Function arg_from_json

pub fn arg_from_json<T: DeserializeOwned>(
    args: &mut Value,
    arg_name: &'static str,
) -> Result<T, AppsyncError>

Extracts and deserializes a named argument from a JSON Value into the specified type

Arguments

• args - Mutable reference to a JSON Value containing arguments
• arg_name - Name of the argument to extract

Returns

• Ok(T) - Successfully deserialized value of type T
• Err(AppsyncError) - Error if argument is missing or invalid format

Examples

let mut args = json!({
    "userId": "123",
    "count": 5
});

// Extract userId as String
let user_id: String = arg_from_json(&mut args, "userId")?;
assert_eq!(user_id, "123");

// Extract count as i32
let count: i32 = arg_from_json(&mut args, "count")?;
assert_eq!(count, 5);

// Error case: invalid type
let result: Result<String, _> = arg_from_json(&mut args, "count");
assert!(result.is_err());

// Error case: missing argument
let result: Result<String, _> = arg_from_json(&mut args, "missing");
assert!(result.is_err());