Initial commit

.gitignore

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+/target
+/Cargo.lock

Cargo.toml

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+[package]
+name = "rewrite-html-blocks"
+version = "1.0.0"
+edition = "2021"
+
+[dependencies]
+html5ever = "0.25"
+kuchiki = "0.8.1"

src/lib.rs

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+use html5ever::QualName;
+use kuchiki::{traits::*, NodeRef};
+
+pub fn rewrite_tags(html: &str, selector: &str, mapping: impl Fn(&NodeRef) -> String) -> String {
+    let document = kuchiki::parse_html().one(html);
+
+    for elem in document
+        .select(selector)
+        .expect("Failed to select document with given selector")
+    {
+        let node = elem.as_node();
+        let new_contents = kuchiki::parse_fragment(
+            elem.name.clone(),
+            elem.attributes
+                .borrow()
+                .map
+                .clone()
+                .into_iter()
+                .map(|(name, value)| html5ever::Attribute {
+                    name: QualName::new(value.prefix, name.ns, name.local),
+                    value: value.value.into(),
+                })
+                .collect(),
+        )
+        .one(mapping(node))
+        .first_child()
+        .expect("Root element somehow missing");
+
+        for child in node.children() {
+            child.detach();
+        }
+
+        for child in new_contents.children() {
+            node.append(child);
+        }
+    }
+
+    let mut out = Vec::new();
+    document
+        .serialize(&mut out)
+        .expect("Failed to serialize document");
+    String::from_utf8_lossy(&out).into_owned()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::rewrite_tags;
+
+    #[test]
+    fn remap_block() {
+        let html = r#"<p>hello, world! <span id="replace-me">REPLACE ME</span></p>"#;
+        let rewritten_html = rewrite_tags(html, "#replace-me", |_| {
+            "<strong>it's a me!</strong>".to_string()
+        });
+
+        println!("{}", rewritten_html)
+    }
+}