perfect-postcode/server-rs/src/og_middleware.rs
2026-07-03 18:01:10 +01:00

531 lines
21 KiB
Rust

use std::sync::Arc;
use axum::body::{to_bytes, Body};
use axum::extract::Request;
use axum::http::{header, StatusCode};
use axum::middleware::Next;
use axum::response::Response;
use tracing::warn;
use crate::language::{
language_from_accept_language, query_string_with_language, supported_languages,
};
use crate::state::AppState;
const OG_PLACEHOLDER: &str =
r#"<meta name="x-og-placeholder" content="__PERFECT_POSTCODE_OG_TAGS__"/>"#;
const BUGSINK_CONFIG_PLACEHOLDER: &str = "__PERFECT_POSTCODE_BUGSINK_CONFIG__";
const HTML_BODY_LIMIT: usize = 5 * 1024 * 1024;
struct SeoPage {
canonical_path: &'static str,
title: &'static str,
description: &'static str,
indexable: bool,
}
/// Escape a string for safe inclusion inside a double-quoted HTML attribute value.
fn escape_attr(s: &str) -> String {
let mut out = String::with_capacity(s.len());
for c in s.chars() {
match c {
'&' => out.push_str("&amp;"),
'<' => out.push_str("&lt;"),
'>' => out.push_str("&gt;"),
'"' => out.push_str("&quot;"),
_ => out.push(c),
}
}
out
}
fn trim_trailing_slash(path: &str) -> &str {
if path.len() > 1 {
path.trim_end_matches('/')
} else {
path
}
}
fn seo_page_for_path(path: &str) -> Option<SeoPage> {
let path = trim_trailing_slash(path);
match path {
"/" => Some(SeoPage {
canonical_path: "/",
title: "Stop searching the wrong places | Perfect Postcode",
description: "Filter every postcode in England by budget, commute, schools, crime, noise, broadband, property prices and amenities before you start chasing viewings.",
indexable: true,
}),
"/learn" | "/support" => Some(SeoPage {
canonical_path: "/learn",
title: "How Perfect Postcode works - Data sources, FAQ and support",
description: "Learn how Perfect Postcode combines property prices, EPC records, travel times, crime, schools, broadband, noise, amenities and open data for postcode research.",
indexable: true,
}),
"/pricing" => Some(SeoPage {
canonical_path: "/pricing",
title: "Perfect Postcode pricing - Lifetime property search map access",
description: "Get lifetime access to the postcode property search map for England, including filters, saved searches, exports, and future data updates.",
indexable: true,
}),
"/property-price-map" => Some(SeoPage {
canonical_path: "/property-price-map",
title: "Property price map for England - Compare postcodes before viewing",
description: "Compare sold prices, estimated current value, price per square metre and local context across English postcodes before searching listings.",
indexable: true,
}),
"/postcode-property-search" => Some(SeoPage {
canonical_path: "/postcode-property-search",
title: "Postcode property search - Find areas that match your criteria",
description: "Search every postcode by budget, property type, floor area, tenure, commute, schools, crime, broadband, noise, parks and local amenities.",
indexable: true,
}),
"/commute-property-search" => Some(SeoPage {
canonical_path: "/commute-property-search",
title: "Commute property search - Find places to live by travel time",
description: "Filter postcodes by commute time, then compare price, schools, safety, broadband, road noise, parks and property data on one map.",
indexable: true,
}),
"/school-property-search" => Some(SeoPage {
canonical_path: "/school-property-search",
title: "School property search - Compare postcodes for family moves",
description: "Compare nearby schools, property size, prices, parks, safety, commute and local amenities before building a viewing shortlist.",
indexable: true,
}),
"/postcode-checker" => Some(SeoPage {
canonical_path: "/postcode-checker",
title: "Postcode checker - Property, crime, broadband, noise and schools",
description: "Check postcode-level property prices, EPC data, crime, broadband, road noise, schools, council tax, amenities and travel-time context.",
indexable: true,
}),
"/property-search/birmingham" => Some(SeoPage {
canonical_path: "/property-search/birmingham",
title: "Birmingham property search - Compare postcodes by price and commute",
description: "Use postcode-level data to compare Birmingham property prices, commute trade-offs, schools, crime, broadband and local amenities before viewings.",
