gristlabs_grist-core/app/gen-server/lib/DocApiForwarder.ts
Paul Fitzpatrick 5ef889addd (core) move home server into core
Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552
2020-07-21 20:39:10 -04:00

104 lines
4.5 KiB
TypeScript

import * as express from "express";
import fetch, { RequestInit } from 'node-fetch';
import { ApiError } from 'app/common/ApiError';
import { removeTrailingSlash } from 'app/common/gutil';
import { HomeDBManager } from "app/gen-server/lib/HomeDBManager";
import { assertAccess, getOrSetDocAuth, getTransitiveHeaders, RequestWithLogin } from 'app/server/lib/Authorizer';
import { IDocWorkerMap } from "app/server/lib/DocWorkerMap";
import { expressWrap } from "app/server/lib/expressWrap";
import { getAssignmentId } from "app/server/lib/idUtils";
/**
* Forwards all /api/docs/:docId/tables requests to the doc worker handling the :docId document. Makes
* sure the user has at least view access to the document otherwise rejects the request. For
* performance reason we stream the body directly from the request, which requires that no-one reads
* the req before, in particular you should register DocApiForwarder before bodyParser.
*
* Use:
* const home = new ApiServer(false);
* const docApiForwarder = new DocApiForwarder(getDocWorkerMap(), home);
* app.use(docApiForwarder.getMiddleware());
*
* Note that it expects userId, and jsonErrorHandler middleware to be set up outside
* to apply to these routes.
*/
export class DocApiForwarder {
constructor(private _docWorkerMap: IDocWorkerMap, private _dbManager: HomeDBManager) {
}
public addEndpoints(app: express.Application) {
// Middleware to forward a request about an existing document that user has access to.
// We do not check whether the document has been soft-deleted; that will be checked by
// the worker if needed.
const withDoc = expressWrap(this._forwardToDocWorker.bind(this, true));
// Middleware to forward a request without a pre-existing document (for imports/uploads).
const withoutDoc = expressWrap(this._forwardToDocWorker.bind(this, false));
app.use('/api/docs/:docId/tables', withDoc);
app.use('/api/docs/:docId/force-reload', withDoc);
app.use('/api/docs/:docId/remove', withDoc);
app.delete('/api/docs/:docId', withDoc);
app.use('/api/docs/:docId/download', withDoc);
app.use('/api/docs/:docId/apply', withDoc);
app.use('/api/docs/:docId/attachments', withDoc);
app.use('/api/docs/:docId/snapshots', withDoc);
app.use('/api/docs/:docId/replace', withDoc);
app.use('/api/docs/:docId/flush', withDoc);
app.use('/api/docs/:docId/states', withDoc);
app.use('/api/docs/:docId/compare', withDoc);
app.use('^/api/docs$', withoutDoc);
}
private async _forwardToDocWorker(withDocId: boolean, req: express.Request, res: express.Response): Promise<void> {
let docId: string|null = null;
if (withDocId) {
const docAuth = await getOrSetDocAuth(req as RequestWithLogin, this._dbManager, req.params.docId);
assertAccess('viewers', docAuth, {allowRemoved: true});
docId = docAuth.docId;
}
// Use the docId for worker assignment, rather than req.params.docId, which could be a urlId.
const assignmentId = getAssignmentId(this._docWorkerMap, docId === null ? 'import' : docId);
if (!this._docWorkerMap) {
throw new ApiError('no worker map', 404);
}
const docStatus = await this._docWorkerMap.assignDocWorker(assignmentId);
// Construct new url by keeping only origin and path prefixes of `docWorker.internalUrl`,
// and otherwise reflecting fully the original url (remaining path, and query params).
const docWorkerUrl = new URL(docStatus.docWorker.internalUrl);
const url = new URL(req.originalUrl, docWorkerUrl.origin);
url.pathname = removeTrailingSlash(docWorkerUrl.pathname) + url.pathname;
const headers: {[key: string]: string} = {
...getTransitiveHeaders(req),
'Content-Type': req.get('Content-Type') || 'application/json',
};
for (const key of ['X-Sort', 'X-Limit']) {
const hdr = req.get(key);
if (hdr) { headers[key] = hdr; }
}
const options: RequestInit = {
method: req.method,
headers,
};
if (['POST', 'PATCH'].includes(req.method)) {
// uses `req` as a stream
options.body = req;
}
const docWorkerRes = await fetch(url.href, options);
res.status(docWorkerRes.status);
for (const key of ['content-type', 'content-disposition', 'cache-control']) {
const value = docWorkerRes.headers.get(key);
if (value) { res.set(key, value); }
}
return new Promise<void>((resolve, reject) => {
docWorkerRes.body.on('error', reject);
res.on('error', reject);
res.on('finish', resolve);
docWorkerRes.body.pipe(res);
});
}
}