Develop Reference

Use the base64 preview of the binary data response (zip file) in angularjs

I always get this error in the downloaded zip file C:\Users\me\Downloads\test.zip: Unexpected end of archive
My current code is:
var blob = new Blob([data], { // data here is the binary content
type: 'octet/stream',
});
var zipUrl = window.URL.createObjectURL(blob);
var fileName = orderNo;
fileName += '.zip';
downloadFile(null, fileName, null, zipUrl, null); // just creates a hidden anchor tag and triggers the download
The response of the call is a binary (I think). Binary Content Here
But the preview is a base64. Base64 Content. And it is the correct one. The way I verify it is by using this fiddle.
You can refer to the screenshot of the network here
I put the base64 content in this line var sampleBytes = base64ToArrayBuffer(''); And the zip downloaded just opens fine.
Things I have tried so far.
Adding this headers to the GET call
var headers = {
Accept: 'application/octet-stream',
responseType: 'blob',
};
But I get Request header field responseType is not allowed by Access-Control-Allow-Headers in preflight response.
We're using an already ajax.service.js in our AngularJS project.
From this answer
var blob = new Blob([yourBinaryDataAsAnArrayOrAsAString], {type: "application/octet-stream"});
var fileName = "myFileName.myExtension";
saveAs(blob, fileName);
There are other things that I have tried that I have not listed. I will edit the questions once I find them again
But where I'm current at right now. The preview is correct base64 of the binary file. Is it possible to use that instead of the binary? (If it is I will not find the other methods that I've tested) I tried some binary to base64 converters but they don't work.

So I just went and ditched using the ajax.service.js, that we have, for this specific call.
I used the xhr snippet from this answer. I just added the headers necessary for our call: tokens and auth stuff.
And I used this code snippet for the conversion thing.
And the code looks like this:
fetchBlob(url, function (blob) {
// Array buffer to Base64:
var base64 = btoa(String.fromCharCode.apply(null, new Uint8Array(blob)));
var blob = new Blob([base64ToArrayBuffer(base64)], {
type: 'octet/stream',
});
var zipUrl = window.URL.createObjectURL(blob);
var fileName = orderNo;
fileName += ' Attachments ';
fileName += moment().format('DD-MMM-YYYY');
fileName += '.zip';
downloadFile(null, fileName, null, zipUrl, null); // create a hidden anchor tag and trigger download
});
function fetchBlob(uri, callback) {
var xhr = new XMLHttpRequest();
xhr.open('GET', uri, true);
xhr.responseType = 'arraybuffer';
var x = AjaxService.getAuthHeaders();
xhr.setRequestHeader('auth_stuff', x['auth_stuff']);
xhr.setRequestHeader('token_stuff', x['token_stuff']);
xhr.setRequestHeader('Accept', 'application/octet-stream');
xhr.onload = function (e) {
if (this.status == 200) {
var blob = this.response;
if (callback) {
callback(blob);
}
}
};
return xhr.send();
};
function base64ToArrayBuffer(base64) {
var binaryString = window.atob(base64);
var binaryLen = binaryString.length;
var bytes = new Uint8Array(binaryLen);
for (var i = 0; i < binaryLen; i++) {
var ascii = binaryString.charCodeAt(i);
bytes[i] = ascii;
};
return bytes;
}

