Struct HtmlRewriter 

pub struct HtmlRewriter { /* private fields */ }

A trillium [Handler] that rewrites HTML response bodies with lol-html, using lol-async.

It wraps the response produced by other handlers: in before_send it inspects the outgoing Content-Type and, if the mime subtype is html (e.g. text/html), replaces the response body with a streaming rewrite driven by the Settings returned from the closure passed to HtmlRewriter::new. Responses with any other content type (or none) are passed through unchanged.

Implementations

impl HtmlRewriter

pub fn new( f: impl Fn() -> Settings<'static, 'static> + Send + Sync + 'static, ) -> Self

Construct a new html rewriter from a closure that builds Settings.

The closure — rather than a Settings value — is required because lol-html’s content handlers are single-use; it is invoked once per rewritten response to produce a fresh set of handlers. Build the settings with [Settings::new_send()] as the base (its handlers are Send, as required here) and populate element_content_handlers / document_content_handlers. See [lol_async::html::Settings] and the lol-html docs for the full rewriting API.

Trait Implementations

impl Debug for HtmlRewriter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Handler for HtmlRewriter

async fn before_send(&self, conn: Conn) -> Conn

Performs any final modifications to this conn after all handlers have been run. Although this is a slight deviation from the simple conn->conn->conn chain represented by most Handlers, it provides an easy way for libraries to effectively inject a second handler into a response chain. This is useful for loggers that need to record information both before and after other handlers have run, as well as database transaction handlers and similar library code.

fn run(&self, conn: Conn) -> impl Future<Output = Conn> + Send

Executes this handler, performing any modifications to the Conn that are desired.

fn init(&mut self, info: &mut Info) -> impl Future<Output = ()> + Send

Performs one-time async set up on a mutable borrow of the Handler before the server starts accepting requests. This allows a Handler to be defined in synchronous code but perform async setup such as establishing a database connection or fetching some state from an external source. This is optional, and chances are high that you do not need this.

fn has_upgrade(&self, upgrade: &Upgrade) -> bool

predicate function answering the question of whether this Handler would like to take ownership of the negotiated Upgrade. If this returns true, you must implement [Handler::upgrade]. The first handler that responds true to this will receive ownership of the [trillium::Upgrade][crate::Upgrade] in a subsequent call to [Handler::upgrade]

fn upgrade(&self, upgrade: Upgrade) -> impl Future<Output = ()> + Send

This will only be called if the handler reponds true to [Handler::has_upgrade] and will only be called once for this upgrade. There is no return value, and this function takes exclusive ownership of the underlying transport once this is called. You can downcast the transport to whatever the source transport type is and perform any non-http protocol communication that has been negotiated. You probably don’t want this unless you’re implementing something like websockets. Please note that for many transports such as TcpStreams, dropping the transport (and therefore the Upgrade) will hang up / disconnect.

fn name(&self) -> Cow<'static, str>

Customize the name of your handler. This is used in Debug implementations. The default is the type name of this handler.