Angular 6 - get csv response from httpClient - html

Question

Can any one please give an example of fetching application/octet-stream response from angular 6 httpClient. I am using the below code and it doesn't work ( I get unknown error - 401 response) -
import { saveAs } from 'file-saver';
getJobOutput() {
this.workflowService.fetchOutput(this.jobId,this.outputId).subscribe((response : any) => { // download file
var blob = new Blob([response.blob()], {type: 'application/octet-stream'});
var filename = 'file.csv';
saveAs(blob, filename);
});
}
Service is as below -
fetchOutput(jobId : string, outputId) {
var jobOutputURL = "myEnpoint";
var params = this.createHttpAuthorization(jobOutputURL,"GET");
params["format"] = "csv";
const options = {
headers: new HttpHeaders( { 'Content-Type': 'application/octet-stream',
'Accept' : 'application/octet-stream',
'Access-Control-Allow-Origin' : '*'}
)};
var endpoint = `${jobOutputURL}?oauth_consumer_key=${params["oauth_consumer_key"]}&oauth_signature_method=${params["oauth_signature_method"]}&oauth_nonce=${params["oauth_nonce"]}&oauth_timestamp=${params["oauth_timestamp"]}&oauth_version=1.0&format=${params["format"]}&oauth_signature=${params["oauth_signature"]}`;
return this.httpClient.get(endpoint, {...options, responseType: 'blob'});
}

Answer 1

To fetch an application/octet-stream, you have to set arraybuffer as the response type in the Angular HttpHeaders.
This is the service method:
fetchOutput(): Observable<ArrayBuffer> {
let headers = new HttpHeaders();
const options: {
headers?: HttpHeaders;
observe?: 'body';
params?: HttpParams;
reportProgress?: boolean;
responseType: 'arraybuffer';
withCredentials?: boolean;
} = {
responseType: 'arraybuffer'
};
return this.httpClient
.get('https://your-service-url.com/api/v1/your-resource', options)
.pipe(
map((file: ArrayBuffer) => {
return file;
})
);
}
This is the call to the service method and to the saveAs function:
this.yourService
.fetchOutput()
.subscribe((data: any) => {
const blob = new Blob([data], { type: 'application/octet-stream' });
const fileName = 'Your File Name.csv';
saveAs(blob, fileName);
})
As other users are suggestion: 401 Unauthorized is usually a client side error due to missing credentials.