feedkit: split the former maximumdirect.net/weatherd project in two.

feedkit now contains a reusable core, while weatherfeeder is a concrete implementation that includes weather-specific functions.

config/params.go

@@ -0,0 +1,72 @@
+// feedkit/config/params.go
+package config
+
+import "strings"
+
+// ParamString returns the first non-empty string found for any of the provided keys.
+// Values must actually be strings in the decoded config; other types are ignored.
+//
+// This keeps cfg.Params flexible (map[string]any) while letting callers stay type-safe.
+func (cfg SourceConfig) ParamString(keys ...string) (string, bool) {
+	if cfg.Params == nil {
+		return "", false
+	}
+	for _, k := range keys {
+		v, ok := cfg.Params[k]
+		if !ok || v == nil {
+			continue
+		}
+		s, ok := v.(string)
+		if !ok {
+			continue
+		}
+		s = strings.TrimSpace(s)
+		if s == "" {
+			continue
+		}
+		return s, true
+	}
+	return "", false
+}
+
+// ParamStringDefault returns ParamString(keys...) if present; otherwise it returns def.
+// This is the “polite default” helper used by drivers for optional fields like user-agent.
+func (cfg SourceConfig) ParamStringDefault(def string, keys ...string) string {
+	if s, ok := cfg.ParamString(keys...); ok {
+		return s
+	}
+	return strings.TrimSpace(def)
+}
+
+// ParamString returns the first non-empty string found for any of the provided keys
+// in SinkConfig.Params. (Same rationale as SourceConfig.ParamString.)
+func (cfg SinkConfig) ParamString(keys ...string) (string, bool) {
+	if cfg.Params == nil {
+		return "", false
+	}
+	for _, k := range keys {
+		v, ok := cfg.Params[k]
+		if !ok || v == nil {
+			continue
+		}
+		s, ok := v.(string)
+		if !ok {
+			continue
+		}
+		s = strings.TrimSpace(s)
+		if s == "" {
+			continue
+		}
+		return s, true
+	}
+	return "", false
+}
+
+// ParamStringDefault returns ParamString(keys...) if present; otherwise it returns def.
+// Symmetric helper for sink implementations.
+func (cfg SinkConfig) ParamStringDefault(def string, keys ...string) string {
+	if s, ok := cfg.ParamString(keys...); ok {
+		return s
+	}
+	return strings.TrimSpace(def)
+}