I have the following code to upload to my Node.js/Express.js backend.
var reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = function (e) {
var result = http.post('/files', e.target.result);
result.success(function () {
alert('done'):
});
}
My route looks like:
app.post('/files', function (req, res) {
var cws = fs.createWriteStream(__dirname + '/media/file');
req.pipe(cws);
res.send('success');
});
When I open /media/file with an image app I get a warning that it cannot read it. When I open the image file with a text-editor I see the base64 encoded string inside. Do I need to convert the string first before writing it to desk?
The problem was that a DataURL is prepended by meta data. You first need to remove that part before you create a base64 buffer.
var data_url = req.body.file;
var matches = data_url.match(/^data:.+\/(.+);base64,(.*)$/);
var ext = matches[1];
var base64_data = matches[2];
var buffer = new Buffer(base64_data, 'base64');
fs.writeFile(__dirname + '/media/file', buffer, function (err) {
res.send('success');
});
Got most code from this question.
Related
I have this function where I call a function and have a local file as the parameter to convert it to base64.
export const fileToBase64 = (filename, filepath) => {
return new Promise(resolve => {
var file = new File([filename], filepath);
var reader = new FileReader();
// Read file content on file loaded event
reader.onload = function(event) {
resolve(event.target.result);
};
// Convert data to base64
reader.readAsDataURL(file);
});
}
Importing the function
fileToBase64("shield.png", "./form").then(result => {
console.log(result);
console.log("here");
});
gives me an output as
data:application/octet-stream;base64,c2hpZWxkLnBuZw==
here
I want base64 information, but noticing the file the application/octet-stream is wrong? I entered an image so shouldn't it be
data:image/pgn;base64,c2hpZWxkLnBuZw==
https://medium.com/#simmibadhan/converting-file-to-base64-on-javascript-client-side-b2dfdfed75f6
try this I think this should helpfull
let buff = new Buffer(result, 'base64');
let text = buff.toString('ascii');
console.log(text)
when i get the image from the input
i have to convert it to a buffer to make some operations with the image, so as a result a i have a buffer instead of file.
im using FileCollection in meteor to store the image in mongo collection
uploadIt(e) {
e.preventDefault();
var reader = new FileReader();
var buffer;
var file = e.currentTarget.files[0];
if (e.currentTarget.files && e.currentTarget.files[0]) {
reader.onload = function(e){
buffer = new Uint8Array(reader.result);
// some operations over the buffer
};
reader.readAsArrayBuffer(file);
if (file) {
let uploadInstance = CourseFilesCollection.insert({
file: buffer,
..
..
})
}
}
but when i insert it got this error
message: "[FilesCollection] [insert] Have you forget to pass a File itself?
the code originally was
if (file) {
let uploadInstance = CourseFilesCollection.insert({
file: file,
..
..
})
}
but since i had to perfom operations over the the image i need to someway conver the buffer to file
any ideas how to solve this ?
Short answer
use the file constructor to turn bits back to a file container:
file: new File([buffer], file.name, file)
you could try using blob also with wider browser support... but if you want to use the latest tech, then:
async uploadIt (evt) {
evt.preventDefault()
const file = evt.currentTarget.files[0]
if (!file) return
const buffer = new Uint8Array(await file.arrayBuffer())
// some operations over the buffer
const uploadInstance = CourseFilesCollection.insert({
file: new File([buffer], file.name, file)
})
}
I am trying to capture the audio that's uploaded by the user, convert it to Blob then using wavesurfer.js to display the waveform.
I am following this instruction here https://bl.ocks.org/nolanlawson/62e747cea7af01542479
And here is the code
// Convert audio to Blob
$('#audioFileInput').on('change', function () {
var file = $('#audioFileInput')[0].files[0];
var fileName = file.name;
var fileType = file.type;
var fileReader = new FileReader();
fileReader.onloadend = function (e) {
var arrayBuffer = e.target.result;
blobUtil.arrayBufferToBlob(arrayBuffer, fileType).then(function (blob) {
console.log('here is a blob', blob);
console.log('its size is', blob.size);
console.log('its type is', blob.type);
surfTheBlob(blob);
}).catch(console.log.bind(console));
};
fileReader.readAsArrayBuffer(file);
});
But it says
blobUtil.arrayBufferToBlob(...).then is not a function
Another issue is that since the user might upload the audio themselves, the audio type might vary, expected to come from native device audio recorder. Anyone can help please? thanks.
