119 lines
4.6 KiB
Racket
119 lines
4.6 KiB
Racket
#lang syndicate
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;; Generic relay for WebSockets/TCP/etc-based participation in a network.
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(provide spawn-broker-server
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spawn-broker-server-connection
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(struct-out broker-scope)
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(struct-out broker-data))
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(require racket/dict)
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(require racket/set)
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(require racket/match)
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(require net/rfc6455)
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(require json)
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;; (require (except-in "../main.rkt" dataspace assert))
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;; (require "../actor.rkt")
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(require syndicate/trie)
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(require syndicate/pattern)
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(require syndicate/patch)
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(require syndicate/demand-matcher)
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(require syndicate/protocol/advertise)
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(require/activate syndicate/drivers/timestate)
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(require/activate syndicate/drivers/web)
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(require "protocol.rkt")
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(define-logger syndicate-broker)
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(struct broker-scope (host port path) #:prefab)
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(struct broker-data (scope assertion) #:prefab)
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;; Depends on timer driver and web driver.
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;; Does not, itself, assert a web-virtual-host; the context must do this.
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(define (spawn-broker-server port
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#:hostname [hostname ?]
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#:path [resource-path-str "/"])
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(spawn #:name 'broker:dm
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(on (web-request-get (id req)
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(web-virtual-host "http" hostname port)
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,(string->resource-path resource-path-str))
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(when (web-request-header-websocket-upgrade? req)
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(spawn-broker-server-connection id req)))))
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(define (http-req->scope http-req)
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(define http-resource (web-request-header-resource http-req))
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(define http-vh (web-resource-virtual-host http-resource))
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(define scope (broker-scope (web-virtual-host-name http-vh)
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(web-virtual-host-port http-vh)
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(resource-path->string (web-resource-path http-resource))))
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(lambda (v) (broker-data scope v)))
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(define (spawn-broker-server-connection req-id http-req
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#:scope [scope (http-req->scope http-req)]
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#:hook [hook void])
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(spawn #:name (list 'broker:connection req-id)
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(hook)
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(on-start (log-syndicate-broker-info "Starting broker connection ~v" req-id))
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(on-stop (log-syndicate-broker-info "Ending broker connection ~v" req-id))
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(on (asserted (web-request-peer-details req-id _ _ $addr $port))
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(log-syndicate-broker-info "Connection ~v is from ~a:~a" req-id addr port))
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(assert (web-response-websocket req-id))
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(stop-when (websocket-connection-closed req-id))
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(define (send-event e)
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(websocket-message-send! req-id (jsexpr->string (lift-json-event e))))
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(field [ping-time-deadline 0])
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(on (asserted (later-than (ping-time-deadline)))
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(ping-time-deadline (+ (current-inexact-milliseconds) (ping-interval)))
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(send-event 'ping))
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(on (websocket-message-recv req-id $data)
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(match (drop-json-action (string->jsexpr data))
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['ping (send-event 'pong)]
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['pong (void)]
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[(? patch? p) (patch! (log-packet req-id 'inbound 'patch (wrap-patch scope p)))]
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[(message body) (send! (log-packet req-id 'inbound 'message (scope body)))]))
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(on-event
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[(? patch? p) (send-event (log-packet req-id 'outbound 'patch (unwrap-patch scope p)))]
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[(message scoped-body)
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(match (match-value/captures scoped-body (scope (?!)))
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[(list body) (send-event (message (log-packet req-id 'outbound 'message body)))]
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[_ (void)])])))
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(define (log-packet c direction kind value)
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(log-syndicate-broker-debug "Broker: ~v: ~a ~a\n~v" c direction kind value)
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value)
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(define (unwrap-patch scope p)
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(match-define (patch added removed) p)
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(patch (unwrap-trie scope added) (unwrap-trie scope removed)))
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(define (wrap-patch scope p)
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(match-define (patch added removed) p)
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(patch (wrap-trie scope added) (wrap-trie scope removed)))
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(define (lift-beneath-observation f t)
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(if (trie-empty? t)
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t
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(let ((observations (trie-step t observe-parenthesis)))
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(trie-union (trie-prepend observe-parenthesis (lift-beneath-observation f observations))
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(f t)))))
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(define (unwrap-trie scope t)
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(lift-beneath-observation (lambda (t) (trie-project t (scope (?!)))) t))
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(define (wrap-trie scope t)
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(lift-beneath-observation (lambda (t) (pattern->trie #t (scope (embedded-trie t)))) t))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(module+ main
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(run-ground
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(activate "..")
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(spawn #:name 'broker:vh (assert (web-virtual-host "http" _ 8000)))
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(spawn-broker-server 8000)))
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