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fix: URL fallback chain in redirect handler #17

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Merged
onamfc merged 1 commit into from
Mar 16, 2026
Merged

fix: URL fallback chain in redirect handler #17

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29 changes: 18 additions & 11 deletions src/lib/utils.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -95,20 +95,27 @@ export function getLocationFromIP(ip: string) {
}

export function buildRedirectUrl(
originalUrl: string,
originalUrl: string | null | undefined,
utmParameters?: Record<string, string>
): string {
const url = new URL(originalUrl);
): string | null {
if (!originalUrl) return null;

if (utmParameters) {
Object.entries(utmParameters).forEach(([key, value]) => {
if (value) {
url.searchParams.set(`utm_${key}`, value);
}
});
}
try {
const url = new URL(originalUrl);

if (utmParameters) {
Object.entries(utmParameters).forEach(([key, value]) => {
if (value) {
url.searchParams.set(`utm_${key}`, value);
}
});
}

return url.toString();
return url.toString();
} catch {
// If URL is invalid, return it as-is rather than crashing
return originalUrl;
}
}

export function detectDevice(userAgent: string): 'ios' | 'android' | 'web' {
Expand Down
87 changes: 65 additions & 22 deletions src/routes/redirect.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -88,20 +88,27 @@ export async function redirectRoutes(fastify: FastifyInstance) {

if (templateSlug) {
// Template-based URL: verify both template and link match
// Also fetch template settings and org settings for URL fallback chain
query = `
SELECT l.* FROM links l
SELECT l.*, t.settings AS template_settings, o.settings AS org_settings
FROM links l
LEFT JOIN link_templates t ON l.template_id = t.id
LEFT JOIN organizations o ON l.organization_id = o.id
WHERE l.short_code = $1 AND t.slug = $2
AND l.is_active = true
AND (l.expires_at IS NULL OR l.expires_at > NOW())
`;
params = [shortCode, templateSlug];
} else {
// Legacy URL: just lookup by short code
// Also fetch template settings and org settings for URL fallback chain
query = `
SELECT * FROM links
WHERE short_code = $1 AND is_active = true
AND (expires_at IS NULL OR expires_at > NOW())
SELECT l.*, t.settings AS template_settings, o.settings AS org_settings
FROM links l
LEFT JOIN link_templates t ON l.template_id = t.id
LEFT JOIN organizations o ON l.organization_id = o.id
WHERE l.short_code = $1 AND l.is_active = true
AND (l.expires_at IS NULL OR l.expires_at > NOW())
`;
params = [shortCode];
}
Expand Down Expand Up @@ -240,6 +247,14 @@ export async function redirectRoutes(fastify: FastifyInstance) {
await storeFingerprintForClick(clickId, fingerprintData);

// Determine redirect URL for event emission (using same logic as main redirect)
// Use the same fallback chain: link → template → workspace
const tplSettings = link.template_settings || {};
const oSettings = link.org_settings || {};
const oAppConfig = oSettings.appConfig || {};
const iosStoreUrl = link.ios_app_store_url || tplSettings.defaultIosUrl || oAppConfig.iosAppStoreUrl || null;
const androidStoreUrl = link.android_app_store_url || tplSettings.defaultAndroidUrl || oAppConfig.androidAppStoreUrl || null;
const webFallback = link.web_fallback_url || tplSettings.defaultWebFallbackUrl || oAppConfig.webFallbackUrl || null;

let redirectUrl = link.original_url;
let redirectReason = 'original_url';

Expand All @@ -250,9 +265,12 @@ export async function redirectRoutes(fastify: FastifyInstance) {
} else if (link.app_scheme && link.deep_link_path) {
redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
redirectReason = 'app_scheme';
} else if (link.ios_app_store_url) {
redirectUrl = link.ios_app_store_url;
} else if (iosStoreUrl) {
redirectUrl = iosStoreUrl;
redirectReason = 'ios_app_store_url';
} else if (webFallback) {
redirectUrl = webFallback;
redirectReason = 'web_fallback_url';
}
} else if (deviceType === 'android') {
if (link.android_app_link) {
Expand All @@ -261,16 +279,19 @@ export async function redirectRoutes(fastify: FastifyInstance) {
} else if (link.app_scheme && link.deep_link_path) {
redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
redirectReason = 'app_scheme';
} else if (link.android_app_store_url) {
redirectUrl = link.android_app_store_url;
} else if (androidStoreUrl) {
redirectUrl = androidStoreUrl;
redirectReason = 'android_app_store_url';
} else if (webFallback) {
redirectUrl = webFallback;
redirectReason = 'web_fallback_url';
}
} else if (deviceType === 'web' && link.web_fallback_url) {
redirectUrl = link.web_fallback_url;
} else if (deviceType === 'web' && webFallback) {
redirectUrl = webFallback;
redirectReason = 'web_fallback_url';
}

const finalRedirectUrl = buildRedirectUrl(redirectUrl, link.utm_parameters);
const finalRedirectUrl = buildRedirectUrl(redirectUrl, link.utm_parameters) || redirectUrl;

