PR 110: new default (#120)

* Use identity as default value for Accept-Encoding if it is blank or not provided

* Updated the lock file.

* Added defaultEncoding.

The code, the tests, the docs.

* Stupid ESLint fix.

Co-authored-by: Dobes Vandermeer <dobesv@gmail.com>

Author: uhop

README.md

@@ -51,9 +51,19 @@ The current encodings are, in order of preference: `br`, `gzip`, `deflate`.
 Setting `options[encoding] = {}` will pass those options to the encoding function.
 Setting `options[encoding] = false` will disable that encoding.
 
-### options.br
+#### options<span></span>.br
 
-[Brotli compression](https://en.wikipedia.org/wiki/Brotli) is supported in node v11.7.0+, which includes it natively. 
+[Brotli compression](https://en.wikipedia.org/wiki/Brotli) is supported in node v11.7.0+, which includes it natively.
+
+### options.defaultEncoding\<String\>
+
+An optional string, which specifies what encoders to use for requests without
+[Accept-Encoding](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding).
+Default `idenity`.
+
+The standard dictates to treat such requests as `*` meaning that all compressions are permissible,
+yet it causes very practical problems when debugging servers with manual tools like `curl`, `wget`, and so on.
+If you want to enable the standard behavior, just set `defaultEncoding` to `*`.
 
 ## Manually turning compression on and off
 

__tests__/index.js

@@ -245,16 +245,55 @@ describe('Compress', () => {
       .expect(200, done)
   })
 
-  it('should not crash if no accept-encoding is sent', (done) => {
+  it('should not compress if no accept-encoding is sent (with the default)', (done) => {
     const app = new Koa()
+    app.use(compress({
+      threshold: 0
+    }))
+    app.use((ctx) => {
+      ctx.type = 'text'
+      ctx.body = buffer
+    })
+    server = app.listen()
 
-    app.use(compress())
-    app.use(sendBuffer)
+    request(server)
+      .get('/')
+      .set('Accept-Encoding', '')
+      .end((err, res) => {
+        if (err) { return done(err) }
+
+        assert(!res.headers['content-encoding'])
+        assert(!res.headers['transfer-encoding'])
+        assert.equal(res.headers['content-length'], '1024')
+        assert.equal(res.headers.vary, 'Accept-Encoding')
+
+        done()
+      })
+  })
+
+  it('should be gzip if no accept-encoding is sent (with the standard default)', (done) => {
+    const app = new Koa()
+    app.use(compress({
+      threshold: 0,
+      defaultEncoding: '*'
+    }))
+    app.use((ctx) => {
+      ctx.type = 'text'
+      ctx.body = buffer
+    })
     server = app.listen()
 
     request(server)
       .get('/')
-      .expect(200, done)
+      .set('Accept-Encoding', '')
+      .end((err, res) => {
+        if (err) { return done(err) }
+
+        assert.equal(res.headers['content-encoding'], 'gzip')
+        assert.equal(res.headers.vary, 'Accept-Encoding')
+
+        done()
+      })
   })
 
   it('should not crash if a type does not pass the filter', (done) => {

lib/index.js

@@ -26,7 +26,7 @@ const NO_TRANSFORM_REGEX = /(?:^|,)\s*?no-transform\s*?(?:,|$)/
  */
 
 module.exports = (options = {}) => {
-  let { filter = compressible, threshold = 1024 } = options
+  let { filter = compressible, threshold = 1024, defaultEncoding = 'identity' } = options
   if (typeof threshold === 'string') threshold = bytes(threshold)
 
   // `options.br = false` would remove it as a preferred encoding
@@ -61,7 +61,7 @@ module.exports = (options = {}) => {
     const encodings = new Encodings({
       preferredEncodings
     })
-    encodings.parseAcceptEncoding(ctx.request.headers['accept-encoding'] || undefined)
+    encodings.parseAcceptEncoding(ctx.request.headers['accept-encoding'] || defaultEncoding)
     const encoding = encodings.getPreferredContentEncoding()
 
     // identity === no compression