feat: add custom exceptions (#38)

lib/src/http_client.dart

@@ -1,3 +1,6 @@
+export './http_client/exceptions/http_exceptions.dart';
+export './http_client/exceptions/token_exceptions.dart';
+export './http_client/exceptions/validation_exceptions.dart';
 export './http_client/models/create_exchange_request.dart';
 export './http_client/models/exchange.dart';
 export './http_client/models/get_offerings_filter.dart';

lib/src/http_client/exceptions/http_exceptions.dart

@@ -0,0 +1,41 @@
+class RequestError implements Exception {
+  final String message;
+  final String? url;
+  final Exception? cause;
+
+  RequestError({
+    required this.message,
+    this.url,
+    this.cause,
+  });
+
+  String get errorType => 'RequestError';
+
+  @override
+  String toString() => [
+        '$errorType: $message',
+        if (url != null) 'Url: $url',
+        if (cause != null) 'Caused by: $cause',
+      ].join('\n');
+}
+
+class ResponseError implements Exception {
+  final String message;
+  final int? status;
+  final String? body;
+
+  ResponseError({
+    required this.message,
+    this.status,
+    this.body,
+  });
+
+  String get errorType => 'ResponseError';
+
+  @override
+  String toString() => [
+        '$errorType: $message',
+        if (status != null) 'Status: $status',
+        if (body != null) 'Body: $body',
+      ].join('\n');
+}

lib/src/http_client/exceptions/token_exceptions.dart

@@ -0,0 +1,83 @@
+// TODO(ethan-tbd): move to web5-dart when kcc is added to web5-dart
+class _TbdexTokenError implements Exception {
+  final String message;
+  final Exception? cause;
+
+  _TbdexTokenError({
+    required this.message,
+    this.cause,
+  });
+
+  String get errorType => 'TbdexValidationError';
+
+  @override
+  String toString() => [
+        '$errorType: $message',
+        if (cause != null) 'Caused by: $cause',
+      ].join('\n');
+}
+
+class RequestTokenError extends _TbdexTokenError {
+  RequestTokenError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'RequestTokenError';
+}
+
+class RequestTokenSigningError extends RequestTokenError {
+  RequestTokenSigningError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'RequestTokenSigningError';
+}
+
+class RequestTokenVerificationError extends RequestTokenError {
+  RequestTokenVerificationError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'RequestTokenVerificationError';
+}
+
+class RequestTokenMissingClaimsError extends RequestTokenError {
+  RequestTokenMissingClaimsError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'RequestTokenMissingClaimsError';
+}
+
+class RequestTokenAudienceMismatchError extends RequestTokenError {
+  RequestTokenAudienceMismatchError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'RequestTokenAudienceMismatchError';
+}

lib/src/http_client/exceptions/validation_exceptions.dart

@@ -0,0 +1,56 @@
+class _TbdexValidationError implements Exception {
+  final String message;
+  final Exception? cause;
+
+  _TbdexValidationError({
+    required this.message,
+    this.cause,
+  });
+
+  String get errorType => 'TbdexValidationError';
+
+  @override
+  String toString() => [
+        '$errorType: $message',
+        if (cause != null) 'Caused by: $cause',
+      ].join('\n');
+}
+
+class ValidationError extends _TbdexValidationError {
+  ValidationError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'ValidationError';
+}
+
+class InvalidDidError extends ValidationError {
+  InvalidDidError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'InvalidDidError';
+}
+
+class MissingServiceEndpointError extends ValidationError {
+  MissingServiceEndpointError({
+    required String message,
+    Exception? cause,
+  }) : super(
+          message: message,
+          cause: cause,
+        );
+
+  @override
+  String get errorType => 'MissingServiceEndpointError';
+}