117 lines
3.9 KiB
JavaScript
117 lines
3.9 KiB
JavaScript
"use strict";
|
||
const path = require("path");
|
||
const fs = require("fs").promises;
|
||
const request = require("requisition");
|
||
const { JSDOM } = require("jsdom");
|
||
|
||
const FILENAME_PREFIX = "chapter";
|
||
|
||
module.exports = async (startChapterURL, cachePath, manifestPath) => {
|
||
let manifestContents;
|
||
try {
|
||
manifestContents = await fs.readFile(manifestPath, { encoding: "utf-8" });
|
||
} catch (e) {
|
||
if (e.code === "ENOENT") {
|
||
return downloadAllChapters(null, startChapterURL, cachePath, manifestPath);
|
||
}
|
||
throw e;
|
||
}
|
||
|
||
const manifest = JSON.parse(manifestContents);
|
||
return downloadAllChapters(manifest, startChapterURL, cachePath, manifestPath);
|
||
};
|
||
|
||
async function downloadAllChapters(manifest, startChapterURL, cachePath, manifestPath) {
|
||
let currentChapter = startChapterURL;
|
||
let chapterIndex = 0;
|
||
if (manifest !== null) {
|
||
currentChapter = manifest[manifest.length - 1].url;
|
||
chapterIndex = manifest.length - 1;
|
||
|
||
// We're going to re-add it to the manifest later, possibly with an updated title.
|
||
manifest.pop();
|
||
} else {
|
||
manifest = [];
|
||
}
|
||
|
||
await fs.mkdir(cachePath, { recursive: true });
|
||
|
||
while (currentChapter !== null) {
|
||
const filename = `${FILENAME_PREFIX}${chapterIndex.toString().padStart(3, "0")}.html`;
|
||
|
||
console.log(`Downloading ${currentChapter}`);
|
||
|
||
const response = await downloadChapter(currentChapter);
|
||
const contents = await response.text();
|
||
console.log("- Response body received");
|
||
const rawChapterJSDOM = new JSDOM(contents, { url: currentChapter });
|
||
console.log("- Response body parsed into DOM");
|
||
|
||
const chapterURLToSave = currentChapter;
|
||
const chapterTitle = getChapterTitle(rawChapterJSDOM.window.document);
|
||
currentChapter = getNextChapterURL(rawChapterJSDOM.window.document);
|
||
|
||
// TODO: this should probably not be necessary... jsdom bug I guess!?
|
||
rawChapterJSDOM.window.close();
|
||
|
||
manifest.push({
|
||
url: chapterURLToSave,
|
||
title: chapterTitle,
|
||
filename
|
||
});
|
||
|
||
await fs.writeFile(path.resolve(cachePath, filename), contents);
|
||
console.log("- Response text saved to cache file");
|
||
|
||
// Incrementally update the manifest after every successful download, instead of waiting until the end.
|
||
const newManifestContents = JSON.stringify(manifest, undefined, 2);
|
||
await fs.writeFile(manifestPath, newManifestContents);
|
||
console.log("- Manifest updated");
|
||
|
||
++chapterIndex;
|
||
}
|
||
}
|
||
|
||
function getNextChapterURL(rawChapterDoc) {
|
||
// `a[title="Next Chapter"]` doesn"t always work. Two different pathologies:
|
||
// - https://parahumans.wordpress.com/2011/09/27/shell-4-2/
|
||
// - https://parahumans.wordpress.com/2012/04/21/sentinel-9-6/
|
||
// So instead search for the first <a> within the main content area starting with "Next", trimmed.
|
||
|
||
const aEls = rawChapterDoc.querySelectorAll(".entry-content a");
|
||
for (let i = 0; i < aEls.length; ++i) {
|
||
if (aEls[i].textContent.trim().startsWith("Next")) {
|
||
return aEls[i].href;
|
||
}
|
||
}
|
||
|
||
return null;
|
||
}
|
||
|
||
function getChapterTitle(rawChapterDoc) {
|
||
// Remove " – " because it's present in Ward but not in Worm, which is inconsistent. (And leaving it in causes slight
|
||
// issues down the line where we remove spaces around em dashes during conversion.) In the future it might be nice to
|
||
// have proper chapter titles, e.g. sections per arc with title pages and then just "1" or similar for the chapter.
|
||
// Until then this is reasonable and uniform.
|
||
return rawChapterDoc.querySelector("h1.entry-title").textContent.replace(/ – /, " ");
|
||
}
|
||
|
||
function retry(times, fn) {
|
||
if (times === 0) {
|
||
return fn();
|
||
}
|
||
|
||
return fn().catch(() => {
|
||
return retry(times - 1, fn);
|
||
});
|
||
}
|
||
|
||
function downloadChapter(url) {
|
||
return retry(3, async () => {
|
||
const response = await request(url).redirects(10);
|
||
if (response.status !== 200) {
|
||
throw new Error(`Response status for ${url} was ${response.status}`);
|
||
}
|
||
return response;
|
||
});
|
||
}
|