WebUI Wire: Automatic Downloader🔗ℹ

1 Getting the webui-wire command🔗ℹ

Typical usage is:

(define cmd (ww-get-webui-wire-command))

(define-values (proc in out err) (process cmd))

Internally, this function:

• checks whether a custom command has been installed via ww-set-custom-webui-wire-command!; if so, that value is returned immediately;

• otherwise, determines a platform-specific default command: on Linux this is typically a flatpak run ... invocation, while on other platforms it is the path to the installed executable;

• ensures that the helper is actually present and executable;

• verifies that the running helper reports a compatible ww-wire-version (from web-racket-version).

If the helper is not installed, cannot be found, or reports an unexpected version, an error is raised with a message indicating that webui-wire needs to be installed (or upgraded) in order to use Web Racket.

The returned string is intended to be passed to process or similar functions from racket/system. The result may contain spaces (for example for Flatpak invocations), so treat it as a single shell command, not as a list of arguments.

2 Getting the installed version🔗ℹ

Conceptually, the function:

• obtains the command via ww-get-webui-wire-command;

• invokes <command> –version;

• reads the stdout of that process;

• trims whitespace and returns the resulting string.

The returned value is the version as reported by the helper itself, for example:

"0.2.3"

In normal operation, this version is expected to match (or be compatible with) the protocol version ww-wire-version that the current Web Racket library was built for.

If the helper is missing or cannot be executed, the same error conditions as ww-get-webui-wire-command apply, and an exception is raised.

3 Overriding the command🔗ℹ

This is useful when:

• webui-wire is installed in a non-standard location;

• you want to run a wrapper script around the real executable;

• you are developing or testing against a different build of the helper.

The command string should be something that can be passed directly to process, for example:

• "/opt/webui-wire/bin/webui-wire"

• "flatpak run --user nl.dijkewijk.webui-wire"

The function stores the override and returns it.

Subsequent calls to ww-get-webui-wire-command will use this custom command as-is; the internal platform detection and default location logic are bypassed. The version check performed by ww-get-webui-wire-version still applies, so your custom binary must speak the expected protocol version.

4 Internal behaviour (informative)🔗ℹ

The details in this section describe the typical internal behaviour of the module. They are not part of the public API and may change without notice, but they are useful to understand how error messages and version checks arise.