Convert byte array into blob (pdf file) and download using angular 5 - asp.net-core

I'm receiving a byte array from server side and has converted it successfully to blob. However, when I'm trying to download it, it shows the file is corrupted. Below are my codes -
// In client side controller
this.contractsService.downloadPdf(id)
.then((result) => {
var blob = new Blob([result], { type: "application/pdf" });
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = "testing.pdf";
link.click();
});
And,
// In client side service
private headers = new HttpHeaders({ 'Content-Type': 'application/json' });
downloadPdf(id: number) {
return this.http.get(this.apiRoutes.download + "/" + id, { headers: this.headers })
.map((res: any) => res)
.toPromise();
}
Any sort of help will be very much appreciated.
Thank you.

Install file-saver
npm i --save file-saver#latest
Your service method
downloadPdf(id: number) {
return this.http
.get(this.apiRoutes.download + "/" + id, { responseType:'blob' })
.toPromise();
}
Now in your component
import { saveAs } from 'file-saver'
this.contractsService.downloadPdf(id)
.then(blob=> {
saveAs(blob, 'testing.pdf');
});
This should do the trick. The HttpClient will now extract the file from the stream. Also have a look in the documentation for blobs with the HttpClient.

In client side service, try explicitly setting the response type of the get request:
downloadPdf(id: number) {
return this.http.get(this.apiRoutes.download + "/" + id, { headers: this.headers; responseType: 'arraybuffer' })
.map((res: any) => res)
.toPromise();
}

Related

How to use Nuxt 3 server as a passthrough API with FormData to hide external endpoints

I'm trying to get my head around the Nuxt /server API and can't seem to figure out how to send a POST request with form-data (ie files) to Nuxt server to forward on to an external service:
In my pages.vue file I have this method:
async function onSubmit() {
const formData = new FormData();
for (let file of form.files) {
await formData.append("image", file);
}
await $fetch("/api/send", {
method: "POST",
body: formData
});
}
and then in /server/api/send.js I have:
export default defineEventHandler(async (event) => {
const { method } = event.node.req;
// I THINK THE ISSUE IS HERE
const body =
method !== "GET" && method !== "HEAD"
? await readMultipartFormData(event)
: undefined;
const response = await $fetch.raw(https://*******, {
method,
baseURL: *********,
headers: {
},
body: body
});
return response._data;
}
I'm effectively creating a passthrough API using Nuxt so that the external endpoint isn't exposed to the end user. Just can't figure out how to access the formData in the correct format to pass through on the server side. I don't think I am supposed to use readMultipartFormData() because that seems to be parsing the data somehow whereas I just want to pass the formData straight through to the external API. Any tips?
I've tried using both readMultipartFormData() and readBody() and neither seem to work. I don't actually need to read the body but rather get it and pass it through without any formatting...
If you want to pass the data with formdata to the endpoint try this library:
https://www.npmjs.com/package/object-to-formdata
code:
import { serialize } from 'object-to-formdata';
const formData = serialize(body);
const response = await $fetch.raw(https://*******, {
method,
baseURL: *********,
headers: {
},
body: formData
});
I managed to make it work with ugly solution, first you have to update nuxt to version 3.2.0 min then here my front side
let jobApplicationDTO = {
firstName: values.firstName,
lastName: values.lastName,
email: values.email,
phoneNumber: values.phoneNumber,
company: values.company,
shortDescription: values.shortDescription
};
const formData = new FormData();
formData.append("application", new Blob([JSON.stringify(jobApplicationDTO)], {type: "application/json"}));
formData.append("file", values.file) ;
//formData.append("file", values.file );
await useFetch("/api/application", {
method: "POST",
body: formData,
onResponse({request, response, options}) {
// Process the response data
if (response.status === 200) {
errorMessage.value = "";
successMessage.value = "Your application wa sent successfully, you will be contacted soon !";
}
},
onResponseError({request, response, options}) {
console.debug(response);
if (response.status === 400) {
successMessage.value = "";
errorMessage.value = "There may be an issue with our server. Please try again later, or send an email to support#mantiq.com";
} else {
successMessage.value = "";
errorMessage.value = "Sorry we couldn’t send the message, there may be an issue with our server. Please try again later, or send an email to support#mantiq.com";
}
},
});
}
and server side
import {FormData} from "node-fetch-native";
export default defineEventHandler(async (event) => {
const {BACKEND_REST_API, ENQUIRY_TOKEN} = useRuntimeConfig();
//retrieve frontend post formData
const form = await readMultipartFormData(event);
const applicationUrl = BACKEND_REST_API + '/job/apply'
console.log("url used for enquiry rest call :" + applicationUrl);
console.log("Job application token :" + ENQUIRY_TOKEN);
const formData = new FormData();
console.log(form);
if (form) {
formData.append(form[0].name, new Blob([JSON.stringify(JSON.parse(form[0].data))], {type: form[0].type}));
formData.append(form[1].name, new Blob([form[1].data], {type: form[1].type}), form[1].filename);
}
console.log(formData.values);
return await $fetch(applicationUrl, {
method: "POST",
body: formData,
headers: {
Authorization: ENQUIRY_TOKEN,
},
});
})
What is funny is on frontend you have to create a formData , then to get content and to recreate a formData from your previous formData converted in MultiFormPart[], i created a ticket on nuxt to see how to do it properly