// Emit click event for real-time streaming to WebSocket clients
emitClickEvent({
Expand Down Expand Up @@ -342,57 +363,79 @@ export async function redirectRoutes(fastify: FastifyInstance) {
});

// Determine redirect URL based on device with smart fallback chain
// Fallback chain: link URLs → template default URLs → workspace settings URLs
const userAgent = request.headers['user-agent'] || '';
const device = detectDevice(userAgent);

// Extract fallback URLs from template settings and org settings
const templateSettings = link.template_settings || {};
const orgSettings = link.org_settings || {};
const orgAppConfig = orgSettings.appConfig || {};

// Resolve platform URLs with fallback chain: link → template → workspace
const iosUrl = link.ios_app_store_url || templateSettings.defaultIosUrl || orgAppConfig.iosAppStoreUrl || null;
const androidUrl = link.android_app_store_url || templateSettings.defaultAndroidUrl || orgAppConfig.androidAppStoreUrl || null;
const webFallbackUrl = link.web_fallback_url || templateSettings.defaultWebFallbackUrl || orgAppConfig.webFallbackUrl || null;

let redirectUrl = link.original_url;
let useSchemeUrl = false; // Track if we're using a URI scheme URL

if (device === 'ios') {
// iOS Priority:
// 1. Universal Link (HTTPS URL with AASA file) - if app installed, opens app
// 2. URI scheme (myapp://path) - fallback when Universal Links fail
// 3. App Store URL - for users who don't have the app
// 4. Original URL - ultimate fallback
// 3. App Store URL (link → template → workspace) - for users who don't have the app
// 4. Web fallback URL - browser-based fallback
// 5. Original URL - ultimate fallback

if (link.ios_universal_link) {
redirectUrl = link.ios_universal_link;
} else if (link.app_scheme && link.deep_link_path) {
// Build URI scheme URL: myapp://product/123
redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
useSchemeUrl = true;
} else if (link.ios_app_store_url) {
redirectUrl = link.ios_app_store_url;
} else if (iosUrl) {
redirectUrl = iosUrl;
} else if (webFallbackUrl) {
redirectUrl = webFallbackUrl;
}

} else if (device === 'android') {
// Android Priority:
// 1. App Link (HTTPS URL with Digital Asset Links) - if app installed, opens app
// 2. URI scheme (myapp://path) - fallback when App Links fail
// 3. Play Store URL - for users who don't have the app
// 4. Original URL - ultimate fallback
// 3. Play Store URL (link → template → workspace) - for users who don't have the app
// 4. Web fallback URL - browser-based fallback
// 5. Original URL - ultimate fallback

if (link.android_app_link) {
redirectUrl = link.android_app_link;
} else if (link.app_scheme && link.deep_link_path) {
// Build URI scheme URL: myapp://product/123
redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
useSchemeUrl = true;
} else if (link.android_app_store_url) {
redirectUrl = link.android_app_store_url;
} else if (androidUrl) {
redirectUrl = androidUrl;
} else if (webFallbackUrl) {
redirectUrl = webFallbackUrl;
}

} else if (device === 'web') {
// Web fallback
redirectUrl = link.web_fallback_url || link.original_url;
redirectUrl = webFallbackUrl || link.original_url;
}

// If no URL found at all, return a user-friendly error
if (!redirectUrl) {
return reply.status(404).send({ error: 'No destination URL configured for this link' });
}

// Build final URL with parameters
let finalUrl = redirectUrl;

if (!useSchemeUrl) {
// For HTTP(S) URLs, add UTM parameters
finalUrl = buildRedirectUrl(redirectUrl, link.utm_parameters);
finalUrl = buildRedirectUrl(redirectUrl, link.utm_parameters) || redirectUrl;

// Add deep link parameters as query params
if (link.deep_link_parameters && Object.keys(link.deep_link_parameters).length > 0) {
Expand Down Expand Up @@ -435,7 +478,7 @@ export async function redirectRoutes(fastify: FastifyInstance) {
fullSchemeUrl += (fullSchemeUrl.includes('?') ? '&' : '?') + params.toString();
}

const storeFallback = link.ios_app_store_url || link.web_fallback_url || link.original_url;
const storeFallback = iosUrl || webFallbackUrl || link.original_url;
return reply
.header('Content-Type', 'text/html; charset=utf-8')
.send(generateInterstitialHTML(fullSchemeUrl, storeFallback, link.title || link.og_title));
Expand Down
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