I'm going to upload files with C++, to a Java spring boot web server.
I constructed the protocol looks like below (in plain text):
POST /gallery/multimedia/uploadvideo HTTP/1.1
Host: 192.168.0.133:8981
Content-Type: multipart/form-data; boundary=------boundary1804289383
Connection: keep-alive
--------boundary1804289383
Content-Type: video/mp4
Content-Disposition: form-data; name="file"; filename="1.mp4"
Content-Length: 948611
Content-Transfer-Encoding: 8bit
... binary video data here ...
--------boundary1804289383--
The server side is Java spring boot server, interface defined as below:
@PostMapping("uploadvideo")
public ResultVo uploadVideo(@RequestParam("file") MultipartFile file);
While posting file, the server responses with code 400, and complains that
Required request part 'file' is not present
However with a simple HTML page, file uploaded successfully, the HTML page listed below:
<html>
<head></head>
<body>
<form id="form" enctype="multipart/form-data" method="post"
action="http://192.168.0.133:8981/gallery/multimedia/uploadvideo">
<input id="file" name="file" type="file" />
<input id="submit" value="submit" type="submit" />
</form>
</body>
</html>
What do I miss?
Edit:
I've tried Postman/Chrome console/curl, all these tools only print the request looks like:
# this is from curl
POST /gallery/multimedia/uploadvideo HTTP/1.1
User-Agent: curl/7.29.0
Host: 192.168.0.133:8981
Accept: */*
Content-Length: 187
Expect: 100-continue
Content-Type: multipart/form-data; boundary=----------------------------3c653d03b97f
How should I construct the file part? Any ideas?
Firstly, thanks for @strupo 's suggestion.
By turning on
--traceoption ofcurland viewing the output log file, I finally fixed this problem.In
curl, it posts file by several packets:The header:
then it waits for server response:
after server responsed code 100, it sends data content, the form-data header goes first:
and file content follows, (in my case, a large memory is allocated, read from file and write to socket in once), and next file.
Finally the protocol should finished with boundary line:
The
Content-Lengthshould include all bytes being sent after header. Theboundaryshould be prefixed with--in file part. Also the\r\neverywhere should be noticed.