I want to download file that can be in any format viz. pdf, jpeg, png, xlsx, csv etc. The download API on backend using pyramid framework is sending FileResponse as below:
def delivery_item_download_view(request, *args, **kw):
context = request.context
item_row = context.item_row
if item_row and item_row["deleted_at"] is None:
print(request.upload_dir+'/'+item_row["file_name"]+'.'+item_row["file_extension"])
response = FileResponse(
request.upload_dir+'/'+item_row["file_name"]+'.'+item_row["file_extension"],
request=request,
)
response.headers["attachment"] = item_row["name"];
return response
This, when executed using POSTMAN works as expected giving file as output. However,when tried implementing same using ReactJS, it's not working as expected. My client-code is as below:
onDownloadItem= (item) => {
console.log("item id is:", item.item_id)
var apiBaseUrl = "https://dev.incodax.com/api/deliveries_items/"+ item.item_id+ "/download";
fetch(apiBaseUrl, {
method: "GET",
}).then((res) => {
fileDownload(res,item.file_name)
console.log(res)
})
}
This fileDownload function simply downloading file but with no content inside. In downloaded file I could see something like:
[object Response]
I am getting 200 response from server. So I dont't think there is any issue with server side code. How can I handle it on client?
Thanks in advance
Will it suit you if you just redirected user to link to file? Browser will automatically handle it and download it.
The issue is in your fileDownload function which you do not post here. It's not clear what the first parameter is supposed to be but likely it is not the response object. Likely you at least need to pull the body out of the response and save that! The response body can be converted to a buffer object which could work (again it depends on what fileDownload is expecting):
res.arrayBuffer().then(buffer => {
fileDownload(buffer, item.file_name);
});
Related
I have an issue to send the contents of a .mat file to my frontend. My end goal is to allow clients to download the content of this .mat file at the click of a button so that they end up with the same file in their possession. I use Next.js + Django Rest Framework.
My first try was as follow:
class Download(APIView):
def get(self, request):
with open('file_path.mat', 'rb') as FID:
fileInstance = FID.read()
return Response(
fileInstance,
status=200,
content_type="application/octet-stream",
)
If I print out the fileInstance element I get some binary results:
z\xe1\xfe\xc6\xc6\xd2\x1e_\xda~\xda|\xbf\xb6\x10_\x84\xb5~\xfe\x98\x1e\xdc\x0f\x1a\xee\xe7Y\x9e\xb5\xf5\x83\x9cS\xb3\xb5\xd4\xb7~XK\xaa\xe3\x9c\xed\x07v\xf59Kbn(\x91\x0e\xdb\xbb\xe8\xf5\xc3\xaa\x94Q\x9euQ\x1fx\x08\xf7\x15\x17\xac\xf4\x82\x19\x8e\xc9...
But I can't send it back to my frontend because of a
"UnicodeDecodeError: 'utf-8' codec can't decode byte 0x9c in position 137: invalid start byte"
This error is always the same regardless of which .mat file I try to send in my response.
Next I tried to use the scipy.io.loadmat() method. In this case, fileInstance gives me a much more readable dictionary object, but I still can't get it to transfer to the frontend because of the presence of NaN in my dict:
ValueError: Out of range float values are not JSON compliant
Finally, some suggested to use h5py to send back the data as such:
with h5py.File('file_path.mat', 'r') as fileInstance:
print(fileInstance)
But in that case the error I get is
Unable to open file (file signature not found)
I know my files are not corrupted because I can open them in Matlab with no problem.
With all this trouble I'm wondering if I'm using the right approach to this problem. I could technically send the dictionary obtained through 'scipy.io.loadmat()' as a str element instead of binary, but I'll have to figure out a way to convert this text back to binary inside a Javascript function. Would anybody have some ideas as to how I should proceed?
The problem was in my frontend after all. Still, here's the correct way to go about it:
class Download(APIView):
parser_classes = [FormParser, MultiPartParser]
def get(self, request):
try:
file_path = "xyz.mat"
response = FileResponse(file_path.open("rb"), content_type="application/octet-stream")
response["Content-Disposition"] = f"attachment; filename=file_name"
return response
except Exception as e:
return Response(status=500)
This should send to the frontend the right file in the right format. No need to worry about encoding and such.
