I am using google drive API to download an excel file in my Flutter app but I want to store the downloaded file content response in a File and then do some update operations using excel dart package, below is the given code from reading an xlsx file from a path location.
var file = "Path_to_pre_existing_Excel_File/excel_file.xlsx"; //here I want to store the response from drive api
var bytes = File(file).readAsBytesSync();
var excel = Excel.decodeBytes(bytes);
//Do some logic here
for (var table in excel.tables.keys) {
print(table); //sheet Name
print(excel.tables[table].maxCols);
print(excel.tables[table].maxRows);
for (var row in excel.tables[table].rows) {
print("$row");
}
}
//then saving the excel file
// updating the excel sheet to Drive
updateToDrive(excel,fileId);
I have created all the required auth functions, drive scopes and my download function looks like this :
Future<void> downloadFile() async{
String fileId = '1TOa4VKfZBHZe######WLA4M95nOWp';
final response = await driveApi.files.get(
fileId,
downloadOptions: drive.DownloadOptions.fullMedia
);
print(response);
}
This function is executing correctely and giving Media type response, but I could not able to read this response so that I could store it in a file.
Any help would be truly appreciated, Thanks
I changed my download function to this, as drive.files.get() was returning a Future Object so I changed it to return Future<Media?> by type casting.
String fileId = "19jF3lOVW563LU6m########jXVLNQ7poXY1Z";
drive.Media? response = (await driveApi.files.get(
fileId,
downloadOptions: drive.DownloadOptions.fullMedia
)) as drive.Media?;
Now response is a Media on which we can listen to the sream to store the response in a file.
To do that first we need to get the app directory by path_provider
final String path = (await getApplicationSupportDirectory()).path;
final String fileName = '$path/Output.xlsx';
File file = File(fileName);
Now we want to write the stream of response Stream<List> into our file object which I found from this link
List<int> dataStore = [];
await response!.stream.listen((data) {
print("DataReceived: ${data.length}");
dataStore.insertAll(dataStore.length, data);
}, onDone: () {
print("Task Done");
file.writeAsBytes(dataStore);
OpenFile.open(file.path);
print("File saved at ${file.path}");
}, onError: (error) {
print("Some Error");
});
Now we can do whatever we want to make changes through excel package.
Related
I have some node.js code that reads in a PDF file using Google Drive API drive.files.get()... (it's a file that is sourced on our Google team/shared drives). I convert the returned stream to a single base64 data chunk with something like this:
// read using drive.files.get() into 'pdfStream'
//...
let pdf64 = '';
pdfSream.on('readable', function () {
var chunk = pdfStream.read();
if (chunk != null) {
var chunk64 = chunk.toString('base64');
pdf64 += chunk64;
}
});
pdfStream.on('end', function () {
// Do SendGrid email with pdf64 as attachment
});
Note that the final goal is to send an email with the PDF. I haven't included much of the code because this all works great - as long as the email recipient is on our company's domain. For external email recipients, the PDF attachment is unviewable and cannot be downloaded - at least this is what the situation appears to be.
I didn't think that access-restrictions and permissions would stay with data that is read directly using drive.files.get(). Is this a thing? I would suspect SendGrid except that we send attachments in other areas of our code with no issue.
Thoughts anyone? Much appreciated!
~Bob
I was able to fix it. The permissions thing was a red herring - the pdf attachments were corrupt and our company email system was just more lenient with the errors than others (like Gmail). I refactored the above code to first create a complete array of data, then converted that array to base64:
// read using drive.files.get() into 'pdfStream'
//...
let pdfChunks = [];
// Read through stream chunks and concat them together
pdfStream.on('readable', function () {
var chunk = pdfStream.read();
if (chunk != null) {
pdfChunks.push(chunk);
}
});
// On the end of the stream, convert to base64 and email the Pdf
pdfStream.once('end', function () {
let pdfBin = Buffer.concat(pdfChunks);
let pdf64 = pdfBin.toString('base64');
//...
