edgeblog/src/main.rs

96 lines
3.2 KiB
Rust

//! Default Compute@Edge template program.
use fastly::http::{header, Method, StatusCode};
use fastly::{mime, Body, Error, Request, Response};
use pulldown_cmark::{html, Options, Parser};
use std::io::Read;
/// The configured backend name.
const BACKEND_NAME: &str = "upstream_ssl";
/// The URL of the header markdown content.
const HEADER_URL: &str = "http://nora.codes/edgeblog/_header.md";
/// The URL of the footer markdown content.
const FOOTER_URL: &str = "http://nora.codes/edgeblog/_footer.md";
fn main() -> Result<(), Error> {
let req = Request::from_client();
// Filter request methods...
match req.get_method() {
// Allow GET and HEAD requests.
&Method::GET | &Method::HEAD => (),
// Deny anything else.
_ => {
Response::from_status(StatusCode::METHOD_NOT_ALLOWED)
.with_header(header::ALLOW, "GET, HEAD")
.with_body_text_plain("This method is not allowed\n")
.send_to_client();
return Ok(());
}
};
// Rewrite the / path to index.md, and construct a Request
let upstream_req = match req.get_path() {
"/" => Request::get("http://nora.codes/edgeblog/index.md"),
path => Request::get(format!("http://nora.codes/edgeblog/{}", path)),
};
// Get the data for the header portion of the page
let mut header_body = match Request::get(HEADER_URL).send(BACKEND_NAME) {
Err(_e) => Body::new(),
Ok(mut r) => r.take_body(),
};
// Get the data for the footer portion of the page
let mut footer_body = match Request::get(FOOTER_URL).send(BACKEND_NAME) {
Err(_e) => Body::new(),
Ok(mut r) => r.take_body(),
};
// Write the header into the synthetic body
let mut md_assembled = String::new();
header_body.read_to_string(&mut md_assembled)?;
md_assembled.push_str("\n");
// Get the geoip info for the client, if possible.
let geotext: String = match req.get_client_ip_addr() {
Some(ip) => match fastly::geo::geo_lookup(ip) {
None => "an undisclosed location".into(),
Some(geo) => format!(
"AS{} '{}', in {}",
geo.as_number(),
geo.as_name(),
geo.city()
)
.into(),
},
None => "an undisclosed location".into(),
};
// Get the content of the page itself. If this fails, pass on the failure.
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 mut client_body = beresp
.clone_without_body()
.with_content_type(mime::TEXT_HTML_UTF_8)
.stream_to_client();
html::write_html(&mut client_body, parser)?;
Ok(())
}