From a http request, a blob (b) (type application/octet-stream ) is downloaded and then needs to be processed, it contains a json object .
I tried the following:
var reader = new FileReader();
reader.readAsText(b);
var readResult = <string> reader.result;
console.log(readResult);
var obj = JSON.parse(readResult);
It doesn´t work, and readResult is null.
How can you process a blob that contains a json into a json object?
You will need an onload event like so:
var blob = new Blob([JSON.stringify({"test": "Hello from JSON!"})], {type : "application/json"}), reader = new FileReader(); reader.onload = function() { document.body.innerText = JSON.parse(this.result).test; }; reader.readAsText(blob);
When the request has responseType: 'blob' it returns binary, but if an error occurs message is returned as JSON inside Blob.
This is how you can decode JSON messages from blob:
(response) => {
return response;
},
async (error) => {
if (error.response.data instanceof Blob) {
const blob = new Blob([error.response.data]);
const data = await blob.text();
const { message, details } = JSON.parse(data);
//display message and details to the user
}
}
Code example :
try{
await this.exampleservice.MygetRequest().then(httpResponse => {
httpResponse.body.text().then(text => {
//console.log(text);
obj = JSON.parse(text);
//console.log('obj after parse:' ,obj);
let data = obj.result.data;
console.log('My data:' ,data);
});
});
}catch (error) {
if (error instanceof HttpErrorResponse) {
Swal({
type: 'error',
title: this.errorsService.getErrorMessage(error.status),
showConfirmButton: false,
timer: 1500
});
this.feedback_errors = error.error.errors;
this.feedback_errors_keys = this.feedback_errors ? Object.keys(this.feedback_errors) : null;
}
}
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