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773 lines (699 loc) · 22.3 KB
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import {deepEqual, JSONValue} from './json.js';
import type {KeyTypeForScanOptions, ScanOptions} from './scan-options.js';
import {
Invoker,
Invoke,
OpenTransactionRequest,
REPMWasmInvoker,
InitInput,
} from './repm-invoker.js';
import {
IndexTransactionImpl,
ReadTransactionImpl,
WriteTransactionImpl,
} from './transactions.js';
import {ScanResult} from './scan-iterator.js';
import type {ReadTransaction, WriteTransaction} from './transactions.js';
type BeginSyncResult = {
syncID: string;
syncHead: string;
};
export const httpStatusUnauthorized = 401;
export type MaybePromise<T> = T | Promise<T>;
/** The key name to use in localStorage when synchronizing changes. */
const storageKeyName = (name: string) => `/replicache/root/${name}`;
/** The maximum number of time to call out to getDataLayerAuth before giving up and throwing an error. */
const MAX_REAUTH_TRIES = 8;
/**
* The options passed to [[Replicache]].
*/
export interface ReplicacheOptions {
batchURL?: string;
dataLayerAuth?: string;
diffServerAuth?: string;
diffServerURL: string;
name?: string;
/**
* The duration between each [[sync]]. Set this to `null` to prevent syncing in
* the background.
*/
syncInterval?: number | null;
/**
* The delay between when a change is made to Replicache and when Replicache
* attempts to push that change.
*/
pushDelay?: number;
/**
* By default we will load the Replicache wasm module relative to the
* Replicache js files but under some circumstances (like bundling with old
* versions of Webpack) it is useful to manually configure where the wasm
* module is located on the web server.
*
* If you provide your own path to the wasm module it probably makes sense to
* use a relative URL relative to your current file.
*
* ```js
* wasmModule: new URL('./relative/path/to/replicache.wasm', import.meta.url),
* ```
*
* You might also want to consider using an absolute URL so that we can find
* the wasm module no matter where your js file is loaded from:
*
* ```js
* wasmModule: '/static/replicache.wasm',
* ```
*/
wasmModule?: InitInput | undefined;
}
export default class Replicache implements ReadTransaction {
private readonly _batchURL: string;
private _dataLayerAuth: string;
private readonly _diffServerAuth: string;
private readonly _diffServerURL: string;
private readonly _name: string;
private readonly _repmInvoker: Invoker;
private _closed = false;
private _online = true;
protected _opened: Promise<unknown> | null = null;
private _root: Promise<string | undefined> = Promise.resolve(undefined);
private readonly _mutatorRegistry = new Map<
string,
(tx: WriteTransaction, args?: JSONValue) => MaybePromise<void | JSONValue>
>();
private _syncPromise: Promise<void> | null = null;
private readonly _subscriptions = new Set<
Subscription<JSONValue | undefined, unknown>
>();
private _syncInterval: number | null;
// NodeJS has a non standard setTimeout function :'(
protected _timerId: ReturnType<typeof setTimeout> | 0 = 0;
/**
* The delay between when a change is made to Replicache and when Replicache
* attempts to push that change.
*/
pushDelay: number;
onSync: ((syncing: boolean) => void) | null = null;
/**
* This gets called when we get an HTTP unauthorized from the client view or
* the batch endpoint. Set this to a function that will ask your user to
* reauthenticate.
*/
getDataLayerAuth:
| (() => MaybePromise<string | null | undefined>)
| null
| undefined = null;
constructor(options: ReplicacheOptions) {
const {
batchURL = '',
dataLayerAuth = '',
diffServerAuth = '',
diffServerURL,
name = 'default',
syncInterval = 60_000,
pushDelay = 300,
wasmModule,
} = options;
this._batchURL = batchURL;
this._dataLayerAuth = dataLayerAuth;
this._diffServerAuth = diffServerAuth;
this._diffServerURL = diffServerURL;
this._name = name;
this._repmInvoker = new REPMWasmInvoker(wasmModule);
this._syncInterval = syncInterval;
this.pushDelay = pushDelay;
this._open();
}
private async _open(): Promise<void> {
this._opened = this._repmInvoker.invoke(this._name, 'open');
this._setRoot(this._getRoot());
await this._root;
if (this._syncInterval !== null) {
await this.sync();
}
window.addEventListener('storage', this._onStorage);
}
get online(): boolean {
return this._online;
}
get closed(): boolean {
return this._closed;
}
/**
* The duration between each [[sync]]. Set this to `null` to prevent syncing in
* the background.
