* works on files matching pattern

* can specify default for when key unspecified
* can test for existence or for lack thereof
* can validate against type or array of types using [check-types](https://github.com/philbooth/check-types.js)
* can match against pattern as RegExp, string, or callback(value) returning boolean

.gitignore

@@ -0,0 +1 @@
+node_modules

HISTORY.md

@@ -0,0 +1,7 @@
+0.1.0 - August 30, 2014
+-----------------------
+* works on files matching pattern
+* can specify default for when key unspecified
+* can test for existence or for lack thereof
+* can validate against type or array of types using [check-types](https://github.com/philbooth/check-types.js)
+* can match against pattern as RegExp, string, or callback(value) returning boolean

Makefile

@@ -0,0 +1,8 @@
+
+node_modules: package.json
+	@npm install
+
+test: node_modules
+	@./node_modules/.bin/mocha --reporter spec
+
+.PHONY: test

README.md

@@ -0,0 +1,98 @@
+# metalsmith-validate
+
+A [Metalsmith](https://github.com/segmentio/metalsmith) plugin that allows you to validate file metadata. You can check existence, type, and regex pattern. Neat.
+
+## Features
+
+  - works on files matching pattern
+  - can specify default for when key unspecified
+  - can test for existence or for lack thereof
+  - can validate against type or array of types using [check-types](https://github.com/philbooth/check-types.js)
+  - can match against pattern as RegExp, string, or callback(value) returning boolean
+
+## Installation
+
+    $ npm install metalsmith-validate
+
+## Usage
+
+### Validate all files
+
+Pass hash of file metadata keys and rules.
+
+```js
+var validate = require('metalsmith-validate');
+
+metalsmith.use(validate({
+  title: {
+  	exists: true,
+  	type: 'String'
+  },
+  date: {
+  	exists: true,
+  	pattern: /^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/
+  },
+  tag: {
+  	default: 'news'
+  },
+  draft: {
+  	exists: false
+  }
+}));
+```
+
+### Validate pattern-matching files
+
+Pass array of hashes with file-matching pattern and metadata validation hash:
+
+```js
+var validate = require('metalsmith-validate');
+
+metalsmith.use(validate([
+	{
+		pattern: 'post/*',
+		metadata: {
+			title: true, // shorthand for title: { exists: true }
+			date: true,
+			invalid: false
+		}
+	},
+	{
+		// pattern defaults to '**/*'
+		metadata: {
+			template: {
+				default: 'default.jade'
+				pattern: function (value) {
+					return value.match(/\.jade$/);
+				}
+			}
+		}
+	}
+));
+```
+
+## CLI Usage
+
+All of the same options apply, just add them to the `"plugins"` key in your `metalsmith.json` configuration:
+
+```json
+{
+  "plugins": {
+    "metalsmith-validate": [
+      {
+        "pattern": "page/*",
+        "metadata": {
+        	"title": {
+        		"exists": true,
+        		"type": "String"
+        	}
+        }
+      }
+    ]
+  }
+}
+```
+
+## License
+
+  MIT