indexable: true,
}),
"/property-search/manchester" => Some(SeoPage {
canonical_path: "/property-search/manchester",
title: "Manchester property search - Compare postcodes before viewing",
description: "Compare Manchester-area postcodes by budget, commute, property type, schools, broadband, crime, noise and amenities before booking viewings.",
indexable: true,
}),
"/property-search/bristol" => Some(SeoPage {
canonical_path: "/property-search/bristol",
title: "Bristol property search - Compare postcodes by commute and price",
description: "Compare Bristol postcodes by price, commute, property size, schools, broadband, crime, road noise, parks and amenities before viewings.",
indexable: true,
}),
"/data-sources" => Some(SeoPage {
canonical_path: "/data-sources",
title: "Perfect Postcode data sources - Property, schools, commute and local context",
description: "Review the public and official datasets used by Perfect Postcode, including property prices, EPC, schools, crime, broadband, noise and travel-time context.",
indexable: true,
}),
"/methodology" => Some(SeoPage {
canonical_path: "/methodology",
title: "Perfect Postcode methodology - How to interpret postcode property data",
description: "Understand how to use postcode filters, property estimates, travel-time data, school context and local signals as a home-buying shortlist tool.",
indexable: true,
}),
"/privacy-security" => Some(SeoPage {
canonical_path: "/privacy-security",
title: "Perfect Postcode privacy and security - Saved searches and account data",
description: "Learn how Perfect Postcode treats saved searches, account data and property research workflows with privacy and security in mind.",
indexable: true,
}),
"/terms" => Some(SeoPage {
canonical_path: "/terms",
title: "Terms of Service | Perfect Postcode",
description: "The terms that govern your use of Perfect Postcode, including lifetime access, acceptable use, data accuracy, payments and refunds.",
indexable: true,
}),
"/privacy" => Some(SeoPage {
canonical_path: "/privacy",
title: "Privacy Policy | Perfect Postcode",
description: "How Perfect Postcode collects, uses and protects your data: account details, payments, saved searches, AI queries, analytics and your UK GDPR rights.",
indexable: true,
}),
"/dashboard" => Some(SeoPage {
canonical_path: "/dashboard",
title: "Perfect Postcode dashboard",
description: "Explore postcode property data, travel times, prices, schools, crime, noise, broadband and amenities on the interactive map.",
indexable: false,
}),
"/saved" => Some(SeoPage {
canonical_path: "/saved",
title: "Perfect Postcode account",
description: "Manage your Perfect Postcode account, saved searches, shared links and invitations.",
indexable: false,
}),
"/invites" => Some(SeoPage {
canonical_path: "/invites",
title: "Perfect Postcode account",
description: "Manage your Perfect Postcode account, saved searches, shared links and invitations.",
indexable: false,
}),
"/account" => Some(SeoPage {
canonical_path: "/account",
title: "Perfect Postcode account",
description: "Manage your Perfect Postcode account, saved searches, shared links and invitations.",
indexable: false,
}),
_ if path.starts_with("/invite/") => Some(SeoPage {
canonical_path: "/invite",
title: "You're invited to Perfect Postcode",
description: "Accept your invitation to explore property prices, energy ratings, crime stats, school ratings, and more across England.",
indexable: false,
}),
// Generated growth pages (cheaper-twin / value-index landing pages). Without this they
// would 404 (should_return_404 keys off seo_page_for_path); see analysis/build_pages.py.
_ => crate::generated_data_pages::data_page(path).map(|d| SeoPage {
canonical_path: d.path,
title: d.title,
description: d.description,
indexable: true,
}),
}
}
fn is_passthrough_path(path: &str) -> bool {
path.starts_with("/api/")
|| path.starts_with("/pb/")
|| path.starts_with("/s/")
|| path.starts_with("/assets/")
|| matches!(
path,
"/health"
| "/metrics"
| "/robots.txt"
| "/sitemap.xml"
| "/favicon.svg"
| "/bundle.js"
| "/main.css"
| "/house.png"
)
|| path
.rsplit('/')
.next()
.is_some_and(|segment| segment.contains('.'))
