Context:¶

Wt::Wresource::handleRequest (const Wt::Http::Request &request, Wt::Http::Response &response)
{
. . .
const Wt::Http::UploadedFileMap& files = request.uploadedFiles();
. . .
}

The issue:¶

When handling inbound HTTP POST messages I have the problem that request.uploadedFiles() will return nullptr for some POSTed files but not for others – even though a Wireshark trace reveals that the HTTP messages are structured in exactly the same way. In point of fact, the sender for all files uses exactly the same CURL-based code.

Below are extracts from the same Wireshark trace .

The first file is not handled correctly (i.e. request.uploadedFiles() returns nullptr), while the next one is handled correctly.

This is NOT handled correctly in Wt¶

Frame 309: 15100 bytes on wire (120800 bits), 15100 bytes captured (120800 bits)
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
Transmission Control Protocol, Src Port: 50926, Dst Port: 8180, Seq: 6226266, Ack: 1, Len: 15034
[194 Reassembled TCP Segments (6241299 bytes): #14(345), #16(32741), #18(32741), #20(54), #22(32741), #23(32741), #24(54), #27(32768), #29(32768), #31(65483), #33(53), #34(65483), #36(53), #37(65483), #39(53), #40(65483), #42(53), #43(65483]
Hypertext Transfer Protocol
POST /lfr/put?filename=LE3188_230502_100730_000042.mp4&source=LC4&mime=video%2fmp4&transaction=4fe7b720-4a5f-4f28-9bb5-b2af7c34a042 HTTP/1.1\r\n
Host: 127.0.0.1:8180\r\n
User-Agent: VMS\r\n
Accept: /\r\n
Satellite: LC4\r\n
Content-Length: 6240954\r\n
Content-Type: multipart/form-data; boundary=------------------------6fea749b4e74880d\r\n
Expect: 100-continue\r\n
\r\n
[Full request URI: http://127.0.0.1:8180/lfr/put?filename=LE3188_230502_100730_000042.mp4&source=LC4&mime=video%2fmp4&transaction=4fe7b720-4a5f-4f28-9bb5-b2af7c34a042]
[HTTP request 1/1]
[Response in frame: 311]
File Data: 6240954 bytes
MIME Multipart Media Encapsulation, Type: multipart/form-data, Boundary: "------------------------6fea749b4e74880d"
[Type: multipart/form-data]
First boundary: --------------------------6fea749b4e74880d\r\n
Encapsulated multipart part: (application/octet-stream)
Content-Disposition: form-data; name="LE3188_230502_100730_000042.mp4"; filename="LE3188_230502_100730_000042.mp4"\r\n
Content-Type: application/octet-stream\r\n\r\n
Data (6240704 bytes)
Last boundary: \r\n--------------------------6fea749b4e74880d--\r\n

This is handled correctly¶

Frame 321: 1044 bytes on wire (8352 bits), 1044 bytes captured (8352 bits)
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
Transmission Control Protocol, Src Port: 50940, Dst Port: 8180, Seq: 313, Ack: 1, Len: 978
[2 Reassembled TCP Segments (1290 bytes): #319(312), #321(978)]
Hypertext Transfer Protocol
POST /lfr/put?filename=VideoDetails.json&source=LC4&mime=application%2fjson&transaction=4fe7b720-4a5f-4f28-9bb5-b2af7c34a042 HTTP/1.1\r\n
Host: 127.0.0.1:8180\r\n
User-Agent: VMS\r\n
Accept: /\r\n
Satellite: LC4\r\n
Content-Length: 978\r\n
Content-Type: multipart/form-data; boundary=------------------------f9f9890042ec6cca\r\n
\r\n
[Full request URI: http://127.0.0.1:8180/lfr/put?filename=VideoDetails.json&source=LC4&mime=application%2fjson&transaction=4fe7b720-4a5f-4f28-9bb5-b2af7c34a042]
[HTTP request 1/1]
[Response in frame: 323]
File Data: 978 bytes
MIME Multipart Media Encapsulation, Type: multipart/form-data, Boundary: "------------------------f9f9890042ec6cca"
[Type: multipart/form-data]
First boundary: --------------------------f9f9890042ec6cca\r\n
Encapsulated multipart part: (application/octet-stream)
Content-Disposition: form-data; name="VideoDetails.json"; filename="VideoDetails.json"\r\n
Content-Type: application/octet-stream\r\n\r\n
Data (756 bytes)
Last boundary: \r\n--------------------------f9f9890042ec6cca--\r\n