be able to get this to work in simple PHP, however java is way over my head and not sure how I could get this to work with my server. Thank you for your help and explanation.

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