No file was sent to SAP Leonardo Image Feature Extraction API using FormData

I'm testing SAP Leonardo Image Feature Extraction API (https://sandbox.api.sap.com/ml/featureextraction/inference_sync). I have the base64 string of the image and I want to transform it to a file object and zip it, then to send the zipped image file to this API using XMLHttpRequest. But the response text is "Service requires a list of (zipped) images".
I attach my HTTP request header and parameters in below screenshots.
Although we see a messy code in parameters, the zipped file Download here is created successfully.
If you cannot download the zipped file, please refer to the screenshot below.
Everything seems to be fine. However, the response text is as below with status 400.
My javascript code is shown below. What is wrong? It drives me crazy...
dataURItoBlob: function(dataURI, fileName) {
//convert base64/URLEncoded data component to raw binary data held in a string
var byteString;
if (dataURI.split(',')[0].indexOf('base64') >= 0)
byteString = atob(dataURI.split(',')[1]);
else
byteString = unescape(dataURI.split(',')[1]);
//separate out the mime component
var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
//write the bytes of the string to a typed array
var ia = new Uint8Array(byteString.length);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
var blob = new Blob([ia], {encoding:"UTF-8",type:mimeString});
//A Blob() is almost a File() - it's just missing the two properties below which we will add
blob.lastModifiedDate = new Date();
blob.name = fileName + '.' + mimeString.split('/')[1];
return blob;
},
onSubmit: function(oEvent) {
var oImage = this.getView().byId('myImage');
//oImage.getSrc() : 'data:image/png;base64,iVBORw0KGgo...'
var imageFile = this.dataURItoBlob(oImage.getSrc(), 'myImage');
var zip = new JSZip();
zip.file(imageFile.name, imageFile);
zip.generateAsync({
type:"blob",
compression: 'DEFLATE', // force a compression for this file
compressionOptions: {
level: 6,
},
}).then(function(content) {
//saveAs(content, "hello.zip");
// start the busy indicator
var oBusyIndicator = new sap.m.BusyDialog();
oBusyIndicator.open();
var formData = new FormData();
formData.append('files', content, 'myImage.zip');
var xhr = new XMLHttpRequest();
xhr.withCredentials = false;
xhr.addEventListener("readystatechange", function () {
if (this.readyState === this.DONE) {
oBusyIndicator.close();
//navigator.notification.alert(this.responseText);
console.log(this.responseText);
}
});
//setting request method
//API endpoint for API sandbox
//Destionation '/SANDBOX_API' in HCP is configured as 'https://sandbox.api.sap.com'
var api = "/SANDBOX_API/ml/featureextraction/inference_sync";
xhr.open("POST", api);
//adding request headers
xhr.setRequestHeader("Content-Type", "multipart/form-data");
xhr.setRequestHeader("Accept", "application/json");
//API Key for API Sandbox
xhr.setRequestHeader("APIKey", "yQd5Oy785NkAIob6g1eNwctBg4m1LGQS");
//sending request
xhr.send(formData);
});
},

I fix this issue by myself. I put my solution just for others' information. It's very easy and only below code needs to be removed before sending request. I have no idea why. Please suggest if you know the reason. Thanks in advance!
xhr.setRequestHeader("Content-Type", "multipart/form-data");
Best Regards,
Shelwin Wei

Downloading a base64 byte array into a file using ajax call

I have the below problem.
I need to send multiple files attached as part of JSON request and save it into database.
followed the below steps:
converted the uploaded file into base64 String and included in JSON with other values.
In server side, using java, converted the base64 string to byte[] and stored in database.
Issue with downloading the file retrieved from database.
I have written a controller method to return the byte[] from database and using XMLHttpRequest, i am trying to save the file. But getting file corrupted error while opening the saved file.
below is my javascript code:
var request = new XMLHttpRequest();
request.open("POST", 'getAttachment/'+idTemp, true);
request.responseType = "blob";
request.onload = function (e) {
if (this.status === 200) {
// `blob` response
console.log(this.response);
var arr = this.response;
var byteArray = new Uint8Array(arr);
// create `objectURL` of `this.response` : `.pdf` as `Blob`
var file = window.URL.createObjectURL(new Blob([byteArray]));
var a = document.createElement("a");
a.href = file;
a.download = this.response.name || fileNameTemp;
document.body.appendChild(a);
a.click();
}
}
request.send();
Please note that, all types of files has to be stored and downloaded.