Meanwhile, on the frontend you should receive the file as follows:
onClick={() => {
const url = '/url_to_your_api/';
axios({ method: 'get', url: url, responseType: 'blob' })
.then((response) => {
const { data } = response;
const fileName = 'file_name';
const blob = new Blob([data], { type: 'application/octet-stream' });
const href = URL.createObjectURL(blob);
const link = document.createElement('a');
link.href = href;
link.download = fileName + '.mat';
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
URL.revokeObjectURL(href);
})
.catch((response) => {
console.error(response);
});
}}
Long story short, the part I was missing was to specify to receive the data as blob inside the 'onClick()' function. By default, responseType from Axios is set to Json/String. For that reason, my file was modified at reception and would not be usable in matlab afterwards. If you face a similar problem in the future, try to use the 'shasum' BASH function to observe the hashed value of the file. It is with the help of that function that I could deduce that my API function would return the correct value and that therefore the problem was happenign on the frontend.
I have ASP.NET Core MVC back-end api. One controller returns File from server. Is there a way to make request to api route by [href] attribute of <a> tag? Looks like it tries to call React route but not make a request to server.
Also I made AJAX call to that controller and got back file as a string (screenshot is attached). Why is it a string, shouldn.t it be a byte array? How to build back file from that string? (it's a .pdf file). I have an empty PDF if use JavaScript new File([], 'name', {options}).
ASP.NET Core controller returns PDF this way:
return PhysicalFile(Path.GetFullPath(relativePath), "application/pdf", reportName);
In React I receive it as a string this way:
let stringPDFBinary = await ReportService.getReport(id, reportFileName)
I just need to download file from api by any way.
So, the answer is here: PDF is blank when downloading using javascript
The same problem. Let it be one more topic, easier to find for others. The AJAX response is encoded string. In request config set 'responseType = 'arraybuffer'' somehow and receiving pdf will not be blank. Solved.
I Just copied and pasted from the code source. The problem seems to be the same that i had:
Asp net controller:
[HttpGet]
[Route("File")]
[AllowAnonymous]
public IActionResult GetFile(string key)
{
var file = (FileCacheValue)_fileCache.Cache[key.Replace(" ", "+")];
if (file == null)
return NotFound();
Response.Headers["content-disposition"] = $"inline;filename={file.Name}.pdf";
return File(file.Data, "application/pdf");
}
In this case comes from a cache system. The data is a byte array.
Front-end React:
const onClick = () =>
{
window.open(pdfByteArray, '_blank', 'fullscreen=yes');
}
Exactly what i have. I just put the data on a new window and open the pdf.
The Ajax part is straight forward, get the value from the response and set it on a variable
I have a simple service on Angular 2 and Typescript that requests Excel files to a server and then opens a download file dialogue for the user. However, as it is currently, the file becomes corrupt when downloaded.
When downloaded, it opens fine in OpenOffice and derivates, but throws a "File is Corrupt" error on Microsoft Excel, and asks if the user wants to recover as much as it can.
When Excel is prompted to recover the file, it does so successfully, and the recovered Excel has all rows and data that is expected for the Excel file. Comparing the recovered file against opening the file in OpenOffice and derivates evidence no outstanding differences.
The concrete Excel I am trying to download is generated with Apache POI in a microservice, then passed to the main backend and finally served to the frontend for the user to download. Both the backend and microservice are written in Java, through Spark Framework.
I made some tests on the backends, and concluded the problem is not the report generation nor the data transfer:
Asking the microservice to save the generated Excel in a file within the server and then opening such file (hereby file A) in Excel shows that file A is not corrupted.
Asking the main backend server to save the Excel file that it receives from the microservice in a file within itself and then opening such file in Excel (hereby file B) shows that file B is not corrupted.
Downloading both file A and file B through FileZilla from their respective servers yields completely uncorrupted files.
As such, I believe it is safe to assume the Excel becomes corrupted somewhere between the time the file is received on the frontend and the time the user downloads such file. Additionally, the Catalina logs do not evidence any error that might potentially be happening.
I have read several posts that deal with the issue, including a bug report (https://github.com/angular/angular/issues/14083) that included a workaround via XMLHTTPRequest. However, none of the workarounds detailed were successful in solving my issue.
