A blogging platform written in Rust for Cloudflare Workers, integrated with Standard Notes
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 

385 lines
14 KiB

// Utility functions and structs for the blogging system
// Due to limitations of the Cloudflare Workers KV, we do not
// store the entire state in one record; instead, different
// parts are stroed in different records. This also increases
// efficiency, since the program won't need to load anything
// unnecessary from KV.
use crate::store;
use crate::utils::*;
use js_sys::{JsString, RegExp};
use pulldown_cmark::*;
use serde::{Serialize, Deserialize};
use std::vec::Vec;
use wasm_bindgen::{JsCast, JsValue};
use wasm_bindgen::closure::Closure;
use wasm_bindgen_futures::future_to_promise;
// A list of the UUIDs of all published blog posts
// This should be SORTED with the newest posts at lower indices (closer to 0)
// The user may edit this via KV UI to change ordering and such
// by default new posts are always added to the top
#[derive(Serialize, Deserialize)]
pub struct PostsList(pub Vec<String>);
impl PostsList {
pub async fn load() -> PostsList {
match store::get_obj("posts_list").await {
Ok(v) => PostsList(v),
// Don't panic on empty
// TODO: What if the user messed up when editing?
// That would cause a decode failure and all data will be gone
// if a new post is added or updated (overwriting the KV value)
// under this logic
// (if no new post is added then nothing bad would happen;
// the user would probably notice when trying to visit the blog home page)
Err(_) => PostsList(vec![])
}
}
pub fn has_post(&self, uuid: &str) -> bool {
self.0.contains(&uuid.into())
}
// Add a post to the list and then update the record in KV
// Also consumes self, as this should normally be the last action
// in an API call
pub async fn add_post(mut self, uuid: &str) -> MyResult<()> {
if self.has_post(uuid) {
return Ok(());
}
self.0.insert(0, uuid.into());
store::put_obj_pretty("posts_list", self.0).await
}
// Remove a post from published list
// may be used when deleting / unpublishing a post
// Does nothing if uuid not found in list
pub async fn remove_post(mut self, uuid: &str) -> MyResult<()> {
self.0.remove_item(&uuid);
store::put_obj_pretty("posts_list", self.0).await
}
}
#[derive(Serialize, Deserialize)]
pub struct Post {
// The UUID of the post (a Standard Notes UUID)
pub uuid: String,
// The UNIX timestamp (in seconds) for the post
pub timestamp: u64,
// URL of the post (relative to the root of the site)
pub url: String,
// Title of the post
pub title: String,
// The Markdown content of the post
// We keep the original content here
// so that we could make changes to the Markdown parser
// in the future; we won't be stuck with a parsed version
pub content: String,
// Some arbitrary data that could be used by the theme
pub theme_config: Option<serde_json::Value>
}
impl Post {
fn uuid_to_post_key(uuid: &str) -> String {
format!("post_by_uuid_{}", uuid)
}
fn url_to_mapping_key(url: &str) -> String {
format!("url_mapping_{}", url)
}
async fn create_url_mapping(url: &str, uuid: &str) -> MyResult<()> {
store::put_str(&Self::url_to_mapping_key(url), uuid).await
}
// Returns Err(InternalError) if the post is not found
// Note that the existence status of a post here must
// be synchronized with the PostsList; that is, if a
// post is not found in PostsList, it must not be found
// here either; if a post is found in PostsList, then
// this method should not return any error.
// (except for hidden posts, in which case they won't be
// present in PostsList)
pub async fn find_by_uuid(uuid: &str) -> MyResult<Post> {
store::get_obj(&Self::uuid_to_post_key(uuid)).await
}
pub async fn find_by_url(url: &str) -> MyResult<Post> {
let uuid = store::get_str(&Self::url_to_mapping_key(url)).await?;
Self::find_by_uuid(&uuid).await
}
// Write the Post to KV storage; this can be a new post or
// update to an existing post; either way, the CALLER is
// responsible for making sure PostsList is updated with the
// latest set of posts sorted in order.
