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 a "strong" or a "weak" ETag will be generated. The ETag can only really be a strong as the given input.

$ 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   425,007 ops/sec ±1.47% (184 runs sampled)
* buffer - weak   x 1,009,859 ops/sec ±0.18% (197 runs sampled)
  string - strong x   442,096 ops/sec ±1.20% (181 runs sampled)
  string - weak   x   325,063 ops/sec ±0.31% (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 263,069 ops/sec ±1.60% (190 runs sampled)
* buffer - weak   x 295,732 ops/sec ±0.43% (199 runs sampled)
  string - strong x 274,822 ops/sec ±1.15% (191 runs sampled)
  string - weak   x 169,473 ops/sec ±1.59% (194 runs sampled)
 
> node benchmark/body2-5kb.js
 
  5KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
  buffer - strong x 104,299 ops/sec ±0.60% (193 runs sampled)
* buffer - weak   x 108,126 ops/sec ±0.65% (196 runs sampled)
  string - strong x 101,736 ops/sec ±0.78% (194 runs sampled)
  string - weak   x 101,266 ops/sec ±0.85% (192 runs sampled)
 
> node benchmark/body3-10kb.js
 
  10KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
  buffer - strong x 59,007 ops/sec ±0.29% (198 runs sampled)
* buffer - weak   x 60,968 ops/sec ±0.48% (197 runs sampled)
  string - strong x 51,873 ops/sec ±1.78% (178 runs sampled)
  string - weak   x 52,307 ops/sec ±2.63% (193 runs sampled)
 
> node benchmark/body4-100kb.js
 
  100KB body
 
  1 test completed.
  2 tests completed.
  3 tests completed.
  4 tests completed.
 
  buffer - strong x 6,712 ops/sec ±0.11% (198 runs sampled)
* buffer - weak   x 6,716 ops/sec ±0.50% (196 runs sampled)
  string - strong x 6,397 ops/sec ±0.36% (196 runs sampled)
  string - weak   x 6,635 ops/sec ±0.15% (198 runs sampled)

MIT