markdown_view_leptos

Compile-time Markdown to Leptos view! with MDX‑like inline components.

• Inline components in Markdown using {{ <MyComp prop=value/> }}
• Use string, file = "...", or url = "..." sources
• Fenced‑code aware: ignores {{ ... }} inside triple‑backtick code blocks
• Works in CSR or SSR; compile-time sources avoid runtime parser cost in the browser

Security note: the generated HTML is injected via inner_html. Only use trusted Markdown or sanitize upstream.

Install

cargo add markdown_view_leptos

For CSR (WASM):

• rustup target add wasm32-unknown-unknown
• Use a bundler like Trunk (cargo install trunk)

Quick start

use leptos::prelude::*;
use markdown_view_leptos::markdown_view;

#[component]
fn Hello() -> impl IntoView {
    view! { <em>"Hello from a component"</em> }
}

#[component]
pub fn App() -> impl IntoView {
    view! { <main>{markdown_view!(r#"
# Title

Some text before the component.

{{ <Hello/> }}

And some text after.
"#)}</main> }
}

Macro inputs

Both markdown_view! and markdown_anchors! accept the same input forms:

• Inline string literals ("...", r#"..."#, String::from("..."), "...".to_string()).
• file = "path.md": resolved at compile time relative to CARGO_MANIFEST_DIR.
• file = <expr>: resolved at compile time if the file exists; otherwise read at runtime (non-wasm only).
• url = "https://...": fetched at compile time (disabled in rust-analyzer). If the URL expression cannot be resolved to a literal, the macro treats it like a dynamic Markdown string expression.
• Any other expression (String/&str): handled at runtime.

Inline string

Works with normal or raw strings; inline {{ ... }} components are spliced in. The same inline forms work with markdown_anchors!.

use leptos::prelude::*;
use markdown_view_leptos::markdown_view;

#[component]
pub fn App() -> impl IntoView {
    view! { <section>{markdown_view!(file = "content.md")}</section> }
}

From a file

file paths are resolved relative to your crate root (CARGO_MANIFEST_DIR). Literal paths are embedded at compile time so edits trigger recompiles.

You can also point to a variable. If the macro can resolve it at compile time (e.g., let content = "content.md"; or format!("content.md") where the file exists), it behaves like a literal path. Otherwise it falls back to reading at runtime (non-wasm only) and inline components are not expanded.

markdown_anchors! accepts the same file = ... forms.

let base = "/opt/articles";
let name = "welcome.md";
let view = markdown_view!(file = format!("{}/{}", base, name));

For wasm builds, use a path the macro can resolve at compile time so the content is embedded (no filesystem at runtime).

Dynamic string at runtime

String/&str variables are accepted.

let body = r#"
# Title

Inline component: {{ <Hello/> }}
"#;
let inline_view = markdown_view!(body); // components work: `body` is a literal binding

let runtime_body: String = fetch_from_server();
let runtime_view = markdown_view!(runtime_body); // runtime parsing, `{{ ... }}` stays literal

If the macro can see a string literal binding in the same file (as with body above), it inlines it so {{ ... }} components still render. Otherwise Markdown is rendered at runtime and {{ ... }} blocks stay literal text.

markdown_anchors! uses the same runtime path for dynamic strings.

From a URL (build-time fetch)

use leptos::prelude::*;
use markdown_view_leptos::markdown_view;
#[component] 
pub fn App() -> impl IntoView {
    view! { 
            <div>{markdown_view!(url = "https://github.com/leptos-rs/awesome-leptos/blob/main/README.md")}</div>
          }
}

• Happens at compile‑time (not client runtime), using a blocking HTTP GET.
• For editor tooling (rust‑analyzer), remote fetch is disabled and a small placeholder is returned for responsiveness.
• Remote fetch happens at build time on non‑wasm targets (blocking HTTP GET). rust‑analyzer and wasm builds get a placeholder for responsiveness. Network errors fall back to a placeholder; otherwise the fetched content is embedded.
• Prefer file = "..." for reproducible builds.

markdown_anchors! accepts the same url = ... forms.

