Azure mobile services service to service communication

Question

Is there a way to call a custom api script from within a table interceptor script on the same mobile service via an internal url?

Or do you always have to use the public url(https://.azure-mobile.net). In this case together with the X-ZUMO-MASTER header because it's service to service communication. The custom api should only be called from this script, not by external applictions or authenticated users. I want to prevent that the master key leaves the server even over an encrypted channel.

carlosfigueira carlosfigueira · Accepted Answer · 2014-10-17T18:14:34

If you're within different services, then you need to use the public URL, and mark the API you want to call as "Admin" access as you mentioned.

If you want to call a custom API from a table script in the same service, then you can just "require" the custom API and call it as a regular JS function. Notice that although the API takes a "request" and a "response" parameter, this is JavaScript, so anything that looks like a request / response will work (duck typing). For example, if I have this custom API called 'calculator' defined as follows:

exports.post = function(request, response) {
    var x = request.body.x || request.param('x');
    var y = request.body.y || request.param('y');
    var op = request.body.op || request.body.operation || request.param('op');
    calculateAndReturn(x, y, op, response);
};

exports.get = function(request, response) {
    var x = request.param('x');
    var y = request.param('y');
    var op = request.param('op') || request.param('operator');
    calculateAndReturn(x, y, op);
};

function calculateAndReturn(x, y, operator, response) {
    var result = calculate(x, y, operator);
    if (typeof result === 'undefined') {
        response.send(400, { error: 'Invalid or missing parameters' });
    } else {
        response.send(statusCodes.OK, { result : result });
    }
}

function calculate(x, y, operator) {
    var undef = {}.a;

    if (_isUndefined(x) || _isUndefined(y) || _isUndefined(operator)) {
        return undef;
    }

    switch (operator) {
        case '+':
        case 'add':
            return x + y;
        case '-':
        case 'sub':
            return x - y;
        case '*':
        case 'mul':
            return x * y;
        case '/':
        case 'div':
            return x / y;
    }

    return undef;
}

function _isUndefined(x) {
    return typeof x === 'undefined';
}

Notice that for the POST operation, it only needs from the request a 'body' parameter with three members (x, y, op), and the only function in the response that is called is send. We can call it from a table script by passing what it needs to the calculator:

function insert(item, user, request) {
    var calculator = require('../api/calculator');
    var quantity = item.quantity;
    var unitPrice = item.unitPrice;
    calculator.post({ body: { x: quantity, y: unitPrice, op: '*' } }, {
        send: function(status, body) {
            if (status === statusCodes.OK) {
                item.totalPrice = body.result;
                request.execute();
            } else {
                request.respond(status, body);
            }
        }
    });
}

Azure mobile services service to service communication

1 Answers