Support and test for specifying mime type of icon

Readme.md

@@ -27,6 +27,7 @@ Returns a middleware serving the favicon found on the given `path`.
 #### options
 
 - `maxAge` cache-control max-age directive in ms, defaulting to 1 day.
+- `mime` specify the mime-type of the favicon, defaults to "image/x-icon"
 
 ## License
 

index.js

@@ -12,6 +12,8 @@ const fs = require('fs');
  *
  * @param {String} path
  * @param {Object} [options]
+ * @param {Number} [options.maxAge=null]
+ * @param {String} [options.mime="image/x-icon"] MIME type of the file at path
  * @return {Function}
  * @api public
  */
@@ -33,6 +35,7 @@ module.exports = function (path, options){
     ? 86400000
     : Math.min(Math.max(0, options.maxAge), 31556926000);
   const cacheControl = `public, max-age=${maxAge / 1000 | 0}`;
+  const mime = options.mime || 'image/x-icon';
 
   return (ctx, next) => {
     if ('/favicon.ico' != ctx.path) {
@@ -46,7 +49,7 @@ module.exports = function (path, options){
       // lazily read the icon
       if (!icon) icon = fs.readFileSync(path);
       ctx.set('Cache-Control', cacheControl);
-      ctx.type = 'image/x-icon';
+      ctx.type = mime;
       ctx.body = icon;
     }
   };

test/index.js

@@ -83,6 +83,18 @@ describe('favicon()', function(){
     .expect(200, body, done);
   });
 
+  it('should send the favicon with a different mime type', done => {
+    const body = fs.readFileSync(path);
+
+    const app = new Koa();
+    app.use(favicon(path, {mime: 'image/png'}));
+
+    request(app.listen())
+    .get('/favicon.ico')
+      .expect('Content-Type', 'image/png')
+    .expect(200, body, done);
+  });
+
   it('should set cache-control headers', done => {
     const app = new Koa();
     app.use(favicon(path));