I'm trying encode an image to base64, (so I can later send it this way to a backend server). Everything seems to work until I use JSON.stringify() on the object that has the encoded image in it.
I think It gets lost in the JSON.stringify() and I can't seem to find a solution. I've been working for weeks on this issue and I couldn't find an answer anywhere. Please help!
const [baseImage, setBaseImage] = useState('');
const [baseImageCorrect, setBaseImageCorrect] = useState('');
const convertBase64 = (file) => {
return new Promise((resolve, reject) => {
const fileReader = new FileReader();
fileReader.readAsDataURL(file);
fileReader.onload = () => {
resolve(fileReader.result);
};
fileReader.onerror = (error) => {
reject(error);
console.log(error);
};
});
};
const uploadImage = async (e) => {
const file = e.target.files[0];
const base64 = await convertBase64(file);
const base64RemovedType = base64.split(',')[1];
setBaseImage(`${base64RemovedType}`);
};
useEffect(() => {
setBaseImageCorrect(baseImage);
console.log('current:' + baseImageCorrect);
//prints out a long string with the RIGHT information
}, [baseImage, baseImageCorrect]);
const EncodedImage = JSON.stringify({
fileBase64: (baseImageCorrect, { encoding: 'base64' }),
});
console.log(EncodedImage)
//PRINTS THIS: "fileBase64":{"encoding":"base64"}} , without the encoded image string
I am assuming u need the key baseImageCorrect and encoding key at the same level.
Use this instead:
const EncodedImage = JSON.stringify({
fileBase64: {baseImageCorrect, encoding: 'base64' },
});
Related
I'm taking input as a PDF file and using javascript to add custom metadata, but I'm not getting a satisfactory result.
Below is a sample method code that I used to add custom metadata that is first converted to blob type and then added, but when we convert its blob data to base64 and download the file and check the properties, we cannot find it.
const blobToBase64 = (blob: any) =>
new Promise((resolve, reject) => {
const reader = new FileReader();
reader.readAsDataURL(blob);
reader.onload = () => resolve(reader.result);
reader.onerror = (error) => reject(error);
});
const updatePDFMetaData = (file: any, metadata: any) => {
let convertBlobToBase64: any;
const selectedFile = file;
const reader = new FileReader();
reader.readAsArrayBuffer(selectedFile);
reader.onload = async (event:any) => {
const fileBuffer: any = event?.target?.result;
const blob: any = new Blob([fileBuffer], { type: selectedFile.type });
Object.keys(metadata).forEach((key: any) => {
blob[key] = metadata[key];
});
convertBlobToBase64 = await blobToBase64(blob);
console.log("convertBlobToBase64", convertBlobToBase64);
};
};
I am using Guacamole.client.createClipboardStream for creating a clipboard stream and send write the stream on paste event but, the remote clipboard is still empty.
const stream = client.createClipboardStream("text/plain");
stream.sendBlob(data);
I had the same issue, but then found that per the Guacamole Common Js spec, the OuputStream.sendBlob method expects a Base64 encoded string representing the blob.
Here's a little snippet from my quite early code to do this
const blobToBase64 = (blob) => {
return new Promise((res, _) => {
const reader = new FileReader();
reader.onloadend = () => res(reader.result);
reader.readAsDataURL(blob);
});
}
const sendBlobBasedOnMimeType = async (item, mimeType) => {
const blob = await item.getType(mimeType);
const blobAsDataUrl = await blobToBase64(blob);
const blobAsB64 = blobAsDataUrl.split(",")[1];
console.log("size of b64 blob", blobAsB64.length);
const stream = guac.current.createClipboardStream(mimeType, "remote");
stream.onack = () => {
stream.sendEnd();
}
stream.sendBlob(blobAsB64);
}
I want to read the contents of the file directly by using the file path. I can do this by having the file selected. But I don't know how to do it using the direct file path. I could not find any examples or sources for this. Below is how I read the file by selecting it from the input.