}
fn should_return_404(path: &str) -> bool {
!is_passthrough_path(path) && seo_page_for_path(path).is_none()
}
fn not_found_response(public_url: &str, path: &str) -> Response {
let public_url_e = escape_attr(public_url);
let path_e = escape_attr(path);
let html = format!(
r#"<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="robots" content="noindex,follow" />
<title>Page not found - Perfect Postcode</title>
<meta name="description" content="This Perfect Postcode page could not be found." />
<link rel="canonical" href="{public_url_e}/" />
<style>
:root {{ color-scheme: dark; }}
* {{ box-sizing: border-box; }}
body {{
margin: 0;
min-height: 100vh;
display: flex;
align-items: center;
justify-content: center;
background: #0b1220;
color: #e7ecf3;
font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
text-align: center;
padding: 24px;
}}
main {{ max-width: 32rem; }}
.brand {{ font-weight: 700; letter-spacing: .01em; color: #2dd4bf; font-size: 1.1rem; margin-bottom: 1.5rem; }}
h1 {{ font-size: 2rem; margin: 0 0 .5rem; }}
p {{ color: #9fb0c3; line-height: 1.6; margin: .5rem 0; }}
code {{ color: #cbd5e1; background: rgba(148,163,184,.15); padding: .1rem .35rem; border-radius: .25rem; word-break: break-all; }}
a.cta {{
display: inline-block;
margin-top: 1.5rem;
padding: .65rem 1.25rem;
border-radius: .5rem;
background: #2dd4bf;
color: #0b1220;
font-weight: 600;
text-decoration: none;
}}
a.cta:hover {{ background: #5eead4; }}
</style>
</head>
<body>
<main>
<div class="brand">Perfect Postcode</div>
<h1>Page not found</h1>
<p>We couldn&#39;t find <code>{path_e}</code>.</p>
<p>It may have moved, or the link might be incomplete.</p>
<a class="cta" href="{public_url_e}/">Back to Perfect Postcode</a>
</main>
</body>
</html>"#
);
let mut response = Response::new(Body::from(html));
*response.status_mut() = StatusCode::NOT_FOUND;
response.headers_mut().insert(
header::CONTENT_TYPE,
header::HeaderValue::from_static("text/html; charset=utf-8"),
);
response
}
fn route_seo_tags(
page: &SeoPage,
path: &str,
query_string: &str,
public_url: &str,
language: &str,
) -> String {
let path_e = escape_attr(path);
let query_e = escape_attr(query_string);
// Generated data pages have a clean URL with no query, but their OG card must frame the finding's
// map view rather than the default whole-England map. Use the registry's screenshot query.
let screenshot_query_base = match crate::generated_data_pages::data_page(trim_trailing_slash(path)) {
Some(dp) if !dp.screenshot_query.is_empty() => dp.screenshot_query,
_ => query_string,
};
let screenshot_query_string = query_string_with_language(screenshot_query_base, language);
let screenshot_query_e = escape_attr(&screenshot_query_string);
let public_url_e = escape_attr(public_url.trim_end_matches('/'));
let canonical_path_e = escape_attr(page.canonical_path);
let title_e = escape_attr(page.title);
let description_e = escape_attr(page.description);
let is_invite = path.starts_with("/invite/");
let og_image_url = if is_invite {
if screenshot_query_string.is_empty() {
format!("{public_url_e}/api/screenshot?og=1&amp;path={path_e}")
} else {
format!("{public_url_e}/api/screenshot?og=1&amp;path={path_e}&amp;{screenshot_query_e}")
}
} else if screenshot_query_string.is_empty() {
format!("{public_url_e}/api/screenshot?og=1")
} else {
format!("{public_url_e}/api/screenshot?og=1&amp;{screenshot_query_e}")
};
let canonical_url = format!("{public_url_e}{canonical_path_e}");
let og_url = if query_string.is_empty() {
format!("{public_url_e}{path_e}")
} else {
format!("{public_url_e}{path_e}?{query_e}")
};
let robots = if page.indexable {
"index,follow"
} else {
"noindex,follow"
};
// Emit hreflang alternates for indexable pages so search engines can serve
// the right localized variant (the SPA switches language via ?lang=).
