/
sse.clj
54 lines (46 loc) · 2.01 KB
/
sse.clj
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
;; Copyright 2014-2015 Red Hat, Inc, and individual contributors.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; You may obtain a copy of the License at
;;
;; http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
(ns immutant.web.sse
"Provides Server-Sent Events via [[immutant.web.async/as-channel]]"
(:require [immutant.web.async :as async]))
(defn ^:no-doc ^:internal with-event-type [m]
(update-in m [:headers] assoc "Content-Type" "text/event-stream; charset=utf-8"))
(defprotocol Event
(event->str [x] "Formats event according to SSE spec"))
(extend-protocol Event
nil
(event->str [_] "data:\n")
Object
(event->str [o] (str "data:" o "\n"))
java.util.Collection
(event->str [c] (apply str (map event->str c)))
java.util.Map
(event->str [m] (apply str
(-> (for [[k v] (dissoc m :data)]
(format "%s:%s\n" (name k) v))
(conj (event->str (:data m)))))))
(def as-channel
"Decorates the result of [[immutant.web.async/as-channel]] with the proper SSE Content-Type."
(comp with-event-type async/as-channel))
(defn send!
"Formats an event according to the SSE spec and sends it via [[immutant.web.async/send!]].
`event` can be one of:
* a Map, with one or more of the following keys: :event, :data, :id, and :retry,
where the :data entry can be an Object or Collection
* an Object, treated as a simple data field (sent as `(str \"data:\" the-object \"\\n\")`)
* a Collecton, treated as a multi-line data field"
([ch event]
(send! ch event nil))
([ch event options]
(async/send! ch (str (event->str event) "\n") options)))