Example Scala Spray project
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README.md

Spray Example

I want this to be an example of a Spray API that goes a bit beyond just the routing layer. In particular, it shows how to wire together an API that uses a separate service and model actor. It also shows off a few things I consider good practice:

  • "Intelligent" cache control. Tailor the upstream cache time per resource.

  • Separate on-the-wire protocol. I often see code bases where the domain objects contain more annotations than code---often for both JSON and ORM mappings. I think this is bad practice and prefer to use different objects.

  • Use sbt-revolver. This is great plugin by the Spray guys to simplify and speed up the dev/build/test cycle.

  • Stub out child actors for testing using the Cake Pattern. See the TopLevelConfig trait and its corresponding ProductionTopLevelConfig implementation for more details.

Running the example service

To start the example service, launch a terminal and cd into the directory and run sbt:

$ sbt

Once sbt starts the prompt will change. You can start the example service in the background using the re-start command, provided by the sbt-revolver plugin:

> re-start

In a different terminal (or a browser), call the service:

$ curl localhost:8080/items

You should see:

[{
  "id": 1,
  "stockLevel": "LowStock",
  "title": "foo"
}, {
  "id": 2,
  "stockLevel": "LowStock",
  "title": "bar"
}, {
  "id": 3,
  "stockLevel": "InStock",
  "title": "qux"
}, {
  "id": 4,
  "stockLevel": "InStock",
  "title": "quux"
}, {
  "id": 5,
  "stockLevel": "InStock",
  "title": "quuux"
}]

You can also try getting only the items where the description contains 'Qu':

$ curl 'localhost:8080/items?q=Qu'

The quotes are necessary because ? would otherwise be interpreted by the shell. Anyway, you should see this:

[{
  "id": 3,
  "stockLevel": "InStock",
  "title": "qux"
}, {
  "id": 4,
  "stockLevel": "InStock",
  "title": "quux"
}, {
  "id": 5,
  "stockLevel": "InStock",
  "title": "quuux"
}]

Now try getting a single item:

$ curl localhost:8080/items/2

You should see:

{
  "id": 2,
  "stockLevel": "LowStock",
  "title": "bar",
  "desc": "More information about Bar"
}

Finally, try getting an item that doesn't exist:

$ curl localhost:8080/items/23

You should get a "Not Found" message, and the status code 404.