in a Node.js app, i send an image via Socket.io to the server. in the server, i get it like this and i wanted to save it on the disk. it save's but i cant open that image and image viewer says it's damaged! file size is correct but i can't open it. is there anything that i miss in the code?
socket.on('newImage', function (data) {
var img = data.image;
var coded_img = new Buffer(img, 'base64');
fs.writeFile("out.png", coded_img,'base64', function(err) {
if (err) throw err;
console.log('File saved.')
});
});
I solved it, With this function, i recovered main image data:
decodeBase64Image = function(dataString) {
var matches = dataString.match(/^data:([A-Za-z-+\/]+);base64,(.+)$/),
response = {};
if (matches.length !== 3) {
return new Error('Invalid input string');
}
response.type = matches[1];
response.data = new Buffer(matches[2], 'base64');
return response;
};
Related
I'm using the gcloud API on a Nodejs web server to upload files. I'd prefer the files not be uploaded on the client side and instead uploaded on the server. Currently, I am producing a blob on the client side, then converting it to text and passing that to the server through a POST request. All of the information gets successfully passed from the client to the server as expected. This data is also uploaded to gcloud, however, Gcloud does not recognize this as a valid file nor does my computer when I download it.
What is the best way to get the contents of the file to gcloud from the server side? I've tried using dataURIs and reading the orignal file by text and both produce similiar issues. I've also explored piping a readFileStream from the blob on the server end but blobs are not natively supported by node so I have not done so yet.
Client Side
function readSingleFile(e, func, func2){
var file = e.target.files[0];
if(!file){
return; // Add error msg_here
}
var reader = new FileReader();
reader.onload = function(e){
let contents = e.target.result;
let img = document.createElement('img')
let cvs = document.createElement('canvas');
img.onload = ()=>{
cvs.width = img.width;
cvs.height= img.height;
let ctx = cvs.getContext('2d');
ctx.drawImage(img,0,0);
cvs.toBlob((res)=>{res.text().then((text)=>{func2(text)})}, "image/jpeg", 0.92);
}
img.src=contents;
func(contents);
}
reader.readAsDataURL(file);
}
Server Side
function publishPrintjob(dataObj){
try{
var newElemKey = database.ref().child('queue').push().key; // Get random Key
// Create a new blob in the bucket and upload the file data.
const gcloudFile = storage.file('images/' + newElemKey + '.jpg');
gcloudFile.save(dataObj.sockImageFile, function(err) {
if (!err) {
Console.log("File Uploaded!")
}
});
var data = {
date: dataObj.Date,
email: dataObj.email,
design: dataObj.Design,
author: dataObj.Author,
address: dataObj.address,
imageKey: newElemKey,
}
admin.database().ref('queue/' + newElemKey).set(data);
} catch(err){
console.log(err)
}
}
Note: func simply shows the image on the client side, func2 just adds the contents to the POST object.
Uploading a file directly from the computer would be easiest using the storage.bucket(bucketName).upload() function from the cloud storage library. However, this uses location of a file locally and thus will not work unless a file is transferred to the server and saved first. This could be achieved using multi-part form data. Using multipart or uploading locally are better methods for uploading to google storage.
Instead, I solve this by first converting the image to a dataURI, sending the data URI to the server via the body of a GET request, and then converting it to a buffer with a readable stream that can be piped to google storage.
Client
let formData = getFormData('myForm');
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// Typical action to be performed when the document is ready:
}
};
xhttp.open("POST", "dashboard", true);
xhttp.setRequestHeader('Content-Type', 'application/json');
xhttp.send(JSON.stringify(formData));
xhttp.onload = ()=> {
console.log(JSON.parse(xhttp.response))
// Handle server response here
};
}
Server
// DataObject is the body of the GET request, the property imageFile is the URI from readFileAsURI
function uploadImageOnServer(dataObj){
try{
var newElemKey = database.ref().child('queue').push().key; // Get random Key to use as filename
// Create a new blob in the bucket and upload the file data.
