Crate fiftyone_javascript_builder 

51Degrees JavaScript builder

The JavaScript builder element renders a client-side JavaScript include from the JSON payload produced by the fiftyone_json_builder crate. The generated script creates a global manager object on the client device, runs any JavaScript-typed properties the JSON carries, and (when a callback URL is configured) posts the evidence it gathers back to the server for a refreshed result. It implements the javascript-builder specification.

The template

The script is rendered from a single Mustache template, JavaScriptResource.mustache, embedded at compile time with include_str!. Rendering uses a small, pure-safe-Rust Mustache renderer (in this crate’s mustache module) with HTML escaping disabled, so the JSON payload, the callback URL and the object name reach the client verbatim.

Configuration and per-request overrides

JavaScriptBuilderElementBuilder sets the host, endpoint, protocol, object name, cookie behavior and minification. Several of those can be overridden per request through evidence (query.fod-js-object-name, query.fod-js-enable-cookies, header.host and header.protocol). See JavaScriptBuilderElement for the full derivation rules.

Minification

With the default-on minify feature the rendered script is minified by the oxc toolchain (see the minify module). A minification failure falls back to the unminified script, so valid JavaScript is always served. The set_minify builder flag turns minification off for an element, and building the crate with default-features = false drops the oxc dependency entirely.

A worked pipeline

use std::sync::Arc;
use fiftyone_pipeline_core::{Evidence, Pipeline};
use fiftyone_json_builder::JsonBuilderElement;
use fiftyone_javascript_builder::{JavaScriptBuilderElement, JAVASCRIPT_BUILDER_DATA_KEY};

let pipeline = Pipeline::builder()
    .add_element(Arc::new(JsonBuilderElement::new()))
    .add_element(Arc::new(JavaScriptBuilderElement::new()))
    .build()
    .unwrap();

let mut data = pipeline.create_flow_data_with(
    Evidence::builder().add("header.host", "localhost").build(),
);
data.process().unwrap();

let js = data.get(JAVASCRIPT_BUILDER_DATA_KEY).unwrap().javascript().to_owned();
assert!(js.contains("fiftyoneDegreesManager"));

Structs

JavaScriptBuilderElement

Generates a JavaScript include to be run on the client device.

JavaScriptBuilderElementBuilder

Configures and constructs a JavaScriptBuilderElement.

JavaScriptBuilderElementData

The element data the JavaScript builder writes into the flow data.

JavaScriptResource

The parameters required by the JavaScriptResource.mustache template.

Constants

BUILDER_DEFAULT_ENABLE_COOKIES

The default value of the flag that controls whether client-side processing stores results in cookies.

BUILDER_DEFAULT_HOST

The default host for the builder. An empty string means the host from the evidence collection (the host the original request used) is applied.

BUILDER_DEFAULT_MINIFY

The default value of the flag that controls minification.

BUILDER_DEFAULT_OBJECT_NAME

The default value for the JavaScript ‘object name’.

BUILDER_DEFAULT_PROTOCOL

The default protocol for the builder. An empty string means the protocol from the evidence collection (the protocol the original request used) is applied.

EVIDENCE_ENABLE_COOKIES

The complete query.fod-js-enable-cookies evidence key.

EVIDENCE_ENABLE_COOKIES_SUFFIX

The suffix used when the JavaScript builder ‘enable cookies’ parameter is supplied as evidence.

EVIDENCE_HOST_KEY

The complete key to use when the Host HTTP header is passed as evidence (header.host).

EVIDENCE_OBJECT_NAME

The complete query.fod-js-object-name evidence key.

EVIDENCE_OBJECT_NAME_SUFFIX

The suffix used when the JavaScript builder ‘object name’ parameter is supplied as evidence.

FALLBACK_PROTOCOL

The protocol used when creating a callback URL if no other protocol value was found or specified.

JAVASCRIPT_BUILDER_DATA_KEY

The typed key for retrieving JavaScriptBuilderElementData from a flow data.

JAVASCRIPT_BUILDER_ELEMENT_DATA_KEY

The element data key under which the JavaScript builder stores its element data.

JAVASCRIPT_PROPERTY_KEY

The name of the single property the JavaScript builder populates: the generated JavaScript, as a string.