Golang: Mailchimp API calls with gochimp3 and an offset loop

golang-mailchimp-api-calls-with-offset-loop.md

Problem: Mailchimp limits you to 1000 entrys at a time, but provides an offset to get the rest.

Solution: In a loop, handle changing the offset so we can collect everything into an array and get the details we need.

• Requires gochimp3

fmt.Println("[Pulling Data From Mailchimp]")
mailchimpListTotalItems, err := mailchimpConnection.NewListResponse("XXXXXXXX").GetMembers(
	&gochimp3.InterestCategoriesQueryParams{
		ExtendedQueryParams: gochimp3.ExtendedQueryParams{
			BasicQueryParams: gochimp3.BasicQueryParams{
				Fields: []string{"total_items"}, // Return less data
			},
			Count: 1,
		},
	},
)
mailchimpListTotalItemsCount := mailchimpListTotalItems.TotalItems
fmt.Printf("Total members: %d\n", mailchimpListTotalItemsCount)
lastTotal := mailchimpListTotalItemsCount

var mailchimpUSCountry []string
var mailchimpOtherCountry []string

count := 1000
offset := mailchimpListTotalItemsCount - 1000
for offset >= 0 && lastTotal > 0 {
	fmt.Printf("Calling entries between %d and %d\n", offset, lastTotal)
	mailchimpList, err := mailchimpConnection.NewListResponse("XXXXXXX").GetMembers(
		&gochimp3.InterestCategoriesQueryParams{
			ExtendedQueryParams: gochimp3.ExtendedQueryParams{
				BasicQueryParams: gochimp3.BasicQueryParams{
					Fields: []string{"members.email_address,members.merge_fields"}, // Return less data
				},
				Count:  count,
				Offset: offset,
			},
		},
	)
	if err != nil {
		fmt.Println("Failed to get list...")
		os.Exit(1)
	}

	for _, member := range mailchimpList.Members {
		// fmt.Printf("%#v %#v\n", member.EmailAddress, member.MergeFields["COUNTRY"])
		if member.MergeFields["COUNTRY"] == "United States" {
			mailchimpUSCountry = append(mailchimpUSCountry, member.EmailAddress)
		}
		if member.MergeFields["COUNTRY"] != "United States" {
			mailchimpOtherCountry = append(mailchimpOtherCountry, member.EmailAddress)
		}
	}
	fmt.Printf("Mailchimp with US Country: %v\n", len(mailchimpUSCountry))
	fmt.Printf("Mailchimp results with non-US Country: %v\n", len(mailchimpOtherCountry))
	if count > offset { // Handle offset < 1000
		count = offset
	}
	lastTotal = offset
	offset = offset - count
	fmt.Println("------------")
}
fmt.Printf("Total: %v", len(mailchimpUSCountry)+len(mailchimpOtherCountry))