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File Serving

Sometimes you want to serve local files, e.g. HTML, JavaScript, or CSS. This is a task for the default flow defined in conf/flow.xml and the serve action.

📎 Note: In the following we assume that the basePath in swagger.yaml is not / so that the default flow will actually be effective.

First, we create flow.xml in conf with the following content:

<flow>
  <serve dir="../htdocs" fallback-doc="/index.html"/>
</flow>

This assumes that the local files should be found in an htdocs directory next to conf (dir="../htdocs") and that there is an index.html fallback document in the htdocs directory.

So, let's create htdocs/index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Fallback page</title>
    <link rel="stylesheet" href="/styles.css">
    <script src="/script.js"></script>
  </head>
  <body>
    <h1>Fallback page</h1>
  </body>
</html>

and some assets:

$ echo 'body { background-color: red }' > htdocs/styles.css
$ echo 'document.write("Hello!")'       > htdocs/script.js

Finally, we create another HTML document in a different directory:

$ mkdir -p htdocs/some/where

$ echo '<html><body><h1>Somewhere</h1></body></html>' > htdocs/some/where/index.html

Let's go surfin' now:

$ curl -si localhost:8080
HTTP/1.1 200 OK
Server: FLAT
Content-Type: text/html
…

    <h1>Fallback page</h1>
  </body>
</html>

$ curl -si localhost:8080/styles.css
HTTP/1.1 200 OK
…
Content-Type: text/css

body { background-color: red }

Note the redirection when we request /some/where without the trailing /:

$ curl -si --location localhost:8080/some/where
HTTP/1.1 301 Moved Permanently
Server: FLAT
Location: /some/where/
Content-Type: text/html
…

HTTP/1.1 200 OK
…
<html><body><h1>Somewhere</h1></body></html>

FLAT responds with index.html just like a web server would do.

📎 Note: Requests to missing resources always return the fallback document. Therefore, any resources therein must be absolutely referenced.

$ curl -si localhost:8080/not/existing/
HTTP/1.1 200 OK
Server: FLAT
Content-Type: text/html
…

    <h1>Fallback page</h1>
  </body>
</html>
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