Serve Static Files
Static files are served directly.
For example, you can drop a photo into your content directory and it'll be accessible:
Static files are served directly.
For example, you can drop a photo into your content directory and it'll be accessible:
Handlebars templates are rendered at request time.
Templates can embed content from other files—even static files and executables—via
{{get "/file"}}. For example,
this content comes from a template, and here's a random number generated by
an executable:
44
Templates are provided render data with information about the request, the server, etc.
Executables in the content directory are run at request time, with standard output piped out as the response body.
Any program that you can run from the command line will work (scripts, compiled binaries, etc). For example, this timestamp is the output of a shell script:
now.html.sh: 2025-07-08T06:50:27Z
Since executables are run as normal programs by your operating system, you can freely mix and match whatever languages you like:
foo.html.js: hello from node, my pid is 1050
bar.html.py: hi from python 3.11.2 running on linux
baz.html.awk: happy Tuesday the 8th from awk (in UTC)
Executables are provided
render data
encoded as JSON in an environment variable named OPERATOR_RENDER_DATA.
Content negotiation is performed based on
the Accept header.
Multiple representations of the same content can be provided by creating files whose names differ only by extension.
For example, if you have
image.png
and
image.webp, the server will be able to satisfy GET /image as either
image/png or image/webp. "Negotiation" means that Operator uses the representation which
best fits the client's preferences. For example, your browser prefers
.
Request URLs with file extensions override the Accept header. For example, you can
GET /image.png or
GET /image.webp to retrieve a specific type no matter
which your browser prefers.
Operator sends chunks of the response body as soon as possible. It doesn't wait for the entire response to be generated.
For example, with
a script that gradually emits its response body
the client can begin processing the response while the script is still running. In this case the
<style> elements are applied one at a time, creating
a colorful effect.
File/directory names which start with _ are hidden from routing, but are still accessible by other
files in the content directory. This can be useful for partials, scripts, or other things which don't make sense out
of context.
For example,
this site
has
a file named _header.html.hbs
in the root of its content directory, but requests for
GET /_header will receive 404 responses instead of the HTML for the page header.
Additionally, file/directory names which start with . are always completely ignored by Operator. You
can safely use them for whatever you want.
You can specify a custom error handler for Operator.
For example, this site uses a custom error handler which presents a friendly message. You can see it in action by visiting a bogus URL.
Error handlers are configured via the --error-handler-route command-line argument. They receive an
error-code variable in their input.