InboxSDK - Unable to attachFiles through composeView object

I am trying to attach an attachment through the composeView object using Inboxsdk. I obtain a blob object from a remote url using the following code.
// FUNCTION TO OPEN A NEW COMPOSE BOX ONCE THE ATTACHMENT BLOB IS OBTAINED FROM REMOTE URL.
function openComposeBox(sdk, blob){
handler = sdk.Compose.registerComposeViewHandler(function(composeView){
if(blob != null){
composeView.attachFiles([blob]);
composeView.setSubject("Testing");
}
});
}
// FETCHING ATTACHMENT FILE FROM REMOTE URL
var file_btn_url = "https://api.hummingbill.com/system/invoices/invoice_files/000/033/393/original/abracadabra.txt";
var file_name = file_btn_url.split("/");
file_name = file_name[file_name.length-1];
file_type = /[^.]+$/.exec(file_name);
var blob = null;
var xhr = new XMLHttpRequest();
xhr.open("GET", file_btn_url);
xhr.responseType = "blob";
xhr.onload = function()
{
blob = xhr.response;
// blob.lastModifiedDate = new Date(); // Since it's not necessary to have it assigned, hence commented.
blob.name = file_name;
console.log(blob);
openComposeBox(sdk, blob);
}
xhr.send();
It shows an Attachment Failed error.
Although I have the correct format of blob object as required as per the documentation.
As per the documentation, I have set the filename for the blob, and passed it in an array to attachFiles function. Can you please look into it and let me know what am I missing?

Posting the solution. The code remains same as in the question, with a slight variation, wherein we convert the blob to a file, in order to make it work.
//... Same as the code in the question
// Fetching attachment file from remote url
var file_btn_url = "https://api.hummingbill.com/system/invoices/invoice_files/000/033/393/original/abracadabra.txt";
var file_name = file_btn_url.split("/");
file_name = file_name[file_name.length-1];
file_type = /[^.]+$/.exec(file_name);
var blob = null;
var xhr = new XMLHttpRequest();
xhr.open("GET", file_btn_url);
xhr.responseType = "blob";
xhr.onload = function()
{
// Solution: Convert the obtained blob to a file
// Pass the file to openComposeBox
blob = new Blob([xhr.response], { type: xhr.responseType });
var file = new File([blob], file_name);
blob.name = file_name;
openComposeBox(sdk, file);
}
xhr.send();
Hope this helps. Cheers!

handling csv response in backbonejs

I am posting some data to server through Backbone.js and server sends a csv file as response. As Backbone.js handles only json format can some body tell me how to handle this case, so that i would be able to download the csv file gracefully.
object = {};
object.c1 = formObj.c1
hash = {
success: function(model, response, options) {
},
error: function(model, response, options) {
return console.log(response);
}
};
model = new P.models.mine(object);
model.doSomething(object, hash);
It always comes to error part.

The ideal way to handle this would be to change your back end code to return JSON, or create another route that returns JSON. Since you are asking this question I'm assuming that isn't an option for you.
Basically you are going to have to parse the CSV on the client side:
https://stackoverflow.com/a/1293163/944006 - Should get you started.
If you are asking to download a csv file, then just pointing the browser at the location should prompt the user for download. You cannot prompt a file download through ajax(for good reason), but there are ways to tiptoe around this limitation:
https://stackoverflow.com/a/9970672/944006

You could also use plain javascript rather than Backbone.js. Believe me this is the best way.
Here is some code:
var xhr = new XMLHttpRequest();
xhr.open('POST', Urls.download, true);
xhr.responseType = 'blob';
xhr.setRequestHeader("Authorization", "Bearer " + access_token);
xhr.setRequestHeader('Content-type', 'application/json; charset=utf-8');
xhr.onload = function (e) {
if (this.status == 200) {
var blob = new Blob([this.response], { type: 'application/vnd.ms-excel' });
var downloadUrl = URL.createObjectURL(blob);
var a = document.createElement("a");
a.id = "a" + new Date().getTime();
a.setAttribute("data-bypass", "");
a.href = downloadUrl;
a.download = "list_" + new Date().getTime() + ".xlsx";
document.body.appendChild(a);
a.click();
} else {
alert('Unable to download excel.')
}
};
xhr.send(JSON.stringify(this.obj));