@drspro (R.van Vessum) posted a new topic, subject "Swi webserver and ssl". It read:

   dear swi prolog,
    
    I am using swi-prolog as a webserver, it uses SSL certificates and it seems to work very good,
    
    although it keeps running and serving data, in the console the server gives error messages
    
    i try to attach here in this message a graphical screen shot of the screen capture of the swi console
    
    SSl_error_forum1024×828 350 KB

To which @jan (Jan Wielemaker) replied

    Please copy/paste messages as text. It is easier and they become searchable.
    
    This is innocent. Typically this is caused by a browser that aborts some connection (for example when switching from a page or reloading a page before the load is finished) before the TLS handshake is completed.
    
    Possibly these should be suppressed, although such messages can be helpful if some client fails to connect.

Then @drspro (R.van Vessum) said

    dear forum and Jan,
    
    thankyou for your effort and information.
    
    these below are the messages in text from the swi prolog console for this subject,  
    I created a web server on ubuntu with swi-prolog as data server, and also  
    I implemented the chat-server on the site through the swi websocket examples  
    it took me a few days to get everything working, therefore i was offline,
    
    https://www.webparadigm.nl
    
    chatroom:
    
    https://www.webparadigm.nl/gymchat/mroom.htm?appdir=kpb
    
    ERROR: [Thread httpsd8443_1] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_5] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_4] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_1] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_5] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_3] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_2] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_4] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_1] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_5] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_3] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_2] SSL(14209102) tls_early_post_process_client_hello: unsupported protocol  
    ERROR: [Thread httpsd8443_3] SSL(1408F10B) ssl3_get_record: wrong version number  
    ERROR: [Thread httpsd8443_5] SSL(1408F09B) ssl3_get_record: https proxy request  
    ERROR: [Thread httpsd8443_2] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_4] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_2] SSL(1408F09C) ssl3_get_record: http request  
    ERROR: [Thread httpsd8443_1] SSL(1408F09C) ssl3_get_record: http request

To which @drspro (R.van Vessum) replied

    is use 2 swi-prolog server instances, 1 for web socket chat server and 1 as data -server,
    
    in de chat-server console it gives these messages, they are different form the previous ones, therefore i post them ,
    
    * * *
    
    Warning: [Thread 27] websocket:ws_send/1: I/O error in write on stream (0x7fc95801fba0) (Broken pipe)  
    Warning: [Thread 24] websocket:ws_send/1: I/O error in write on stream (0x7fc970019eb0) (Broken pipe)

To which @jan (Jan Wielemaker) replied

    Broken pipe means the other end (browser) closes the connection unexpectedly. In the context of web sockets this typically indicate you close the websocket (leave the page) without doing the websocket close sequence. Another reason for this message is a network error.
    
    The latter is fully harmless. The former can be avoided by nicely closing the websocket.


{'source': 'discourse', 'url': 'https://swi-prolog.discourse.group/t/swi-webserver-and-ssl/2742', 'title': 'Swi webserver and ssl', 'views': 352, 'has_accepted_answer': False, 'word_count': 484, 'like_count': 1, 'reply_count': 1, 'participant_count': 2, 'posts': 5, 'tags': '', 'author': '@drspro (R.van Vessum)', 'participants': '@drspro (R.van Vessum), @jan (Jan Wielemaker)', 'image_url': ['https://canada1.discourse-cdn.com/free1/uploads/swiprolog/original/2X/5/59807c9962630d79858882d1e372a12a3810a87e.png'], 'created_at': '2020-08-03T06:05:57.513Z', 'last_posted_at': '2020-08-20T14:22:07.264Z'}