Add a HasLink instance for ServerSentEvents'

changelog.d/pr-1926

@@ -0,0 +1,7 @@
+synopsis: Add a `HasLink` instance for `ServerSentEvents'`
+packages: servant
+prs: #1926
+description: {
+  `safeLink`, `allLinks` and `fieldLink` now work on APIs that contain
+  `ServerSentEvents` endpoints.
+}

servant/src/Servant/Internal/Links.hs

@@ -129,6 +129,7 @@ import Servant.API.QueryString
 import Servant.API.Raw (Raw, RawM)
 import Servant.API.RemoteHost (RemoteHost)
 import Servant.API.ReqBody (ReqBody')
+import Servant.API.ServerSentEvents (ServerSentEvents')
 import Servant.API.Stream (Stream, StreamBody')
 import Servant.API.Sub (type (:>))
 import Servant.API.TypeErrors
@@ -572,6 +573,10 @@ instance HasLink (Stream m status fr ct a) where
   type MkLink (Stream m status fr ct a) r = r
   toLink toA _ = toA
 
+instance HasLink (ServerSentEvents' m status kind a) where
+  type MkLink (ServerSentEvents' m status kind a) r = r
+  toLink toA _ = toA
+
 -- UVerb instances
 instance HasLink (UVerb m ct a) where
   type MkLink (UVerb m ct a) r = r

servant/test/Servant/LinksSpec.hs

@@ -30,6 +30,8 @@ type TestApi =
     :<|> "say" :> Fragment String :> Get '[JSON] NoContent
     -- UVerb
     :<|> "uverb-example" :> UVerb 'GET '[JSON] '[WithStatus 200 NoContent]
+    -- ServerSentEvents
+    :<|> "events" :> ServerSentEvents 'JsonEvent Int
     -- DeepQuery
     :<|> "books" :> DeepQuery "filter" BookQuery :> Get '[JSON] [Book]
     -- All of the verbs
@@ -155,6 +157,10 @@ spec = describe "Servant.Links" $ do
     apiLink (Proxy :: Proxy ("uverb-example" :> UVerb 'GET '[JSON] '[WithStatus 200 NoContent]))
       `shouldBeLink` "uverb-example"
 
+  it "generates correct links for ServerSentEvents" $ do
+    apiLink (Proxy :: Proxy ("events" :> ServerSentEvents 'JsonEvent Int))
+      `shouldBeLink` "events"
+
   it "generates correct links for query flags" $ do
     let l1 =
           Proxy