如何在Dart/Flutter中向api发送图像？

Question

  void onTakePictureButtonPressed() {
    takePicture().then((String filePath) {
      if (mounted) {
        setState(() {
          imagePath = filePath;
          videoController?.dispose();
          videoController = null;
        });

        http.post('http://ip:8082/composer/predict', headers: {
          "Content-type": "multipart/form-data",
        }, body: {
          "image": filePath,
        }).then((response) {
          print("Response status: ${response.statusCode}");
          print("Response body: ${response.body}");
        });


        if (filePath != null) showInSnackBar('Picture saved to $filePath');
      }
    });
  }

Answer 1

最简单的方法是发布一个多部分请求，如本文中所示，然后将其发布到服务器。

确保在文件的开头导入这些内容：

import 'package:path/path.dart';
import 'package:async/async.dart';
import 'dart:io';
import 'package:http/http.dart' as http;
import 'dart:convert';

在代码中添加此类：

upload(File imageFile) async {    
      // open a bytestream
      var stream = new http.ByteStream(DelegatingStream.typed(imageFile.openRead()));
      // get file length
      var length = await imageFile.length();

      // string to uri
      var uri = Uri.parse("http://ip:8082/composer/predict");

      // create multipart request
      var request = new http.MultipartRequest("POST", uri);

      // multipart that takes file
      var multipartFile = new http.MultipartFile('file', stream, length,
          filename: basename(imageFile.path));

      // add file to multipart
      request.files.add(multipartFile);

      // send
      var response = await request.send();
      print(response.statusCode);

      // listen for response
      response.stream.transform(utf8.decoder).listen((value) {
        print(value);
      });
    }

upload(File(filePath));

void onTakePictureButtonPressed() {
    takePicture().then((String filePath) {
      if (mounted) {
        setState(() {
          imagePath = filePath;
          videoController?.dispose();
          videoController = null;
        });

       // initiate file upload
       Upload(File(filePath));

        if (filePath != null) showInSnackBar('Picture saved to $filePath');
      }
    });
  }