Merge branch 'charlesmchen/linkPreviewsUserAgent'

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.m

@@ -719,11 +719,6 @@ const CGFloat kMaxTextViewHeight = 98;
 {
     OWSAssertIsOnMainThread();
 
-    if (self.wasLinkPreviewCancelled) {
-        [self clearLinkPreviewStateAndView];
-        return;
-    }
-
     NSString *body =
         [[self messageText] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
     if (body.length < 1) {
@@ -732,6 +727,11 @@ const CGFloat kMaxTextViewHeight = 98;
         return;
     }
 
+    if (self.wasLinkPreviewCancelled) {
+        [self clearLinkPreviewStateAndView];
+        return;
+    }
+
     // Don't include link previews for oversize text messages.
     if ([body lengthOfBytesUsingEncoding:NSUTF8StringEncoding] >= kOversizeTextMessageSizeThreshold) {
         [self clearLinkPreviewStateAndView];

SignalServiceKit/src/Messages/Interactions/OWSLinkPreview.swift

@@ -434,6 +434,15 @@ public class OWSLinkPreview: MTLModel {
     public class func previewUrl(forMessageBodyText body: String?) -> String? {
         AssertIsOnMainThread()
 
+        // Exit early if link previews are not enabled in order to avoid
+        // tainting the cache.
+        guard OWSLinkPreview.featureEnabled else {
+            return nil
+        }
+        guard SSKPreferences.areLinkPreviewsEnabled() else {
+            return nil
+        }
+
         if let cachedUrl = previewUrlCache.object(forKey: body as AnyObject) as? String {
             Logger.verbose("URL parsing cache hit.")
             guard cachedUrl.count > 0 else {
@@ -501,6 +510,16 @@ public class OWSLinkPreview: MTLModel {
 
     private class func setCachedLinkPreview(_ linkPreviewDraft: OWSLinkPreviewDraft,
                                             forPreviewUrl previewUrl: String) {
+
+        // Exit early if link previews are not enabled in order to avoid
+        // tainting the cache.
+        guard OWSLinkPreview.featureEnabled else {
+            return
+        }
+        guard SSKPreferences.areLinkPreviewsEnabled() else {
+            return
+        }
+
         serialQueue.sync {
             previewUrlCache.setObject(linkPreviewDraft, forKey: previewUrl as AnyObject)
         }

SignalServiceKit/src/Network/ProxiedContentDownloader.swift

@@ -644,7 +644,7 @@ open class ProxiedContentDownloader: NSObject, URLSessionTaskDelegate, URLSessio
             request.httpMethod = "HEAD"
             request.httpShouldUsePipelining = true
             // Some services like Reddit will severely rate-limit requests without a user agent.
-            request.addValue("Signal", forHTTPHeaderField: "User-Agent")
+            request.addValue("Signal iOS (+https://signal.org/download)", forHTTPHeaderField: "User-Agent")
 
             let task = downloadSession.dataTask(with: request, completionHandler: { data, response, error -> Void in
                 if let data = data, data.count > 0 {