I am trying to download a blob from a windows azure blob storage, straight to a string. Currently I can get it to a file. But can not find any documentation of how to get the data straight to a variable.
blobService.getBlobToStream('ratings'
, '0001'
, fs.createWriteStream('output.txt')
, function(error){
if(!error){
// Wrote blob to stream
console.log("blob written");
}
});
Any Ideas?
There's a function called getBlobToText in node.js SDK (Source code here: https://github.com/Azure/azure-sdk-for-node/blob/master/lib/services/blob/blobservice.js). Give that a try.
Related
I am using Nativescript 4.2.0 and trying to upload an image from a local image to Azure Blob storage.
Most approaches recommended use the nativescript-background-http plugin. However by including this plugin, there are errors that start coming up requiring other npm modules. I haven't seen this reported anywhere, so I am unsure if I am doing something wrong or there are any other commands to run beside
tns install nativescript-background-http
The other plugin "nativescript-azure-storage" seems to work fine. This requires us to base64 encode our images. After Base64 encoding, the image gets uploaded to Azure Storage. However, since the image is now base64 encoded, it can't be used directly in .
Code used:
const azureNSStorage = new nsAzureStorage.NativeScriptAzureStorage(config.AZURE_STORAGE_CONNECTION_STRING);
let path = selected.android;
const imageFromLocalFile = imageSourceModule.fromFile(path);
let base64string = imageFromLocalFile.toBase64String('png');
azureNSStorage.uploadBlob(mycontainer, blobName,
base64string)
.then(() => alert(`Uploaded successfuly`))
.catch((err) => alert(`Error uploading: ${err}`));
What is the recommended way to upload images on Azure Blob so that we can reference them back in Nativescript page?
Cheers
Abhishek
It actually depends on what you need or what your backend / service provider supports. So until azure works for you as expected, there is nothing wrong with converting the image into base64 string.
Between nativescript-background-http should work too, let's know what are the errors you are facing here.
Check this sample. For Azure Blob does not accept base 64 string. You need to send the stream. https://baskarrao.wordpress.com/2018/10/12/day-3-nativescript-post-series/
I am new to azure and working on the storage account for one my application.Basically I have json files stored in azure blob storage.
I want to read the data from these files in Node JS application and do some filtering on the data, which is eventually secured REST end point to view data in the UI/Client as HTTP response.
I have gone through the docs about different operations on the blob storage which is exposed as NODE SDK, we can see find them in below link,
https://github.com/Azure/azure-storage-node
But the question I have is "How to read the json files". I see one method getBlobToStream. Is this going to give me json content in the callback, so that I can do further processing on the data and send as response to clients who requested.
Please some one explain how to do this in better way or is this the only option we have.
Thanks for the help.
To use getBlobToStream, you have to define a writable stream.
So I recommend you to use getBlobToText to avoid trouble.
If no error occurs, this method will get blob content into text in callback. You can then parse it to a JSON string. A simple example is as below.
blobService.getBlobToText(container, blobname, function(error, text){
if(error){
console.error(error);
res.status(500).send('Fail to download blob');
} else {
var data = JSON.parse(text);
res.status(200).send('Filtered Data you want to send back');
}
});
I am trying to create a blob from a pdf I am creating from pdfmake so that I can send it to a remote api that only handles blobs.
This is how I get my PDF file:
var docDefinition = { content: 'This is an sample PDF printed with pdfMake' };
pdfDoc.pipe(fs.createWriteStream('./pdfs/test.pdf'));
pdfDoc.end();
The above lines of code do produce a readable pdf.
Now how can I get a blob from there? I have tried many options (creating the blob from the stream with the blob-stream module, creating from the file with fs, creating it from a base64 string with b64toBlob) but all of them require at some point to use the constructor Blob for which I always get an error even if I require the module blob:
TypeError: Blob is not a constructor
After some research I found that it seems that the Blob constructor is only supported client-side.
All the npm packages that I have found and which seem to deal with this issue seem to only work client-side: blob-stream, blob, blob-util, b64toBlob, etc.
So, how can I create a blob server-side on Node?
I don't understand why almost nobody also needs to create a blob server-side? The only thread I could find on the subject is this one.
According to that thread, apparently:
The Solution to this problem is to create a function which can convert between Array Buffers and Node Buffers. :)
Unfortunately this does not help me much as I clearly seem to lack some important knowledge here to be able to comprehend this.
use node-blob npm package
const Blob = require('node-blob');
let myBlob = new Blob(["something"], { type: 'text/plain' });
I'm testing the functionality of uploading a file to Azure File Storage with this github sample: Node Getting Started
I modified line 111 to include an option for the contentSettings:
var options = { contentSettings: { contentType: 'application/pdf'}};
fileService.createFileFromLocalFile(shareName, directoryName, fileName, imageToUpload, options, function (error) {
if (error) {
callback(error);
} else {
... and whether I upload a PDF with contentType of 'application/pdf' or an image with 'image/png', the file content type is not set once it's posted to Azure storage.
When I copy the URL to the file in my website, the error comes back saying the content type is incorrect.
What am I doing wrong? How do I set the content types of the uploaded files to make them work in my website?
what's the version of azure-storage package you are using? I tried the code you pasted and the content type is set successfully to Azure Storage (latest version).
After uploading successfully, try to call getFileProperties and you can see the properties stored on the Azure Storage server side.
And my very clear about the scenario of "copying the URL to the file in my website" and the error.
I have a nodejs app running as a Worker Role in Azure Cloud Services where I have two blob storage containers that the app will read from when responding to certain user requests.
Here's my setup:
Using the azure-storage package to interface with my blob storage.
Two containers, each holding files of different types that the user may ask for at some point.
And I use the following code to stream the files to the HTTP response:
exports.getBlobToStream = function(containerName, fileName, res) {
var blobService = azure.createBlobService();
blobService.getBlobProperties(containerName, fileName, function(error, properties, status){
if(error || !status.isSuccessful)
{
res.header('Content-Type', "text/plain");
res.status(404).send("File " + fileName + " not found");
}
else
{
res.header('Content-Type', properties.contentType);
res.header('Content-Disposition', 'attachment; filename=' + fileName);
blobService.createReadStream(containerName, fileName).pipe(res);
}
});
};
One important
In the past I've had no issues reading from either container. In my research on the problemI've found an identical (but outdated) issue on the all-encompassing azure-sdk-for-node here https://github.com/Azure/azure-sdk-for-node/issues/434. The solution that fixed that problem also fixed mine, but I can't understand why. Particularly when I can read from the other container from within the same app and using the same code without any issues.
I can live with the solution but want to understand what's going on. Any thoughts or suggestions?
#winsome, thanks for raising this issue to us. If you set EMULATED, it means the code will call the local storage emulator other than the real storage account and expected to fail. Regarding the one container works under EMULATED, a guess is your local storage emulator also has a same container. Please check.