[Dart] Flutter 上传文件

/** * 请求响应数据 */class MsgResponse { ?int code; // 状态代码，0 表示没有错误 ?Object data; // 数据内容，一般为字符串 ?String errmsg; // 错误消息 ?MsgResponse([this.code = 0, this.data = null, this.errmsg = ""]);}static Map _makeHttpHeaders( ?????[String contentType, ?????String accept, ?????String token, ?????String XRequestWith, ?????String XMethodOverride]) { ???Map headers = new Map<String, String>(); ???int i = 0; ???if (!strIsEmpty(contentType)) { ?????i++; ?????headers["Content-Type"] = contentType; ???} ???if (!strIsEmpty(accept)) { ?????i++; ?????headers["Accept"] = accept; ???} ???if (!strIsEmpty(token)) { ?????i++; ?????headers["Authorization"] = "bearer " + token; ???} ???if (!strIsEmpty(XRequestWith)) { ?????i++; ?????headers["X-Requested-With"] = XRequestWith; ???} ???if (!strIsEmpty(XMethodOverride)) { ?????i++; ?????headers["X-HTTP-Method-Override"] = XMethodOverride; ???} ???if (i == 0) return null; ???// print(headers.toString()); ???return headers; ?}/** HTTP POST 上传文件 */ ?static Future<MsgResponse> httpUploadFile( ???final String url, ???final File file, { ???String accept = "*/*", ???String token, ???String field = "picture-upload", ???String file_contentType, // 默认为null，自动获取 ?}) async { ???try { ?????List<int> bytes = await file.readAsBytes(); ?????return await httpUploadFileData(url, bytes, ?????????accept: accept, ?????????token: token, ?????????field: field, ?????????file_contentType: file_contentType, ?????????filename: file.path); ???} catch (e) { ?????return new MsgResponse(699, null, e.toString()); ???} ?} ?/** HTTP POST 上传文件 */ ?static Future<MsgResponse> httpUploadFileData( ???final String url, ???final List<int> filedata, { ???String accept = "*/*", ???String token, ???String field = "picture-upload", ???String file_contentType, // 默认为null，自动获取 ???String filename, ?}) async { ???try { ?????List<int> bytes = filedata; ?????var boundary = _boundaryString(); ?????String contentType = ‘multipart/form-data; boundary=$boundary‘; ?????Map headers = ?????????_makeHttpHeaders(contentType, accept, token); //, "XMLHttpRequest"); ?????// 构造文件字段数据 ?????String data = ?????????‘--$boundary\r\nContent-Disposition: form-data; name="$field"; ‘ + ?????????????‘filename="${getFileFullName(filename)}"\r\nContent-Type: ‘ + ?????????????‘${(file_contentType == null) ? getMediaType(getFileExt(filename).toLowerCase()): file_contentType}\r\n\r\n‘; ?????var controller = new StreamController<List<int>>(sync: true); ?????controller.add(data.codeUnits); ?????controller.add(bytes); ?????controller.add("\r\n--$boundary--\r\n".codeUnits); ?????controller.close(); ?????bytes = await new Http.ByteStream(controller.stream).toBytes(); ?????//print("bytes: \r\n" + UTF8.decode(bytes, allowMalformed: true)); ?????Http.Response response = ?????????await Http.post(url, headers: headers, body: bytes); ?????if (response.statusCode == 200) { ???????return new MsgResponse(0, response.body); ?????} else ???????return new MsgResponse(response.statusCode, response.body); ???} catch (e) { ?????return new MsgResponse(699, null, e.toString()); ???} ?} ?/** 生成随机字符串 */ ?static String randomStr( ?????[int len = 8, List<int> chars = _BOUNDARY_CHARACTERS]) { ???var list = new List<int>.generate( ???????len, (index) => chars[_random.nextInt(chars.length)], ???????growable: false); ???return new String.fromCharCodes(list); ?} ?static const List<int> _BOUNDARY_CHARACTERS = const <int>[ ???0x30, ???0x31, ???0x32, ???0x33, ???0x34, ???0x35, ???0x36, ???0x37, ???0x38, ???0x39, ???0x61, ???0x62, ???0x63, ???0x64, ???0x65, ???0x66, ???0x67, ???0x68, ???0x69, ???0x6A, ???0x6B, ???0x6C, ???0x6D, ???0x6E, ???0x6F, ???0x70, ???0x71, ???0x72, ???0x73, ???0x74, ???0x75, ???0x76, ???0x77, ???0x78, ???0x79, ???0x7A, ???0x41, ???0x42, ???0x43, ???0x44, ???0x45, ???0x46, ???0x47, ???0x48, ???0x49, ???0x4A, ???0x4B, ???0x4C, ???0x4D, ???0x4E, ???0x4F, ???0x50, ???0x51, ???0x52, ???0x53, ???0x54, ???0x55, ???0x56, ???0x57, ???0x58, ???0x59, ???0x5A ?]; ?static const int _BOUNDARY_LENGTH = 48; ?static final Random _random = new Random(); ?static String _boundaryString() { ???var prefix = "---DartFormBoundary"; ???var list = new List<int>.generate( ???????_BOUNDARY_LENGTH - prefix.length, ???????(index) => ???????????_BOUNDARY_CHARACTERS[_random.nextInt(_BOUNDARY_CHARACTERS.length)], ???????growable: false); ???return "$prefix${new String.fromCharCodes(list)}"; ?} ?static MediaType getMediaType(final String fileExt) { ???switch (fileExt) { ?????case ".jpg": ?????case ".jpeg": ?????case ".jpe": ???????return new MediaType("image", "jpeg"); ?????case ".png": ???????return new MediaType("image", "png"); ?????case ".bmp": ???????return new MediaType("image", "bmp"); ?????case ".gif": ???????return new MediaType("image", "gif"); ?????case ".json": ???????return new MediaType("application", "json"); ?????case ".svg": ?????case ".svgz": ???????return new MediaType("image", "svg+xml"); ?????case ".mp3": ???????return new MediaType("audio", "mpeg"); ?????case ".mp4": ???????return new MediaType("video", "mp4"); ?????case ".htm": ?????case ".html": ???????return new MediaType("text", "html"); ?????case ".css": ???????return new MediaType("text", "css"); ?????case ".csv": ???????return new MediaType("text", "csv"); ?????case ".txt": ?????case ".text": ?????case ".conf": ?????case ".def": ?????case ".log": ?????case ".in": ???????return new MediaType("text", "plain"); ???} ???return null; ?}