*/
get syncInterval(): number | null {
return this._syncInterval;
}
set syncInterval(duration: number | null) {
this._clearTimer();
this._syncInterval = duration;
this._scheduleSync(this._syncInterval);
}
private _scheduleSync(interval: number | null): void {
if (interval) {
this._timerId = setTimeout(() => this.sync(), interval);
}
}
private _clearTimer() {
if (this._timerId !== 0) {
clearTimeout(this._timerId);
this._timerId = 0;
}
}
async close(): Promise<void> {
this._closed = true;
const p = this._invoke('close');
this._clearTimer();
window.removeEventListener('storage', this._onStorage);
// Clear subscriptions
for (const subscription of this._subscriptions) {
subscription.onDone?.();
}
this._subscriptions.clear();
await p;
}
private async _getRoot(): Promise<string | undefined> {
if (this._closed) {
return undefined;
}
const res = await this._invoke('getRoot');
return res.root;
}
private _setRoot(root: Promise<string | undefined>) {
this._root = root;
this._setStorage(root);
}
private async _setStorage(root: Promise<string | undefined>) {
// Also set an item in localStorage so that we can synchronize multiple
// windows/tabs.
localStorage[storageKeyName(this._name)] = await root;
}
// Callback for when window.onstorage fires which happens when a different tab
// changes the db.
private _onStorage = (e: StorageEvent): void => {
if (e.key === storageKeyName(this._name)) {
this._checkChange(e.newValue as string);
}
};
private async _checkChange(root: string | undefined): Promise<void> {
const currentRoot = await this._root; // instantaneous except maybe first time
if (root !== undefined && root !== currentRoot) {
this._setRoot(Promise.resolve(root));
await this._fireOnChange();
}
}
private _invoke: Invoke = async (
rpc: string,
args?: JSONValue,
): Promise<JSONValue> => {
await this._opened;
return await this._repmInvoker.invoke(this._name, rpc, args);
};
/** Get a single value from the database. */
get(key: string): Promise<JSONValue | undefined> {
return this.query(tx => tx.get(key));
}
/** Determines if a single key is present in the database. */
has(key: string): Promise<boolean> {
return this.query(tx => tx.has(key));
}
/**
8000
* Gets many values from the database. This returns a `ScanResult` which
* implements `AsyncIterable`. It also has methods to iterate over the `keys`
* and `entries`.
*
* If `options` has an `indexName`, then this does a scan over an index with
* that name. A scan over an index uses a tuple for the key consisting of
* `[secondary: string, primary: string]`.
*/
scan<O extends ScanOptions, K extends KeyTypeForScanOptions<O>>(
options?: O,
): ScanResult<K> {
let tx: ReadTransactionImpl;
return new ScanResult<K>(
options,
this._invoke,
async () => {
if (tx) {
return tx;
}
tx = new ReadTransactionImpl(this._invoke);
await tx.open({});
return tx;
},
true,
);
}
/**
* Convenience form of `scan()` which returns all the entries as an array.
*/
async scanAll<O extends ScanOptions, K extends KeyTypeForScanOptions<O>>(
options?: O,
): Promise<[K, JSONValue][]> {
const tx = new ReadTransactionImpl(this._invoke);
try {
await tx.open({});
return await tx.scanAll(options);
} finally {
tx.close();
}
}
/**
* Creates a persistent secondary index in Replicache which can be used with scan.
*
* If the named index already exists with the same definition this returns success
* immediately. If the named index already exists, but with a different definition
* an error is returned.
*/
async createIndex(def: {
name: string;
keyPrefix?: string;
jsonPointer: string;
}): Promise<void> {
await this._indexOp(tx => tx.createIndex(def));
}
/**
* Drops an index previously created with {@link createIndex}.