Vue.js Axios responseType blob or json object

I have an Axios request to download the .xls file. Problem is that the object returned as a response from backend doesn't always has to be a real file. If I return json object instead of file data. How I would read this json then?
Here is the function:
downloadReport() {
let postConfig = {
headers: {
'X-Requested-With': 'XMLHttpRequest'
},
responseType: 'blob',
} as AxiosRequestConfig
axios
.post(this.urls.exportDiscountReport, this.discount.id, postConfig)
.then((response) => {
let blob = new Blob([response.data], { type: 'application/vnd.ms-excel' });
let url = window['URL'].createObjectURL(blob);
let a = document.createElement('a');
a.href = url;
a.download = this.discount.id + ' discount draft.xlsx';
a.click();
window['URL'].revokeObjectURL(url);
})
.catch(error => {
})
}
I would like to read the response and if it contains some data in it - don't create the blob and initiate the download, instead, just show some message or whatever. If I remove the responseType: 'blob' then the .xls file downloads as unreadable and not valid file.
So the problem is that every returned response becomes blob type and I don't see my returned data in it. Any ideas?
I solved this by reading the blob response and checking if it has JSON parameter status. But this looks like an overengineering to me. Is there a better solution?
let postConfig = {
headers: {
'X-Requested-With': 'XMLHttpRequest'
},
responseType: 'blob',
} as AxiosRequestConfig
axios
.post(this.urls.exportDiscountReport, this.discount.id, postConfig)
.then((responseBlob) => {
const self = this;
let reader = new FileReader();
reader.onload = function() {
let response = { status: true, message: '' };
try {
response = JSON.parse(<string>reader.result);
} catch (e) {}
if (response.status) {
let blob = new Blob([responseBlob.data], { type: 'application/vnd.ms-excel' });
let url = window['URL'].createObjectURL(blob);
let a = document.createElement('a');
a.href = url;
a.download = self.discount.id + ' discount draft.xlsx';
a.click();
window['URL'].revokeObjectURL(url);
} else {
alert(response.message)
}
}
reader.readAsText(responseBlob.data);
})
.catch(error => {
})
I also found the same solution here: https://github.com/axios/axios/issues/815#issuecomment-340972365
Still looks way too hacky.
Have you tried checking the responseBlob.type property? It gives the MIME type of the returned data.
So for example you could have something like this:
const jsonMimeType = 'application/json';
const dataType = responseBlob.type;
// The instanceof Blob check here is redundant, however it's worth making sure
const isBlob = responseBlob instanceof Blob && dataType !== jsonMimeType;
if (isBlob) {
// do your blob download handling
} else {
responseBlob.text().then(text => {
const res = JSON.parse(text);
// do your JSON handling
});
}
This I find is much simpler and works for me, however it depends on your backend setup. The BLOB response is still a text response, but it's handled slightly differently.

Network Error when sending file in react native with axios

I am trying to send a file to a nodejs server from react native using axios, this is my code:
const createFormData = (file) => {
const data = new FormData();
data.append('message', text);
data.append('receiver',doctorid);
if(file !== ''){
data.append('file', {
type: file.type,
uri: file.uri,
name: file.name.replace(/\s/g,'')
})
}
return data;
}
const onSend = async() => {
const newMessages = [...messages]
newMessages.push({"sender": currentuserID, "id": 339, "message": 'sending...', "attachment": '', "receiver": doctorid, "type": 0},)
setMessages(newMessages)
const token = await AsyncStorage.getItem('token');
const data = createFormData(singleFile)
await appApi.post('/chats', data, {
headers: { 'Authorization': 'Bearer ' + token }
}).then(()=>{
socket.emit('sendmessage', text, (err) => {
messageInit()
});
})
.catch(err => console.log(err.message))
}
This code works perfectly if there's no image attached, but ones there's an image attached, I get the network error message immediately.
For a little bit of troubleshooting, I tried sending request to my local machine, using ngrok. From ngrok, I realized the request wasn't sent at all to the url. So it just fails immediately, without the request been made to the url.
Anyone with solution to this.
I'm testing on an android emulator
send using formdata
try this
let formData = new FormData();
let imagefile = document.querySelector('#file');
formData.append("image", imagefile.files[0]);
axios.post('upload_file', formData, {
headers: {
'Content-Type': 'multipart/form-data'
}
})