Attached is the code I am using to both obtain the Excel file from the backend and serve it to the user. I am including both an XMLHTTPRequest and an Angular http call (within comments) since those are the two main ways I have been trying to make this work. Additionally, please do take into account the code has been altered to remove information I do not wish to make public.
download(body) {
let reply = Observable.create(observer => {
let xhr = new XMLHttpRequest();
xhr.open('POST', 'URL', true);
xhr.setRequestHeader('Content-type', 'application/json;charset=UTF-8');
xhr.setRequestHeader('Accept', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
xhr.setRequestHeader('Authorization', 'REDACTED');
xhr.responseType = 'blob';
xhr.onreadystatechange = function () {
if(xhr.readyState === 4) {
if(xhr.status === 200) {
var contentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
var blob = new Blob([xhr.response], { type: contentType });
observer.next(blob);
observer.complete();
}
else {
observer.error(xhr.response);
}
}
}
xhr.send(JSON.stringify(body));
});
return reply;
/*let headers = new Headers();
headers.set("Authorization", 'REDACTED');
headers.set("Accept", 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
let requestOptions :RequestOptions = new RequestOptions({headers: headers, responseType: ResponseContentType.Blob});
return this.http.post('URL', body, requestOptions);*/
}
Hereby is the code to prompt the user to download the Excel. It is currently made to work with the XMLHTTPRequest. Please do note that I have also attempted to download without resorting to FileSaver, with no luck.
downloadExcel(data) {
let body = {
/*REDACTED*/
}
this.service.download(body)
.subscribe(data => {
FileSaver.saveAs(data, "Excel.xlsx");
});
}
Hereby are the versions of the tools I am using:
NPM: 5.6.0
NodeJs: 8.11.3
Angular JS: ^6.1.0
Browsers used: Chrome, Firefox, Edge.
Any help on this issue would be appreciated. Any additional information you may need I will be happy to provide.
I think what you want is CSV format which open in Excel, update your sevice as follow:
You should tell Angular you are expecting a response of type blob (Binary Large Object) that is your Excel/Csv file.
Also make sure the URL/API on your server is set to accept content-type='text/csv'.
Here's an example with Angular 2.
#Injectable()
export class YourService {
constructor(private http: Http) {}
download() { //get file from the server
this.http.get("http://localhost/..", {
responseType: ResponseContentType.Blob,
headers: new Headers({'Content-Type', 'text/csv'})
}).subscribe(
response => {
var blob = new Blob([response.blob()], {type: 'text/csv'});
FileSaver.saveAs(blob, 'yourFileName.csv');
},
error => {
console.error('something went wrong');
}
);
}
}
Have you tried uploading/downloading your xls file as base64?
var encodedXLSToUpload = 'data:application/xls;base64,' + btoa(file);
Check this for more details: Creating a Blob from a base64 string in JavaScript
I've built a React frontend along with a Rails API only backend. I want to allow the user to create a task and enter a title, description and upload an image.
So I've attempted to use DropZone to get access to the image and then send the image info along with the title and description to my Rails API via a post request using Axios.
I set up Carrierwave on my Rails API in hopes of uploading to an AWS S3 bucket once my Task has been added to the database per the post request.
None of this is working so my question is, should I take care of the image uploading to AWS on the react side and if so, how do I associate that image with the additional information I'm saving to my Rails database (title and description).
Thanks!
First, on React side, there should be no proble with title and description, but for image, you need to encode the image to Base64 string. It is something like this.
getBase64 = (callback) => {
const fileReader = new FileReader();
fileReader.onload = () => {
console.log(fileReader.result);
};
fileReader.readAsDataURL(fileToLoad);
fileReader.onerror = (error) => {
console.log('Error :', error);
};
}
Then, on Axios, send those 3 parameters alltogether with one POST request.
For Rails, you need to set up code that can read the Base64 string. Usually, you can use Paperclip or CarrierWavegem to add image attachment. It will look like this.
property_image = listing.property_images.new(param_image)
if param_image[:file_data]
image_file = Paperclip.io_adapters.for(param_image[:file_data])
image_file.original_filename = param_image[:image_file_name]
image_file.content_type = "image/png"
property_image.image = image_file
end
private
def param_image
params.permit(:image, :image_file_name, :file_data)
end
I think the title is weird but just says all i want.
I got the following API call
this.myAPI.get("/endpoint/toget/pdf/")
.then(response => {
}, function(error) {
});
The API response with a PDF file not a link but a PDF file. How do i capture that file and allow the user to ng-click and open the file?
Ideas.. Anyone?
Okay if you get a base64 string the following works perfect but sadly and obviously not in IE.
window.open("data:application/pdf;base64," + response.data.content);