英文:
Sending a list of images along with data in http post flutter
问题
我有一组图像和数据（字符串），需要发送到我的后端。这是重要的函数：
Future MakePostPetOfferRequest({required String title,required String description,required String price,required String city,required String species,required String sex,required String ageYears,required String ageMonths,required String breed,required List<File?> images}) async {Uri url = Uri.parse('http://$ip/create_sale_post');Map<String, dynamic> body = {"Title": title,"Description": description,"City": city,"Species": species,"Price": price,"Sex": sex,"Years": ageYears,"Months": ageMonths,"Breed": breed,"images": images,};var response = await http.post(url, headers: {"cookie": sessionCookie}, body: body);if (response.headers['set-cookie'] != null) {String initSessionCookie = response.headers['set-cookie']!;if (sessionCookie != "") sessionCookie = initSessionCookie.substring(0, initSessionCookie.indexOf(";"));}return response;}
但是我遇到了不同的错误，首先是错误：
类型 'List<File?>' 不是 'String' 类型的子类型
我也不确定如何将图像添加到一个单一字段，就像在 Postman 中这样做：
希望问题清楚，感谢您的帮助。
英文:
I have a list of images and data (string) that I need to send to my backend.
This is the important function:
Future MakePostPetOfferRequest({required String title,required String description,required String price,required String city,required String species,required String sex,required String ageYears,required String ageMonths,required String breed,required List<File?> images}) async {Uri url = Uri.parse('http://$ip/create_sale_post');Map<String, dynamic> body = {"Title": title,"Description": description,"City": city,"Species": species,"Price": price,"Sex": sex,"Years": ageYears,"Months": ageMonths,"Breed": breed,"images": images,};var response = await http.post(url, headers: {"cookie": sessionCookie}, body: body);if (response.headers['set-cookie'] != null) {String initSessionCookie = response.headers['set-cookie']!;if (sessionCookie != "") sessionCookie = initSessionCookie.substring(0, initSessionCookie.indexOf(";"));}return response;}
But I am faced with different errors, the first is the error:
>type 'List<File?>' is not a subtype of type 'String' in type cast
I also am not sure how I can add the images to one single field, like I do it on Post man here:
I hope the question is clear and thank you for the assistance.
答案1
得分: 2
要上传图片，你应该使用表单数据（formdata）。
import 'package:dio/dio.dart' as formDataMap;formDataMap.FormData formData = formDataMap.fromMap({"Title": title,"Description": description,"City": city,"Species": species,"Price": price,"Sex": sex,"Years": ageYears,"Months": ageMonths,"Breed": breed});for (var file in images) {formData.files.addAll([MapEntry("images[]", await formDataMap.MultipartFile.fromFile(file.path)),]);}
这段代码用于创建表单数据，以便上传图像。
英文:
To post image you should use a formdata.
import 'package:dio/dio.dart' as formDataMap;formDataMap.FormData formData = formDataMap.fromMap({"Title": title,"Description": description,"City": city,"Species": species,"Price": price,"Sex": sex,"Years": ageYears,"Months": ageMonths,"Breed": breed});for (var file in images) {formData.files.addAll([MapEntry("images[]",await formDataMap.MultipartFile.fromFile(file.path)),]);}
答案2
得分: 0
我已找到一个方法来实现这个，而且它非常简单，只使用了内置的 *http.MultipartRequest()* 方法。
Uri url = Uri.parse('http://$ip/create_sale_post');var request = http.MultipartRequest('POST', url);for (var i = 0; i < images.length; i++) {var image = await http.MultipartFile.fromPath('images',images[i]!.path,);request.files.add(image);}request.headers['cookie'] = sessionCookie;request.fields["Title"] = title;request.fields["Description"] = description;request.fields["City"] = city;request.fields["Species"] = species;request.fields["Price"] = price;request.fields["Sex"] = sex;request.fields["Years"] = ageYears;request.fields["Months"] = ageMonths;request.fields["Breed"] = breed;request.headers['Content-Type'] = 'multipart/form-data';var response = await request.send();
<details><summary>英文:</summary>I have found a way to do it, and it is fairly simple, using no third party packages, only the built in *http.MultipartRequest()* method.
Uri url = Uri.parse('http://$ip/create_sale_post');var request = http.MultipartRequest('POST', url);for (var i = 0; i < images.length; i++) {var image = await http.MultipartFile.fromPath('images',images[i]!.path,);request.files.add(image);}request.headers['cookie'] = sessionCookie;request.fields["Title"] = title;request.fields["Description"] = description;request.fields["City"] = city;request.fields["Species"] = species;request.fields["Price"] = price;request.fields["Sex"] = sex;request.fields["Years"] = ageYears;request.fields["Months"] = ageMonths;request.fields["Breed"] = breed;request.headers['Content-Type'] = 'multipart/form-data';var response = await request.send();
</details>
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