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Prevent Server Errors from Malformed URL Requests #915

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Prevent Server Errors from Malformed URL Requests #915

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11 changes: 11 additions & 0 deletions server/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,17 @@ app.use((req, res, next) => {
next()
})

// Ensure URL is properly encoded to prevent decoding errors and malformed requests
app.use((req, res, next) => {
try {
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Why don’t we use URL.canParse for this? https://developer.mozilla.org/en-US/docs/Web/API/URL/canParse_static

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ive tested both, URL.canParse returns true because it only checks if the URL is syntactically valid. It doesn’t validate percent-encoded sequences, so malformed encodings (e.g., %AD) pass even though decodeURIComponent would fail.

decodeURIComponent(req.url); // Validate the URL
next();
} catch (err) {
console.error('Malformed URL detected:', req.url);
return res.status(400).send('Bad Request: Malformed URL');
}
});

// no ending slashes for SEO reasons
// https://github.com/epicweb-dev/epic-stack/discussions/108
app.get('*', (req, res, next) => {
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