starter

Node.js Crypto Starters

Starter for the most common usage.

Create a MD5 hex hash:

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require('crypto').createHash('md5').update(data, 'utf8').digest('hex');

Create a SHA256 base64 hash:

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require('crypto').createHash('sha256').update(data, 'utf8').digest('base64');

Calculating the digest varies with encoding:

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> data = 'secret'
'secret'
> require('crypto').createHash('sha256').update(data, 'utf8').digest('hex');
'2bb80d537b1da3e38bd30361aa855686bde0eacd7162fef6a25fe97bf527a25b'
> require('crypto').createHash('sha256').update(data, 'utf8').digest('base64');
'K7gNU3sdo+OL0wNhqoVWhr3g6s1xYv72ol/pe/Unols='
> require('crypto').createHash('sha256').update(data, 'utf8').digest('binary');
'+¸\rS{\u001d£ãÓ\u0003aªV½àêÍqbþö¢_é{õ\'¢['
> require('crypto').createHash('sha256').update(data, 'utf8').digest();
<Buffer 2b b8 0d 53 7b 1d a3 e3 8b d3 03 61 aa 85 56 86 bd e0 ea cd 71 62 fe f6 a2 5f e9 7b f5 27 a2 5b>
> require('crypto').createHash('sha256').update(data, 'utf8').digest().toString();
'+�\rS{\u001d����\u0003a��V�����qb���_�{�\'�['

Both hex and base64 are commonly used ones.

Needs an input_encoding when update data, otherwise there will be different results:

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> data = '秘密'
'秘密'
> require('crypto').createHash('sha256').update(data, 'ascii').digest('hex');
'7588bc51fd0ff10db9c66549e5cb7969b9f6b7cf3ccee080137a8eb1aa06e718'
> require('crypto').createHash('sha256').update(data, 'utf8').digest('hex');
'062a2931da683a9897c5a0b597113b1e9fd0d5bfb63e2a5d7c88b724f7f55c02'
> require('crypto').createHash('sha256').update(data, 'binary').digest('hex');
'7588bc51fd0ff10db9c66549e5cb7969b9f6b7cf3ccee080137a8eb1aa06e718'
> require('crypto').createHash('sha256').update(data).digest('hex');
'7588bc51fd0ff10db9c66549e5cb7969b9f6b7cf3ccee080137a8eb1aa06e718'

Don’t assume ASCII.

Parameter data must be a string or buffer, otherwise there will be an error:

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TypeError: Not a string or buffer

Google Cloud Datastore Starter: Dataset

Google Cloud Datastore dataset starter, part of a starter collection:

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// Google Cloud Datastore Starter: Dataset
// =======================================
'use strict';
// Define a dataset.
var params = {
  projectId: 'MY_PROJECT',
  keyFilename: '/path/to/key/file.json',
  namespace: 'MY_NAMESPACE'
};
var dataset = require('gcloud').datastore.dataset(params);
// Define an entity (including both key and data).
var kind = 'MY_KIND';
var key = dataset.key(kind);
var data = [
  {
    name: 'title',
    value: 'Google Cloud Datastore Starter',
    excludeFromIndexes: false
  }
];
// var data = { title: 'Google Cloud Datastore Starter' }; // Simple version
var entity = {
  key: key,
  data: data
};
// Save a single entity.
dataset.save(entity, function (err) {
  if (err) {
    throw err;
  }
});

Node.js HTTP Server One Liner

One liner to create a Node.js HTTP server:

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require('http').createServer(function (req, res) { res.end('OK'); }).listen(3000);

Print out the process ID instead:

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require('http').createServer(function (req, res) { res.end('' + process.pid); }).listen(3000);

This is useful with the worker process when implementing the cluster module.

Changelog Starter

A changelog starter to be consistent with my coding style:

  • Two header levels only with setext style.
  • Use underlines for first-level headers and dashes for second-level headers.
  • Each release is a section, hence use second-level header.
  • Each category in a release is not a section, hence use emphasis with double asterisks.
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Changelog
=========
Guideline:
1. Record notable changes.
2. List releases in reversed chronological order, newest on top.
3. Write all dates in `YYYY-MM-DD` format.
4. Follow [SemVer] format for each release.
5. Creating a new release by copying the **Example** section (on the bottom)
   to the top and rename it **Unreleased**.
6. Keep an **Unreleased** section on top for tracking any changes in order to
   minimize required effort.
7. Change _Unreleased_ to a release name with the date when ready.
_The guideline attempts to follow [Keep a CHANGELOG][1]._
[SemVer]: http://semver.org/
[1]: http://keepachangelog.com/
0.1.0 / 2015-01-01
------------------
**Security**
 - Inform users to upgrade for vulnerabilities.
**Removed**
 - Remove a deprecated feature in this release.
**Deprecated**
 - Deprecate a feature in the upcoming release.
**Changed**
 - Change an existing functionality.
**Added**
 - Add a new feature.
**Fixed**
 - Fix a bug.
Example / YYYY-MM-DD
--------------------
**Security**
 - Inform users to upgrade for vulnerabilities.
 - Each sentence must use the present tense and ends with a period.
**Removed**
 - Remove a deprecated feature in this release.
 - Basic Authentication is dropped in favor of Digest Authentication.
**Deprecated**
 - Deprecate a feature in the upcoming release.
 - Basic Authentication will be replaced by Digest Authentication in the next
   release.
**Changed**
 - Change an existing functionality.
 - User session data is added to the user object upon initialization.
**Added**
 - Add a new feature.
 - A new endpoint `/users` is added to handle user CRUD.
**Fixed**
 - Fix a bug.
 - Add the default case to handle unknown cases in user group assigning.