The supporter email's button opens a page on the site

tools/kofi-worker/email.js

@@ -25,9 +25,13 @@ export function codeLines(code) {
   return lines.map((line, index) => (index < lines.length - 1 ? `${line}-` : line))
 }
 
-/** Folio's own link for a code (RedeemActivity, since 0.6.5): on an Android phone with Folio it adds the code in one tap. */
+/**
+ * The link in the email: a page on the site that shows the code and, on Android, opens Folio's own redeem link
+ * (folio://redeem, handled by RedeemActivity since 0.6.5). The email cannot link to folio:// itself, because Gmail does
+ * nothing with a custom scheme. The code sits after the #, so a browser never sends it to a server.
+ */
 export function redeemLink(code) {
-  return `folio://redeem?c=${encodeURIComponent(String(code))}`
+  return `https://foliolauncher.com/redeem/#${encodeURIComponent(String(code))}`
 }
 
 const SUBJECT = 'Your Folio supporter code'
@@ -44,7 +48,7 @@ export function supporterEmail({ name = '', code, pool = '' }) {
     '',
     `    ${code}`,
     '',
-    'On your Android phone, this link adds it in one tap:',
+    'On your Android phone, this link opens a page that adds it to Folio:',
     `    ${redeemLink(code)}`,
     '',
     'In Folio: Settings › Supporter › Redeem a Code, and paste it in. It is checked on your phone, so it works',
@@ -109,10 +113,10 @@ export function supporterEmail({ name = '', code, pool = '' }) {
         <tr><td class="pad" style="padding:20px 32px 0">
           <table role="presentation" cellpadding="0" cellspacing="0" border="0" width="100%"><tr>
             <td class="btn" align="center" bgcolor="${TEAL}" style="background:${TEAL};border-radius:12px">
-              <a href="${link}" class="btntext" style="display:block;padding:15px 22px;font:600 16px/1.2 ${font};color:#ffffff;text-decoration:none">Open in Folio</a>
+              <a href="${link}" class="btntext" style="display:block;padding:15px 22px;font:600 16px/1.2 ${font};color:#ffffff;text-decoration:none">Add to Folio</a>
             </td>
           </tr></table>
-          <p class="dim" style="margin:10px 0 0;font:400 13px/1.5 ${font};color:#6c6c70;text-align:center">On your Android phone, this adds the code in one tap.</p>
+          <p class="dim" style="margin:10px 0 0;font:400 13px/1.5 ${font};color:#6c6c70;text-align:center">Opens a page that adds the code in Folio on your Android phone.</p>
         </td></tr>
         <tr><td class="pad" style="padding:22px 32px 4px">
           <p class="ink" style="margin:0 0 14px;font:400 16px/1.55 ${font};color:#1c1c1e">In Folio: <span class="path" style="background:#f2f2f7;color:#1c1c1e;border-radius:6px;padding:2px 7px;font-weight:600;white-space:nowrap">Settings › Supporter › Redeem a Code</span>, and paste it in. It is checked on your phone, so it works offline and tells nobody that you supported.</p>

tools/kofi-worker/email.test.mjs

@@ -1,6 +1,6 @@
 /**
  * The supporter email: McCal's words kept as written, the HTML safe to build from a name anyone can type on Ko-fi, and
- * the "Open in Folio" link in the exact shape RedeemActivity (app/.../RedeemActivity.kt, since 0.6.5) accepts.
+ * the button's link to the redeem page on foliolauncher.com, which hands the code to Folio's RedeemActivity.
  * Run with `node --test email.test.mjs`; no network.
  */
 import assert from 'node:assert/strict'
@@ -53,14 +53,15 @@ test('the HTML has no script, no javascript: link, and reaches out to nowhere bu
   for (const line of codeLines(CODE)) assert.ok(html.includes(line))
 })
 
-test('the Open in Folio link is the one RedeemActivity reads', () => {
+test('the button opens the redeem page on the site, with the code after the # so it never reaches a server', () => {
   const link = redeemLink(CODE)
-  assert.equal(link, `folio://redeem?c=${CODE}`)
-  assert.ok(supporterEmail({ code: CODE, pool: 'm1' }).html.includes(`href="${link}"`))
-  assert.ok(supporterEmail({ code: CODE, pool: 'm1' }).text.includes(link))
-  // The app's redeemCode(): the prefix, a c= parameter, and 20 to 200 letters, digits and hyphens.
-  const query = link.slice('folio://redeem'.length).split('?')[1]
-  const code = decodeURIComponent(query.split('&').find((p) => p.startsWith('c=')).slice(2))
-  assert.ok(code.length >= 20 && code.length <= 200 && /^[A-Za-z0-9-]+$/.test(code))
-  assert.equal(code, CODE)
+  assert.equal(link, `https://foliolauncher.com/redeem/#${CODE}`)
+  const { html, text } = supporterEmail({ code: CODE, pool: 'm1' })
+  assert.ok(html.includes(`href="${link}"`))
+  assert.ok(text.includes(link))
+  assert.ok(!html.includes('folio://') && !text.includes('folio://'), 'Gmail does nothing with a custom scheme')
+  // The page (folio-site public/redeem.js) takes letters, digits and hyphens, 20 to 200 of them, from the fragment.
+  const fragment = decodeURIComponent(link.split('#')[1])
+  assert.ok(/^[A-Za-z0-9-]{20,200}$/.test(fragment))
+  assert.equal(fragment, CODE)
 })

tools/kofi-worker/worker.test.mjs

@@ -198,6 +198,6 @@ test('the email goes to Resend as both HTML and plain text, with the link and th
   assert.equal(body.reply_to, 'me@example.com')
   assert.equal(body.subject, 'Your Folio supporter code')
   assert.ok(body.text.includes('CODE-1') && body.html.includes('CODE-1'))
-  assert.ok(body.html.includes('href="folio://redeem?c=CODE-1"'))
+  assert.ok(body.html.includes('href="https://foliolauncher.com/redeem/#CODE-1"'))
   assert.equal(DB.handled.get('m1').emailed, 1)
 })