Working With Files

Finatra provides basic file server support which is not meant for high traffic file serving. Do not use the file server for production apps requiring a robust high performance file serving solution.

File Locations

By default, files are served from the root of the classpath. You can use the flag


to customize the classpath root for finding files.

To serve files from the local filesystem, set the flag


to the location of the file serving directory.

Note that setting Java System Property -Denv=env is no longer required nor supported. Setting the -local.doc.root flag will trigger the same localFileMode behavior from Finatra v1.x.

Also note that it is an error to attempt to set both the -doc.root and the -local.doc.root flags.


  • do nothing to load resources from the classpath root or
  • configure a classpath “namespace” by setting the -doc.root flag or
  • load files from the local filesystem directory location specified by the -local.doc.root flag.

Additionally, it is recommend to use local filesystem serving only during testing and not in production. It is recommended that you include files to be served as classpath resources in production.

For changes from Finatra v1.x static files behavior see the Static Files section in the Version 1 Migration Guide.

To set a flag value, pass the flag and its value as an argument to your server:

$ java -jar finatra-hello-world-assembly-2.0.0.jar -doc.root=/namespace

For more information on using and setting command-line flags see Flags.

File Serving Examples

get("/file") { request: Request =>

get("/:*") { request: Request =>

Mustache Templating

Finatra supports the rendering of mustache templates. The framework provides a default MustacheModule but this is configurable. To set your own module, override the mustacheModule def in c.t.finatra.http.HttpServer, e.g.,

class ExampleServer extends HttpServer {
  override val mustacheModule = MyCustomizedMustacheModule

See the “Overriding Default Behavior” section for more information on providing a customized framework module in your server.

By default mustache templates are loaded from the classpath root. To configure a classpath “namespace” for loading mustache templates, set the -mustache.templates.dir flag.

Local filesystem

When you set the -local.doc.root flag, the MustacheModule will instead load templates from the local filesystem and templates will be reloaded on every render. This is to aid in local development. Note, that the interplay between the mustache.temaplates.dir and the local.doc.root flag is as follows:

  • in “local file mode” (e.g., when the -local.doc.root flag is set to a non-empty value) the framework will try to load a template first from the absolute path under mustache.templates.dir

  • if the template is not found it will then be loaded from a location of mustache.templates.dir relative to the specified -local.doc.root, value e.g,



The framework will use mustache to render callback return types that are annotated with the @Mustache annotation.

case class FooView(
  name: String)

get("/foo") { request: Request =>

The value of the @Mustache annotation is assumed by the MustacheMessageBodyWriter to be the template filename without the suffix (which the framework always assumes to be .mustache).

Or you can manually create a response that explicitly references a template, e.g.,

get("/foo") { request: Request =>

Or you can programmatically render a template into a string using c.t.finatra.http.marshalling.mustache.MustacheService#createString method. This is useful for embedding the resultant content inside a field in a response.

case class TestUserView(
  age: Int,
  name: String,
  friends: Seq[String])

case class TestCaseClassWithHtml(
  address: String,
  phone: String,
  renderedHtml: String)

get("/testClassWithHtml") { r: Request =>
  val testUser = TestUserView(
    "Bob Smith",
    Seq("user1", "user2"))

    address = "123 Main St. Anywhere, CA US 90210",
    phone = "+12221234567",
    renderedHtml = xml.Utility.escape(mustacheService.createString("testHtml.mustache", testUser)))

See the test class for more examples.