The Express4.x version uses socket.io

how to use socket.io in express4.x version routing? I"ve been looking for the answer for a long time. The Internet is full of express3.x version

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Feb.27,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bdf066-30c9b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bdf066-30c9b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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