*/
async dropIndex(name: string): Promise<void> {
await this._indexOp(tx => tx.dropIndex(name));
}
private async _indexOp(
f: (tx: IndexTransactionImpl) => Promise<void>,
): Promise<void> {
const tx = new IndexTransactionImpl(this._invoke);
try {
await tx.open({});
await f(tx);
} finally {
tx.commit();
}
}
private async _sync(): Promise<void> {
let >
try {
const beginSyncResult = await this._beginSync(MAX_REAUTH_TRIES);
// repc sends empty string for null sync.
if (beginSyncResult.syncHead !== '') {
await this._maybeEndSync(beginSyncResult);
}
} catch (e) {
// The error paths of beginSync and maybeEndSync need to be reworked.
//
// We want to distinguish between:
// a) network requests failed -- we're offline basically
// b) sync was aborted because one's already in progress
// c) oh noes - something unexpected happened
//
// Right now, all of these come out as errors. We distinguish (b) with a
// hacky string search. (a) and (c) are not distinguishable currently
// because repc doesn't provide sufficient information, so we treat all
// errors that aren't (b) as (a).
if (e.toString().includes('JSLogInfo')) {
>
}
console.info(`Sync returned: ${e}`);
}
this._online = online;
}
protected async _beginSync(maxAuthTries: number): Promise<BeginSyncResult> {
const beginSyncResult = await this._invoke('beginSync', {
batchPushURL: this._batchURL,
diffServerURL: this._diffServerURL,
dataLayerAuth: this._dataLayerAuth,
diffServerAuth: this._diffServerAuth,
});
const {syncInfo, syncHead} = beginSyncResult;
let reauth = false;
function checkStatus(
data: {httpStatusCode: number; errorMessage: string},
serverName: string,
serverURL: string,
) {
const {httpStatusCode, errorMessage} = data;
if (errorMessage || httpStatusCode >= 400) {
console.error(
`Got error response from ${serverName} server (${serverURL}): ${httpStatusCode}` +
(errorMessage ? `: ${errorMessage}` : ''),
);
}
if (httpStatusCode === httpStatusUnauthorized) {
reauth = true;
}
}
const {batchPushInfo, clientViewInfo, syncID} = syncInfo;
if (batchPushInfo) {
checkStatus(batchPushInfo, 'batch', this._batchURL);
const mutationInfos = batchPushInfo.batchPushResponse?.mutationInfos;
if (mutationInfos != null) {
for (const mutationInfo of mutationInfos) {
console.error(
`MutationInfo: ID: ${mutationInfo.id}, Error: ${mutationInfo.error}`,
);
}
}
}
if (clientViewInfo) {
checkStatus(clientViewInfo, 'client view', this._diffServerURL);
}
if (reauth && this.getDataLayerAuth) {
if (maxAuthTries === 0) {
console.info('Tried to reauthenticate too many times');
return {syncID, syncHead: ''};
}
const dataLayerAuth = await this.getDataLayerAuth();
if (dataLayerAuth != null) {
this._dataLayerAuth = dataLayerAuth;
// Try again now instead of waiting for another 5 seconds.
return await this._beginSync(maxAuthTries - 1);
}
}
return {syncID, syncHead};
}
protected async _maybeEndSync(
beginSyncResult: BeginSyncResult,
): Promise<void> {
if (this._closed) {
return;
}
let {syncHead} = beginSyncResult;
const {replayMutations} = await this._invoke(
'maybeEndSync',
beginSyncResult,
);
if (!replayMutations || replayMutations.length === 0) {
// All done.
await this._checkChange(syncHead);
return;
}
// Replay.
console.group('Replaying');
for (const mutation of replayMutations) {
const {original} = mutation;
syncHead = await this._replay(
syncHead,
original,
mutation.name,
JSON.parse(mutation.args),
);
}
console.groupEnd();
const {syncID} = beginSyncResult;
await this._maybeEndSync({syncID, syncHead});
}
private async _replay<A extends JSONValue>(
basis: string,
original: string,
name: string,
args: A,
): Promise<string> {
let mutatorImpl = this._mutatorRegistry.get(name);
if (!mutatorImpl) {
// Developers must not remove mutator names from the set once registered,
// because Replicache needs to be able to replay mutations during sync.
