Handle API error more gracefully

server.ss

@@ -38,10 +38,6 @@
 ;; /
 (def (departures-handler req res)
   (let/cc return
-    (infof "~a ~a ~a"
-	   (http-request-method req)
-	   (http-request-path req)
-	   (inet-address->string (http-request-client req)))
     (def sncf-key (getenv "SNCF_AUTH_KEY" #f))
     (unless sncf-key
       (errorf "No SNCF API authentication key found. Set the SNCF_AUTH_KEY environment variable.")
@@ -52,8 +48,6 @@
     (def accept-header (assoc "Accept" headers))
     (when accept-header (set! accept-header (cdr accept-header)))
     (def params (parse-request-params (http-request-params req)))
-    (def station (assoc "station" params))
-    (when station (set! station (cdr station)))
     (def datetime-str (assoc "datetime" params))
     (def datetime (if datetime-str
 		    (try
@@ -65,10 +59,23 @@
 						    (cdr datetime-str)))
 		       (return)))
 		    #f))
+    (def station (assoc "station" params))
+    (when station (set! station (cdr station)))
     (define-values (station-name station-id)
       (if (string? station)
 	(get-station-id sncf-key station)
 	(values "Vernon - Giverny (Vernon)" "stop_area:SNCF:87415604")))
+    (unless station-name
+      (set! station-name "Vernon - Giverny"))
+    (unless station-id
+      (set! station-id "stop_area:SNCF:87415604"))
+    (infof "~a ~a ~a ~a (\"~a\")~a"
+	   (inet-address->string (http-request-client req))
+	   (http-request-method req)
+	   (http-request-path req)
+	   station-name
+	   station
+	   (if datetime (string-append " at " (cdr datetime-str)) ""))
     (define-values (departures disruptions) (get-departures sncf-key station-id datetime))
     (def content
       (cond

sncf.ss

@@ -20,6 +20,10 @@
     (if station
       (get-station-id sncf-key station)
       (values "Vernon - Giverny (Vernon)" "stop_area:SNCF:87415604")))
+  (unless station-name
+    (set! station-name "Vernon - Giverny"))
+  (unless station-id
+    (set! station-id "stop_area:SNCF:87415604"))
   (define-values (departures disruptions) (get-departures sncf-key station-id datetime))
   (display-all departures disruptions station-name datetime)
   (when mattermost-url

sncf/api.ss

@@ -4,6 +4,7 @@
 
 (import :std/format
 	:std/iter
+	:std/logger
 	:std/net/request
 	:std/net/uri
 	:std/srfi/19
@@ -19,11 +20,11 @@
       (let ((pts (hash-ref req-json 'pt_objects #f)))
 	(if (and pts (not (null? pts)))
 	  (values (hash-ref (car pts) 'name) (hash-ref (car pts) 'id))
-	  (begin (display (format "No station found for \"~a\".\n" station) (current-error-port))
-		 (exit 1)))))
-    (begin (display (format "Failed to query the SNCF API: ~a ~a\n"
-			    (request-status req) (request-status-text req)))
-	   (exit 1))))
+	  (begin (warnf  "No station found for \"~a\"." station)
+		 (values #f #f)))))
+    (begin (warnf "Failed to query the SNCF API: ~a ~a"
+		  (request-status req) (request-status-text req))
+	   (values #f #f))))
 
 (def (get-departures sncf-key station-id (datetime #f))
   (def url (format "~a/stop_areas/~a/departures" +sncf-url+ station-id))
@@ -35,9 +36,9 @@
     (let (req-json (request-json req))
       (values (parse-departures (hash-ref req-json 'departures))
 	      (hash-ref req-json 'disruptions)))
-    (begin (display (format "Failed to query the SNCF API: ~a ~a\n"
-			    (request-status req) (request-status-text req)))
-	   (exit 1))))
+    (begin (warnf "Failed to query the SNCF API: ~a ~a"
+		  (request-status req) (request-status-text req))
+	   (values #f #f))))
 
 (defstruct departure (network direction base-datetime datetime))
 

sncf/display.ss

@@ -45,15 +45,21 @@
       (displayln (if (null? messages) "[Pas de message]" (hash-ref (car messages) 'text))))))
 
 (def (display-all departures disruptions station-name (datetime #f) style: (style 'unicode))
-  (display
-   (if (eq? style 'markdown)
-     (format "Prochains départs de **~a** " station-name)
-     (parse-markup
-      (format "[bold]Prochains départs de [green]~a[/green] " station-name))))
-  (when datetime
-    (display (format "le ~a à ~a "
-		     (date->string datetime "~d ~b ~Y")
-		     (date->string datetime "~H:~M"))))
-  (displayln (if (eq? style 'markdown) ":\n" ":"))
-  (display-departures-table departures style: style)
-  (display-disruptions disruptions style: style))
+  (let/cc return
+    (unless departures
+      (displayln (format "Aucun départ prévu de ~a~a"
+			 station-name
+			 (if datetime (string-append " le " (date->string datetime "~d ~b ~Y")))))
+      (return))
+    (display
+     (if (eq? style 'markdown)
+       (format "Prochains départs de **~a** " station-name)
+       (parse-markup
+	(format "[bold]Prochains départs de [green]~a[/green] " station-name))))
+    (when datetime
+      (display (format "le ~a à ~a "
+		       (date->string datetime "~d ~b ~Y")
+		       (date->string datetime "~H:~M"))))
+    (displayln (if (eq? style 'markdown) ":\n" ":"))
+    (display-departures-table departures style: style)
+    (display-disruptions disruptions style: style)))