new method retry.wrap

[kof]

I am often writing the same stuff over and over, this function would reduce a lot, but it is only possible to implement it based on 2 conventions:
- callback is always the last argument
- err is always the first argument

So basically I want to say: wrap all functions of object obj into retry logic, use opts for retry options, optionally props is a list of props I need to wrap, otherwise wrap all functions.

retry.wrap(opts, obj, props)

Would you accept a pull request implementing this?

[tim-kos]

Hey kof,

please explain "all functions of object obj". Shouldn't this be an array of functions? Or maybe I am not getting the big picture.

[kof]

// wrap all methods of myLibrary object
retry.wrap({retries: 3}, myLibrary);
// wrap only named methods of myLibrary object
retry.wrap({retries: 3}, myLibrary, ['method1', 'method2', 'method3']);

[kof]

even better

// wrap all mehtods of myLibrary using default options
retry.wrap(myLibrary);

// wrap all methods of myLibrary object
retry.wrap(myLibrary, {retries: 3});

// wrap only named methods of myLibrary object
retry.wrap(myLibrary, {retries: 3}, ['method1', 'method2', 'method3']);

[kof]

function wrap(obj, options, methods) {
    if (options instanceof Array) {
        methods = options;
        options = null;
    }

    if (!methods) {
        methods = Object.keys(obj);
    }

    methods.forEach(function(method) {
        var origin = obj[method];

        if (typeof origin != 'function') {
            return;
        }

        obj[method] = function() {
            var op = retry.operation(options),
                args = Array.prototype.slice.call(arguments),
                callback = args.pop();

            args.push(function(err) {
                if (op.retry(err)) {
                    return;
                }
                if (err) {
                    arguments[0] = op.mainError();
                }
                callback.apply(this, arguments);
            });

            op.attempt(function() {
                origin.apply(obj, args);
            });
        };
    });    
}

[kof]

It needs some changes to support all browsers ... but basically thats it.

[tim-kos]

I see. Pretty interesting.

If you could also write some tests for it I'd merge a PR for this one.

[kof]

What are requirements for the environment? Is this module supposed to be used in browser? Or just node?

[tim-kos]

For now it's just supposed to be used out of node, but I am sure it can be used easily in the browser with node-browserify.

[seriousManual]

bump!

[tim-kos]

Will finish this and merge the related PR.