A File object, like the ones you get in the input.files FileList, is already a Blob:
inp.onchange = e =>
console.log(inp.files[0] instanceof Blob) // true
<input type="file" id="inp">
So all you really need is to pass directly this File to your library:
$('#audioFileInput').on('change', function () {
var file = this.files[0];
surfTheBlob(file);
});
Found the answer already.
// Convert audio to Blob
$('#audioFileInput').on('change', function () {
var file = $('#audioFileInput')[0].files[0];
var fileName = file.name;
var fileType = file.type;
var url = URL.createObjectURL(file);
fetch(url).then(function(response) {
if(response.ok) {
return response.blob();
}
throw new Error('Network response was not ok.');
}).then(function(blob) {
surfTheBlob(blob);
}).catch(function(error) {
console.log('There has been a problem with your fetch operation: ', error.message);
});
});
Cheers!
Converting an image to base64 in angular 2, image is uploaded from local . Current am using fileLoadedEvent.target.result. The problem is, when I send this base64 string through REST services to java, it is not able to decode it. When i try this base64 string with free online encoder-decoder, there also I cannot see decoded image. I tried using canvas also. Am not getting proper result. One thing is sure the base64 string what am getting is not proper one, do I need to add any package for this ? Or in angular 2 is there any perticular way to encode the image to base64 as it was there in angular 1 - angular-base64-upload package.
Pls find below my sample code
onFileChangeEncodeImageFileAsURL(event:any,imgLogoUpload:any,imageForLogo:any,imageDiv:any)
{
var filesSelected = imgLogoUpload.files;
var self = this;
if (filesSelected.length > 0) {
var fileToLoad = filesSelected[0];
//Reading Image file, encode and display
var reader: FileReader = new FileReader();
reader.onloadend = function(fileLoadedEvent:any) {
//SECOND METHO
var imgSrcData = fileLoadedEvent.target.result; // <--- data: base64
var newImage = imageForLogo;
newImage.src = imgSrcData;
imageDiv.innerHTML = newImage.outerHTML;
}
reader.readAsDataURL(fileToLoad);
}
}
Working plunkr for base64 String
https://plnkr.co/edit/PFfebmnqH0eQR9I92v0G?p=preview
handleFileSelect(evt){
var files = evt.target.files;
var file = files[0];
if (files && file) {
var reader = new FileReader();
reader.onload =this._handleReaderLoaded.bind(this);
reader.readAsBinaryString(file);
}
}
_handleReaderLoaded(readerEvt) {
var binaryString = readerEvt.target.result;
this.base64textString= btoa(binaryString);
console.log(btoa(binaryString));
}
I modified Parth Ghiya answer a bit, so you can upload 1- many images, and they are all stored in an array as base64 encoded strings
base64textString = [];
onUploadChange(evt: any) {
const file = evt.target.files[0];
if (file) {
const reader = new FileReader();
reader.onload = this.handleReaderLoaded.bind(this);
reader.readAsBinaryString(file);
}
}
handleReaderLoaded(e) {
this.base64textString.push('data:image/png;base64,' + btoa(e.target.result));
}
HTML file
<input type="file" (change)="onUploadChange($event)" accept=".png, .jpg, .jpeg, .pdf" />
<img *ngFor="let item of base64textString" src={{item}} alt="" id="img">
another solution thats works for base64 is something like this post
https://stackoverflow.com/a/36281449/6420568
in my case, i did
getImagem(readerEvt, midia){
//console.log('change no input file', readerEvt);
let file = readerEvt.target.files[0];
var reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = function () {
//console.log('base64 do arquivo',reader.result);
midia.binario = btoa(reader.result);
//console.log('base64 do arquivo codificado',midia.binario);
};
reader.onerror = function (error) {
console.log('Erro ao ler a imagem : ', error);
};
}
and html component
<input type="file" class="form-control" (change)="getImagem($event, imagem)">
<img class="img-responsive" src="{{imagem.binario | decode64 }}" alt="imagem..." style="width: 200px;"/>
to display the image, i created the pipe decode64
#Pipe({
name: 'decode64'
})
export class Decode64Pipe implements PipeTransform {
transform(value: any, args?: any): any {
let a = '';
if(value){
a = atob(value);
}
return a;
}
}
Have you tried using btoa or Crypto.js to encode the image to base64 ?
