Add upstream polling
This commit is contained in:
Tony Garnock-Jones
parent
9a98bcac0d
commit
38e6510b52
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@ -91,6 +91,7 @@
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#:body (string->bytes/utf-8
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(alist->form-urlencoded
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`((hub.callback . "http://localhost:7000/sink")
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(hub.poll_interval_seconds . "10")
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(hub.mode . "subscribe")
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(hub.topic . ,topic))))))
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158
rmq/server.rkt
158
rmq/server.rkt
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@ -8,6 +8,7 @@
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(require racket/set)
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(require net/url)
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(require net/uri-codec)
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(require file/sha1)
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(require/activate syndicate/drivers/timer)
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(require/activate syndicate/drivers/timestate)
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@ -27,17 +28,22 @@
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;; and numbers indicate a moment in time as a Unix epoch timestamp as
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;; might be returned from `current-seconds`.
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;; (notification Topic Bytes String (Option URIString))
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;; (notification Topic Bytes (Option String))
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(struct notification (topic-name content content-type) #:prefab)
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;; (subscription Topic Deadline URLString URLString (Option Bytes))
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(struct subscription (topic-name expiry-deadline canonical-hub callback secret) #:prefab)
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(struct subscription (topic-name ;; Topic
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expiry-deadline ;; Deadline
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canonical-hub ;; URLString
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callback ;; URLString
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secret ;; Option Bytes
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poll-interval-seconds) ;; Option Number
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#:prefab)
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;; (local-topic-config Topic (Option Number) (Option Number))
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(struct local-topic-config (name max-age max-count) #:prefab)
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;; (topic-demand Topic)
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(struct topic-demand (topic-name) #:prefab)
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;; (topic-demand Topic (Option Number))
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(struct topic-demand (topic-name poll-interval-seconds) #:prefab)
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;; (local-topic-demand String)
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(struct local-topic-demand (name) #:prefab)
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@ -115,7 +121,7 @@
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(actor #:name 'topic-demand-analyzer
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(define/query-set local-hosts (local-host $host-name) host-name)
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(during/actor (topic-demand $full-topic)
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(during/actor (topic-demand $full-topic _)
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#:name (list 'general-topic full-topic)
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#:let [(local-hosts-snapshot (local-hosts))]
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(with-handlers [(exn? (lambda (e)
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@ -124,11 +130,10 @@
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(url->resource (string->url full-topic)))
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(define maybe-local-topic
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(match topic-path [`("topic" (,topic ())) topic] [_ #f]))
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(on-start
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(general-topic-main full-topic
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topic-host
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maybe-local-topic
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(set-member? local-hosts-snapshot topic-host))))))
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(general-topic-main full-topic
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topic-host
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maybe-local-topic
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(set-member? local-hosts-snapshot topic-host)))))
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(define (general-topic-main full-topic topic-host maybe-local-topic start-as-local?)
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(define (local-state)
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@ -139,17 +144,25 @@
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(react (stop-when #:when maybe-local-topic (asserted (local-host topic-host)) (local-state))
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(remote-topic-main full-topic)))
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(if (and maybe-local-topic start-as-local?)
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(local-state)
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(remote-state)))
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(on-start
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(if (and maybe-local-topic start-as-local?)
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(local-state)
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(remote-state))))
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(define (req-content-type req)
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(dict-ref (web-request-header-headers req) 'content-type "application/octet-stream"))
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(dict-ref (web-request-header-headers req) 'content-type #f))
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(define (canonical-url canonical-host-name path)
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(url->string (resource->url (web-resource (vh canonical-host-name) path))))
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(define (local-topic-main topic)
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(field [max-age #f]
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[max-count #f])
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(field [current-content #f]
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[current-content-type #f]
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[last-modified-seconds #f])
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(on (asserted (local-topic-config topic $age $count))
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(max-age age)
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(max-count count))
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@ -163,25 +176,80 @@
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(on-stop (log-info "Terminating local topic ~v" topic))
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(during (local-host $host-name)
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(during (canonical-local-host $canonical-host-name)
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(define hub-url (canonical-url canonical-host-name `("hub" ())))
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(define self-url (canonical-url canonical-host-name `("topic" (,topic ()))))
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(define discovery-headers (list (cons 'link (format "<~a>; rel=hub" hub-url))
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(cons 'link (format "<~a>; rel=self" self-url))))
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(on (web-request-get (id req) (vh host-name) ("topic" (,topic ())))
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(if (current-content)
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(web-respond/bytes! id
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#:header (web-response-header
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#:last-modified-seconds (last-modified-seconds)
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#:mime-type (and (current-content-type)
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(string->bytes/utf-8
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(current-content-type)))
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#:headers discovery-headers)
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(current-content))
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(web-respond/bytes! id
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#:header (web-response-header
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#:code 204
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#:message #"No Content"
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#:mime-type #f
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#:headers discovery-headers)
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#"")))) ;; MUST NOT include a response body for 204
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(on (web-request-incoming (id req) (vh host-name) 'post ("topic" (,topic ())) $body)
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(define content-type (req-content-type req))
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(log-info "Local topic ~a got ~v message ~v" topic content-type body)
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(current-content body)
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(current-content-type content-type)
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(last-modified-seconds (current-seconds))
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(actor*
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(define content-type (req-content-type req))
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(log-info "Local topic ~a got ~v message ~v" topic content-type body)
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(define full-topic (url->string (resource->url (web-request-header-resource req))))
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(send! (notification full-topic body content-type))
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(web-respond/status! id 201 #"Created")))))
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(define (maintain-remote-subscription full-topic canonical-host-name sub-id)
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(define callback (url->string
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(resource->url
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(web-resource (vh canonical-host-name) `("sub" (,sub-id ()))))))
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(define callback (canonical-url canonical-host-name `("sub" (,sub-id ()))))
