From a5881627c5c849ec2ff7e20112e492e301627ae3 Mon Sep 17 00:00:00 2001
From: Chris Novakovic <chris@chrisn.me.uk>
Date: Thu, 15 Mar 2018 19:01:45 +0000
Subject: [PATCH] GCal events_list(): return all events, not just first 250

The Google Calendar API v3 limits the number of events returned by the
"Events: list" endpoint to 250 by default, and API::Google::GCal
provides no means of overriding this behaviour. This commit makes two
changes to API::Google::GCal's events_list() method so that it returns
all events in the requested calendar:

* Iterate over all pages of the event result list by using the
  nextPageToken property in each API response as the value of the
  pageToken parameter in the next API request.

* Set the maxResults query parameter to its maximum permitted value
  under the v3 API (2500), to minimise the number of API requests that
  must be made to iterate over all of the result pages.
---
 lib/API/Google/GCal.pm | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/lib/API/Google/GCal.pm b/lib/API/Google/GCal.pm
index 95a550d..69173ff 100755
--- a/lib/API/Google/GCal.pm
+++ b/lib/API/Google/GCal.pm
@@ -161,15 +161,22 @@ sub events_list {
 
    if (!defined $params->{calendarId}) { die "No calendarId provided as parameter"}
    if (!defined $params->{user}) { die "No user  provided as parameter"}
-   
-   my $res = $self->api_query({ 
-      method => 'get', 
-      route => $self->{api_base}.'/calendars/'.$params->{calendarId}.'/events',
-      user => $params->{user}
-    });
 
-   if (defined $res->{items}) { return $res->{items} };
-   if (defined $res->{error}) { return $res };
+   my (@events, $page_token);
+   do {
+      my $res = $self->api_query({
+         method => 'get',
+         route => $self->{api_base}.'/calendars/'.$params->{calendarId}.'/events?maxResults=2500' . (defined $page_token ? "&pageToken=$page_token" : ''),
+         user => $params->{user}
+      });
+
+      return $res->{error} if defined $res->{error};
+
+      push @events, @{$res->{items}} if defined $res->{items};
+      $page_token = $res->{nextPageToken};
+   } while (defined $page_token);
+
+   return \@events;
 };