Missing data when using busboy inside Lambda?

Hi,

First off, thank you for writing this library. I’m hoping to use it in my current project. I am trying to use busboy on a lambda function to process a post request which is supposed to upload an image file. This is what I have in my client code:

const formData = new FormData();
formData.append("file", params.file, params.file.name);

const request = new XMLHttpRequest();
request.open("POST", "https://myapi/uploadphoto");
request.setRequestHeader('Authorization', this.props.idToken);
request.send(formData);

and in my lambda function I have this method to get the file contents:

function getFile(event) {
   const busboy = new Busboy({headers: event.headers});
   const result = {};

   return new Promise((resolve, reject) => {
      busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
         file.on('data', data => {
            result.content = data;
            console.log("got data... " + data.length + ' bytes');
         });

         file.on('end', () => {
            result.filename = filename;
            result.contentType = mimetype;
            resolve(result);
         });
      });

      busboy.on('error', error => reject(error));
      busboy.write(event.body, event.isBase64Encoded ? 'base64' : 'binary');
      busboy.end();
   });
}

When trying with an example photo, I notice that the “got data” console log is showing me that I am not receiving the whole file. The file I am using is 229707 bytes but the console log says that it received 217351 bytes.

I tried changing the call to busboy.write to just use ‘base64’ since it looks like the file arrives in binary, but that didn’t work either.

I am wondering if I am using busboy wrong or if this is some quirk of lambda + api gateway. Any ideas or help troubleshooting is much appreciated. Thank you!

[Smoodle]

Hey sorry for the late response, had the same issue and finally got it working. In my case i use AWS Lambdas so anyone still looking for a solution this is how i did it.

This is not a busboy issue, you just need to enable binary support in API Gateway (https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-payload-encodings-configure-with-console.html)

All your initial code is correct, this is my code:

module.exports.parseFormData = (event) => new Promise((resolve, reject) => {
	const busboy = new Busboy({
		headers: event.headers
	});

	let result = {
		files: []
	};

	busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
		file.on('data', data => {
			result.files.push({
				file: data,
				fileName: filename,
				contentType: mimetype
			});
		});
	});

	busboy.on('field', (fieldname, value) => {
		try {
			result[fieldname] = JSON.parse(value);
		} catch (err) {
			result[fieldname] = value;
		}
	});

	busboy.on('error', error => reject(`Parse error: ${error}`));
	busboy.on('finish', () => {
		event.body = result;
		resolve(event);
	});

	busboy.write(event.body, event.isBase64Encoded ? 'base64' : 'binary');
	busboy.end();
});

If you use serverless framework to manage your lambdas you just need to add this to provider setting

provider:
    apiGateway:
    binaryMediaTypes:
            - '*/*'

Hope this helps.

[FaridSafi]

Thank you @Smoodle, you saved me a lot of time. Here my version with little improvements.

const Busboy = require("busboy");
const parseFormData = (event) => {
  return new Promise((resolve, reject) => {
    const busboy = new Busboy({
      headers: {
        ...event.headers,
        "content-type":
          event.headers["Content-Type"] || event.headers["content-type"],
      },
    });
    const result = {
      files: [],
    };

    busboy.on("file", (fieldname, file, filename, encoding, mimetype) => {
      file.on("data", (data) => {
        result.files.push({
          file: data,
          fileName: filename,
          contentType: mimetype,
        });
      });
    });
    busboy.on("field", (fieldname, value) => {
      try {
        result[fieldname] = JSON.parse(value);
      } catch (err) {
        result[fieldname] = value;
      }
    });
    busboy.on("error", (error) => reject(`Parse error: ${error}`));
    busboy.on("finish", () => {
      event.body = result;
      resolve(event);
    });
    busboy.write(event.body, event.isBase64Encoded ? "base64" : "binary");
    busboy.end();
  });
};