lib/index.js

@@ -0,0 +1,110 @@
+'use strict';
+
+var debug = require('debug')('metalsmith-validate');
+var Matcher = require('minimatch').Minimatch;
+var typeCheck = require('type-check').typeCheck;
+
+/**
+ * Expose `plugin`.
+ */
+
+module.exports = plugin;
+
+/**
+ * Metalsmith plugin that allows you to easily validate file metadata, checking existence, type, and regex pattern. Can also supply default value.
+ *
+ * @param {Array|Object} matchers array of rules applied to pattern-matched files, or hash of metadata validators to apply to all files
+ * @option {*} matchers[key].default set key to value if unset
+ * @option {Boolean} matchers[key].exists whether the key should exist
+ * @option {Array|string} matchers[key].type array of strings (or single string) of types which key must match at least one of
+ * @option {RegExp|string|Function} matchers[key].pattern regex pattern as RegExp or string to compare against key, or callback(value) returning Boolean
+ * @return {Function}
+ */
+
+function plugin(matchers) {
+	if (!Array.isArray(matchers)) {
+		matchers = [
+			{
+				metadata: matchers,
+			}
+		];
+	}
+
+	matchers = matchers.map(function (rule) {
+		rule.pattern = rule.pattern || '**/*';
+		debug('Normalize rule with pattern %s', rule.pattern);
+		rule.matcher = new Matcher(rule.pattern);
+		rule.metadata = rule.metadata || {};
+
+		Object.keys(rule.metadata).forEach(function (key) {
+			rule.metadata[key] = typeof rule.metadata[key] === 'object' ? rule.metadata[key] : {
+				exists: rule.metadata[key],
+			};
+
+			var validator = rule.metadata[key];
+
+			if (validator.type && !Array.isArray(validator.type)) {
+				validator.type = [validator.type];
+			}
+
+			if (typeof validator.pattern === 'string') {
+				validator.pattern = new RegExp(validator.pattern);
+			}
+		});
+
+		return rule;
+	});
+
+	return function (files, metalsmith, done) {
+		var err;
+
+		Object.keys(files).forEach(function (file) {
+			debug('Validate file %s', file);
+			var data = files[file];
+
+			matchers.forEach(function (rule) {
+				if (rule.matcher.match(file)) {
+					debug('Validate against rule with matching pattern %s', rule.pattern);
+					Object.keys(rule.metadata).every(function (key) {
+						var validator = rule.metadata[key];
+
+						if ('default' in validator && !(key in data)) {
+							return data[key] = validator.default;
+						}
+
+						if ('exists' in validator && validator.exists != key in data) {
+							err = new Error('File "' + file + '" ' + (validator.exists ? 'does not have' : 'has') + ' value "' + key + '".');
+							return false;
+						}
+
+						if ('type' in validator && validator.type.indexOf(typeof data[key]) === -1) {
+							var valid = false;
+
+							validator.type.some(function (type) {
+								return valid = typeCheck(type, data[key]);
+							});
+
+							if (!valid) {
+								err = new Error('File "' + file + '" value "' + key + '" must be of type [' + validator.type.join(', ') + '].');
+								return false;
+							}
+						}
+
+						if ('pattern' in validator && key in data && ((typeof validator.pattern === 'function' && !validator.pattern(data[key])) || !data[key].match(validator.pattern))) {
+							err = new Error('File "' + file + '" value "' + key + '" does not match ' + validator.pattern + '.');
+							return false;
+						}
+
+						return true;
+					});
+				}
+
+				if (err) {
+					return false;
+				}
+			});
+		});
+
+		done(err);
+	};
+}

package.json

@@ -0,0 +1,18 @@
+{
+  "name": "metalsmith-validate",
+  "description": "A Metalsmith plugin that allows you to easily validate file metadata, checking existence, type, and regex pattern.",
+  "repository": "git://github.com/mikestopcontinues/metalsmith-validate.git",
+  "version": "0.1.0",
+  "author": "Mike Stop Continues <mikestopcontinues@gmail.com>",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "dependencies": {
+    "debug": "~0.7.4",
+    "minimatch": "^0.3.0",
+    "type-check": "^0.3.1"
+  },
+  "devDependencies": {
+    "metalsmith": "0.x",
+    "mocha": "1.x"
+  }
+}

test/fixtures/callback/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/callback/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/callback/src/one.md

@@ -0,0 +1,5 @@
+---
+pattern: match
+---
+
+one

test/fixtures/callback/src/two.md

@@ -0,0 +1,5 @@
+---
+pattern: unmatched
+---
+
+one

test/fixtures/default/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/default/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/default/src/one.md

@@ -0,0 +1,5 @@
+---
+default: specified
+---
+
+one

test/fixtures/default/src/two.md

@@ -0,0 +1,4 @@
+---
+---
+
+one

test/fixtures/exists/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/exists/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/exists/src/one.md

@@ -0,0 +1,5 @@
+---
+exists: true
+---
+
+one

test/fixtures/exists/src/two.md

@@ -0,0 +1,4 @@
+---
+---
+
+one

test/fixtures/hash/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/hash/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/hash/src/one.md

@@ -0,0 +1,5 @@
+---
+default: specified
+---
+
+one

test/fixtures/hash/src/two.md

@@ -0,0 +1,4 @@
+---
+---
+
+one

test/fixtures/missing/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/missing/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/missing/src/one.md

@@ -0,0 +1,5 @@
+---
+exists: true
+---
+
+one

test/fixtures/missing/src/two.md

@@ -0,0 +1,4 @@
+---
+---
+
+one

test/fixtures/pattern/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/pattern/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/pattern/src/one.md

@@ -0,0 +1,5 @@
+---
+pattern: match
+---
+
+one

test/fixtures/pattern/src/two.md

@@ -0,0 +1,5 @@
+---
+pattern: unmatched
+---
+
+one

test/fixtures/regex/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/regex/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/regex/src/one.md

@@ -0,0 +1,5 @@
+---
+pattern: match
+---
+
+one

test/fixtures/regex/src/two.md

@@ -0,0 +1,5 @@
+---
+pattern: unmatched
+---
+
+one

test/fixtures/type/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/type/build/two.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/type/src/one.md

@@ -0,0 +1,5 @@
+---
+type: string
+---
+
+one

test/fixtures/type/src/two.md

@@ -0,0 +1,7 @@
+---
+type: 
+ - string
+ - array
+---
+
+one

test/fixtures/types/build/one.md

@@ -0,0 +1,2 @@
+
+one

test/fixtures/types/build/two.md

@@ -0,0 +1,2 @@
+
+one