Improve install command to resolve best plugin version

lib/configuration.js

@@ -1,7 +1,6 @@
 var _ = require("lodash");
 var Q = require("q");
 var path = require("path");
-var npmi = require('npmi');
 var semver = require('semver');
 
 var pkg = require('../package.json');
@@ -126,40 +125,6 @@ Configuration.prototype.normalizeLanguage = function() {
     return _.first(this.options.language.split("-")).toLowerCase();
 };
 
-// Install plugins
-Configuration.prototype.installPlugins = function(options) {
-    var that = this;
-    options = _.defaults(options || {
-        log: true
-    });
-
-    // Remov defaults (no need to install)
-    var plugins = _.filter(that.options.plugins, function(plugin) {
-        return !_.contains(defaultsPlugins, plugin.name);
-    });
-
-    // Install plugins one by one
-    if (options.log) that.book.log.info.ln(plugins.length+" plugins to install");
-    return _.reduce(plugins, function(prev, plugin) {
-        return prev.then(function() {
-            var fullname = "gitbook-plugin-"+plugin.name;
-            if (options.log) that.book.log.info.ln("install plugin", plugin.name, "from npm ("+fullname+") with version", (plugin.version || "*"));
-            return Q.nfcall(npmi, {
-                'name': fullname,
-                'version': plugin.version,
-                'path': that.book.root,
-                'npmLoad': {
-                    'loglevel': 'silent',
-                    'loaded': false,
-                    'prefix': that.book.root
-                }
-            })
-            .then(function() {
-                that.book.log.info.ok("plugin", plugin.name, "installed with success");
-            });
-        });
-    }, Q());
-}
 
 // Default configuration
 Configuration.DEFAULT = {

lib/index.js

@@ -186,9 +186,7 @@ module.exports = {
 
 				return book.config.load()
 				.then(function() {
-					return book.config.installPlugins({
-						log: true
-					});
+					return book.plugins.install();
 				})
 				.then(function(){
 					console.log("");

lib/pluginslist.js

@@ -1,7 +1,16 @@
 var _ = require("lodash");
 var Q = require("q");
+var npmi = require('npmi');
+var npm = require('npm');
+var semver = require('semver');
 
 var Plugin = require("./plugin");
+var pkg = require("../package.json");
+
+var initNPM = _.memoize(function() {
+	return Q.nfcall(npm.load, { silent: true, loglevel: 'silent' });
+});
+
 
 var PluginsList = function(book, plugins) {
 	this.book = book;
@@ -138,4 +147,79 @@ PluginsList.prototype.resources = function(namespace) {
 	return this.namespaces[namespace].resources;
 };
 
+// Install plugins from a book
+PluginsList.prototype.install = function() {
+	var that = this;
+	var defaultsPlugins = _.pluck(that.book.options.defaultsPlugins)
+
+    // Remove defaults (no need to install)
+    var plugins = _.filter(that.book.options.plugins, function(plugin) {
+        return !_.contains(defaultsPlugins, plugin.name);
+    });
+
+    // Install plugins one by one
+    that.book.log.info.ln(plugins.length+" plugins to install");
+    return _.reduce(plugins, function(prev, plugin) {
+        return prev.then(function() {
+            var fullname = "gitbook-plugin-"+plugin.name;
+
+            return Q()
+
+            // Resolve version if needed
+            .then(function() {
+            	if (plugin.version) return plugin.version;
+
+            	that.book.log.info.ln("No version specified, resolve plugin", plugin.name);
+            	return initNPM()
+            	.then(function() {
+            		return Q.nfcall(npm.commands.view, [fullname+"@>=0.0.0", "engines"], true);
+            	})
+            	.then(function(versions) {
+            		return _.chain(versions)
+            			.pairs()
+            			.map(function(v) {
+            				return {
+            					version: v[0],
+            					gitbook: (v[1].engines || {})["gitbook"]
+            				}
+            			})
+            			.filter(function(v) {
+            				return v.gitbook && semver.satisfies(pkg.version, v.gitbook);
+            			})
+            			.sort(function(v1, v2) {
+            				return semver.lt(v1.version, v2.version)? 1 : -1;
+            			})
+            			.pluck("version")
+            			.first()
+            			.value();
+            	});
+            })
+
+            // Install the plugin with the resolved version
+            .then(function(version) {
+            	if (!version) {
+            		throw "Found no satisfactory version for plugin "+plugin.name;
+            	}
+
+            	that.book.log.info.ln("install plugin", plugin.name, "from npm ("+fullname+") with version", version);
+	            return Q.nfcall(npmi, {
+	                'name': fullname,
+	                'version': version,
+	                'path': that.book.root,
+	                'npmLoad': {
+	                    'loglevel': 'silent',
+	                    'loaded': true,
+	                    'prefix': that.book.root
+	                }
+	            });
+            })
+            .then(function() {
+                that.book.log.info.ok("plugin", plugin.name, "installed with success");
+            });
+        });
+    }, Q());
+};
+
+
+
 module.exports = PluginsList;

package.json

@@ -29,6 +29,7 @@
         "bash-color": "0.0.3",
         "URIjs": "1.14.1",
         "request": "2.51.0",
+        "npm": "2.4.1",
         "dom-serializer": "git+https://github.com/SamyPesse/dom-serializer.git#58d8ea24b9b7b4137ee5f30a41abce4d7c4a922a"
     },
     "devDependencies": {