// This function will also create a mapping from URL to UUID in the KV
pub async fn write_to_kv(self) -> MyResult<()> {
Self::create_url_mapping(&self.url, &self.uuid).await?;
store::put_obj(&Self::uuid_to_post_key(&self.uuid), self).await
}
pub async fn delete_by_uuid(uuid: &str) -> MyResult<()> {
store::delete(&Self::uuid_to_post_key(uuid)).await
}
}
lazy_static! {
// Whenever this is changed, all cache will be invalided
// Use build timestamp string
static ref CACHE_VERSION: String = {
format!("{}", BUILD_TIMESTAMP)
};
}
// The prefix path used for caching remote images
pub const IMG_CACHE_PREFIX: &'static str = "/imgcache/";
// The divider for summary
// Insert this into the article as a standalone line to
// make everything above it the summary. DO NOT insert
// it within paragraph or anything else otherwise
// the layout may break.
const SUMMARY_DIVIDER: &'static str = "<!-- More -->";
// Cached version of rendered blog content HTMLs
// compiled from Markdown
// This is needed because
// (1) we have to extract some information from
// the Markdown source code before anyone
// visits, e.g. pictures it refers to (
// for whitelisting the cache URL)
// (2) Markdown parsing is slower than filling in
// HTML templates of the entire page. If these
// Markdown compilation results are cached,
// page generation can be very fast while still
// keeping some dynamic features available to us
#[derive(Serialize, Deserialize)]
pub struct PostContentCache {
// UUID of the original post
uuid: String,
// If version != CACHE_VERSION, the cache is invalidated
version: String,
// Digest of the original content
orig_digest: String,
// Summary can be defined by inserting SUMMARY_DIVIDER
// into the article. Everything before this tag will be
// the summary. Becuase it's an HTML comment, it won't
// show up in the rendered result.
pub summary: String,
// Compiled content in HTML
pub content: String
}
impl PostContentCache {
fn uuid_to_cache_key(uuid: &str) -> String {
format!("content_cache_{}", uuid)
}
fn url_to_cache_whitelist_key(url: &str) -> String {
format!("cache_whitelist_{}", url)
}
pub async fn is_external_url_whitelisted_for_cache(url: &str) -> bool {
if let Some(list) = &crate::CONFIG.extra_remote_proxy_whitelist {
if list.contains(&url.into()) {
return true;
}
}
match store::get_str(&Self::url_to_cache_whitelist_key(url)).await {
Ok(s) => s == "Y",
Err(_) => false
}
}
async fn find_by_uuid(uuid: &str) -> MyResult<PostContentCache> {
store::get_obj(&Self::uuid_to_cache_key(uuid)).await
}
pub async fn find_by_post(post: &Post) -> Option<PostContentCache> {
let cache = match Self::find_by_uuid(&post.uuid).await {
Ok(cache) => cache,
Err(_) => return None
};
if cache.version != *CACHE_VERSION {
return None;
}
if cache.orig_digest != crate::utils::sha1(&post.content).await {
return None;
}
Some(cache)
}
fn transform_tag<'a>(tag: &mut Tag<'a>) {
match tag {
Tag::Image(_, url, _) => {
// Convert all external image to our cached URL
// to protect users and speed up page loading
let url_encoded: String = js_sys::encode_uri_component(url).into();
// Also write this URL to whitelist
// (just throw the task onto the JS ev loop,
// because to make this function async we MUST need to
// allocate Vec later in the render function)
// we don't care about if this write succeeds or not,
// because even if it breaks we still can recover by a simple refresh
// and once it's written, it's permanent, so we expect the write
// to succeed as soon as the article is submitted
let url_cache_key = Self::url_to_cache_whitelist_key(url);
crate::EVENT.with(move |ev| {
ev.wait_until(&future_to_promise(async move {
let _ = store::put_str(&url_cache_key, "Y").await;
Ok(JsValue::TRUE)
})).unwrap();
});
// Now we can overwrite the tag URL
*url = format!("{}{}", IMG_CACHE_PREFIX, url_encoded).into();
},
_ => ()
}
}
fn transform_tags<'ev>(
parser: impl Iterator<Item = Event<'ev>>
) -> impl Iterator<Item = Event<'ev>> {
parser.map(|mut ev| {
match ev {
Event::Start(ref mut tag) | Event::End(ref mut tag) => {
Self::transform_tag(tag);
ev
},
_ => ev
}
})
}
fn transform_code_block_highlight<'ev>(
parser: impl Iterator<Item = Event<'ev>>
) -> impl Iterator<Item = Event<'ev>> {
let mut in_code_block = false;
let mut code_block_lang = None;
parser.map(move |ev| {
match &ev {
Event::Start(Tag::CodeBlock(block)) => {
in_code_block = true;
match block {
CodeBlockKind::Fenced(lang) => code_block_lang = Some(lang.to_string()),
CodeBlockKind::Indented => code_block_lang = None
}
},
Event::End(Tag::CodeBlock(_)) => {
in_code_block = false;
code_block_lang = None;
},
Event::Text(text) => {
if in_code_block {
let highlighted = if let Some(ref code_block_lang) = code_block_lang {
crate::hljs::highlight(&code_block_lang, text)
} else {
crate::hljs::highlight_auto(text)
};
return Event::Html(
highlighted.into());
}
}
_ => ()
}
ev
})
}
// Do some HTML-level transformations to the compiled result
// Because the Markdown parser doesn't always allow us to do
// everything, like adding `id` attributes to tags
fn transform_html(html: String) -> String {
let js_html: JsString = html.into();
// Add `id="xxx"` to all headings for anchoring
// Replacing is done in a Closure in order to generate
// the proper anchor string for each heading
// This matches only a single line, which is good because
// we only want it to match a single heading tag
// If it matched multiple lines, then it may match the
// ending tag of another heading.
