;; pub/sub with envelope address
;; Note that if you don't insert a sleep, the server will crash with SIGPIPE as soon
;; as a client disconnects. Also a remaining client may receive tons of
;; messages afterward.
(use zmq srfi-18 sqlite3)
(define pub (make-socket 'pub))
(define pull (make-socket 'pull))
(define cname "server")
(bind-socket pub "tcp://*:5563")
(bind-socket pull "tcp://*:5564")
(define (open-db)
(let* ((dbpath "mockup.db")
(dbexists (file-exists? dbpath))
(db (open-database dbpath)) ;; (never-give-up-open-db dbpath))
(handler (make-busy-timeout 10)))
(set-busy-handler! db handler)
(if (not dbexists)
(for-each
(lambda (stmt)
(execute db stmt))
(list
"PRAGMA SYNCHRONOUS=0;"
"CREATE TABLE clients (id INTEGER PRIMARY KEY,name TEXT,num_accesses INTEGER DEFAULT 0);"
"CREATE TABLE vars (var TEXT,val TEXT,CONSTRAINT vars_constraint UNIQUE (var));")))
db))
(define cid-cache (make-hash-table))
(define (get-client-id db cname)
(let ((cid (hash-table-ref/default cid-cache cname #f)))
(if cid
cid
(begin
(execute db "INSERT OR REPLACE INTO clients (name) VALUES(?);" cname)
(for-each-row
(lambda (id)
(set! cid id))
db
"SELECT id FROM clients WHERE name=?;" cname)
(hash-table-set! cid-cache cname cid)
cid))))
(define (count-client db cname)
(let ((cid (get-client-id db cname)))
(execute db "UPDATE clients SET num_accesses=num_accesses+1 WHERE id=?;" cid)))
(define db (open-db))
;; (define queuelst '())
;; (define mx1 (make-mutex))
(define (process-queue queuelst)
(for-each
(lambda (item)
(let ((cname (vector-ref item 1))
(clcmd (vector-ref item 2))
(cdata (vector-ref item 3)))
(send-message pub cname send-more: #t)
(send-message pub (case clcmd
((sync)
"ok")
((set)
(apply execute db "INSERT OR REPLACE INTO vars (var,val) VALUES (?,?);" (string-split cdata))
"ok")
((get)
(let ((res "noval"))
(for-each-row
(lambda (val)
(set! res val))
db
"SELECT val FROM vars WHERE var=?;" cdata)
res))
(else (conc "unk cmd: " clcmd))))))
queuelst))
(define th1 (make-thread
(lambda ()
(let ((last-run 0)) ;; current-seconds when run last
(let loop ((queuelst '()))
(let* ((indat (receive-message* pull))
(parts (string-split indat ":"))
(cname (car parts)) ;; client name
(clcmd (string->symbol (cadr parts))) ;; client cmd
(cdata (caddr parts)) ;; client data
(svect (vector (current-seconds) cname clcmd cdata))) ;; record for the queue
(count-client db cname)
(case clcmd
((sync) ;; just process the queue
(print "Got sync from " cname)
(process-queue (cons svect queuelst))
(loop '()))
((get)
(process-queue (cons svect queuelst))
(loop '()))
(else
(loop (cons svect queuelst))))))))
"server thread"))
(include "mockupclientlib.scm")
;; send a sync to the pull port
(define th2 (make-thread
(lambda ()
(let loop ()
(thread-sleep! 5)
;; (print "Sending sync from server")
(dbaccess "server" 'sync "nada" #f)
(loop)))
"sync thread"))
(thread-start! th1)
(thread-start! th2)
(thread-join! th1)