/// <summary>
/// Initializes a new <see cref="ALambdaTopicFunction{TMessage}"/> instance using a
/// custom implementation of <see cref="ILambdaFunctionDependencyProvider"/>.
/// </summary>
/// <param name="serializer">Custom implementation of <see cref="ILambdaJsonSerializer"/>.</param>
/// <param name="provider">Custom implementation of <see cref="ILambdaFunctionDependencyProvider"/>.</param>
protected ALambdaTopicFunction(ILambdaJsonSerializer serializer, ILambdaFunctionDependencyProvider?provider) : base(provider)
{
LambdaSerializer = serializer ?? throw new ArgumentNullException(nameof(serializer));
}
//--- Constructors ---
/// <summary>
/// Initializes a new <see cref="ALambdaTopicFunction{TMessage}"/> instance using the default
/// implementation of <see cref="ILambdaFunctionDependencyProvider"/>.
/// </summary>
/// <param name="serializer">Custom implementation of <see cref="ILambdaJsonSerializer"/>.</param>
protected ALambdaTopicFunction(ILambdaJsonSerializer serializer) : this(serializer, provider : null)
{
}
//--- Constructors ---
/// <summary>
/// Initializes a new <see cref="ALambdaApiGatewayFunction"/> instance using the default implementation of <see cref="ILambdaFunctionDependencyProvider"/>.
/// </summary>
/// <param name="serializer">Custom implementation of <see cref="ILambdaJsonSerializer"/>.</param>
protected ALambdaApiGatewayFunction(ILambdaJsonSerializer serializer) : this(serializer, provider : null)
{
}
/// <summary>
/// Initializes a new <see cref="ALambdaQueueFunction{TMessage}"/> instance using a
/// custom implementation of <see cref="ILambdaQueueFunctionDependencyProvider"/>.
/// </summary>
/// <param name="serializer">Custom implementation of <see cref="ILambdaJsonSerializer"/>.</param>
/// <param name="provider">Custom implementation of <see cref="ILambdaQueueFunctionDependencyProvider"/>.</param>
protected ALambdaQueueFunction(ILambdaJsonSerializer serializer, ILambdaQueueFunctionDependencyProvider?provider) : base(provider ?? new LambdaQueueFunctionDependencyProvider())
{
LambdaSerializer = serializer ?? throw new System.ArgumentNullException(nameof(serializer));
}
//--- Constructors ---
/// <summary>
/// Initializes a new <see cref="ALambdaCustomResourceFunction{TProperties,TAttributes}"/> instance using the default
/// implementation of <see cref="ILambdaFunctionDependencyProvider"/>.
/// </summary>
/// <param name="serializer">Custom implementation of <see cref="ILambdaJsonSerializer"/>.</param>
protected ALambdaCustomResourceFunction(ILambdaJsonSerializer serializer) : this(serializer, provider : null)
{
}
private static Func <APIGatewayProxyRequest, InvocationTargetState, object?> CreateParameterResolver(ILambdaJsonSerializer serializer, MethodInfo method, ParameterInfo parameter)
{
// check if [FromUri] or [FromBody] attributes are present
var hasFromUriAttribute = parameter.GetCustomAttribute <FromUriAttribute>() != null;
var hasFromBodyAttribute = parameter.GetCustomAttribute <FromBodyAttribute>() != null;
if (hasFromUriAttribute && hasFromBodyAttribute)
{
throw new ApiGatewayInvocationTargetParameterException(method, parameter, "cannot have both [FromUri] and [FromBody] attributes");
}
// check if parameter is a proxy request
var isProxyRequest = parameter.ParameterType == typeof(APIGatewayProxyRequest);
if (isProxyRequest)
{
// parameter is the proxy request itself
return((request, state) => request);
}
// check if parameter needs to deserialized from URI or BODY
var isSimpleType = parameter.ParameterType.IsValueType || (parameter.ParameterType == typeof(string));
if ((isSimpleType && !hasFromBodyAttribute) || hasFromUriAttribute)
{
// check if parameter is read from URI string directly or if its members are read from the URI string
if (isSimpleType)
{
// create function for getting default parameter value
Func <object?> getDefaultValue;
if (parameter.IsOptional)
{
getDefaultValue = () => parameter.DefaultValue;
}
else if ((Nullable.GetUnderlyingType(parameter.ParameterType) == null) && (parameter.ParameterType.IsValueType || parameter.ParameterType == typeof(string)))
{
getDefaultValue = () => throw new ApiGatewayInvocationTargetParameterException(method, parameter, "missing value");
}
else
{
getDefaultValue = () => null;
}
// create function to resolve parameter
return((request, state) => {
string?value = null;
// attempt to resolve the parameter from stage variables, path parameters, and query string parameters
var success = (request.PathParameters?.TryGetValue(parameter.Name, out value) ?? false) ||
(request.QueryStringParameters?.TryGetValue(parameter.Name, out value) ?? false);
// if resolved, return the converted value; otherwise the default value
if (success)
{
try {
return Convert.ChangeType(value, parameter.ParameterType);
} catch (FormatException) {
throw new ApiGatewayInvocationTargetParameterException(method, parameter, "invalid parameter format");
}
}
return getDefaultValue();
});
}
else
{
var queryParameterType = parameter.ParameterType;
// parameter represents the query-string key-value pairs
return((request, state) => {
try {
// construct a unified JSON representation of the path and query-string parameters
if (state.PathQueryParametersJson == null)
{
var pathParameters = request.PathParameters ?? Enumerable.Empty <KeyValuePair <string, string> >();
var queryStringParameters = request.QueryStringParameters ?? Enumerable.Empty <KeyValuePair <string, string> >();
state.PathQueryParametersJson = serializer.Serialize(
pathParameters.Union(queryStringParameters)
.GroupBy(kv => kv.Key)
.Select(grouping => grouping.First())
.ToDictionary(kv => kv.Key, kv => kv.Value)
);
}
return serializer.Deserialize(state.PathQueryParametersJson, parameter.ParameterType);
} catch {
throw new ApiGatewayInvocationTargetParameterException(method, parameter, "invalid path/query-string parameters format");
}
});
}
}
else
{
// parameter represents the body of the request
return((request, state) => {
try {
return serializer.Deserialize(request.Body, parameter.ParameterType);
} catch {
throw new ApiGatewayInvocationTargetParameterException(method, parameter, "invalid JSON document in request body");
}
});
}
}
