[Download de Arquivo via xmlhttprequest] #ajax #xmlhttprequest

requisicao_ajax_xmlhttprequest_download_arquivo.js

var form = document.getElementById('frm_upload');
var formData = new FormData(form);


************************************************** Com arrayBuffer ***************************************************************
var xhr = new XMLHttpRequest();
xhr.open('POST', 'exibirProtocoloDigital.do?action=exibirVolumePDF&arquivo='+codArquivo+'&codigoOrgaoPara='+codigoOrgaoPara, true);
xhr.responseType = 'arraybuffer';
xhr.send(formData);
xhr.onload = function(e) {
	if (this.status == 200) {
		var blob=new Blob([this.response], {type:"application/pdf"});
		var pdfurl = window.URL.createObjectURL(blob);
		window.open(pdfurl);
	}
};
xhr.send(formData);

OUTRA FORMA DE FAZER - arrayBuffer

var xhr=new XMLHTTPRequest();
xhr.open("GET", url, true);
//Now set response type
xhr.responseType = 'arraybuffer';
xhr.addEventListener('load',function(){
  if (xhr.status === 200){
    console.log(xhr.response) // ArrayBuffer
    console.log(new Blob([xhr.response])) // Blob
  }
})
xhr.send();


************************************************** Com blob direto ***************************************************************
var xhr = new XMLHttpRequest();
xhr.open('POST', 'URL', true);
xhr.responseType = 'blob';
xhr.send(formData);
xhr.onload = function(e) {
	if (this.status == 200) {
		var blob = this.response;
		var pdfurl = window.URL.createObjectURL(blob);
		window.open(pdfurl);
	} else {
		console.log(xhr.responseText);
	}
};
xhr.send(formData);


************************************************** responseType dinamico - trata erro**************************************************
var xhr = new XMLHttpRequest();
xhr.open('POST', 'exibirProtocoloDigital.do?action=exibirVolumePDF&numeroProtocolo='+numeroProtocolo+'&codigoOrgaoPara='+codigoOrgaoPara, true);
xhr.onreadystatechange = function() {
	if (xhr.readyState == 2) {
		if (xhr.status == 200) {
			xhr.responseType = 'blob';
		} else {
			xhr.responseType = 'text/html';
		}
	} else if (xhr.readyState == 4) {
		if (xhr.status == 200) {
			var blob = this.response;
			var pdfurl = window.URL.createObjectURL(blob);
			window.open(pdfurl);
		} else {
			exibirMsg(xhr.responseText, "erro")
		}
	}
};
xhr.send();