Initial timeline HTML support.

2026-11-02 12:07:55 +00:00 · 2022-03-24 14:47:55 +02:00
parent d3588cf6f1
commit cf42d61d27
20 changed files with 683 additions and 51 deletions
@@ -0,0 +1,71 @@
+//
+//  DTHTMLElement+AttributedStringBuilder.swift
+//  ElementX
+//
+//  Created by Stefan Ceriu on 24/03/2022.
+//  Copyright © 2022 Element. All rights reserved.
+//
+
+import Foundation
+import DTCoreText
+
+public extension DTHTMLElement {
+    /// Sanitize the element using the given parameters.
+    /// - Parameters:
+    ///   - allowedHTMLTags: An array of tags that are allowed. All other tags will be removed.
+    ///   - font: The default font to use when resetting the content of any unsupported tags.
+    ///   - imageHandler: An optional image handler to be run on `img` tags (if allowed) to update the `src` attribute.
+    @objc func sanitize(font: UIFont) {
+        if let name = name, !Self.allowedHTMLTags.contains(name) {
+            
+            // This is an unsupported tag.
+            // Remove any attachments to fix rendering.
+            textAttachment = nil
+            
+            // If the element has plain text content show that,
+            // otherwise prevent the tag from displaying.
+            if let stringContent = attributedString()?.string,
+               !stringContent.isEmpty,
+               let element = DTTextHTMLElement(name: nil, attributes: nil) {
+                element.setText(stringContent)
+                removeAllChildNodes()
+                addChildNode(element)
+                
+                if let parent = parent() {
+                    element.inheritAttributes(from: parent)
+                } else {
+                    fontDescriptor = DTCoreTextFontDescriptor()
+                    fontDescriptor.fontFamily = font.familyName
+                    fontDescriptor.fontName = font.fontName
+                    fontDescriptor.pointSize = font.pointSize
+                    paragraphStyle = DTCoreTextParagraphStyle.default()
+                    
+                    element.inheritAttributes(from: self)
+                }
+                element.interpretAttributes()
+                
+            } else if let parent = parent() {
+                parent.removeChildNode(self)
+            } else {
+                didOutput = true
+            }
+            
+        } else {
+            // This element is a supported tag, but it may contain children that aren't,
+            // so santize all child nodes to ensure correct tags.
+            if let childNodes = childNodes as? [DTHTMLElement] {
+                childNodes.forEach { $0.sanitize(font: font) }
+            }
+        }
+    }
+    
+    private static var allowedHTMLTags = {
+        ["font", // custom to matrix for IRC-style font coloring
+         "del", // for markdown
+         "body", // added internally by DTCoreText
+         "mx-reply",
+         "h1", "h2", "h3", "h4", "h5", "h6", "blockquote", "p", "a", "ul", "ol",
+         "nl", "li", "b", "i", "u", "strong", "em", "strike", "code", "hr", "br", "div",
+         "table", "thead", "caption", "tbody", "tr", "th", "td", "pre"]
+    }()
+}