Support images and embeds properly.

This commit is contained in:
Leonora Tindall 2022-09-20 11:44:20 -05:00
parent 9829ba7310
commit 338e22dc69
1 changed files with 44 additions and 25 deletions

View File

@ -1,11 +1,12 @@
//! Default Compute@Edge template program. //! Compute@Edge service which renders markdown from external sources.
use fastly::http::{header, Method, StatusCode}; use fastly::http::{header, Method, StatusCode};
use fastly::{mime, Body, Error, Request, Response}; use fastly::{mime, Body, Error, Request, Response};
use pulldown_cmark::{html, Options, Parser}; use pulldown_cmark::{html, Options, Parser};
use std::io::Read; use std::io::Read;
/// The configured backend name. /// The configured backend name. This is set up in the Fastly interface, and in fastly.toml
/// for local development.
const BACKEND_NAME: &str = "upstream_ssl"; const BACKEND_NAME: &str = "upstream_ssl";
/// The URL of the header markdown content. /// The URL of the header markdown content.
@ -13,9 +14,12 @@ const HEADER_URL: &str = "http://nora.codes/edgeblog/_header.md";
/// The URL of the footer markdown content. /// The URL of the footer markdown content.
const FOOTER_URL: &str = "http://nora.codes/edgeblog/_footer.md"; const FOOTER_URL: &str = "http://nora.codes/edgeblog/_footer.md";
/// This function is invoked for every request. If it returns Err(), the user will see a 500.
fn main() -> Result<(), Error> { fn main() -> Result<(), Error> {
// Get the request sent by the client. This hooks into the Compute@Edge runtime interface.
let req = Request::from_client(); let req = Request::from_client();
// Filter request methods...
// Filter out unrelated request methods.
match req.get_method() { match req.get_method() {
// Allow GET and HEAD requests. // Allow GET and HEAD requests.
&Method::GET | &Method::HEAD => (), &Method::GET | &Method::HEAD => (),
@ -30,33 +34,61 @@ fn main() -> Result<(), Error> {
} }
}; };
// Rewrite the / path to index.md, and construct a Request // Rewrite the / path to index.md, and construct a Request for the main body content.
let upstream_req = match req.get_path() { let upstream_req = match req.get_path() {
"/" => Request::get("http://nora.codes/edgeblog/index.md"), "/" => Request::get("http://nora.codes/edgeblog/index.md"),
path => Request::get(format!("http://nora.codes/edgeblog/{}", path)), path => Request::get(format!("http://nora.codes/edgeblog/{}", path)),
}; };
// Get the data for the header portion of the page // Get the data for the body portion of the page, and write the content into the Markdown
// document.
// This backend response is used as the template for the synthetic response.
let mut beresp = upstream_req.send(BACKEND_NAME)?;
// It's important to set Markdown's MIME type as "text" on your webserver;
// I used "text/markdown".
// Here, we check whether or not the object being requested is text. If so, we'll render it
// inline; otherwise, we'll serve it as is. This allows supporting images, other documents,
// and so forth without any extra effort.
if beresp
.get_content_type()
.map(|mime| mime.type_() != mime::TEXT)
.unwrap_or(true)
{
beresp.send_to_client();
return Ok(());
}
// Get the data for the header portion of the page, making a backend request to the origin
// server. This will be cached.
let mut header_body = match Request::get(HEADER_URL).send(BACKEND_NAME) { let mut header_body = match Request::get(HEADER_URL).send(BACKEND_NAME) {
Err(_e) => Body::new(), Err(_e) => Body::new(),
Ok(mut r) => r.take_body(), Ok(mut r) => r.take_body(),
}; };
// Get the data for the footer portion of the page // Start off the Markdown document with the header content.
let mut md_assembled = String::new();
header_body.read_to_string(&mut md_assembled)?;
md_assembled.push_str("\n");
beresp.take_body().read_to_string(&mut md_assembled)?;
// Get the data for the footer portion of the page, making a backend request to the origin
// server. This will be cached.
let mut footer_body = match Request::get(FOOTER_URL).send(BACKEND_NAME) { let mut footer_body = match Request::get(FOOTER_URL).send(BACKEND_NAME) {
Err(_e) => Body::new(), Err(_e) => Body::new(),
Ok(mut r) => r.take_body(), Ok(mut r) => r.take_body(),
}; };
// Write the header into the synthetic body // Write the footer into the synthetic body
let mut md_assembled = String::new();
header_body.read_to_string(&mut md_assembled)?;
md_assembled.push_str("\n"); md_assembled.push_str("\n");
footer_body.read_to_string(&mut md_assembled)?;
// Get the geoip info for the client, if possible. // Get the geoip info for the client, if possible.
const UNKNOWN_LOCATION_STRING: &str = "unknown";
let geotext: String = match req.get_client_ip_addr() { let geotext: String = match req.get_client_ip_addr() {
Some(ip) => match fastly::geo::geo_lookup(ip) { Some(ip) => match fastly::geo::geo_lookup(ip) {
None => "an undisclosed location".into(), None => UNKNOWN_LOCATION_STRING.into(),
Some(geo) => format!( Some(geo) => format!(
"AS{} '{}', in {}", "AS{} '{}', in {}",
geo.as_number(), geo.as_number(),
@ -65,24 +97,11 @@ fn main() -> Result<(), Error> {
) )
.into(), .into(),
}, },
None => "an undisclosed location".into(), None => UNKNOWN_LOCATION_STRING.into(),
}; };
// Get the content of the page itself. If this fails, pass on the failure. md_assembled.push_str(&format!("\n<h5> Your provider: {} </h5>", geotext));
let mut beresp = upstream_req.send(BACKEND_NAME)?;
if beresp.get_status() == StatusCode::OK {
beresp.take_body().read_to_string(&mut md_assembled)?;
md_assembled = md_assembled.replace("{{geo}}", &geotext);
} else {
beresp.send_to_client();
return Ok(());
}
// Write the footer into the synthetic body
md_assembled.push_str("\n");
footer_body.read_to_string(&mut md_assembled)?;
let md_assembled = md_assembled.replace("{{geo}}", &geotext);
let parser = Parser::new_ext(&md_assembled, Options::empty()); let parser = Parser::new_ext(&md_assembled, Options::empty());
let mut client_body = beresp let mut client_body = beresp