etag

Create simple ETags

etag

Create simple ETags

$ npm install etag
var etag = require('etag')

Generate a strong ETag for the given entity. This should be the complete body of the entity. Strings, Buffers, and fs.Stats are accepted. By default, a strong ETag is generated except for fs.Stats, which will generate a weak ETag (this can be overwritten by options.weak).

res.setHeader('ETag', etag(body))

etag accepts these properties in the options object.

Specifies if the generated ETag will include the weak validator mark (that is, the leading W/). The actual entity tag is the same. The default value is false, unless the entity is fs.Stats, in which case it is true.

$ npm test
$ npm run-script bench
 
> etag@1.6.0 bench nodejs-etag
> node benchmark/index.js
 
  http_parser@1.0
  node@0.10.33
  v8@3.14.5.9
  ares@1.9.0-DEV
  uv@0.10.29
  zlib@1.2.3
  modules@11
  openssl@1.0.1j
 
> node benchmark/body0-100b.js
 
  100B body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* buffer - strong x 289,198 ops/sec ±1.09% (190 runs sampled)
* buffer - weak   x 287,838 ops/sec ±0.91% (189 runs sampled)
* string - strong x 284,586 ops/sec ±1.05% (192 runs sampled)
* string - weak   x 287,439 ops/sec ±0.82% (192 runs sampled)
 
> node benchmark/body1-1kb.js
 
  1KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* buffer - strong x 212,423 ops/sec ±0.75% (193 runs sampled)
* buffer - weak   x 211,871 ops/sec ±0.74% (194 runs sampled)
  string - strong x 205,291 ops/sec ±0.86% (194 runs sampled)
  string - weak   x 208,463 ops/sec ±0.79% (192 runs sampled)
 
> node benchmark/body2-5kb.js
 
  5KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* buffer - strong x 92,901 ops/sec ±0.58% (195 runs sampled)
* buffer - weak   x 93,045 ops/sec ±0.65% (192 runs sampled)
  string - strong x 89,621 ops/sec ±0.68% (194 runs sampled)
  string - weak   x 90,070 ops/sec ±0.70% (196 runs sampled)
 
> node benchmark/body3-10kb.js
 
  10KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* buffer - strong x 54,220 ops/sec ±0.85% (192 runs sampled)
* buffer - weak   x 54,069 ops/sec ±0.83% (191 runs sampled)
  string - strong x 53,078 ops/sec ±0.53% (194 runs sampled)
  string - weak   x 53,849 ops/sec ±0.47% (197 runs sampled)
 
> node benchmark/body4-100kb.js
 
  100KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* buffer - strong x 6,673 ops/sec ±0.15% (197 runs sampled)
* buffer - weak   x 6,716 ops/sec ±0.12% (198 runs sampled)
  string - strong x 6,357 ops/sec ±0.14% (197 runs sampled)
  string - weak   x 6,344 ops/sec ±0.21% (197 runs sampled)
 
> node benchmark/stats.js
 
  stats
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
* real - strong x 1,671,989 ops/sec ±0.13% (197 runs sampled)
* real - weak   x 1,681,297 ops/sec ±0.12% (198 runs sampled)
  fake - strong x   927,063 ops/sec ±0.14% (198 runs sampled)
  fake - weak   x   914,461 ops/sec ±0.41% (191 runs sampled)

MIT