const gcloudFile = storage.file('images/' + newElemKey + '.jpeg');
var fs = require('fs'); // Should be required at the top of the file
var string = dataObj.ImageFile;
var regex = /^data:.+\/(.+);base64,(.*)$/;
var matches = string.match(regex);
var ext = matches[1];
var data = matches[2];
var buffer = Buffer.from(data, 'base64');
// Create the readstream
const readableInstanceStream = new Readable({
read() {
this.push(buffer);
this.push(null);
}
});
readableInstanceStream.pipe(gcloudFile.createWriteStream()) // link to gcloud storage api
.on('error', function(err) {
console.log('error')
})
.on('finish', function() {
console.log('upload complete')
});
} catch(err){
console.log(err)
}
}
I created a generator for PDF files that creates the file and sends to a specific path automatically after creation. Still I want to download it right after but didn't know how to do that. Any help would be appreciated. This is my generatorPdf.js :
module.exports={
pdfGenerator:function(data,pathfile){
var fonts = {
Roboto: {
normal: 'server/pdfgenerator/fonts/Roboto-Regular.ttf',
bold: 'server/pdfgenerator/fonts/Roboto-Medium.ttf',
italics: 'server/pdfgenerator/fonts/Roboto-Italic.ttf',
bolditalics: 'server/pdfgenerator/fonts/Roboto-MediumItalic.ttf'
}
};
var datePaiements='';
var dateFinPaiements='';
if(data.abonnement[0].datePaiement!=null)
datePaiements= new Date( data.abonnement[0].datePaiement.toString());
if(datePaiements!=='')
{
dateFinPaiements= ('0'+datePaiements.getDate()).slice(-2).toString()+'/'+('0'+(datePaiements.getMonth()+1)).slice(-2).toString()+'/'+(datePaiements.getFullYear()+1).toString();
datePaiements=('0'+datePaiements.getDate()).slice(-2).toString()+'/'+('0'+(datePaiements.getMonth()+1)).slice(-2).toString()+'/'+datePaiements.getFullYear().toString();
}
var dateFacture= new Date(data.abonnement[0].timestampCreation.toString());
dateFacture= ('0'+dateFacture.getDate()).slice(-2).toString()+'/'+('0'+(dateFacture.getMonth()+1)).slice(-2).toString()+'/'+dateFacture.getFullYear().toString();
var PdfPrinter = require('pdfmake/src/printer');
var printer = new PdfPrinter(fonts);
var fs = require('fs');
var dd = {
content: [ ..............],
footer:{.............}
}
try{
var pdfDoc = printer.createPdfKitDocument(dd);
if (fs.existsSync(pathfile)) {//server/pdfgenerator/documentpdf/basics21.pdf
fs.unlink(pathfile, (err) => {//server/pdfgenerator/documentpdf/basics21.pdf
if (err) {
console.error(err)
return
}
})
}
pdfDoc.pipe(fs.createWriteStream(pathfile)).on('finish',function(){//server/pdfgenerator/documentpdf/basics21.pdf
});
}
catch(e){
console.log(e);
return null;
}
}
}
and this is my remote method in Loopback to send the pdf to a path and where probably I have to do the download of the file:
cm_abonnements.getAbonnementById= async (options,req,res)=>{
const token = options && options.accessToken;
const userId = token && token.userId;
try{
if(userId!==null){
let dataComedien= await app.models.cm_comediens.getComedienByUser(userId);
let argAbn={};
const form = new formidable.IncomingForm();
var formPromise = await new Promise(function(resolve,reject){
form.parse(req,function(err,fields,files){
if(err)
{
reject(err);
return-1
}
console.log(fields.key)
argAbn.idAbonnement=fields.key;
resolve();
})
})
let dataFac=await cm_abonnements.find({where :{and :[{idAbonnement:argAbn.idAbonnement},{idComedien : dataComedien.idComedien}]}});
var data={abonnement:[]};
data.abonnement=dataFac;
var str_date= new Date(dataFac[0].timestampCreation.toString());
var nameFile= 'Fac_'+dataFac[0].idFacture+'_'+str_date.getFullYear().toString()+'-'+('0'+str_date.getMonth()+1).slice(-2).toString()+'-'+('0'+str_date.getDate()).slice(-2).toString()+'.pdf';
var path='public/upload/Comediens/'+dataComedien.idComedien.toString()+'/factures/'+nameFile;
createPdf.pdfGenerator(data,path);
return dataFac;
}
return null;
}
catch(e){
console.log(e);
return null;
}
}
cm_abonnements.remoteMethod(
'getAbonnementById',{
http:{
verb:'POST'
},
description:'Get detail facture by number facture',
accepts:[
{arg:"options", "type":"object","http":"optionsFromRequest"},
{ arg: 'req', type: 'object', 'http': {source: 'req'}},
{arg: 'res', type: 'object', 'http': {source: 'res'}}
],
returns:{arg:'data',root:true}
}
);
Any help would be appreciated. Thank you
You need to send the following HTTP headers:
Content-Type: application/pdf
Content-Disposition: inline; filename="download.pdf"
After data is generated and pdf file is stored, there are 2 steps left to implement the "download" feature:
Return HTTP response to browser, with Content-Type header as application/pdf, and Content-Disposition header as attachment; filename="yourname.pdf". Normally, this would be handled automatically by web framework. I'm not familiar with loopback, so take Express for example:
In generatorPdf.js, add a callback to listen the finish event:
pdfGenerator:function(data, pathfile, callback){
...
pdfDoc.pipe(fs.createWriteStream(pathfile)).on('finish', callback);
...