import * as XLSX from 'xlsx';
var items = [];
readExcel = (file) => {
const promise = new Promise((resolve, reject) => {
const fileReader = new FileReader();
fileReader.readAsArrayBuffer(file);
fileReader.onload = (e) => {
const bufferArray = e.target.result;
const wb = XLSX.read(bufferArray, { type: "buffer" });
const wsname = wb.SheetNames[0];
const ws = wb.Sheets[wsname];
const data = XLSX.utils.sheet_to_json(ws);
resolve(data);
};
fileReader.onerror = (error) => {
reject(error);
};
});
promise.then((d) => {
this.items = d;
console.log(this.items)
// fill dictionary
this.dictionary = Object.assign({}, ...this.items.map((x) => ({ [x.PartNumber]: x.Cost })));
console.log(this.dictionary)
});
};
<input
type="file"
onChange={(e) => {
const file = e.target.files[0];
this.readExcel(file);
}}
/>
I beleive it should work:
const req = new XMLHttpRequest();
req.responseType = "arraybuffer";
req.open("GET", "https://.../MyExcelFile.xlsx", true);
req.onload = () => {
const bufferArray = req.response;
const wb = XLSX.read(bufferArray, { type: "buffer" });
...
I couldn't find a direct read operation. I converted the excel file to json format and got my job done.
I was trying to create an API endpoint for rotating images uploaded from client side. I'm sending images as base64 type, converted from blob (from simple <input tag), as follows:
const addImageBase64 = async (fileData) => {
const file = fileData;
return new Promise((resolve, reject) => {
const reader = new FileReader();
reader.onload = (event) => {
resolve(event.target.result);
};
reader.onerror = (err) => {
reject(err);
};
reader.readAsDataURL(file);
});
};
Then, on the server side, that's how the endpoint looks like:
app.post("/api/rotate-image", async (req, res) => {
try {
let buffer = Buffer.from(req.body.imageData, "base64"); //not working
let array = new Uint8Array(buffer); //not working
const image = await sharp(buffer)
.rotate(180)
.png({ quality: 100 })
.toBuffer();
console.log("success");
res.status(200).send({
success: true,
result: image,
});
} catch (e) {
console.warn(e);
}
});
And here, every my attempt is ending up with '[Error: Input buffer contains unsupported image format]' - either for Buffer or Uint8Array. Can anyone help me with this issue? What is the right input type for Sharp that acctually works?
Edit:
Error with logged buffer obj:
On my NodeJS server I download an image that I need to embed in an email. My bucket is NOT public so just using the link will not work, as is not the solution I want for the requirements of either this question or the project.
I'm using a HTML email for this with something like:
<p>Embedded image: <img src="data:image/jpeg;charset=utf-8;base64,{{url}}" /></p>
So I download from S3
s3.getObject(
{ Bucket: "mybucket", Key: "mykey" },
function (error, data) {
if (error != null) {
console.log("Errror" + error)
} else {
console.log("Loaded " + data.ContentLength + " bytes")
and then I'm trying to convert data.body to UTF-8 base 64
I thought something like
"data:image/png;base64," + new String(encoder.encode(data.body), "UTF-8")
But it doesn't seem to work, and I'm struggling to define encoder to be able to do this.
Make sure you are getting image data in data.Body. I think data.Body already a buffer and you can construct src URL as bellow:
// Convert Body from a Buffer to a String
let base64String= data.Body.toString('base64');
let src = "data:image/jpeg;base64,"+base64String;
if you store s3 bucket object in binary format, to received it and convert it to base64 can be done:
const blobToBase64 = (blob) => {
const reader = new FileReader()
reader.readAsDataURL(blob)
return new Promise((rs, rj) => {
reader.onloadend = () => {
rs(reader.result)
}
reader.onerror = rj
})
}
function useImage({s3Link}) {
const [src, setSrc] = React.useState(null)
React.useEffect(() => {
async function query({link}) {
//link is link to s3 bucket URL link e.g
// const link = s3.getSignedUrl('getObject', {
// Bucket: bucketnamw,
// Key: key,
// Expires: 30,
// })
const r = await fetch(link)
const blob = await r.blob()
const base64 = await blobToBase64(blob)
console.log(`base64!`, base64)
setSrc(base64)
}
if (s3Link) {
query({link: s3Link})
}
}, [s3Link, setSrc])
return [{src}]
}