问如何使用渡槽线束测试文件上传？

EN

Default headers to be added to requests made by this agent.

By default, this value is the empty map.

Do not provide a 'content-type' key. If the key 'content-type' is present, it will be removed prior to sending the request. It is replaced by the value of TestRequest.contentType, which also controls body encoding.

See also setBasicAuthorization, bearerAuthorization, accept, contentType for setting common headers.

import 'multipart_body_parser.dart';
//[...]
    test('POST /upload-file uploads a file to the server', () async {
      final boundary = '7d82a244f2ea5xd0s046';
      final file = File('test.txt');

      var encodedBody = MultipartBodyParser(boundary).parse([
        FileBodyPart(
          'file',
          'test.txt',
          File('test.txt'),
        ),
      ]);

      final response = await harness.agent.post(
        '/upload-file',
        body: encodedBody,
      );

      expectResponse(response, 200);
    });

import 'dart:convert';
import 'dart:io';

class MultipartBodyParser {
  final String boundary;

  MultipartBodyParser(this.boundary)
      : assert(
          boundary != null,
          'The boundary is empty. Please set it ' +
              'and keep on mind that it MUST NOT appear inside any of the ' +
              'encapsulated parts. Example: "sampleBoundary7da24f2e50046".',
        );

  List<int> get encodedNonLastBoundary =>
      ascii.encode('\r\n--' + boundary + '\r\n');

  List<int> get encodedLastBoundary =>
      ascii.encode('\r\n--' + boundary + '--\r\n\r\n');

  List<int> parse(List<_BodyPart> parts) {
    if (parts == null || parts.isEmpty) {
      throw MultipartBodyParserException(
        'Parts CAN NOT be empty. Please set at least one part of body.',
      );
    }
    var body = encodedNonLastBoundary;
    parts.forEach((part) {
      body += part.parse();
      if (parts.last != part) {
        body += encodedNonLastBoundary;
      }
    });
    body += encodedLastBoundary;
    return body;
  }
}

class TextBodyPart extends _BodyPart {
  final String content;

  TextBodyPart(formFieldName, _content)
      : content = _content ?? '',
        super(
          _ContentDisposition(
            formFieldName,
            'form-data',
          ),
          _ContentType(),
        );

  @override
  List<int> get encodedContent => ascii.encode(content);
}

class FileBodyPart extends _BodyPart {
  final File file;
  final String fileName;

  FileBodyPart(formFieldName, this.fileName, this.file)
      : super(
          _ContentDisposition(
            formFieldName,
            'form-data',
            '; filename="$fileName"',
          ),
          _ContentType('application/octet-stream'),
        );

  @override
  List<int> get encodedContent => file.readAsBytesSync();
}

abstract class _BodyPart {
  final _ContentDisposition contentDisposition;
  final _ContentType contentType;

  _BodyPart(this.contentDisposition, this.contentType)
      : assert(contentDisposition != null),
        assert(contentType != null);

  String get partHeader =>
      contentDisposition.toString() + contentType.toString();

  List<int> get encodedContent;

  List<int> parse() => ascii.encode(partHeader) + encodedContent;
}

class _ContentDisposition {
  final String formFieldName;
  final String formFieldType;
  final String additionalParams;
  _ContentDisposition(this.formFieldName, [_formFieldType, _additionalParams])
      : formFieldType = _formFieldType ?? 'form-data',
        additionalParams = _additionalParams ?? '',
        assert(formFieldName != null);

  @override
  String toString() =>
      'content-disposition: $formFieldType; name="$formFieldName"$additionalParams\r\n';
}

class _ContentType {
  final String type;
  _ContentType([this.type = 'text/plain']) : assert(type != null);

  @override
  String toString() => 'content-type: $type\r\n\r\n';
}

class MultipartBodyParserException implements Exception {
  final String message;

  const MultipartBodyParserException([this.message]);
}