Send multiple files in json body - json

Question

I am new in flutter, trying to send multiple files in single request but failing miserably. I have attached the json body parameter screenshot also.
I have to send an array of multiple pdf files along with other parameters.
qualifications:{"qualifications": [{"id": "25", "qualification": "nurse", "grade": 11, "date": "2020-07-20", "proof": "file"}]}
nurse_id:26
This is what i did
List<Map> _jsonArray = new List();
Map<String, String> arrayBody = {
'id': '',
'qualification': 'nurse',
'grade': '13',
'date': _dateController.text,
};
List<http.MultipartFile> _mfiles = new List();
_jsonArray.add(arrayBody);
var body = json.encode({'qualifications':_jsonArray });
_mfiles.add( await http.MultipartFile.fromPath(
'proof',
_file
),
);
_mfiles.add( await http.MultipartFile.fromPath(
'qt_statement',
_qtStatement
),);
final Map<String, String> requestheaders = {
'Authorization': 'Bearer '+token_id,
};
var request = http.MultipartRequest('POST', Uri.parse(Urls.PERSONAL_DETAILS));
request.headers.addAll(requestheaders);
request.files.addAll(_mfiles);
request.fields[Constants.nurse_id] = nurse_id;
var res = await request.send();
var content = StringBuffer();
if(res.statusCode == 200){
res.stream.transform(utf8.decoder).listen((value) {
content.write(value);
},
onDone: (){
var data = json.decode(content.toString());
print(data);
});
}
The json i am sending looks like this
{"qualifications":[{"id":"","qualification":"nurse","grade":"13","date":"2020-07-31"}]}
Here 'proof' key is missing. Hence, getting 'Proof cannot be null' as response from server.
Struggling with this issue for more than 3 hours. Any suggestion or help will be highly appreciated

Answer 1

i assume your server expects the request to have a field called proof which contains the file data as part of the json post data. In this case, you can encode the file content (bytes) as base64 and set it inside your json data.
something like:
string proof = read_file_as_base64(filepath); //you need to read and encode the file content here.
Map<String, String> arrayBody = {
'id': '',
'qualification': 'nurse',
'grade': '13',
'date': _dateController.text,
'proof': proof
};