I am frequently asked by colleagues for advice on how to be a good Scrum Master. I will discuss some of the tips I share in a couple of blog posts. First of all I do like to state that I believe it's best to have a Scrum Master that is able to get his hands dirty in the activities of the team (i.e. coding, analyzing, designing, testing etc.). It will enable him/her to engage and coach at more levels than just overall process. In my opinion one of the most important things a Scrum Master has to do is to make things transparant for the whole team. Now this seems like very simple advice, and it is. However, when you are in the middle of a sprint and all kinds of (potential) impediments are making successfully reaching the sprint goal harder and harder, the danger of losing transparency always pops up. Here are three practical tips:

• Is it clear for everybody what we as a team should  focus on right now?
• Is everybody focussing on the things that we should focus on right now?
• Are we going to reach our sprint goal?

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NOTE: Just released version 0.3 of ngImprovedTesting with lots of bug fixes.
Check out this blog post or the README of the GitHub repo for more info.

Being able to easily test your application is one of the most powerful features that AngularJS offers. All the services, controllers, filters even directives you develop can be fully (unit) tested. However the learning curve for writing (proper) unit tests tends to be quite steep. This is mainly because AngularJS doesn't really offer any high level API's to ease the unit testing. Instead you are forced to use the same (low level) services that AngularJS uses internally. That means you have to gain in dept knowledge about the internals of $controller, when to $digest and how to use $provide in order to mock these services. Especially mocking out a dependency of controller, filter or another service is too cumbersome. This blog will show how you would normally create mocks in AngularJS, why its troublesome and finally introduces the new ngImprovedTesting library that makes mock testing much easier.

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Sometimes we want to support in our RESTful API a different level of detail in the output for the same resource. For example a default output with the basic fields and a more detailed output with all fields for a resource. The client of our API can then choose if the default or detailed output is needed. One of the ways to implement this in Grails is using converter named configurations.

Grails converters, like JSON and XML, support named configurations. First we need to register a named configuration with the converter. Then we can invoke the use method of the converter with the name of the configuration and a closure with statements to generate output. The code in the closure is executed in the context of the named configuration.

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In Grails we can apply the @Resource AST (Abstract Syntax Tree) annotation to a domain class. Grails will generate a complete new controller which by default extends grails.rest.RestfulController. We can use our own controller class that will be extended by the @Resource transformation. For example we might want to disable the delete action, but still want to use the @Resource transformation. We simply write a new RestfulController implementation and use the superClass attribute for the annotation to assign our custom controller as the value.

First we write a new RestfulController and we override the delete action. We return a HTTP status code 405 Method not allowed:

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We can write a RESTful application with Grails and define our API in different ways. One of them is to subclass the grails.rest.RestfulController. The RestfulController already contains a lot of useful methods to work with resources. For example all CRUD methods (save/show/update/delete) are available and are mapped to the correct HTTP verbs using a URL mapping with the resource(s) attribute.

We can define which content types are supported with the static variable responseFormats in our controller. The variable should be a list of String values with the supported formats. The list of supported formats applies to all methods in our controller. The names of the formats are defined in the configuration property grails.mime.types. We can also use a Map notation with the supportedFormats variable. The key of the map is the method name and the value is a list of formats.

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Especially when we use Grails to create a RESTful API we want to enable the request header Accept, so Grails can do content negotiation based on the value in the header. For example we could use the request header Accept: application/json to get a JSON response. Grails will look at the boolean configuration property grails.mime.use.accept.header to see if the Accept header must be parsed. The default value is true so the Accept header is used. But there is another property which determines if the Accept header is used: grails.mime.disable.accept.header.userAgents. The value must contain a list or a regular expression pattern of user agents which are ignored for the Accept header. The default value is ~/(Gecko(?i)|WebKit(?i)|Presto(?i)|Trident(?i))/. So for any request from these user agents, mostly our web browser, the Accept header is ignored.

If we use REST web services test tools from our browser, for example Postman, then any Accept header we set in the tool is ignored by Grails. We must change the value of the configuration property grails.mime.disable.accept.header.userAgents to for example an empty list. Then we know for every request send to our Grails application, either from a web browser or command-line tool like curl, the Accept header is interpreted by Grails.

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