feat: add BindArguments and helper functions for CallToolRequest

Author: ezynda3

mcp/tools.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"strconv"
 )
 
 var errToolSchemaConflict = errors.New("provide either InputSchema or RawInputSchema, not both")
@@ -73,6 +74,205 @@ func (r CallToolRequest) GetRawArguments() any {
 	return r.Params.Arguments
 }
 
+// BindArguments unmarshals the Arguments into the provided struct
+// This is useful for working with strongly-typed arguments
+func (r CallToolRequest) BindArguments(target any) error {
+	data, err := json.Marshal(r.Params.Arguments)
+	if err != nil {
+		return fmt.Errorf("failed to marshal arguments: %w", err)
+	}
+	
+	return json.Unmarshal(data, target)
+}
+
+// GetString returns a string argument by key, or the default value if not found
+func (r CallToolRequest) GetString(key string, defaultValue string) string {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		if str, ok := val.(string); ok {
+			return str
+		}
+	}
+	return defaultValue
+}
+
+// RequireString returns a string argument by key, or an error if not found or not a string
+func (r CallToolRequest) RequireString(key string) (string, error) {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		if str, ok := val.(string); ok {
+			return str, nil
+		}
+		return "", fmt.Errorf("argument %q is not a string", key)
+	}
+	return "", fmt.Errorf("required argument %q not found", key)
+}
+
+// GetInt returns an int argument by key, or the default value if not found
+func (r CallToolRequest) GetInt(key string, defaultValue int) int {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case int:
+			return v
+		case float64:
+			return int(v)
+		case string:
+			if i, err := strconv.Atoi(v); err == nil {
+				return i
+			}
+		}
+	}
+	return defaultValue
+}
+
+// RequireInt returns an int argument by key, or an error if not found or not convertible to int
+func (r CallToolRequest) RequireInt(key string) (int, error) {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case int:
+			return v, nil
+		case float64:
+			return int(v), nil
+		case string:
+			if i, err := strconv.Atoi(v); err == nil {
+				return i, nil
+			}
+			return 0, fmt.Errorf("argument %q cannot be converted to int", key)
+		default:
+			return 0, fmt.Errorf("argument %q is not an int", key)
+		}
+	}
+	return 0, fmt.Errorf("required argument %q not found", key)
+}
+
+// GetFloat returns a float64 argument by key, or the default value if not found
+func (r CallToolRequest) GetFloat(key string, defaultValue float64) float64 {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case float64:
+			return v
+		case int:
+			return float64(v)
+		case string:
+			if f, err := strconv.ParseFloat(v, 64); err == nil {
+				return f
+			}
+		}
+	}
+	return defaultValue
+}
+
+// RequireFloat returns a float64 argument by key, or an error if not found or not convertible to float64
+func (r CallToolRequest) RequireFloat(key string) (float64, error) {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case float64:
+			return v, nil
+		case int:
+			return float64(v), nil
+		case string:
+			if f, err := strconv.ParseFloat(v, 64); err == nil {
+				return f, nil
+			}
+			return 0, fmt.Errorf("argument %q cannot be converted to float64", key)
+		default:
+			return 0, fmt.Errorf("argument %q is not a float64", key)
+		}
+	}
+	return 0, fmt.Errorf("required argument %q not found", key)
+}
+
+// GetBool returns a bool argument by key, or the default value if not found
+func (r CallToolRequest) GetBool(key string, defaultValue bool) bool {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case bool:
+			return v
+		case string:
+			if b, err := strconv.ParseBool(v); err == nil {
+				return b
+			}
+		case int:
+			return v != 0
+		case float64:
+			return v != 0
+		}
+	}
+	return defaultValue
+}
+
+// RequireBool returns a bool argument by key, or an error if not found or not convertible to bool
+func (r CallToolRequest) RequireBool(key string) (bool, error) {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case bool:
+			return v, nil
+		case string:
+			if b, err := strconv.ParseBool(v); err == nil {
+				return b, nil
+			}
+			return false, fmt.Errorf("argument %q cannot be converted to bool", key)
+		case int:
+			return v != 0, nil
+		case float64:
+			return v != 0, nil
+		default:
+			return false, fmt.Errorf("argument %q is not a bool", key)
+		}
+	}
+	return false, fmt.Errorf("required argument %q not found", key)
+}
+
+// GetStringSlice returns a string slice argument by key, or the default value if not found
+func (r CallToolRequest) GetStringSlice(key string, defaultValue []string) []string {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case []string:
+			return v
+		case []any:
+			result := make([]string, 0, len(v))
+			for _, item := range v {
+				if str, ok := item.(string); ok {
+					result = append(result, str)
+				}
+			}
+			return result
+		}
+	}
+	return defaultValue
+}
+
+// RequireStringSlice returns a string slice argument by key, or an error if not found or not convertible to string slice
+func (r CallToolRequest) RequireStringSlice(key string) ([]string, error) {
+	args := r.GetArguments()
+	if val, ok := args[key]; ok {
+		switch v := val.(type) {
+		case []string:
+			return v, nil
+		case []any:
+			result := make([]string, 0, len(v))
+			for i, item := range v {
+				if str, ok := item.(string); ok {
+					result = append(result, str)
+				} else {
+					return nil, fmt.Errorf("item %d in argument %q is not a string", i, key)
+				}
+			}
+			return result, nil
+		default:
+			return nil, fmt.Errorf("argument %q is not a string slice", key)
+		}
+	}
+	return nil, fmt.Errorf("required argument %q not found", key)
+}
+
 // ToolListChangedNotification is an optional notification from the server to
 // the client, informing it that the list of tools it offers has changed. This may
 // be issued by servers without any previous subscription from the client.