let regex_heading = RegExp::new(r"<h(\d)>([^<]*)<\/h\1>", "ig");
let closure = Closure::wrap(Box::new(|_m: String, p1: String, p2: String| {
let anchor = filter_non_ascii_alphanumeric(
&p2.to_lowercase()).replace(" ", "-");
format!("<h{} id=\"{}\">{}</h{}>", p1, anchor, p2, p1)
}) as Box<dyn Fn(String, String, String) -> String>);
let js_html = js_html.replace_by_pattern_with_function(&regex_heading, closure.as_ref().unchecked_ref());
// Transform all <pre><code> to <pre><code class="hljs">
// For syntax highlighting
// We don't match the end tag because it may span multiple lines
// trying to match the end tag could result in accidentally matching
// the end tag of another code block.
let regex_code = RegExp::new("<pre><code( class=\"language-([^\"]*)\")?>", "ig");
let js_html = js_html.replace_by_pattern(&regex_code, "<pre><code class=\"hljs\">");
// Transform all non-self-refernece links (does not start with "#") to target="_blank"
let regex_links = RegExp::new("<a href=\"((?!#)[^\"]*)\">", "ig");
let js_html = js_html.replace_by_pattern(&regex_links, "<a target=\"_blank\" href=\"$1\">");
js_html.into()
}
// Only renders the content and spits out a cache object
// can be used to display the page or to write to cache
// Despite the signature, this function BLOCKS
// async only comes from digesting via SubtleCrypto
pub async fn render(post: &Post) -> PostContentCache {
let parser = Parser::new_ext(&post.content, Options::all());
// Apply code highlighting via Highlight.js
let parser = Self::transform_code_block_highlight(parser);
// Apply tag transform
let parser = Self::transform_tags(parser);
let mut html_output = String::new();
html::push_html(&mut html_output, parser);
html_output = Self::transform_html(html_output);
PostContentCache {
uuid: post.uuid.clone(),
version: CACHE_VERSION.to_owned(),
orig_digest: crate::utils::sha1(&post.content).await,
summary: match html_output.find(SUMMARY_DIVIDER) {
None => html_output.clone(),
Some(x) => (&html_output[0..x]).to_owned()
},
content: html_output
}
}
// Tries to find the rendered content cache of post
// if a valid cache cannot be found, this method
// will render the content, write that into cache
// and return this newly-rendered one
// This will block if it tries to render; if that's a
// concern, use find_by_post
pub async fn find_or_render(post: &Post) -> PostContentCache {
match Self::find_by_post(post).await {
Some(cache) => cache,
None => {
let ret = Self::render(post).await;
// Ignore save error since if save failed, it can be regenerated anyway
let _ = ret.save().await;
ret
}
}
}
// Save the current cache object to KV
pub async fn save(&self) -> MyResult<()> {
store::put_obj(&Self::uuid_to_cache_key(&self.uuid), self).await
}
pub async fn delete_by_uuid(uuid: &str) -> MyResult<()> {
store::delete(&Self::uuid_to_cache_key(uuid)).await
}
}