I am receiving a base64 encoded image from the client (as a screenshot) and would like to upload it to another server using multipart encoding
var base64Encoded="iVBORw0KGgoAAAANSUhEUgAAAAoAAABkCAYAAAC/zKGXAAAAK0lEQVR42u3KMQ0AAAgDsOFfJwcusMBL0t6tSToHJYqiKIqiKIqiKIri57hqIbTd/KhOmQAAAABJRU5ErkJggg==";
const x =Axios({url:"https://slack.com/api/files.upload",method:"POST", data:{title:"Hello", file: <INSERT HERE>, filetype:"png", channel: "testchannel"},headers:{Authorization: authorization,'Content-Type': 'multipart/form-data'}});
I've tried a lot here
Converting it to a buffer
var buffer = Buffer.from("iVBORw0KGgoAAAANSUhEUgAAAAoAAABkCAYAAAC/zKGXAAAAK0lEQVR42u3KMQ0AAAgDsOFfJwcusMBL0t6tSToHJYqiKIqiKIqiKIri57hqIbTd/KhOmQAAAABJRU5ErkJggg==", 'base64');
Converting the buffer into a readable stream
var buffer = Buffer.from("iVBORw0KGgoAAAANSUhEUgAAAAoAAABkCAYAAAC/zKGXAAAAK0lEQVR42u3KMQ0AAAgDsOFfJwcusMBL0t6tSToHJYqiKIqiKIqiKIri57hqIbTd/KhOmQAAAABJRU5ErkJggg==", 'base64');
console.log(buffer);
const readable = new Readable();
readable._read = function(){};
readable.push(buffer)
readable.push(null)
None of these seem to work. Slack API simply gives me a invalid form data response
It works if i upload via postman
PS: I have to send axios request using the nodejs server, not browser
Related
I want send a part of bigFile to serve by pure nodejs+axios+form-data.
nodejs v16.14.0
but I don't know how to send buffer direct to server
import FormData from 'form-data'
const buffer = fs.readFileSync(filePath)
const chunk = buffer.slice(start, end)
// some code ...
// below code can work
// but the way need write file to disk
fs.writeFileSync(chunkPath, chunk)
formData.append('file', fs.createReadStream(chunkPath))
// end below code can work
// below code doesn't work
import { Readable } from 'stream'
formData.append('file', Readable.from(chunk).read())
dont's save buffer to disk, and send to server
So, I'm trying to pass an image to a Node Lambda through API Gateway and this is automatically base64 encoded. This is fine, and my form data all comes out correct, except somehow my image is being corrupted, and I'm not sure how to decode this properly to avoid this. Here is the relevant part of my code:
const multipart = require('aws-lambda-multipart-parser');
exports.handler = async (event) => {
console.log({ event });
const buff = Buffer.from(event.body, 'base64');
// using utf-8 appears to lose some of the data
const decodedEventBody = buff.toString('ascii');
const decodedEvent = { ...event, body: decodedEventBody };
const jsonEvent = multipart.parse(decodedEvent, false);
const asset = Buffer.from(jsonEvent.file.content, 'ascii');
}
First off, it would be good to know if aws-sdk had a way of parsing the multipart form data rather than using this unsupported third party code. Next, the value of asset ends with a buffer that's exactly the same size as the original file, but some of the byte values are off. My assumption is that the way this is being encoded vs decoded is slightly different and maybe some of the characters are being interpreted differently.
Just an update in case anybody else runs into a similar problem - updated 'ascii' to 'latin1' in both places and then it started working fine.
I am making a react app where I have a field that allows users to upload PDF files.
I have successfuly uploaded and sent the files as base64 string to the server and I do receive it, however I am having trouble with saving the file back to pdf, here is what I have tried:
const fs = require("fs");
const invoice = { fileData: "data:application/pdf;base64,JVBERi0xLjandtherestofthedatastring..." };
const invoiceFileContents = new Buffer.from(invoice.fileData, "base64");
fs.writeFileSync(__dirname + "invoicetest.pdf", invoiceFileContents);
This does create a pdf file, but I am unable to open it, Adobe says its broken.
I managed to solve it, the appended string infront of the whole data string data:application/pdf;base64, should be trimmed:
const invoiceFileContents = new Buffer.from(
invoice.fileData.substring(invoice.fileData.indexOf("base64") + 7),
"base64"
);
I have the following code:
const formData = new FormData();
formData.append("filedata", myImage);
fetch("/extension/api/uploadtofb", {
method: "POST",
body: formData
})
If myImage is a base64 string representation (dataURL) of an image, multer considers it not as a file but as a text. Therefore it is found in req.body, not in req.file. How can I upload this image to my NodeJS (Express) server so it can be recognized and read as an image? (Doesn't need to use multer, I just followed instructions I found so far.)
I was able to work around it by converting the base64 string to blob and send it as blob instead. The image now can be correctly found in the req.file. But I need to send a post request with this image from the NodeJS (Express) server. FormData doesn't accept req.file or req.file.bufferin append. How can I convert received blob to a format, that can be accepted by FormData and sent with POST request?
I think that if the first problem can be solved, the second problem will also solve itself.
You can directly upload base64 image data
var base64Data = JSON.parse(res.body).data;
var filename = "test.png";
var base64_attachement = base64Data.replace(/-/g, '+').replace(/_/g, '/').replace(/ /g, '+');
filepath = (__dirname + './../../public/temp');
if (!fs.existsSync(filepath)) {
fs.mkdirSync(filepath, 0744); //Set Folder Permission
}
filepath = filepath + '/' + _filename;
//TempFilePath
require("fs").writeFile(filepath, base64_attachement, 'base64', function (err) {
console.log(err);
return cb(filepath);
});
I am receiving string base64 encoded, when I try to decode and save in to an image file, it seems to be everything working fine, but when I download open the file, my viewer does not recognize it.
I know my string is a valid image because I use http://www.freeformatter.com/base64-encoder.html
and it sends me the right image.
Is there something I am missing?
var imagestring = "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";
var decodedImage = new Buffer(imagestring, 'base64');
fs.writeFile('imagedecoded.jpg', decodedImage , function(err) {});