//
// If we detect that this has happened, stub in a no-op mutator so that at
// least sync can move forward. Note that the server-side mutation will
// still get sent. This doesn't remove the queued local mutation, it just
// removes its visible effects.
console.error(`Unknown mutator ${name}`);
mutatorImpl = async () => {
// no op
};
}
const res = await this._mutate(name, mutatorImpl, args, {
invokeArgs: {
rebaseOpts: {basis, original},
},
shouldCheckChange: false,
});
return res.ref;
}
/**
* Synchronizes this cache with the server. New local mutations are sent to
* the server, and the latest server state is applied to the cache. Any local
* mutations not included in the new server state are replayed. See the
* Replicache design document for more information on sync:
* https://github.com/rocicorp/replicache/blob/master/design.md
*/
async sync(): Promise<void> {
if (this._closed) {
return;
}
if (this._syncPromise !== null) {
await this._syncPromise;
await this.sync();
return;
}
this._clearTimer();
this._fireOnSync(true);
try {
this._syncPromise = this._sync();
await this._syncPromise;
} finally {
this._syncPromise = null;
this._fireOnSync(false);
this._scheduleSync(this._syncInterval);
}
}
private _fireOnSync(syncing: boolean): void {
queueMicrotask(() => this.onSync?.(syncing));
}
private async _fireOnChange(): Promise<void> {
type R =
| {ok: true; value: JSONValue | undefined}
| {ok: false; error: unknown};
const subscriptions = [...this._subscriptions];
const results = await this.query(async tx => {
const promises = subscriptions.map(async s => {
// Tag the result so we can deal with success vs error below.
try {
return {ok: true, value: await s.body(tx)} as R;
} catch (ex) {
return {ok: false, error: ex} as R;
}
});
return await Promise.all(promises);
});
for (let i = 0; i < subscriptions.length; i++) {
const s = subscriptions[i];
const result = results[i];
if (result.ok) {
const value: JSONValue | undefined = result.value;
if (!deepEqual(value, s.lastValue)) {
s.lastValue = value;
s.onData(value);
}
} else {
s.onError?.(result.error);
}
}
}
/**
* Subcribe to changes to the underlying data. Every time the underlying data
* changes `body` is called and if the result of `body` changes compared to
* last time `onData` is called. The function is also called once the first
* time the subscription is added.
*
* This returns a function that can be used to cancel the subscription.
*
* If an error occurs in the `body` the `onError` function is called if
* present. Otherwise, the error is thrown.
*/
subscribe<R extends JSONValue | undefined, E>(
body: (tx: ReadTransaction) => Promise<R>,
{
onData,
onError,
onDone,
}: {
onData: (result: R) => void;
onError?: (error: E) => void;
onDone?: () => void;
},
): () => void {
const s = {
body,
onData,
onError,
onDone,
lastValue: undefined,
} as Subscription<R, E>;
this._subscriptions.add(
(s as unknown) as Subscription<JSONValue | undefined, unknown>,
);
(async () => {
try {
const res = await this.query(s.body);
s.lastValue = res;
s.onData(res);
} catch (ex) {
if (s.onError) {
s.onError(ex);
} else {
throw ex;
}
}
})();
return (): void => {
this._subscriptions.delete(
(s as unknown) as Subscription<JSONValue | undefined, unknown>,
);
};
}
/**
* Query is used for read transactions. It is recommended to use transactions
* to ensure you get a consistent view across multiple calls to `get`, `has`
* and `scan`.
*/
async query<R>(body: (tx: ReadTransaction) => Promise<R> | R): Promise<R> {
const tx = new ReadTransactionImpl(this._invoke);
await tx.open({});
try {
return await body(tx);
} finally {
// No need to await the response.
tx.close();
}
}
/**
* Registers a *mutator*, which is used to make changes to the data.
*
* ## Replays
*
* Mutators run once when they are initially invoked, but they might also be
* *replayed* multiple times during sync. As such mutators should not modify
* application state directly. Also, it is important that the set of
* registered mutator names only grows over time. If Replicache syncs and
* needed mutator is not registered, it will substitute a no-op mutator, but
* this might be a poor user experience.
