Make default length of content configurable (#51)

* added option for max length of feed content (previously fixed to 140); defaults to 140;

* bumped version to 1.2.1

* fixed config option reference;

* playing around with only cutting post content at delim for feed summary

* playing around with only cutting post content at delim for feed summary

* implemented content delimiter also for rss2; updated README and included new content_limit_delim option; bumped package version to 1.2.2;

README.md

@@ -28,10 +28,14 @@ feed:
   limit: 20
   hub:
   content:
+  content_limit: 140
+  content_limit_delim: ' '
 ```
 
 - **type** - Feed type. (atom/rss2)
 - **path** - Feed path. (Default: atom.xml/rss2.xml)
 - **limit** - Maximum number of posts in the feed (Use `0` or `false` to show all posts)
 - **hub** - URL of the PubSubHubbub hubs (Leave it empty if you don't use it)
 - **content** - (optional) set to 'true' to include the contents of the entire post in the feed.
+- **content_limit** - (optional) Default length of post content used in summary. Only used, if **content** setting is false and no custom post description present.
+- **content_limit_delim** - (optional) If **content_limit** is used to shorten post contents, only cut at the last occurrence of this delimiter before reaching the character limit. Not used by default.

atom.xml

@@ -31,7 +31,17 @@
     {% elif post.excerpt %}
       {{ post.excerpt }}
     {% elif post.content %}
-      {{ post.content.substring(0, 140) }}
+      {% set short_content = post.content.substring(0, config.feed.content_limit) %}
+      {% if config.feed.content_limit_delim %}
+        {% set delim_pos = short_content.lastIndexOf(config.feed.content_limit_delim) %}
+        {% if delim_pos > -1 %}
+          {{ short_content.substring(0, delim_pos) }}
+        {% else %}
+          {{ short_content }}
+        {% endif %}
+      {% else %}
+        {{ short_content }}
+      {% endif %}
     {% endif %}
     </summary>
     {% for category in post.categories.toArray() %}

index.js

@@ -8,7 +8,9 @@ var config = hexo.config.feed = assign({
   type: 'atom',
   limit: 20,
   hub: '',
-  content: true
+  content: true,
+  content_limit: 140,
+  content_limit_delim: ''
 }, hexo.config.feed);
 
 var type = config.type.toLowerCase();

rss2.xml

@@ -22,7 +22,17 @@
       {% elif post.excerpt %}
         {{ post.excerpt }}
       {% elif post.content %}
-        {{ post.content.substring(0, 140) }}
+        {% set short_content = post.content.substring(0, config.feed.content_limit) %}
+        {% if config.feed.content_limit_delim %}
+          {% set delim_pos = short_content.lastIndexOf(config.feed.content_limit_delim) %}
+          {% if delim_pos > -1 %}
+            {{ short_content.substring(0, delim_pos) }}
+          {% else %}
+            {{ short_content }}
+          {% endif %}
+        {% else %}
+          {{ short_content }}
+        {% endif %}
       {% endif %}
       </description>
       {% if config.feed.content and post.content %}