URLConnection

From Xojo Documentation

Revision as of 18:09, 10 March 2021 by Gperlman (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Class (inherits from Object)


New in 2018r4

Used to send and receive data using the HTTP 1.1+ protocol.

Events
AuthenticationRequested FileReceived SendingProgressed
ContentReceived HeadersReceived
Error ReceivingProgressed
Properties
AllowCertificateValidation HTTPStatusCode fa-lock-32.png
Methods
ClearRequestHeaders ResponseHeader SendSync
Disconnect ResponseHeaders SetRequestContent
RequestHeader Send

Notes

Usage on Linux requires libsoup 2.4.

URLConnection handles both standard "http" connections and secure "https" connections.

macOS Information (App Transport Security)

Starting with OS X 10.11, you have to use secure "https" connections or you will get this error: "The resource could not be loaded because the App Transport Security policy requires the use of a secure connection". To continue to connect to non-secure "http" connections that you do not control you'll have to provide a plist with a temporary exception specified for each site you are accessing via http:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>NSAppTransportSecurity</key>
	<dict>
		<key>NSExceptionDomains</key>
		<dict>
			<key>firstsite.com</key>
			<dict>
				<key>NSIncludesSubdomains</key>
				<true/>
				<key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>
				<true/>
			</dict>
			<key>secondsite.com</key>
			<dict>
				<key>NSIncludesSubdomains</key>
				<true/>
				<key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>
				<true/>
			</dict>
		</dict>
	</dict>
</dict>
</plist>

If you don't know the specific sites, you can request access to everything using a single key:

<key>NSAppTransportSecurity</key>
<dict>
  <!-- Include to allow all connections; avoid if possible -->
  <key>NSAllowsArbitraryLoads</key>
      <true/>
</dict>

Apple may reject an App Store submission if the app uses these settings without valid reasons.

For more information about this, refer to NSAppTransportSecurity in Apple's docs.

For more information: UserGuide:App Transport Security, UserGuide:Using_a_plist

To test a site to see what plist exceptions it might need you can use this Terminal command:

/usr/bin/nscurl --ats-diagnostics --verbose https://example.com

Sample Projects

These sample projects are included with Xojo:

  • Examples/Communication/Internet/URLConnection/FileDownloader
  • Examples/Communication/Internet/URLConnection/URLConnectionGET
  • Examples/Communication/Internet/URLConnection/URLConnectionPOST

See Also

UserGuide:App Transport Security, UserGuide:Using_a_plist topics; Paw Extension on GitHub