chore: small consistency and documentation fixes

- AnalyticsRules and CurationSets now memoize their resource proxies in
  `[]`, matching the pattern every other collection class already uses
  (Collections, Documents, Aliases, Keys, Presets, SynonymSets, etc).
  Calls like `client.curation_sets['x']` now return the same instance
  across calls, which is the documented contract elsewhere.
- Remove an unreachable `|| 3` fallback from `Configuration#num_retries`:
  the LHS is always an integer because `validate!` rejects empty `nodes`.
- Replace `node.send(:[], attr)` with `node[attr]` in
  `Configuration#node_missing_parameters?` — same behaviour, less
  indirection.
- Document `Typesense::Error#data` in the README so callers know how to
  read the HTTP status and body from a raised exception.

Author: erimicel

README.md

@@ -29,6 +29,22 @@ Here are some examples with inline comments that walk you through how to use the
 
 Tests are also a good place to know how the the library works internally: [spec](spec)
 
+### Error handling
+
+Failed requests raise a subclass of `Typesense::Error`. The exception's `message` is the API error string (`"Object Not Found"`, etc.), and the underlying Faraday response is available on `#data` for callers that need the HTTP status, headers, or raw body:
+
+```ruby
+begin
+  client.collections['unknown'].retrieve
+rescue Typesense::Error::ObjectNotFound => e
+  e.message       # => "Not Found"
+  e.data.status   # => 404
+  e.data.body     # => raw response body
+end
+```
+
+The exception classes that map to specific status codes are: `RequestMalformed` (400), `RequestUnauthorized` (401), `ObjectNotFound` (404), `ObjectAlreadyExists` (409), `ObjectUnprocessable` (422), `ServerError` (5xx), `HTTPStatus0Error` (status 0), `TimeoutError`, and `HTTPError` (anything else).
+
 ## Compatibility
 
 | Typesense Server | typesense-ruby |

lib/typesense/analytics_rules.rb

@@ -6,6 +6,7 @@ class AnalyticsRules
 
     def initialize(api_call)
       @api_call = api_call
+      @analytics_rules = {}
     end
 
     def create(rules)
@@ -17,7 +18,7 @@ def retrieve
     end
 
     def [](rule_name)
-      AnalyticsRule.new(rule_name, @api_call)
+      @analytics_rules[rule_name] ||= AnalyticsRule.new(rule_name, @api_call)
     end
   end
 end

lib/typesense/configuration.rb

@@ -11,7 +11,7 @@ def initialize(options = {})
       @nearest_node = options[:nearest_node]
       @connection_timeout_seconds = options[:connection_timeout_seconds] || options[:timeout_seconds] || 10
       @healthcheck_interval_seconds = options[:healthcheck_interval_seconds] || 15
-      @num_retries = options[:num_retries] || (@nodes.length + (@nearest_node.nil? ? 0 : 1)) || 3
+      @num_retries = options[:num_retries] || (@nodes.length + (@nearest_node.nil? ? 0 : 1))
       @retry_interval_seconds = options[:retry_interval_seconds] || 0.1
       @api_key = options[:api_key]
 
@@ -36,7 +36,7 @@ def validate!
     private
 
     def node_missing_parameters?(node)
-      %i[protocol host port].any? { |attr| node.send(:[], attr).nil? }
+      %i[protocol host port].any? { |attr| node[attr].nil? }
     end
 
     def show_deprecation_warnings(options)

lib/typesense/curation_sets.rb

@@ -6,6 +6,7 @@ class CurationSets
 
     def initialize(api_call)
       @api_call = api_call
+      @curation_sets = {}
     end
 
     def upsert(curation_set_name, curation_set_data)
@@ -17,7 +18,7 @@ def retrieve
     end
 
     def [](curation_set_name)
-      CurationSet.new(curation_set_name, @api_call)
+      @curation_sets[curation_set_name] ||= CurationSet.new(curation_set_name, @api_call)
     end
   end
 end