How it works

• Markdown → HTML: Compile-time sources use pulldown‑cmark with the full option set (definition lists, footnotes, GFM, math, heading attributes, metadata blocks, and more). Runtime strings use a lightweight built-in parser (headings + paragraphs + heading IDs). Injected via inner_html into a view! tree.
• Inline components: Any {{ ... }} outside fenced code blocks is parsed as Rust/RSX and spliced into the view! tree for compile-time sources (string literal, file, url, or identifiers that resolve to literals in the same file). Runtime String inputs render {{ ... }} literally.
• Fenced code: Triple‑backtick fences (```) are respected; {{ ... }} inside them is ignored and rendered literally.
• Parse fallback: If a snippet inside {{ ... }} doesn’t parse, it is rendered as plain Markdown so your build doesn’t fail unexpectedly.
• Metadata blocks: Compile-time sources honor YAML/TOML front matter (--- or +++) via pulldown‑cmark’s metadata block options.
• Anchor extraction: markdown_anchors! uses pulldown‑cmark at compile time; runtime strings use the lightweight parser and honor {#id} (other attributes are ignored).

Options: heading anchors

Headings get IDs plus an anchor link (rendered before the heading text). IDs are slugified by lowercasing, stripping accents, and replacing non-alphanumeric runs with - (for example, Último parágrafo becomes ultimo-paragrafo). Customize or disable:

let view = markdown_view!(
    file = "content.md",
    anchor = true,
    anchor_class = "my-anchor",
    anchor_style = "color: #f40;",
    anchor_wrapper_class = "anchor-wrap",
    anchor_wrapper_style = "display: inline-block;",
    anchor_symbol = "§"
);

anchor_wrapper_class and anchor_wrapper_style apply to the heading element that wraps the anchor link for additional layout control.

To disable anchor links (IDs still render for deep links):

let view = markdown_view!(
    file = "content.md",
    anchor = false
);

Anchor styling is handled via CSS. A VitePress-like pattern:

.markdown-view { --mdv-anchor-color: #6b7280; --mdv-anchor-hover-color: #111827; }
.markdown-view :is(h1, h2, h3, h4, h5, h6) { position: relative; }
.markdown-view .header-anchor {
  position: absolute;
  left: -0.9em;
  opacity: 0;
  text-decoration: none;
  color: var(--mdv-anchor-color);
  transition: opacity 0.15s ease, color 0.15s ease;
}
.markdown-view :is(h1, h2, h3, h4, h5, h6):hover .header-anchor {
  opacity: 1;
  color: var(--mdv-anchor-hover-color);
}

Utility: collect anchors

Use markdown_anchors! to get all heading (title, id) pairs (for TOCs or navigation). The same slug rules apply when headings do not define a custom {#id}:

use markdown_view_leptos::markdown_anchors;

let anchors = markdown_anchors!(r#"
# Getting Started
## Install
## Install {#custom-install}
"#);
// anchors == [
//   ("Getting Started", "getting-started"),
//   ("Install", "install"),
//   ("Install", "custom-install")
// ]

let toc = anchors
    .iter()
    .map(|(title, id)| format!("<li><a href=\"#{}\">{}</a></li>", id, title))
    .collect::<String>();

markdown_anchors! only returns anchors when the input contains [[toc]]. The marker is stripped from markdown_view! output and never rendered.

When you pass a dynamic string expression to markdown_anchors!, the runtime path uses the lightweight parser and honors {#id} (other heading attributes are ignored).

Example

This repo includes a CSR example (Trunk):

• examples/markdown-csr-example: Renders a canvas‑based ParticleText component from within Markdown.

Run with Trunk:

cd examples/markdown-csr-example
trunk serve --open

Tips & caveats

• Scope: Components referenced inside {{ ... }} must be in scope where you invoke the macro.
• Styling: Wrap the macro output with your own container and styles, then target markdown elements with CSS.
• Sanitization: If you need strict XSS safety, sanitize before compile time or filter the source.
• Rebuilds: file = "..." uses include_str! to make the file a build input; saving it triggers a rebuild.

Testing & contributing

• Run tests: cargo test
• Lint & format: cargo clippy --all-targets -- -D warnings and cargo fmt --all
• Issues & PRs welcome. Keep scopes small and messages clear (Conventional Commits).

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