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Diffstat (limited to 'guide/loop_handlers.md')
-rw-r--r-- | guide/loop_handlers.md | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/guide/loop_handlers.md b/guide/loop_handlers.md index 41f9e76..64cf80a 100644 --- a/guide/loop_handlers.md +++ b/guide/loop_handlers.md @@ -16,15 +16,23 @@ While the same can be accomplished using plain HTTP handlers, it is recommended to use loop handlers because they are well-tested and allow using built-in features like hibernation and timeouts. -Callbacks ---------- - -@todo Describe the callbacks. - Usage ----- -@todo Explain how to use them. +Loop handlers are used for requests where a response might not +be immediately available, but where you would like to keep the +connection open for a while in case the response arrives. The +most known example of such practice is known as long-polling. + +Loop handlers can also be used for requests where a response is +partially available and you need to stream the response body +while the connection is open. The most known example of such +practice is known as server-sent events. + +Loop handlers essentially wait for one or more Erlang messages +and feed these messages to the `info/3` callback. It also features +the `init/3` and `terminate/2` callbacks which work the same as +for plain HTTP handlers. The following handler waits for a message `{reply, Body}` before sending a response. If this message doesn't arrive within 60 |