-
Notifications
You must be signed in to change notification settings - Fork 0
/
index.js
429 lines (345 loc) · 10.3 KB
/
index.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
import fs from 'fs';
import path from 'path';
/*
* Create a cache (default options are shown below)
*
* const cache = new Cache(
* {
* // The directory where the cache is stored.
* //
* // Default is a dir called 'cache'
* dir: './cache'
*
* // Duration ttl in ms for each entry.
* //
* // Default is 1 day
* duration: 1 * 24 * 60 * 60 * 1000,
*
* // A namespace to isolate the cache.
* // Namespaces can be cleared without clearing the
* // entire cache. For example, if there are multiple
* // namespaces -- 'default', 'employees', 'partner' --
* // cache.clear('employees') will clear only that
* // namespace and leave the others alone.
* //
* // Default is 'default'.
* namespace: 'default',
*
* // cache methods synchronous or asynchronous. An
* // async cache uses async/await
* //
* // Default is sync = true
* sync: true
* });
*
* The following methods are available
*
* =================================================================
* method | description
* -----------------------------------------------------------------
* get | get(key) retrieves key from cache
* set | set(key, val) sets key to val in cache
* has | has(key) returns true if key exists in cache
* rm | rm(key) removes key from cache
* delete | delete(key) -- synonym for rm
* clear | clear(namespace) deletes the entire cache namespace
* keys | keys() lists all the keys in the cache
* all | all() lists all the keys and their values in the cache
* opts | opts() lists all the cache options
* =================================================================
*
*/
class Cache {
constructor(opts) {
const defaultOpts = {
dir: './cache',
namespace: 'default',
// one day in milliseconds
duration: 1 * 24 * 60 * 60 * 1000,
// use synchronous or asynchronous methods
sync: true
}
Object.assign(this, defaultOpts, opts);
this.nsdir = `${this.dir}/${this.namespace}`;
this.sync
? mkdirSync(this.dir)
: mkdirAsync(this.dir);
}
get = (key) => {
if (!key) {
console.error("error: 'key' is required to get its value");
return false;
}
return this.sync
? getSync(this.nsdir, key)
: getAsync(this.nsdir, key);
}
set = (key, val) => {
if (!key) {
console.error("error: 'key' is required to set its value");
return false;
}
const data = {
item: val,
stored: Date.now(),
ttl: this.duration
};
return this.sync
? setSync(this.nsdir, key, data)
: setAsync(this.nsdir, key, data);
}
has = (key) => {
if (!key) {
console.error("error: 'key' is required for has(key) to work");
return false;
}
const file = `${this.nsdir}/${key2path(key)}/${key}.json`;
return this.sync
? hasSync(file)
: hasAsync(file);
}
rm = (key) => {
if (!key) {
console.error("error: 'key' is required to remove it from cache");
return false;
}
const file = `${this.nsdir}/${key2path(key)}/${key}.json`;
return this.sync
? rmSync(file)
: rmAsync(file);
}
delete = (key) => this.rm(key);
clear = (namespace) => {
if (!namespace) {
console.error("error: 'namespace' is required to clear cache");
return false;
}
return this.sync
? clearSync(this.nsdir)
: clearAsync(this.nsdir);
}
keys = () => this.sync
? walkSync(this.nsdir)
: walkAsync(this.nsdir);
all = () => this.sync
? allSync(this.nsdir)
: allAsync(this.nsdir);
opts = () => {
return {
dir: this.dir,
namespace: this.namespace,
duration: this.duration,
sync: this.sync
};
}
}
/*******************************
* common utility functions *
*******************************/
/*
* key2path
* convert a key into a 3-level directory path
*/
const key2path = (key) => {
const one = key.substring(0, 1);
const two = key.substring(0, 2);
const thr = key.substring(0, 3);
return `${one}/${two}/${thr}`;
}
/*******************************/
/* synchronous functions */
/*******************************/
const mkdirSync = (dir) => {
if (!fs.existsSync(dir)) {
fs.mkdirSync(dir, { recursive: true });
}
}
/*
* walk a directory and return all the entries as an array
* see https://stackoverflow.com/a/16684530/183692
*/
const walkSync = function(dir, results = []) {
// the `withFileTypes` option saves having to call stat() on every file
