fileAttachment.js

import {autoType, csvParse, csvParseRows, tsvParse, tsvParseRows} from "d3-dsv";
import {arrow4, arrow9, arrow11, jszip, exceljs} from "./dependencies.js";
import {cdn, requireDefault} from "./require.js";
import {SQLiteDatabaseClient} from "./sqlite.js";
import {inferSchema, coerceRow} from "./table.js";
import {Workbook} from "./xlsx.js";

async function remote_fetch(file) {
  const response = await fetch(await file.url());
  if (!response.ok) throw new Error(`Unable to load file: ${file.name}`);
  return response;
}

export function enforceSchema(source, schema) {
  const types = new Map(schema.map(({name, type}) => [name, type]));
  return Object.assign(source.map(d => coerceRow(d, types, schema)), {schema});
}

async function dsv(file, delimiter, {array = false, typed = false} = {}) {
  const text = await file.text();
  const parse = (delimiter === "\t"
    ? (array ? tsvParseRows : tsvParse)
    : (array ? csvParseRows : csvParse));
  if (typed === "auto" && !array) {
    const source = parse(text);
    return enforceSchema(source, inferSchema(source, source.columns));
  }
  return parse(text, typed && autoType);
}

export class AbstractFile {
  constructor(name, mimeType) {
    Object.defineProperty(this, "name", {value: name, enumerable: true});
    if (mimeType !== undefined) Object.defineProperty(this, "mimeType", {value: mimeType + "", enumerable: true});
  }
  async blob() {
    return (await remote_fetch(this)).blob();
  }
  async arrayBuffer() {
    return (await remote_fetch(this)).arrayBuffer();
  }
  async text() {
    return (await remote_fetch(this)).text();
  }
  async json() {
    return (await remote_fetch(this)).json();
  }
  async stream() {
    return (await remote_fetch(this)).body;
  }
  async csv(options) {
    return dsv(this, ",", options);
  }
  async tsv(options) {
    return dsv(this, "\t", options);
  }
  async image(props) {
    const url = await this.url();
    return new Promise((resolve, reject) => {
      const i = new Image();
      if (new URL(url, document.baseURI).origin !== new URL(location).origin) {
        i.crossOrigin = "anonymous";
      }
      Object.assign(i, props);
      i.onload = () => resolve(i);
      i.onerror = () => reject(new Error(`Unable to load file: ${this.name}`));
      i.src = url;
    });
  }
  async arrow({version = 4} = {}) {
    switch (version) {
      case 4: {
        const [Arrow, response] = await Promise.all([requireDefault(arrow4.resolve()), remote_fetch(this)]);
        return Arrow.Table.from(response);
      }
      case 9: {
        const [Arrow, response] = await Promise.all([import(`${cdn}${arrow9.resolve()}`), remote_fetch(this)]);
        return Arrow.tableFromIPC(response);
      }
      case 11: {
        const [Arrow, response] = await Promise.all([import(`${cdn}${arrow11.resolve()}`), remote_fetch(this)]);
        return Arrow.tableFromIPC(response);
      }
      default: throw new Error(`unsupported arrow version: ${version}`);
    }
  }
  async sqlite() {
    return SQLiteDatabaseClient.open(remote_fetch(this));
  }
  async zip() {
    const [JSZip, buffer] = await Promise.all([requireDefault(jszip.resolve()), this.arrayBuffer()]);
    return new ZipArchive(await JSZip.loadAsync(buffer));
  }
  async xml(mimeType = "application/xml") {
    return (new DOMParser).parseFromString(await this.text(), mimeType);
  }
  async html() {
    return this.xml("text/html");
  }
  async xlsx() {
    const [ExcelJS, buffer] = await Promise.all([requireDefault(exceljs.resolve()), this.arrayBuffer()]);
    return new Workbook(await new ExcelJS.Workbook().xlsx.load(buffer));
  }
}

export class FileAttachment extends AbstractFile {
  constructor(url, name, mimeType) {
    super(name, mimeType);
    Object.defineProperty(this, "_url", {value: url});
  }
  async url() {
    return (await this._url) + "";
  }
}

export function NoFileAttachments(name) {
  throw new Error(`File not found: ${name}`);
}

export function FileAttachments(resolve) {
  return Object.assign(
    name => {
      const result = resolve(name += "");
      if (result == null) throw new Error(`File not found: ${name}`);
      if (typeof result === "object" && "url" in result) {
        const {url, mimeType} = result;
        return new FileAttachment(url, name, mimeType);
      }
      return new FileAttachment(result, name);
    },
    {prototype: FileAttachment.prototype} // instanceof
  );
}

export class ZipArchive {
  constructor(archive) {
    Object.defineProperty(this, "_", {value: archive});
    this.filenames = Object.keys(archive.files).filter(name => !archive.files[name].dir);
  }
  file(path) {
    const object = this._.file(path += "");
    if (!object || object.dir) throw new Error(`file not found: ${path}`);
    return new ZipArchiveEntry(object);
  }
}

class ZipArchiveEntry extends AbstractFile {
  constructor(object) {
    super(object.name);
    Object.defineProperty(this, "_", {value: object});
    Object.defineProperty(this, "_url", {writable: true});
  }
  async url() {
    return this._url || (this._url = this.blob().then(URL.createObjectURL));
  }
  async blob() {
    return this._.async("blob");
  }
  async arrayBuffer() {
    return this._.async("arraybuffer");
  }
  async text() {
    return this._.async("text");
  }
  async json() {
    return JSON.parse(await this.text());
  }
}