*
* ## Server application
*
* During sync, a description of each mutation is sent to the server's [batch
* endpoint](https://github.com/rocicorp/replicache/blob/master/README.md#step-5-upstream-sync)
* where it is applied. Once the mutation has been applied successfully, as
* indicated by the [client
* view](https://github.com/rocicorp/replicache/blob/master/README.md#step-2-downstream-sync)'s
* `lastMutationId` field, the local version of the mutation is removed. See
* the [design
* doc](https://github.com/rocicorp/replicache/blob/master/design.md) for
* additional details on the sync protocol.
*
* ## Transactionality
*
* Mutators are atomic: all their changes are applied together, or none are.
* Throwing an exception aborts the transaction. Otherwise, it is committed.
* As with [query] and [subscribe] all reads will see a consistent view of
* the cache while they run.
*/
register<Return extends JSONValue | void>(
name: string,
mutatorImpl: (tx: WriteTransaction) => MaybePromise<Return>,
): () => Promise<Return>;
register<Return extends JSONValue | void, Args extends JSONValue>(
name: string,
mutatorImpl: (tx: WriteTransaction, args: Args) => MaybePromise<Return>,
): (args: Args) => Promise<Return>;
register<Return extends JSONValue | void, Args extends JSONValue>(
name: string,
mutatorImpl: (tx: WriteTransaction, args?: Args) => MaybePromise<Return>,
): (args?: Args) => Promise<Return> {
this._mutatorRegistry.set(
name,
mutatorImpl as (
tx: WriteTransaction,
args: JSONValue | undefined,
) => Promise<void | JSONValue>,
);
return async (args?: Args): Promise<Return> =>
(await this._mutate(name, mutatorImpl, args, {shouldCheckChange: true}))
.result;
}
private async _mutate<R extends JSONValue | void, A extends JSONValue>(
name: string,
mutatorImpl: (tx: WriteTransaction, args?: A) => MaybePromise<R>,
args: A | undefined,
{
invokeArgs,
shouldCheckChange,
}: {invokeArgs?: OpenTransactionRequest; shouldCheckChange: boolean},
): Promise<{result: R; ref: string}> {
let actualInvokeArgs: OpenTransactionRequest = {
args: args !== undefined ? JSON.stringify(args) : 'null',
name,
};
if (invokeArgs !== undefined) {
actualInvokeArgs = {...actualInvokeArgs, ...invokeArgs};
}
let result: R;
const tx = new WriteTransactionImpl(this._invoke);
await tx.open(actualInvokeArgs);
try {
result = await mutatorImpl(tx, args);
} catch (ex) {
// No need to await the response.
tx.close();
throw ex;
}
const {ref} = await tx.commit();
if (shouldCheckChange) {
await this._checkChange(ref);
}
this._clearTimer();
this._scheduleSync(this.pushDelay);
return {result, ref};
}
/**
* When this is set to `true` the internal Replicache wasm module will log
* more things to the console (using `console.debug`). Setting this to false
* reduces the amount of logging done by the wasm module.
*
* If you want to see the verbose logging from Replicache in Devtools/Web
* Inspector you also need to change the console log level to `Verbose`.
*/
async setVerboseWasmLogging(verbose: boolean): Promise<void> {
await this._invoke('setLogLevel', {level: verbose ? 'debug' : 'info'});
}
}
export class ReplicacheTest extends Replicache {
static async new({
batchURL,
dataLayerAuth,
diffServerAuth,
diffServerURL,
name = '',
}: {
diffServerURL: string;
batchURL?: string;
dataLayerAuth?: string;
diffServerAuth?: string;
name?: string;
}): Promise<ReplicacheTest> {
const rep = new ReplicacheTest({
batchURL,
dataLayerAuth,
diffServerAuth,
diffServerURL,
name,
syncInterval: null,
pushDelay: 0,
});
await rep._opened;
return rep;
}
beginSync(): Promise<BeginSyncResult> {
return super._beginSync(MAX_REAUTH_TRIES);
}
maybeEndSync(beginSyncResult: BeginSyncResult): Promise<void> {
return super._maybeEndSync(beginSyncResult);
}
}
type Subscription<R extends JSONValue | undefined, E> = {
body: (tx: ReadTransaction) => Promise<R>;
onData: (r: R) => void;
onError?: (e: E) => void;
onDone?: () => void;
lastValue?: R;
};
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