How to display pdf from network in iOS [duplicate] - ios

Question

This question already has answers here:
How to display remote document using QLPreviewController in swift
(2 answers)
Closed 5 years ago.
Currently I am using QuickLook module to open pdf from network, but it shows a blank page with error "Couldn't issue file extension for url: https://testing-xamidea.s3.amazonaws.com/flowchart/20171103182728150973368.pdf" in console. I guess QuickLook can only open locally saved Pdf files. Is is possible to load pdf from network using quicklook? . This is my code so far- {fileURL contains url from which pdf is to be loaded, also ive set the delegates etc)
extension FlowchartVC:QLPreviewControllerDelegate,QLPreviewControllerDataSource {
func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
return 1
}
func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
let url : NSURL! = NSURL(string : fileURL)
return url
}
func previewControllerWillDismiss(_ controller: QLPreviewController) {
self.dismiss(animated: true, completion: nil)
}
}

Answer 1

You need to save the file to disk first and then you can present the pdf. There is no way to present it with QuickLook if the file is in a remote location. The file is saved in the temporary directory. Here is an example view controller showing how it could be done.
Swift 5:
import UIKit
import QuickLook
class ViewController: UIViewController, QLPreviewControllerDataSource {
// Remote url pdf I found on google
let itemURL = URL(string: "https://www.ets.org/Media/Tests/GRE/pdf/gre_research_validity_data.pdf")!
var fileURL: URL?
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let quickLookController = QLPreviewController()
quickLookController.dataSource = self
do {
// Download the pdf and get it as data
// This should probably be done in the background so we don't
// freeze the app. Done inline here for simplicity
let data = try Data(contentsOf: itemURL)
// Give the file a name and append it to the file path
fileURL = FileManager().temporaryDirectory.appendingPathComponent("sample.pdf")
if let fileUrl = fileURL {
// Write the pdf to disk in the temp directory
try data.write(to: fileUrl, options: .atomic)
}
// Make sure the file can be opened and then present the pdf
if QLPreviewController.canPreview(fileUrl as QLPreviewItem) {
quickLookController.currentPreviewItemIndex = 0
present(quickLookController, animated: true, completion: nil)
}
} catch {
// cant find the url resource
}
}
func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
return 1
}
func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
return fileURL! as QLPreviewItem
}
}
Swift 3:
import UIKit
import QuickLook
class ViewController: UIViewController, QLPreviewControllerDataSource {
// Remote url pdf I found on google
let itemURL = URL(string: "https://www.ets.org/Media/Tests/GRE/pdf/gre_research_validity_data.pdf")!
var fileURL = URL(string: "")
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let quickLookController = QLPreviewController()
quickLookController.dataSource = self
do {
// Download the pdf and get it as data
// This should probably be done in the background so we don't
// freeze the app. Done inline here for simplicity
let data = Data(contentsOf: itemURL)
// Give the file a name and append it to the file path
fileURL = FileManager().temporaryDirectory.appendingPathComponent("sample.pdf")
// Write the pdf to disk
try data?.write(to: fileURL!, options: .atomic)
// Make sure the file can be opened and then present the pdf
if QLPreviewController.canPreview(fileUrl as QLPreviewItem) {
quickLookController.currentPreviewItemIndex = 0
present(quickLookController, animated: true, completion: nil)
}
} catch {
// cant find the url resource
}
}
func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
return 1
}
func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
return fileURL! as QLPreviewItem
}
}
Here is the file showing in the simulator. Using a sample project with just that code.