105 lines
2.8 KiB
TypeScript
105 lines
2.8 KiB
TypeScript
import path from "path-browserify";
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import { Buffer } from "buffer";
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import { bodyToBuffer, getAuthHeader, isWriteable } from "./util";
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import { Pointer } from "./pointers";
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import { HTTPRequest, BasicAuth } from "./types";
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import { PromiseFsClient } from "isomorphic-git";
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interface LFSInfoResponse {
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objects: {
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actions: {
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download: {
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href: string;
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header?: Record<string, string>;
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};
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};
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}[];
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}
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function isValidLFSInfoResponseData(
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val: Record<string, any>
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): val is LFSInfoResponse {
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return val.objects?.[0]?.actions?.download?.href?.trim !== undefined;
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}
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/**
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* Downloads, caches and returns a blob corresponding to given LFS pointer.
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* Uses already cached object, if size matches.
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*/
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export default async function downloadBlobFromPointer(
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fs: PromiseFsClient | null,
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url: string,
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auth: BasicAuth | {},
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{ info, objectPath }: Pointer
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): Promise<Blob> {
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if (fs) {
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try {
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const cached = await fs?.promises.readFile(objectPath);
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if (cached.byteLength === info.size) {
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return cached;
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}
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} catch (e) {
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// Silence file not found errors (implies cache miss)
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if ((e as any).code !== "ENOENT") {
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throw e;
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}
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}
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}
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const authHeaders: Record<string, string> =
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"username" in auth ? getAuthHeader(auth) : {};
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// Request LFS transfer
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const lfsInfoRequestData = {
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operation: "download",
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transfers: ["basic"],
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objects: [info],
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};
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const lfsInfoRes = await fetch(`${url}/info/lfs/objects/batch`, {
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method: "POST",
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headers: {
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// Github LFS doesn’t seem to accept this UA, but works fine without any
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// 'User-Agent': `git/isomorphic-git@${git.version()}`,
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...authHeaders,
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Accept: "application/vnd.git-lfs+json",
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"Content-Type": "application/vnd.git-lfs+json",
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},
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body: JSON.stringify(lfsInfoRequestData),
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});
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const lfsInfoResponseData = await lfsInfoRes.json();
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if (isValidLFSInfoResponseData(lfsInfoResponseData)) {
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// Request the actual blob
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const downloadAction = lfsInfoResponseData.objects[0].actions.download;
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const lfsObjectDownloadURL = downloadAction.href;
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const lfsObjectDownloadHeaders = downloadAction.header ?? {};
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const lfsObjectRes = await fetch(lfsObjectDownloadURL, {
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method: "GET",
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headers: {
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...authHeaders,
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...lfsObjectDownloadHeaders,
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},
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});
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const blob = await lfsObjectRes.blob();
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if (fs) {
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// Write LFS cache for this object, if cache path is accessible.
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if (await isWriteable(fs, objectPath)) {
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await fs.promises.mkdir(path.dirname(objectPath), { recursive: true });
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await fs.promises.writeFile(objectPath, blob);
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}
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}
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return blob;
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} else {
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throw new Error(
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"Unexpected JSON structure received for LFS download request"
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);
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}
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}
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