Support root path configure for img tag

Current img tag doesn't prepend root path if it's not a slash. With
this fix, the root path will be prepend to the img src if it's not a
slash.
This fix only works for the hexo tags, does not work for the markdown
syntax of links and images. The issues of markdown links and images should
be fixed in the hexo-renderer-marked module.

Resolves: #1440

Author: liuhongjiang

lib/plugins/tag/img.js

@@ -12,67 +12,66 @@ var rMeta = /["']?([^"']+)?["']?\s*["']?([^"']+)?["']?/;
 * Syntax:
 *   {% img [class names] /path/to/image [width] [height] [title text [alt text]] %}
 */
+module.exports = function(ctx) {
+  return function imgTag(args, content){
+    var classes = [];
+    var meta = '';
+    var width;
+    var height;
+    var title;
+    var alt;
+    var src;
+    var item = '';
+    var url_for = ctx.extend.helper.get('url_for');
 
-function imgTag(args, content){
-  var classes = [];
-  var meta = '';
-  var width;
-  var height;
-  var title;
-  var alt;
-  var src;
-  var item = '';
-
-  // Find image URL and class name
-  for (var i = 0, len = args.length; i < len; i++){
-    item = args[i];
-
-    if (rUrl.test(item)){
-      src = item;
-      break;
-    } else {
-      if (item[0] === '/'){
-        src = item;
+    // Find image URL and class name
+    for (var i = 0, len = args.length; i < len; i++){
+      item = args[i];
+      if (rUrl.test(item)){
+        src = url_for.call(ctx, item);
         break;
       } else {
-        classes.push(item);
+        if (item[0] === '/'){
+          src = url_for.call(ctx, item);
+          break;
+        } else {
+          classes.push(item);
+        }
       }
     }
-  }
 
-  // Delete image URL and class name from arguments
-  args = args.slice(i + 1);
+    // Delete image URL and class name from arguments
+    args = args.slice(i + 1);
 
-  // Find image width and height
-  if (args.length){
-    if (!/\D+/.test(args[0])){
-      width = args.shift();
+    // Find image width and height
+    if (args.length){
+      if (!/\D+/.test(args[0])){
+        width = args.shift();
 
-      if (args.length && !/\D+/.test(args[0])){
-        height = args.shift();
+        if (args.length && !/\D+/.test(args[0])){
+          height = args.shift();
+        }
       }
+
+      meta = args.join(' ');
     }
 
-    meta = args.join(' ');
-  }
+    // Find image title and alt
+    if (meta && rMeta.test(meta)){
+      var match = meta.match(rMeta);
+      title = match[1];
+      alt = match[2];
+    }
 
-  // Find image title and alt
-  if (meta && rMeta.test(meta)){
-    var match = meta.match(rMeta);
-    title = match[1];
-    alt = match[2];
-  }
+    var attrs = {
+      src: src,
+      class: classes.join(' '),
+      width: width,
+      height: height,
+      title: title,
+      alt: alt
+    };
 
-  var attrs = {
-    src: src,
-    class: classes.join(' '),
-    width: width,
-    height: height,
-    title: title,
-    alt: alt
+    return htmlTag('img', attrs);
   };
-
-  return htmlTag('img', attrs);
-}
-
-module.exports = imgTag;
+};

lib/plugins/tag/index.js

@@ -17,7 +17,7 @@ module.exports = function(ctx){
 
   tag.register('iframe', require('./iframe'));
 
-  var img = require('./img');
+  var img = require('./img')(ctx);
 
   tag.register('img', img);
   tag.register('image', img);

test/scripts/tags/img.js

@@ -1,10 +1,15 @@
 'use strict';
 
+var pathFn = require('path');
 var cheerio = require('cheerio');
 var should = require('chai').should();
+var Promise = require('bluebird');
 
 describe('img', function(){
-  var img = require('../../../lib/plugins/tag/img');
+  var Hexo = require('../../../lib/hexo');
+  var hexo = new Hexo(pathFn.join(__dirname, 'img_test'));
+  hexo.init();
+  var img = require('../../../lib/plugins/tag/img')(hexo);
 
   it('src', function(){
     var $ = cheerio.load(img(['http://placekitten.com/200/300']));
@@ -13,9 +18,13 @@ describe('img', function(){
   });
 
   it('internal src', function(){
+    hexo.config.root = '/';
     var $ = cheerio.load(img(['/images/test.jpg']));
-
     $('img').attr('src').should.eql('/images/test.jpg');
+
+    hexo.config.root = '/root/';
+    $ = cheerio.load(img(['/images/test.jpg']));
+    $('img').attr('src').should.eql('/root/images/test.jpg');
   });
 
   it('class + src', function(){
@@ -26,10 +35,15 @@ describe('img', function(){
   });
 
   it('class + internal src', function(){
+    hexo.config.root = '/';
     var $ = cheerio.load(img('left /images/test.jpg'.split(' ')));
-
     $('img').attr('src').should.eql('/images/test.jpg');
     $('img').attr('class').should.eql('left');
+
+    hexo.config.root = '/root/';
+    $ = cheerio.load(img('left /images/test.jpg'.split(' ')));
+    $('img').attr('src').should.eql('/root/images/test.jpg');
+    $('img').attr('class').should.eql('left');
   });
 
   it('multiple classes + src', function(){
@@ -40,10 +54,15 @@ describe('img', function(){
   });
 
   it('multiple classes + internal src', function(){
+    hexo.config.root = '/';
     var $ = cheerio.load(img('left top /images/test.jpg'.split(' ')));
-
     $('img').attr('src').should.eql('/images/test.jpg');
     $('img').attr('class').should.eql('left top');
+
+    hexo.config.root = '/root/';
+    $ = cheerio.load(img('left top /images/test.jpg'.split(' ')));
+    $('img').attr('src').should.eql('/root/images/test.jpg');
+    $('img').attr('class').should.eql('left top');
   });
 
   it('class + src + width', function(){