How to handle HTTP_PUT?

[Levak]

Hi,
I am porting to ESPAsyncWebServer a codebase that worked with the Webserver lib.
One of the requests had method type HTTP_PUT. I tried to find in documentation and in the source code any mention of PUT as a method type, but I cannot wrap my head around it.

Here is a link to the existing code:
https://github.com/tiredboffin/sdwifi/blob/2f045716dc03dca25dccdf4d0004d5a2209a4665/sdwifi.ino#L751-L771

From what I understand, ArUploadHandlerFunction is only for multipart POST requests, while PUT requests send a continuous stream for one file. ArBodyHandlerFunction is also tagged to be POST-only.

Which leaves us to only use ArRequestHandlerFunction.
Any hints where to start ?

void init()
{
  server.on("^\\/upload\\/([^/]+)$", HTTP_PUT, handleUploadPUT);
}
void handleUploadPUT(AsyncWebServerRequest *request)
{
  String path = request->pathArg(0);
  [...]
}

[mathieucarbou]

From what I understand, ArUploadHandlerFunction is only for multipart POST requests, while PUT requests send a continuous stream for one file. ArBodyHandlerFunction is also tagged to be POST-only.

Where do you see that ?

I saw no such thing in the code, plus, the HTTP spec supports a body, even for GET requests strangely.

[Levak]

[[EDIT: I was writting this answer 10min after the OP. But I had troubles validating that it works. ]]

I guess I misread the source code of ESPAsyncWebServer. ArBodyHandlerFunction is used when NOT a POST Plain text :D

Here is a simple snippet for future references:
⚠️ Important: define ASYNCWEBSERVER_REGEX in build properties (in Arduino IDE, my trick is to add it to pins_arduino.h), otherwise, the regex won't be effective.

#include <ESPAsyncWebServer.h>

void init() {
  server.on("^/upload/(.+)$", HTTP_PUT, handleUpload, nullptr, handleUploadPUT);
}

struct HandlePUTStates {
  File dataFile;
};

void handleUploadPUT(AsyncWebServerRequest *request, uint8_t* data, size_t len, size_t index, size_t total)
{
  String path = request->pathArg(0);
  struct HandlePUTStates * states;

  if (index == 0) {
    states = new HandlePUTStates();
    states->dataFile = File();
    request->_tempObject = states;

    File dataFile = fileSystem.open(path, FILE_WRITE);

    states->dataFile = dataFile;
  } else {
    states = (struct HandlePUTStates *) request->_tempObject;
  }

  states->dataFile.write(data, len);

  if(index + len == total) {
    states->dataFile.close();
    states->dataFile = File();
  }
}

I am just missing this piece:

  case RAW_ABORTED:
    dataFile.close();
    fileSystem.remove(path);
    log_v("Upload PUT: file aborted");
    break;

I did not find yet a way to detect a request abort.

[mathieucarbou]

I did not find yet a way to detect a request abort.

aborting a request from client-side would close the connection thus trigger the disconnect clalback.

did you try request->onDisconnect([]() { ... }) ?

Never tried, but it is implemented.

[Levak]

Great!
That does the trick. Inside the if (index == 0) I added:

    request->onDisconnect([states, path](){
      states->dataFile.close();
      states->dataFile = File();
      fileSystem.remove(path);
    });

And after testing, it works fine. a /list returns 404 if upload was aborted, 200 if upload was successful.

Have a good one 👍