const files = fs.readdirSync(dir, { withFileTypes: true });
for (let file of files) {
const fullPath = path.join(dir, file.name);
if (file.isDirectory()) {
walkSync(fullPath, results);
}
else if (path.extname(file.name) === '.json') {
/* Is a file */
const key = path.basename(file.name, '.json');
results.push(key);
}
}
return results;
}
const getSync = (dir, key) => {
const filepath = key2path(key);
const file = `${dir}/${filepath}/${key}.json`;
// const error_is_stale = `error: value of key '${key}' is stale`;
// const error_no_exist = `error: key '${key}' doesn't exist`;
if (fs.existsSync(file)) {
const d = JSON.parse(fs.readFileSync(file));
if ((d.stored + d.ttl) > Date.now()) {
return d;
}
//console.error(error_is_stale);
return false;
}
//console.error(error_no_exist);
return false;
}
const setSync = (dir, key, data) => {
const filepath = `${dir}/${key2path(key)}`;
const file = `${filepath}/${key}.json`;
mkdirSync(filepath);
fs.writeFileSync(file, JSON.stringify(data));
return data;
}
const hasSync = (file) => {
if (fs.existsSync(file)) {
return true;
}
return false;
}
const rmSync = (file) => {
if (fs.existsSync(file)) {
fs.unlinkSync(file);
return true;
}
//console.error(error_exist);
return false;
}
const clearSync = (dir) => {
if (fs.existsSync(dir)) {
fs.unlinkSync(dir);
return true;
}
//console.error(`error: '${dir}' doesn't exist`);
return false;
}
const allSync = (dir) => {const all = [];
const keys = walkSync(dir);
for (let key of keys) {
const val = getSync(dir, key);
all.push([key, val])
}
return all;
}
/*******************************/
/* asynchronous functions */
/*******************************/
const mkdirAsync = async (dir) => {
try {
// check if dir exists
await fs.promises.access(dir, fs.constants.F_OK);
// yes, it does
// move on
}
catch (error) {
// dir doesn't exist, so make it first
try {
await fs.promises.mkdir(dir, { recursive: true });
}
catch (error) {
console.error(error);
}
}
}
/*
* walk a directory and return all the entries as an array
* see https://stackoverflow.com/a/16684530/183692
*/
const walkAsync = async (dir, results = []) => {
// the `withFileTypes` option saves having to call stat() on every file
const files = await fs.promises.readdir(dir, { withFileTypes: true });
for (const file of files) {
const fullPath = path.join(dir, file.name);
if (file.isDirectory()) {
await walkAsync(fullPath, results);
}
else if (path.extname(file.name) === '.json') {
/* Is a file */
const key = path.basename(file.name, '.json');
results.push(key);
}
}
return results;
}
const getAsync = async (dir, key) => {
const filepath = key2path(key);
const file = `${dir}/${filepath}/${key}.json`;
// const error_is_stale = `error: value of key '${key}' is stale`;
// const error_no_exist = `error: key '${key}' doesn't exist`;
try {
const data = await fs.promises.readFile(file, 'utf8');
const d = JSON.parse(data);
if (d.stored + d.ttl > Date.now()) {
return d;
}
//console.error(error_is_stale);
return false;
}
// if there was an error reading the file
catch (error) {
console.error(error);
return false;
}
}
const setAsync = async (dir, key, data) => {
const filepath = `${dir}/${key2path(key)}`;
const file = `${filepath}/${key}.json`;
await mkdirAsync(filepath);
await fs.promises.writeFile(file, JSON.stringify(data));
return data;
}
const hasAsync = async (file) => {
try {
// check if file exists
await fs.promises.access(file, fs.constants.F_OK);
// yes, it does
// move on
return true;
}
catch (error) {
// file doesn't exist
return false;
}
}
const rmAsync = async (file) => {
try {
// check if file exists
await fs.promises.access(file, fs.constants.F_OK);
// yes, it does, remove it
await fs.promises.rm(file);
return true;
}
catch (error) {
// file doesn't exist
return false;
}
}
const clearAsync = async (dir) => {
try {
// check if file exists
await fs.promises.access(dir, fs.constants.F_OK);
// yes, it does, remove it
await fs.promises.rm(dir, { recursive: true });
return true;
}
catch (error) {
// file doesn't exist
return false;
}
}
const allAsync = async (dir) => {
const all = [];
const keys = await walkAsync(dir);
for (let key of keys) {
const val = await getAsync(dir, key);
all.push([key, val])
}
return all;
}
export { Cache };