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phantom-pool

Resource pool based on generic-pool for PhantomJS.

Creating new phantom instances with phantom.create() can be slow. If you are frequently creating new instances and destroying them, as a result of HTTP requests for example, this module can help by keeping a pool of phantom instances alive and making it easy to re-use them across requests.

Here's an artificial benchmark to illustrate:

Starting benchmark without pool

noPool-0: 786.829ms
noPool-1: 790.822ms
noPool-2: 795.150ms
noPool-3: 788.928ms
noPool-4: 793.788ms
noPool-5: 798.075ms
noPool-6: 813.130ms
noPool-7: 803.801ms
noPool-8: 782.936ms
noPool-9: 805.630ms

Starting benchmark with pool

pool-0: 48.160ms
pool-1: 98.966ms
pool-2: 89.573ms
pool-3: 99.057ms
pool-4: 101.970ms
pool-5: 102.967ms
pool-6: 102.938ms
pool-7: 99.359ms
pool-8: 101.972ms
pool-9: 103.309ms

Done

Using pool in this benchmark results in an average >8x speed increase.

Install

npm install --save phantom-pool

Requires Node v6+

Usage

See ./test directory for usage examples.

const createPhantomPool = require('phantom-pool')

// Returns a generic-pool instance
const pool = createPhantomPool({
  max: 10, // default
  min: 2, // default
  // how long a resource can stay idle in pool before being removed
  idleTimeoutMillis: 30000, // default.
  // maximum number of times an individual resource can be reused before being destroyed; set to 0 to disable
  maxUses: 50, // default
  // function to validate an instance prior to use; see https://github.com/coopernurse/node-pool#createpool
  validator: () => Promise.resolve(true), // defaults to always resolving true
  // validate resource before borrowing; required for `maxUses and `validator`
  testOnBorrow: true, // default
  // For all opts, see opts at https://github.com/coopernurse/node-pool#createpool
  phantomArgs: [['--ignore-ssl-errors=true', '--disk-cache=true'], {
    logLevel: 'debug',
  }], // arguments passed to phantomjs-node directly, default is `[]`. For all opts, see https://github.com/amir20/phantomjs-node#phantom-object-api
})

// Automatically acquires a phantom instance and releases it back to the
// pool when the function resolves or throws
pool.use(async (instance) => {
  const page = await instance.createPage()
  const status = await page.open('http://google.com', { operation: 'GET' })
  if (status !== 'success') {
    throw new Error('cannot open google.com')
  }
  const content = await page.property('content')
  return content
}).then((content) => {
  console.log(content)
})

// Destroying the pool:
pool.drain().then(() => pool.clear())

// For more API doc, see https://github.com/coopernurse/node-pool#generic-pool

Security

When using phantom-pool, you should be aware that the phantom instance you are getting might not be in a completely clean state. It could have browser history, cookies or other persistent data from a previous use.

If that is an issue for you, make sure you clean up any sensitive data on the phantom instance before returning it to the pool.