}
When pdfGenerator function is used, pass a callback function parameter. If the pdf work is "finished", return response to browser using res.download() (It's Express API, but I believe loopback has similar API as loopback is built on top of Express):
var nameFile=...
var path=...
createPdf.pdfGenerator(data, path, function() {
res.download(path, nameFile);
});
In browser side, if it's an AJAX request (I guess so, as you mentioned it is a POST request), you need to handle the request with some blob operation. Here is an example snippet, with explanation comment:
var req = new XMLHttpRequest();
req.open('POST', '/download', true); // Open an async AJAX request.
req.setRequestHeader('Content-Type', 'application/json'); // Send JSON data
req.responseType = 'blob'; // Define the expected data as blob
req.onreadystatechange = function () {
if (req.readyState === 4) {
if (req.status === 200) { // When data is received successfully
var data = req.response;
var defaultFilename = 'default.pdf';
// Or, you can get filename sent from backend through req.getResponseHeader('Content-Disposition')
if (typeof window.navigator.msSaveBlob === 'function') {
// If it is IE that support download blob directly.
window.navigator.msSaveBlob(data, defaultFilename);
} else {
var blob = data;
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = defaultFilename;
document.body.appendChild(link);
link.click(); // create an <a> element and simulate the click operation.
}
}
}
};
req.send(JSON.stringify({test: 'test'}));
I use jsPDF to generate multiple PDFs.
Is there a way for me to save all the PDFs as a single ZIP through jsZIP?
For anyone coming here to find a more direct answer to this question, I have this example:
var zip = new JSZip();
angular.forEach ($scope.students, function (student) {
//The createFile() function returns a jsPDF
var doc = createFile(student);
if (typeof doc !== 'undefined') {
try {
zip.file(student.name + '.pdf', doc.output('blob'));
}
catch {
console.error('Something went wrong!');
}
}
});
zip.generateAsync({type:'blob'}).then(function(content) {
saveAs(content, 'reports.zip');
});
Basically, zip.file() adds a new file to the zip with (name, data). You add the jsPDF document as a blob by calling doc.output('blob'). Don't forget to add '.pdf' at the end of the name.
Then you generate a zip file by calling the zip.generateAsync() function and save it when it finishes generating.
In this example I used jsPDF, JSZip and FileSaver.js
Does this help?
https://gist.github.com/noelvo/4502eea719f83270c8e9
var zip = new JSZip();
var count = 0;
var zipFilename = "zipFilename.zip";
var urls = [
'http://image-url-1',
'http://image-url-2',
'http://image-url-3'
];
urls.forEach(function(url){
var filename = "filename";
// loading a file and add it in a zip file
JSZipUtils.getBinaryContent(url, function (err, data) {
if(err) {
throw err; // or handle the error
}
zip.file(filename, data, {binary:true});
count++;
if (count == urls.length) {
var zipFile = zip.generate({type: "blob"});
saveAs(zipFile, zipFilename);
}
});
});
I'm trying to convert heic to jpg. I use the official library on js. The problem is that I can decode a heic photo from the repository (callback returns an array of data), but I can't decode heic photos taken on the iPhone (In this case, the callback doesn't return anything at all).
Has anyone tried to convert a heic photo, that was made on an iPhone to jpg?
var reader = new HEIFReader('test/1.heic');
var decoder = new HevcDecoder();
var imgData = new ImageProvider(reader, decoder);
reader.requestFileInfo(function(payload) {
if (payload.success !== true) {
console.error("Could not read file:", url);
} else {
var fileInfo = payload;
console.log("FileInfo contents:", fileInfo);
if (fileInfo.rootLevelMetaBoxProperties) {
var masterContextId = fileInfo.rootLevelMetaBoxProperties.contextId;
var masterItemIds = [];
var imageFeaturesMap = fileInfo.rootLevelMetaBoxProperties.imageFeaturesMap;
for (i in imageFeaturesMap) {
if (imageFeaturesMap.hasOwnProperty(i) && imageFeaturesMap[i].isMasterImage === true) {
masterItemIds.push(parseInt(i));
}
}
console.log("Master images in the file:", masterItemIds);
imgData.requestImageData(masterContextId, masterItemIds, function(data) {
console.log(data);
});
}
}
});
I am trying to send a file(with a size of 64Kb) in base64 format to my .Net web service in node js using soap, but the result is empty. I don't know if it is because of the size of the base64 string, because when I send this string empty it responded normally.
file = req.file;
if(file){
file64 = base64_encode('public/assets/uploads/' + file.filename);
}
var args = {file: file64};
soapClient.uploadFile(args, function(err, result) {
if(err){
console.log(err);
}else{
var response = JSON.parse(result.uploadFileResult);
if(!response.response){
console.log(response.message);
}else{
//Handlers
}
}
});
When I print the result in console it shows: {}