通过UIWebView下载PDF

Question

我有一个使用基本身份验证加载PDF的UIWebView，如下所示

NSURL* url = [[NSURL alloc] initWithString:_urlString];
NSString *authStr = [NSString stringWithFormat:@"%@:%@", usr, pwd];
NSData *authData = [authStr dataUsingEncoding:NSASCIIStringEncoding];
NSString *authValue = [NSString stringWithFormat:@"Basic %@", [authData base64EncodedStringWithOptions:NSDataBase64Encoding76CharacterLineLength]];
NSMutableURLRequest *mutableRequest = [[NSMutableURLRequest alloc] initWithURL:url];
[mutableRequest setValue:authValue forHTTPHeaderField:@"Authorization"];
[_webView loadRequest:mutableRequest];

有没有办法让我轻松地将此PDF文件保存到磁盘上？我试过这个，但失败了：

NSData *fileData = [[NSData alloc] initWithContentsOfURL:_webView.request.URL];

我的网址如下所示：www.domain.com/files/foo.pdf

Answer 1

-initWithContentsOfURL:NSData方法执行简单的HTTP GET，但您需要设置一些授权参数，这就是它失败的原因。

为避免下载两次数据，您可以使用NSURLSession下载、保存并使用UIWebView-loadData:MIMEType:textEncodingName:baseURL:加载它。

NSMutableURLRequest *mutableRequest = //Your Custom request with URL and Headers
[[[NSURLSession sharedSession] dataTaskWithRequest:mutableRequest completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) 
{
if (data) 
{ 
//SaveDataIntoDisk
dispatch_async(dispatch_get_main_queue(), ^(){ 
[_webView loadData:data MIMEType:@"application/pdf" textEncodingName:@"UTF-8" baseURL:nil]; 
}); 
} 
}] resume];

Answer 2

对于 Swift ：

let webView = UIWebView()
let url = URL(string: "")!
let urlRequest : URLRequest = URLRequest(url: url)
let task = URLSession.shared.dataTask(with: urlRequest , completionHandler: { (data, urlResponse, error) in
if (data != nil){
DispatchQueue.main.async {
webView.load(data!, mimeType: "application/pdf", textEncodingName: "UTF-8", baseURL: url)
}
}
})
task.resume()

Answer 3

另一种方法：- 您可以下载PDF文件数据并将其保存在临时目录或首选目录中。 然后使用该保存的目录在 WebView 中打开该文件。

URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil else {
return
}
//MARK:- Now Saving the Document Data into Directory. I am using the temp directory you can change it to yours.
let tempDirectory = URL(fileURLWithPath: NSTemporaryDirectory())
self.tmpURL = tempDirectory.appendingPathComponent(response?.suggestedFilename ?? "fileName.png")
do {
try data.write(to: self.tmpURL! )
} catch {
print(error)
}
DispatchQueue.main.async {
//MARK:- Instead of using MIME type and NSData .now you can use the file directory to open the file in WEBView
self.webView.loadFileURL(self.tmpURL!, allowingReadAccessTo: self.tmpURL!)     
}
}