// Do SendGrid email with pdf64 as attachment
});
Cheers!
~Bob
I'm trying to upload a file from my phone to azure blob storage as a BlockBlob with a SAS. I can get the file to upload, but it can't be opened once downloaded. The file gets corrupted somehow. I thought this was a content-type problem, but I have tried several different approaches to changing to content-type. Nothing has worked so far.
My code:
FileInfo _fileInfo = await filePicker(); // get the file path and file name
// my getUploadInfo fires a call to my backend to get a SAS.
// I know for a fact that this works because my website uses this SAS to upload files perfectly fine
UploadInfo uploadInfo = await getUploadInfo(_fileInfo.fileName, _fileInfo.filePath);
final bytes = File(_fileInfo.filePath).readAsBytesSync();
try {
final response = await myDio.put(
uploadInfo.url,
data: bytes,
onSendProgress:
(int sent, int total) {
if (total != -1) {
print((sent / total * 100).toStringAsFixed(0) + "%");
}
},
options:
dioPrefix.Options(headers: {
'x-ms-blob-type': 'BlockBlob',
'Content-Type': mime(_fileInfo.filePath),
})
);
} catch (e) {
print(e);
}
This code uploads a file just fine. But I can't open the file since it becomes corrupted. At first, I thought this was a Content-Type problem, so I've tried changing the content type header to: application/octet-stream and multipart/form-data as well. That doesn't work.
I've also tried to do
dioPrefix.FormData formData =
new dioPrefix.FormData.fromMap({
'file': await MultipartFile.fromFile(
_fileInfo.filePath,
filename: _fileInfo.fileName,
)
});
...
final response = await myDio.put(
uploadInfo.url,
data: formData, // This approach is recommended on the dio documentation
onSendProgress:
...
but this also corrupts the file. It gets uploaded, but I can't open it.
I have been able to successfully upload a file with this code, but with this approach I cannot get any type of response so I have no idea whether it uploaded successfully or not (Also, I can't get the progress of the upload):
try {
final data = imageFile.readAsBytesSync();
final response = await http.put( // here, response is empty no matter what i try to print
url,
body: data,
headers: {
'x-ms-blob-type': 'BlockBlob',
'Content-Type': mime(filePath),
});
...
Any help would be greatly appreciated. Thanks
I tried to upload a file using dio in Dart to Azure Blob Storage, and then download and print the content of the file, as the code below.
import 'package:dio/dio.dart';
import 'dart:io';
main() async {
var accountName = '<account name>';
var containerName = '<container name>';
var blobName = '<blob name>';
var sasTokenContainerLevel = '<container level sas token copied from Azure Storage Explorer, such as `st=2019-12-31T07%3A17%3A31Z&se=2020-01-01T07%3A17%3A31Z&sp=racwdl&sv=2018-03-28&sr=c&sig=xxxxxxxxxxxxxxxxxxxxxxxxxx`';
var url = 'https://$accountName.blob.core.windows.net/$containerName/$blobName?$sasTokenContainerLevel';
var data = File(blobName).readAsBytesSync();
var dio = Dio();
try {
final response = await dio.put(
url,
data: data,
onSendProgress:
(int sent, int total) {
if (total != -1) {
print((sent / total * 100).toStringAsFixed(0) + "%");
}
},
options: Options(
headers: {
'x-ms-blob-type': 'BlockBlob',
'Content-Type': 'text/plain',
})
);
print(response.data);
} catch (e) {
print(e);
}
Response response = await dio.get(url);
print(response.data);
}
Then, I ran it and got the result as the figure below.
The content of the uploaded file as blob is the json string encoded from a Uint8List bytes from the funtion readAsBytesSync.
I researched the description and the source code of dio, actually I found dio is only suitable for sending the request body of json format, not for raw content as request body.
