Pagination

The Web client natively supports cursor pagination for methods that allow it, such as users_list. Supply a block and the client will make repeated requests adjusting the value of cursor with every response. The default limit is set to 100 and can be adjusted via Slack::Web::Client.config.default_page_size or by passing it directly into the API call.

all_members = []
client.users_list(presence: true, limit: 10) do |response|
  all_members.concat(response.members)
end
all_members # many thousands of team members retrieved 10 at a time

When using cursor pagination the client will automatically pause and then retry the request if it runs into Slack rate limiting. (It will pause according to the Retry-After header in the 429 response before retrying the request.) If it receives too many rate-limited responses in a row it will give up and raise an error. The default number of retries is 100 and can be adjusted via Slack::Web::Client.config.default_max_retries or by passing it directly into the method as max_retries.

You can also proactively avoid rate limiting by adding a pause between every paginated request with the sleep_interval parameter, which is given in seconds.

all_members = []
client.users_list(presence: true, limit: 10, sleep_interval: 5, max_retries: 20) do |response|
  # pauses for 5 seconds between each request
  # gives up after 20 consecutive rate-limited responses
  all_members.concat(response.members)
end
all_members # many thousands of team members retrieved 10 at a time