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package streaming
import (
"fmt"
"net/http"
"time"
"github.com/gin-gonic/gin"
"github.com/gorilla/websocket"
)
// StreamGETHandler handles the creation of a new websocket streaming request.
func (m *Module) StreamGETHandler(c *gin.Context) {
l := m.log.WithField("func", "StreamGETHandler")
streamType := c.Query(StreamQueryKey)
if streamType == "" {
c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("no stream type provided under query key %s", StreamQueryKey)})
return
}
accessToken := c.Query(AccessTokenQueryKey)
if accessToken == "" {
c.JSON(http.StatusUnauthorized, gin.H{"error": fmt.Sprintf("no access token provided under query key %s", AccessTokenQueryKey)})
return
}
// make sure a valid token has been provided and obtain the associated account
account, err := m.processor.AuthorizeStreamingRequest(accessToken)
if err != nil {
c.JSON(http.StatusUnauthorized, gin.H{"error": "could not authorize with given token"})
return
}
// prepare to upgrade the connection to a websocket connection
upgrader := websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
// we fully expect cors requests (via something like pinafore.social) so we should be lenient here
return true
},
}
// do the actual upgrade here
conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
if err != nil {
l.Infof("error upgrading websocket connection: %s", err)
return
}
defer conn.Close() // whatever happens, when we leave this function we want to close the websocket connection
// inform the processor that we have a new connection and want a stream for it
stream, errWithCode := m.processor.OpenStreamForAccount(account, streamType)
if errWithCode != nil {
c.JSON(errWithCode.Code(), errWithCode.Safe())
return
}
defer close(stream.Hangup) // closing stream.Hangup indicates that we've finished with the connection (the client has gone), so we want to do this on exiting this handler
// spawn a new ticker for pinging the connection periodically
t := time.NewTicker(30 * time.Second)
// we want to stay in the sendloop as long as possible while the client is connected -- the only thing that should break the loop is if the client leaves or something else goes wrong
sendLoop:
for {
select {
case m := <-stream.Messages:
// we've got a streaming message!!
l.Trace("received message from stream")
if err := conn.WriteJSON(m); err != nil {
l.Debugf("error writing json to websocket connection: %s", err)
// if something is wrong we want to bail and drop the connection -- the client will create a new one
break sendLoop
}
l.Trace("wrote message into websocket connection")
case <-t.C:
l.Trace("received TICK from ticker")
if err := conn.WriteMessage(websocket.PingMessage, []byte(": ping")); err != nil {
l.Debugf("error writing ping to websocket connection: %s", err)
// if something is wrong we want to bail and drop the connection -- the client will create a new one
break sendLoop
}
l.Trace("wrote ping message into websocket connection")
}
}
l.Trace("leaving StreamGETHandler")
}
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