Fig 1. The default transformer apply for POST method
Fig 2. https://github.com/flutterchina/dio/blob/master/dio/lib/src/transformer.dart
So to fix it is to write a custom transformer class PutTransformerForRawData instead of the default one to override the function transformRequest, as the code below.
import 'dart:typed_data';
class PutTransformerForRawData extends DefaultTransformer {
#override
Future<String> transformRequest(RequestOptions options) async {
if(options.data is Uint8List) {
return new String.fromCharCodes(options.data);
} else if(options.data is String) {
return options.data;
}
}
}
And to replace the default transformer via the code below.
var dio = Dio();
dio.transformer = PutTransformerForRawData();
Then, you can get the data via the code below.
var data = File(blobName).readAsBytesSync();
Or
var data = File(blobName).readAsStringSync();
Note: the custom transfer PutTransformerForRawData is only for uploading, please remove the download & print code Response response = await dio.get(url); print(response.data);, the default transformer seems to check the response body whether be json format, I got the exception as below when my uploaded file is my sample code.
Unhandled exception:
DioError [DioErrorType.DEFAULT]: FormatException: Unexpected character (at character 1)
import 'dart:typed_data';
My Azure Web app calls html2pdfrocket with this code:
MemoryStream stream = new MemoryStream(result.Content.ReadAsByteArrayAsync().Result);
System.IO.File.WriteAllText(path, stream.ToString());
But I get back an invalid PDF of just a few bytes. I know the URL I pass to html2pdfrocket is valid because I can paste it into their Website to test it. Do I need to async/await or something else to get all the data before attempting to save it to a folder?
No need to use async/await, the .Result does the thing like await.
A similar error in your code, stream.ToString() only converts the stream object itself to a string, but does not contain the content.
I suggest you use byte[] array instead of stream(I did test with stream, but the saved .pdf file is empty even though the content length is correct).
Try use byte[] array like below, and it works at my side:
using (var client = new HttpClient())
{
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("apikey","xxxxx"),
new KeyValuePair<string, string>("value", "the url")
});
var result = client.PostAsync("http://api.html2pdfrocket.com/pdf", content).Result;
if (result.IsSuccessStatusCode)
{
// change the path as per your need
System.IO.File.WriteAllBytes(#"d:\temp\0618.pdf", result.Content.ReadAsByteArrayAsync().Result);
}
}
I've seen some people try. I could not reproduce their results. Happy to use any language. I can create an xlsx from an HTTP Trigger. I want to return that file from another HTTP Trigger.
If you have already generated the file, returning it is just creating an HTTP response with an attachment:
var result = new HttpResponseMessage(HttpStatusCode.OK);
result.Content = new ByteArrayContent(xlsxBytes);
result.Content.Headers.ContentDisposition =
new ContentDispositionHeaderValue("attachment") { FileName = "Book1.xlsx" };
result.Content.Headers.ContentType =
new MediaTypeHeaderValue("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
return result;
I am working with Windows 10 universal app and i want to download a file in that. The file link to Sharepoint server. I have passed token in headr to a web service and then service returned byte array to my WinJS.
Now i want to save the file, how can i do this? I tried several code samples but not working.
var folder = Windows.Storage.ApplicationData.current.localFolder;
folder.createFileAsync("document.docx", Windows.Storage.CreationCollisionOption.replaceExisting).then(function (file) {
return Windows.Storage.FileIO.writeTextAsync(file, result.response);
}).then(function () {
//saved
});
I am using above code and it is creating new file but no content is placed there. Please suggest what to do.
You never open the file for WriteAccess. I have included code from my working app. First do this command
StorageFile ageFile = await local.CreateFileAsync("Age.txt", CreationCollisionOption.FailIfExists);
then do this:
// Get the file.
var ageFile = await local.OpenStreamForWriteAsync("Age.txt",CreationCollisionOption.OpenIfExists);
// Read the data.
using (StreamWriter streamWriter = new StreamWriter(ageFile))
{
streamWriter.WriteLine(cmbAgeGroup.SelectedIndex + ";" + DateTime.Now);
streamWriter.Flush();
}
ageFile.Dispose();