how to download a pdf file from an url in angular 5

I currently spend one day in this issue,still failed to download a file from an url in angular 5
leadGenSubmit() {
return this.http.get('http://kmmc.in/wp-content/uploads/2014/01/lesson2.pdf',
{responseType:ResponseContentType.Blob}).subscribe((data)=>{
console.log(data);
var blob = new Blob([data], {type: 'application/pdf'});
console.log(blob);
saveAs(blob, "testData.pdf");
},
err=>{
console.log(err);
}
)
}
when I run above code it shows following error
ERROR TypeError: req.responseType.toLowerCase is not a function
at Observable.eval [as _subscribe] (http.js:2187)
at Observable._trySubscribe (Observable.js:172)
how can I solve this issue.Can any one post the correct code to download a pdf file from an url in angular 5?
I think you should define header and responseType like this:
let headers = new HttpHeaders();
headers = headers.set('Accept', 'application/pdf');
return this.http.get(url, { headers: headers, responseType: 'blob' });
Here is my simple solution to open a PDF based on an ID in Angular :
In my service, I created this method :
public findById(id?: string): Observable<Blob> {
return this.httpClient.get(`${this.basePath}/document/${id}`, {responseType: 'blob'});
}
Then in my component, I can do use this method (behind a button or whatever):
showDocument(documentId: string): void {
this.yourSuperService.findById(documentId)
.subscribe((blob: Blob): void => {
const file = new Blob([blob], {type: 'application/pdf'});
const fileURL = URL.createObjectURL(file);
window.open(fileURL, '_blank', 'width=1000, height=800');
});
}
Try this
let headers = new HttpHeaders();
headers = headers.set('Accept', 'application/pdf');
return this.http.get(url, { headers: headers, responseType: 'blob' as 'json' });
References:
Discussion on Angular Github
Stackoverflow

Angular 2 RC 5 Attempting to Get and Display a PDF from a Server

I am trying to display a PDF that is generated from a server onto a view in my Angular 2 RC 5 project. Right now, the ASPNETCORE server is returning the object as an 'application/pdf' and the Angular client is trying to parse the response as a blob. However, I get the following error on the client side:
Error: The request body isn't either a blob or an array buffer
The code that I'm using to call the PDF server is essentially:
getHeaders() : Headers {
var headers = new Headers({
'responseType': 'application/blob'
});
return headers;
}
getBlob() {
return this.http.get(uri, new RequestOptions({headers: this.getHeaders()}, body: "" }))
.map(response => (<Response>response).blob());
}
Try to set the responseType to Blob, it should work:
getBlob() {
return this.http.get(uri, {responseType: ResponseContentType.Blob})
.map(response => (<Response>response).blob());
}
Work's for me :
Component :
downloadInvoice(invoice) {
this.loading = true;
this.invoiceDataService
.downloadInvoice(invoice)
.subscribe(
(blob) => {
FileSaver.saveAs(blob, 'test.pdf');
},
error => this.error = error,
() => {
this.loading = false;
console.log('downloadInvoices : Request Complete')
}
)
}
Data service :
downloadInvoice(invoice): Observable<Blob> {
return this.api.downloadInvoice(invoice);
}
Api service :
downloadInvoice(invoice: Invoice): Observable<Blob> {
return this.authHttp
.get(this.apiBase + '/invoices/' + invoice.hashid + '/download', {responseType: ResponseContentType.Blob})
.map(response => {
return new Blob([response.blob()], {type: 'application/pdf'});
})
.catch(this.handleError.bind(this));
}
Enjoy :)
For Angular 5, ResponseContentType has been deprecated, so a current solution I found was to use:
getFile(): Observable<File> {
let options = {
headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
responseType: 'blob' as 'json'
};
return this.http.get<File>(uri, options);
}