Updated the code to show the document interaction controller for text files as well

Session/Conversations/ConversationVC+Interaction.swift

@@ -472,7 +472,7 @@ extension ConversationVC : InputViewDelegate, MessageCellDelegate, ContextMenuAc
                     Storage.shared.getContact(with: thread.contactSessionID())?.isTrusted != true {
                     confirmDownload()
                 }
-                else if viewItem.attachmentStream?.contentType == OWSMimeTypeApplicationPdf, let filePathString: String = viewItem.attachmentStream?.originalFilePath {
+                else if (viewItem.attachmentStream?.isText == true || viewItem.attachmentStream?.contentType == OWSMimeTypeApplicationPdf), let filePathString: String = viewItem.attachmentStream?.originalFilePath {
                     let fileUrl: URL = URL(fileURLWithPath: filePathString)
                     let interactionController: UIDocumentInteractionController = UIDocumentInteractionController(url: fileUrl)
                     interactionController.delegate = self

SessionMessagingKit/Sending & Receiving/Attachments/TSAttachment.h

@@ -84,6 +84,7 @@ typedef NS_ENUM(NSUInteger, TSAttachmentType) {
 @property (nonatomic, readonly) BOOL isAudio;
 @property (nonatomic, readonly) BOOL isVoiceMessage;
 @property (nonatomic, readonly) BOOL isVisualMedia;
+@property (nonatomic, readonly) BOOL isText;
 @property (nonatomic, readonly) BOOL isOversizeText;
 
 + (NSString *)emojiForMimeType:(NSString *)contentType;

SessionMessagingKit/Sending & Receiving/Attachments/TSAttachment.m

@@ -3,6 +3,14 @@
 #import "TSAttachmentPointer.h"
 #import <SignalCoreKit/NSString+OWS.h>
 
+#if TARGET_OS_IPHONE
+#import <MobileCoreServices/MobileCoreServices.h>
+
+#else
+#import <CoreServices/CoreServices.h>
+
+#endif
+
 NS_ASSUME_NONNULL_BEGIN
 
 NSUInteger const TSAttachmentSchemaVersion = 4;
@@ -229,6 +237,10 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
     return [MIMETypeUtil isVisualMedia:self.contentType];
 }
 
+- (BOOL)isText {
+    return [MIMETypeUtil isText:self.contentType];
+}
+
 - (BOOL)isOversizeText
 {
     return [self.contentType isEqualToString:OWSMimeTypeOversizeTextMessage];

SessionUtilitiesKit/Media/MIMETypeUtil.h

@@ -41,6 +41,7 @@ extern NSString *const kSyncMessageFileExtension;
 + (BOOL)isImage:(NSString *)contentType;
 + (BOOL)isVideo:(NSString *)contentType;
 + (BOOL)isAudio:(NSString *)contentType;
++ (BOOL)isText:(NSString *)contentType;
 + (BOOL)isVisualMedia:(NSString *)contentType;
 
 // filename is optional and should not be trusted.

SessionUtilitiesKit/Media/MIMETypeUtil.m

@@ -279,6 +279,17 @@ NSString *const kSyncMessageFileExtension = @"bin";
     return [MIMETypeUtil isSupportedAudioMIMEType:contentType];
 }
 
++ (BOOL)isText:(NSString *)contentType {
+    return [
+        @[
+            @"text/plain",
+            @"text/csv",
+            @"text/tab-separated-values"
+        ]
+        containsObject:contentType
+    ];
+}
+
 + (BOOL)isVisualMedia:(NSString *)contentType
 {
     if ([self isImage:contentType]) {