Manipulate HTTP Response

Changing the default Content-Type

The result content type is automatically inferred from the value you specify in the body of the produced result.

For example, in:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=text]

Wisdom automatically sets the Content-Type header to text/plain, while in:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=json]

it sets the Content-Type header to application/json.

This is pretty useful, but sometimes you want to change it. Just use the as(newContentType) method on a result to create a new similar result with a different Content-Type header:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=html-2]

You can also use the methods html() and json() to set the content type respectively to HTML and JSON.

Setting HTTP response headers

You can add (or update) any HTTP response header:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=headers]

The previous action returns a result with the header set to the expected values:

Content-Length: 21
Connection: keep-alive
Etag: xxx
Cache-Control: max-age=3600
Content-Type: text/html; UTF-8

Important

Setting an HTTP header will automatically discard any previous values.

Setting and discarding cookies

Cookies are just a special form of HTTP headers, but Wisdom provides a set method to manipulate them easily. You can easily add a Cookie to the HTTP response:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=cookies]

Note	You can configure all aspects of the built cookie such as the max age, domain, and path.

Also, to discard a Cookie previously stored on the Web browser:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=remove-cookies]

Tip	Two methods are available to remove things from an existing `Result`. `without(String)` removes a header while `discard(String)` removes a cookie. However, if `without(String)` does not find a matching header, it will try to remove a cookie.

Specifying the character encoding for text results

For a text-based HTTP response it is very important to handle the character encoding correctly. Wisdom handles that for you and uses UTF-8 by default. The encoding is used to both convert the text response to the corresponding bytes to send over the network socket, and to add the proper ;charset=xxx extension to the Content-Type header.

The encoding can be specified when you are generating the Result value:

include::{sourcedir}/controllers/ManipulateResponse.java[tags=charset]

Response encoding

Wisdom can automatically encode response content according to the client Accept_Encoding header . The default behavior is to automatically encode all traffic which has a size between 1KB and 10MB. Encoders currently available are gzip and deflate

Activate / Deactivate encoding

You can disable encoding globally by setting the key encoding.global to false in the configuration file.

Wisdom also provides two annotations allowing you to finely tune encoding behaviors.

@DenyEncoding can be used to disable encoding on Controllers and Routes ;
@AllowEncoding can be used to enable encoding on Controllers and Routes.

In case of multiple instructions, priority is as follow : Route > Method > Configuration.

Control encoding activation size

By default, Wisdom encodes content whose size is between 1KB and 10MB. If you want a different behavior, you can tune theses values with :

encoding.max.size and encoding.min.size configuration keys (long value in bytes)
@AllowEncoding maxSize and minSize parameters (long value in bytes)

MimeType filtering

By default already encoded mime types are not encoded by Wisdom. This includes audio/, video/, image/ MimeType groups as well as all common compressed MimeType (7z, rar, …)

URL encoding

Content whose size can’t be found by Wisdom is not encoded, for performance reasons. Thus Stream contents are not encoded.

We have an exception for URL, as we are able to determine the mime type. By default, URL content is encoded but you can deactivate this using the global configuration key encoding.url. Setting this key to false disables URL content encoding (this include assets and resources).

If you want to deactivate URL content encoding on a particular Route or Controller, you can still use @DenyEncoding to not encode URL returned by theses routes.