link to cryptojs - https://code.google.com/archive/p/crypto-js/
var imgSrcData = window.btoa(fileLoadedEvent.target.result);
or
var imgSrcData = CryptoJS.enc.Base64.stringify(fileLoadedEvent.target.result);
Here is the same code from Parth Ghiya but written in ES6/TypeScript format
picture: string;
handleFileSelect(evt){
const file = evt.target.files[0];
if (!file) {
return false;
}
const reader = new FileReader();
reader.onload = () => {
this.picture = reader.result as string;
};
console.log(btoa(this.picture));
}
I have a come up with an answer with calling the HTTP request for post method with a json
1.event param is coming from the HTML input tag.
2. self.imagesrc is a component variable to store the data and to use that in the header file we need to cast the "this" to a self variable and use it in the reader. Onload function
3. this.server is the API calling service component variable I used in this component
UploadImages(event) {
var file = event.target.files[0];
var reader = new FileReader();
reader.readAsDataURL(file);
var self = this;
reader.onload = function() {
self.imageSrc = reader.result.toString();
};
var image_data = {
authentication_token: this.UD.getAuth_key ,
fileToUpload: this.imageSrc,
attachable_type: "Photo"
};
this.server.photo_Upload(image_data).subscribe(response => {
if (response["success"]) {
console.log(response);
} else {
console.log(response);
}
});
}
Please consider using this package: image-to-base64
Generate a image to base64, you can make this using a path or url.
Or this accepted answer
I am using ngCordova Capture to write this code by recording audio and send the base64 somewhere (via REST). I could get the Capture Audio to work but once it returns the audioURI, I cannot get the data from the filesystem as base64. My code is below:
$cordovaCapture.captureAudio(options).then(function(audioURI) {
$scope.post.tracId = $scope.tracId;
$scope.post.type = 'audio';
console.log('audioURI:');
console.log(audioURI);
var path = audioURI[0].localURL;
console.log('path:');
console.log(path);
window.resolveLocalFileSystemURL(path, function(fileObj) {
var reader = new FileReader();
console.log('fileObj:');
console.log(fileObj);
reader.onloadend = function (event) {
console.log('reader.result:');
console.log(reader.result);
console.log('event.result:');
console.log(event.result);
}
reader.onload = function(event2) {
console.log('event2.result:');
console.log(event2.target.result);
};
reader.readAsDataURL(fileObj);
console.log(fileObj.filesystem.root.nativeURL + ' ' + fileObj.name);
$cordovaFile.readAsDataURL(fileObj.filesystem.root.nativeURL, fileObj.name)
.then(function (success) {
console.log('success:');
console.log(success);
}, function (error) {
// error
});
});
Here is the output in console log:
So how do I get the base64 data from the .wav file?
I have been reading these links:
PhoneGap FileReader/readAsDataURL Not Triggering Callbacks
https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsDataURL
http://jsfiddle.net/eliseosoto/JHQnk/
http://community.phonegap.com/nitobi/topics/filereader_onload_not_working_with_phonegap_build_2_5_0
Had same problem, which I fixed using both the Cordova Capture and Cordova File plugin.
navigator.device.capture.captureAudio(function (audioFiles) {
var audioFile = audioFiles[0],
fileReader = new FileReader(),
file;
fileReader.onload = function (readerEvt) {
var base64 = readerEvt.target.result;
};
//fileReader.reasAsDataURL(audioFile); //This will result in your problem.
file = new window.File(audioFile.name, audioFile.localURL,
audioFile.type, audioFile.lastModifiedDate, audioFile.size);
fileReader.readAsDataURL(file); //This will result in the solution.
});