My app needs to create a PDF file and then upload it to another server. The upload happens down the line via the post method from the request NPM package. Everything works fine if I pass in an fs.createReadStream:
const fs = require('fs');
const params = {file: fs.createReadStream('test.pdf')};
api.uploadFile(params);
Since PDFKit instantiates a read stream as well, I'm trying to pass that directly into the post params like this:
const PDFDocument = require('pdfkit');
const doc = new PDFDocument();
doc.text('steam test');
doc.end();
const params = {file: doc};
api.uploadFile(params);
However, this produces an error:
TypeError: Path must be a string. Received [Function]
If I look at PDFKit source code I see (in coffeescript):
class PDFDocument extends stream.Readable
I'm new to streams and it's clear I'm not understanding the difference here. To me if they are both readable streams, they should both be able to be passed in the same way.
Related
At my endpoint in my NodeJS server, after retrieving an audio file stored as a Buffer in MongoDB, I want to represent it with a URL (much like how you do with URL.createObjectURL(blob) in the frontend on the browser). I then plan to res.render() the URL in HTML through Handlebars on the client, so that the user can click on it to download it:
<a href={{url}}>Click me to download the file!</a>
In the NodeJs server, I have converted the MongoDB Buffer into a JavaScript ArrayBuffer through:
var buffer = Buffer.from(recordingFiles[0].blobFile);
var arrayBuffer = Uint8Array.from(buffer).buffer;
I am unsure where to proceed from here. I seen solutions using fs or res.download(), but they don't seem applicable to my situation. Thanks in advance for any help!
Hopefully this can help.
var blob = new Blob(BUFFER, {type: "audio mime type"});
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
var fileName = reportName;
link.download = fileName;
link.click();
Do you always need to preload the audio file onto the page?
If not, then I would advise you to add a separate endpoint to download the file on demand. The frontend link can send a get request to the endpoint and download the file only if the user clicked it.
Otherwise you'd always be downloading the buffer behind the scenes, even if the user didn't intend to download it. This is especially problematic on slow connections.
Frontend:
<a href={{`${baseUrl}/download/${audioId}`}}>Click me to download the file!</a>
Backend:
const stream = require('stream');
app.get('/download/:audioId', function (request, response) {
// Retrieve the tag from our URL path
const audioId = request.params.audioId;
const fileData; // TODO: Get file buffer from mongo.
const fileContents = Buffer.from(fileData, 'base64');
const readStream = new stream.PassThrough();
readStream.end(fileContents);
response.set('Content-disposition', 'attachment; filename=' + fileName);
response.set('Content-Type', '<your MIME type here>');
readStream.pipe(response);
});
A list of relevant MIME types can be found here.
I have a very huge xml file that I got by exporting all the data from tally, I am trying to use web scraping to get elements out of my code using cheerio, but I am having trouble with the formatting or something similar. Reading it with fs.readFileSync() works fine and the console.log shows complete xml file but when I write the file using the fs.writeFileSync it makes it look like this:
And my web scraping code outputs empty file:
const cheerio = require('cheerio');
const fs = require ('fs');
var xml = fs.readFileSync('Master.xml','utf8');
const htmlC = cheerio.load(xml);
var list = [];
list = htmlC('ENVELOPE').find('BODY>TALLYMESSAGE>STOCKITEM>LANGUAGENAME.LIST>NAME.LIST>NAME').each(function (index, element) {
list.push(htmlC(element).attr('data-prefix'));
})
console.log(list)
fs.writeFileSync("data.html",list,()=>{})
You might try checking to make sure that Cheerio isn't decoding all the HTML entities. Change:
const htmlC = cheerio.load(xml);
to:
const htmlC = cheerio.load(xml, { decodeEntities: false });
I have a local module (speech.js) in my create-react-app src folder that is the google text to speech code on their website. I adjusted it to be an arrow function and use that specific export syntax.
const textToSpeech = require('#google-cloud/text-to-speech');
// Import other required libraries
const fs = require('fs');
const util = require('util');
export const main = async () => {
// Creates a client
const client = new textToSpeech.TextToSpeechClient();
// The text to synthesize
const text = "Hello world";
// Construct the request
const request = {
input: {text: text},
// Select the language and SSML Voice Gender (optional)
voice: {languageCode: 'en-US', ssmlGender: 'NEUTRAL'},
// Select the type of audio encoding
audioConfig: {audioEncoding: 'MP3'},
};
// Performs the Text-to-Speech request
const [response] = await client.synthesizeSpeech(request);
// Write the binary audio content to a local file
const writeFile = util.promisify(fs.writeFile);
await writeFile('output.mp3', response.audioContent, 'binary');
console.log('Audio content written to file: output.mp3');
};
What I'm not understanding is why this syntax isn't working in App.js.
import {main} from './speech';
I get the error, Error: not support and "4 stack frames were collapsed". Quite informative!
Does anyone know what the error could be here? I thought as long as I used es6 style imports and exports I wouldn't receive errors. Could this be due to the first require() statement of speech.js? Any help would be appreciated. I've felt like banging my head against the wall for the past 40 minutes.
May not be the correct answer but I believe it has a good chance of being right. I believe that since node is just a runtime environment and not a part of the actual browser, you aren't able to use node modules with react (a frontend framework). The solution to this quandary would be to use something like electron.
I'm trying to analyze a file I'll be uploading from react, I need to know if it can be uploaded based on several factors.
I found https://github.com/TooTallNate/node-wav
It works great on nodejs and I'm trying to use it on react. The sample creates a readable stream and pipes it to the wav reader.
var fs = require('fs');
var wav = require('wav');
var file = fs.createReadStream('track01.wav');
var reader = new wav.Reader();
// the "format" event gets emitted at the end of the WAVE header
reader.on('format', function (format) {
//Format of the file
console.log(format);
});
file.pipe(reader);
Using FilePond controller I'm able to get a base64 string of the file. But I can't figure out how to pass it to the reader
this is what I have so far on ReactJS:
var reader = new wav.Reader();
reader.on('format', function (format) {
//Format of file
console.log('format', format);
});
const buffer = new Buffer(base64String, 'base64')
const readable = new Readable()
readable._read = () => { }
readable.push(buffer)
readable.push(null)
readable.pipe(reader)
But I get Error: bad "chunk id": expected "RIFF" or "RIFX", got "u+Zj"
Since this file works on NodeJS with the same lib is obvious I'm doing something wrong.
EDIT:
this was a problem with my Base64 string, this method works if anyone needs to analyze a wav on the frontend
I have a paginated request that gives me a list of objects, which I later concat to get the full list of objects.
If I attempt to JSON.stringify this, it fails for large objects with range error. I was looking for a way to zlib.gzip to handle large JSON objects.
Try installing stream-json it will solve your problem, It's a great wrapper around streams and parsing a JSON.
//require the modules stream-json
const StreamArray = require('stream-json/utils/StreamArray');
// require fs if your using a file
const fs = require('fs');
const zlib = require('zlib');
// Create an instance of StreamArray
const streamArray = StreamArray.make();
fs.createReadStream('./YOUR_FILE.json.gz')
.pipe(zlib.createUnzip()) // Unzip
.pipe(streamArray.input); //Read the stream
//here you can do whatever you want with the stream,
//you can stream it to response.
streamArray.output.pipe(process.stdout);
In the example, I'm using a JSON (file) but you can use a collection and pass it to the stream.
Hope that's help.