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(react
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(field [next-upstream-check (current-inexact-milliseconds)])
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(on (asserted (later-than (next-upstream-check)))
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(log-info "Rechecking upstream for ~a" full-topic)
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(field [last-upstream-check 0]
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[poll-interval-seconds #f])
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(field [current-content-hash #f]
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[current-content-type #f])
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(define/query-set poll-intervals (topic-demand full-topic $i) i)
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(begin/dataflow
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(poll-interval-seconds (for/fold [(i #f)] [(candidate (in-set (poll-intervals)))]
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(cond [(not i) candidate]
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[(< candidate i) candidate]
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[else i]))))
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(begin/dataflow
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(log-info "Poll interval for ~a is now ~a"
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full-topic
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(match (poll-interval-seconds)
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[#f "disabled"]
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[n (format "~a seconds" n)])))
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(on (asserted (later-than (+ (last-upstream-check) (* 1000 (or (poll-interval-seconds) 0)))))
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(log-info "Checking upstream ~a" full-topic)
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(define-values (resp response-body)
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(web-request! 'get full-topic #:redirect-budget 5))
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(log-info "Resource: ~v" resp))))
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(last-upstream-check (current-inexact-milliseconds))
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(match (web-response-header-code-type resp)
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['successful
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(define new-content-hash (sha1 (open-input-bytes response-body)))
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(define new-content-type (dict-ref (web-response-header-headers resp) 'content-type #f))
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(when (not (and (equal? (current-content-hash) new-content-hash)
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(equal? (current-content-type) new-content-type)))
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(current-content-hash new-content-hash)
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(current-content-type new-content-type)
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(send! (notification full-topic response-body new-content-type)))]
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[other
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(log-warning "Upstream ~a yielded ~a code ~a"
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full-topic
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other
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(web-response-header-code resp))]))))
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(define (remote-topic-main full-topic)
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(define sub-id (random-hex-string 16))
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@ -218,6 +286,10 @@
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(match (hash-ref params 'hub.lease_seconds "unbounded")
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["unbounded" #f]
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[n (string->number n)]))
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(define poll-interval-seconds
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(match (hash-ref params 'hub.poll_interval_seconds "none")
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["none" #f]
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[n (string->number n)]))
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(define secret-string (hash-ref params 'hub.secret #f))
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(define secret-bytes (and secret-string (string->bytes/utf-8 secret-string)))
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(define expiry-deadline (and lease-seconds (+ (current-seconds) lease-seconds)))
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@ -230,9 +302,13 @@
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topic
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callback)
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(begin
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(retract! (subscription topic ? ? callback ?))
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(assert!
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(subscription topic expiry-deadline canonical-hub callback secret-bytes))
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(retract! (subscription topic ? ? callback ? ?))
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(assert! (subscription topic
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expiry-deadline
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canonical-hub
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callback
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secret-bytes
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poll-interval-seconds))
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#t)
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#f)]
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['unsubscribe
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@ -241,16 +317,16 @@
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topic
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callback)
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(begin
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(retract! (subscription topic ? ? callback ?))
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(retract! (subscription topic ? ? callback ? ?))
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#t)
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#f)])))
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(if ok?
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(web-respond/status! id 202 #"Accepted")
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(web-respond/status! id 403 #"Forbidden" #"Validation failed"))))
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(during/actor (subscription $partial-topic _ _ $callback _)
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(during/actor (subscription $partial-topic _ _ $callback _ _)
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#:name (list 'subscription partial-topic callback)
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#:on-crash (retract! (subscription partial-topic ? ? callback ?))
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#:on-crash (retract! (subscription partial-topic ? ? callback ? ?))
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(subscription-main partial-topic callback)))
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(define (subscription-change-validate mode lease topic callback)
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@ -289,14 +365,16 @@
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(define-values (n newq) (dequeue (message-queue)))
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(message-queue newq)
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(match-define (notification topic body content-type) n)
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(define link-headers (list (cons 'link (format "<~a>; rel=hub" canonical-hub))
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(cons 'link (format "<~a>; rel=self" topic))))
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(let deliver-one ((retries-remaining 1)
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(retry-delay 5.0))
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(define-values (resp _body)
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(web-request! 'post
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callback
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#:headers (list (cons 'content-type content-type)
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(cons 'link (format "<~a>; rel=hub" canonical-hub))
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(cons 'link (format "<~a>; rel=self" topic)))
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#:headers (if content-type
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(cons (cons 'content-type content-type) link-headers)
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link-headers)
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#:body body))
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(cond
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[(eq? (web-response-header-code-type resp) 'successful)
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@ -317,17 +395,23 @@
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(min (* retry-delay 1.618) 30))]))))
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(delivery-active? #f))
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(during (subscription partial-topic $expiry-deadline $canonical-hub callback $secret-bytes)
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(during (subscription partial-topic
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$expiry-deadline
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$canonical-hub
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callback
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$secret-bytes
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$poll-interval-seconds)
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(define topic (url->string (combine-url/relative (canonical-topic-base-url canonical-hub)
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partial-topic)))
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(assert (topic-demand topic))
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(assert (topic-demand topic poll-interval-seconds))
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(on-start (log-info "Subscription configured: ~v ~v ~v ~v"
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(on-start (log-info "Subscription configured: ~v ~v ~v ~v ~v"
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topic
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expiry-deadline
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canonical-hub
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secret-bytes)
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secret-bytes
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poll-interval-seconds)
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(cond
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[expiry-deadline
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(expiry-timer-id (gensym 'subscription-expiry))
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