let hreflang = if page.indexable {
let mut tags = String::new();
for lang in supported_languages() {
tags.push_str(&format!(
"\n <link rel=\"alternate\" hreflang=\"{lang}\" href=\"{public_url_e}{canonical_path_e}?lang={lang}\" />"
));
}
tags.push_str(&format!(
"\n <link rel=\"alternate\" hreflang=\"x-default\" href=\"{public_url_e}{canonical_path_e}\" />"
));
tags
} else {
String::new()
};
format!(
r#"<meta name="robots" content="{robots}" />
<link rel="canonical" href="{canonical_url}" />{hreflang}
<meta property="og:title" content="{title_e}" />
<meta property="og:description" content="{description_e}" />
<meta property="og:type" content="website" />
<meta property="og:url" content="{og_url}" />
<meta property="og:site_name" content="Perfect Postcode" />
<meta property="og:logo" content="{public_url_e}/favicon.svg" />
<meta property="og:image" content="{og_image_url}" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />
<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:title" content="{title_e}" />
<meta name="twitter:description" content="{description_e}" />
<meta name="twitter:image" content="{og_image_url}" />"#
)
}
fn inject_tags(mut html: String, page: &SeoPage, tags: &str) -> String {
if let Some(start) = html.find("<title>") {
if let Some(end_offset) = html[start..].find("</title>") {
let end = start + end_offset + "</title>".len();
html.replace_range(
start..end,
&format!("<title>{}</title>", escape_attr(page.title)),
);
}
}
if let Some(start) = html.find(r#"<meta name="description""#) {
if let Some(end_offset) = html[start..].find('>') {
let end = start + end_offset + 1;
html.replace_range(
start..end,
&format!(
r#"<meta name="description" content="{}" />"#,
escape_attr(page.description)
),
);
}
}
if html.contains(OG_PLACEHOLDER) {
return html.replace(OG_PLACEHOLDER, tags);
}
if let Some(index) = html.find("</head>") {
html.insert_str(index, tags);
}
html
}
fn escape_json_for_script_tag(json: &str) -> String {
json.replace('&', "\\u0026")
.replace('<', "\\u003c")
.replace('>', "\\u003e")
}
fn inject_bugsink_config(html: String, config: Option<&crate::bugsink::FrontendConfig>) -> String {
if !html.contains(BUGSINK_CONFIG_PLACEHOLDER) {
return html;
}
let json = config
.and_then(|config| serde_json::to_string(config).ok())
.unwrap_or_else(|| "{}".to_string());
html.replace(
BUGSINK_CONFIG_PLACEHOLDER,
&escape_json_for_script_tag(&json),
)
}
pub async fn og_middleware(request: Request, next: Next) -> Response {
let path = request.uri().path().to_string();
// Capture the query string before passing the request through
let query_string = request.uri().query().unwrap_or("").to_string();
let language = language_from_accept_language(
request
.headers()
.get(header::ACCEPT_LANGUAGE)
.and_then(|value| value.to_str().ok()),
);
// Get state from extensions
let state = request.extensions().get::<Arc<AppState>>().cloned();
if let Some(st) = &state {
if !st.is_dev && should_return_404(&path) {
return not_found_response(&st.public_url, &path);
}
}
let response = next.run(request).await;
// Only inject OG tags into SPA HTML responses, not proxied PocketBase responses
if path.starts_with("/pb/") || path.starts_with("/api/") || path.starts_with("/s/") {
return response;
}
let content_type = response
.headers()
.get(header::CONTENT_TYPE)
.and_then(|val| val.to_str().ok())
.unwrap_or("");
if !content_type.contains("text/html") {
return response;
}
let state = match state {
Some(st) => st,
None => return response,
};
let page = seo_page_for_path(&path);
if page.is_none() && state.bugsink_frontend_config.is_none() {
return response;
}
let (mut parts, body) = response.into_parts();
let bytes = match to_bytes(body, HTML_BODY_LIMIT).await {
Ok(bytes) => bytes,
Err(err) => {
warn!("Failed to buffer HTML body for SEO tag injection: {err}");
let mut response = Response::from_parts(parts, Body::empty());
*response.status_mut() = StatusCode::INTERNAL_SERVER_ERROR;
return response;
}
};
let html = String::from_utf8_lossy(&bytes).into_owned();
let mut html = inject_bugsink_config(html, state.bugsink_frontend_config.as_ref());
if let Some(page) = page {
let tags = route_seo_tags(&page, &path, &query_string, &state.public_url, language);
html = inject_tags(html, &page, &tags);
}
parts.headers.remove(header::CONTENT_LENGTH);
Response::from_parts(parts, Body::from(html))
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn legal_pages_resolve_and_are_not_404() {
for path in ["/terms", "/privacy", "/terms/", "/privacy/"] {
assert!(
seo_page_for_path(path).is_some(),
"{path} should resolve to an SEO page (legal pages must render, not 404)"
);
assert!(
!should_return_404(path),
"{path} must not return a server 404"
);
}
}
#[test]
fn unknown_paths_still_404() {
assert!(should_return_404("/definitely-not-a-real-page"));
}
#[test]
fn indexable_pages_emit_hreflang() {
let page = seo_page_for_path("/terms").expect("terms page");
let tags = route_seo_tags(&page, "/terms", "", "https://perfect-postcode.co.uk", "en");
assert!(tags.contains(r#"hreflang="x-default""#));
assert!(tags.contains(r#"hreflang="de""#));
}
#[test]
fn noindex_pages_omit_hreflang() {
let page = seo_page_for_path("/dashboard").expect("dashboard page");
let tags = route_seo_tags(
&page,
"/dashboard",
"",
"https://perfect-postcode.co.uk",
"en",
);
assert!(!tags.contains("hreflang"));
}
}