@loaders.gl/core/dist/lib/api/encode.js

The core API for working with loaders.gl loaders and writers

// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import { canEncodeWithWorker, NodeFile, resolvePath, isBrowser } from '@loaders.gl/loader-utils';
import { processOnWorker } from '@loaders.gl/worker-utils';
import { fetchFile } from "../fetch/fetch-file.js";
import { getLoaderOptions } from "./loader-options.js";
/**
 * Encode loaded data into a binary ArrayBuffer using the specified Writer.
 */
export async function encode(data, writer, options_) {
    const globalOptions = getLoaderOptions();
    // const globalOptions: WriterOptions = {}; // getWriterOptions();
    const options = { ...globalOptions, ...options_ };
    // Handle the special case where we are invoking external command-line tools
    if (writer.encodeURLtoURL) {
        return encodeWithCommandLineTool(writer, data, options);
    }
    // Worker support
    if (canEncodeWithWorker(writer, options)) {
        return await processOnWorker(writer, data, options);
    }
    // TODO Merge default writer options with options argument like it is done in load module.
    return await writer.encode(data, options);
}
/**
 * Encode loaded data into a binary ArrayBuffer using the specified Writer.
 */
export function encodeSync(data, writer, options) {
    if (writer.encodeSync) {
        return writer.encodeSync(data, options);
    }
    if (writer.encodeTextSync) {
        return new TextEncoder().encode(writer.encodeTextSync(data, options));
    }
    throw new Error(`Writer ${writer.name} could not synchronously encode data`);
}
/**
 * Encode loaded data to text using the specified Writer
 * @note This is a convenience function not intended for production use on large input data.
 * It is not optimized for performance. Data maybe converted from text to binary and back.
 * @throws if the writer does not generate text output
 */
export async function encodeText(data, writer, options) {
    if (writer.encodeText) {
        return await writer.encodeText(data, options);
    }
    if (writer.encodeTextSync) {
        return writer.encodeTextSync(data, options);
    }
    if (writer.text) {
        const arrayBuffer = await writer.encode(data, options);
        return new TextDecoder().decode(arrayBuffer);
    }
    throw new Error(`Writer ${writer.name} could not encode data as text`);
}
/**
 * Encode loaded data to text using the specified Writer
 * @note This is a convenience function not intended for production use on large input data.
 * It is not optimized for performance. Data maybe converted from text to binary and back.
 * @throws if the writer does not generate text output
 */
export function encodeTextSync(data, writer, options) {
    if (writer.encodeTextSync) {
        return writer.encodeTextSync(data, options);
    }
    if (writer.text && writer.encodeSync) {
        const arrayBuffer = encodeSync(data, writer, options);
        return new TextDecoder().decode(arrayBuffer);
    }
    throw new Error(`Writer ${writer.name} could not encode data as text`);
}
/**
 * Encode loaded data into a sequence (iterator) of binary ArrayBuffers using the specified Writer.
 */
export function encodeInBatches(data, writer, options) {
    if (writer.encodeInBatches) {
        const dataIterator = getIterator(data);
        // @ts-expect-error
        return writer.encodeInBatches(dataIterator, options);
    }
    // TODO -fall back to atomic encode?
    throw new Error(`Writer ${writer.name} could not encode in batches`);
}
/**
 * Encode loaded data into a sequence (iterator) of binary ArrayBuffers using the specified Writer.
 */
export function encodeTextInBatches(data, writer, options) {
    if (writer.encodeTextInBatches) {
        const dataIterator = getIterator(data);
        // @ts-expect-error
        return writer.encodeTextInBatches(dataIterator, options);
    }
    // TODO -fall back to atomic encode?
    throw new Error(`Writer ${writer.name} could not encode text in batches`);
}
/**
 * Encode data stored in a file (on disk) to another file.
 * @note Node.js only. This function enables using command-line converters as "writers".
 */
export async function encodeURLtoURL(inputUrl, outputUrl, writer, options) {
    inputUrl = resolvePath(inputUrl);
    outputUrl = resolvePath(outputUrl);
    if (isBrowser || !writer.encodeURLtoURL) {
        throw new Error();
    }
    const outputFilename = await writer.encodeURLtoURL(inputUrl, outputUrl, options);
    return outputFilename;
}
/** Helper function to encode via external tool (typically command line execution in Node.js) */
async function encodeWithCommandLineTool(writer, data, options) {
    if (isBrowser) {
        throw new Error(`Writer ${writer.name} not supported in browser`);
    }
    // TODO - how to generate filenames with correct extensions?
    const tmpInputFilename = getTemporaryFilename('input');
    const file = new NodeFile(tmpInputFilename, 'w');
    await file.write(data);
    const tmpOutputFilename = getTemporaryFilename('output');
    const outputFilename = await encodeURLtoURL(tmpInputFilename, tmpOutputFilename, writer, options);
    const response = await fetchFile(outputFilename);
    return response.arrayBuffer();
}
/**
 * @todo TODO - this is an unacceptable hack!!!
 */
function getIterator(data) {
    const dataIterator = [{ ...data, start: 0, end: data.length }];
    return dataIterator;
}
/**
 * @todo Move to utils
 */
function getTemporaryFilename(filename) {
    return `/tmp/${filename}`;
}