{"data":[{"id":106417,"title":"ENABLE.AUTO.COMMIT: NGH\u1ec6 THU\u1eacT X\u00c1C NH\u1eacN TIN NH\u1eaeN TRONG KAFKA","slug":"yZJZlzobVjm","url":"https:\/\/viblo.asia\/p\/enableautocommit-nghe-thuat-xac-nhan-tin-nhan-trong-kafka-yZJZlzobVjm","user_id":182653,"moderation":null,"transliterated":"enableautocommit-nghe-thuat-xac-nhan-tin-nhan-trong-kafka","contents_short":"Trong ng\u00e0nh c\u00f4ng nghi\u1ec7p x\u1eed l\u00fd s\u1ef1 ki\u1ec7n b\u1ea5t \u0111\u1ed3ng b\u1ed9 v\u1edbi Apache Kafka, c\u1ea5u h\u00ecnh l\u00e0 y\u1ebfu t\u1ed1 s\u1ed1ng c\u00f2n quy\u1ebft \u0111\u1ecbnh li\u1ec7u h\u1ec7 th\u1ed1ng c\u1ee7a b\u1ea1n c\u00f3 ch\u1ea1y m\u01b0\u1ee3t m\u00e0 hay s\u1ebd \u00e2m th\u1ea7m nu\u1ed1t ch\u1eedng d\u1eef li\u1ec7u c\u1ee7a ng\u01b0\u1eddi d\u00f9ng. D\u00f2ng c\u1ea5u h\u00ecnh nh\u1ecf g\u1ecdn:\n\nTh\u01b0\u1eddng xu\u1ea5t hi\u1ec7n trong c\u00e1c file config Kafka c\u1ee7a Laravel (nh\u01b0 config\/kafka.php), \u0111\u00e2y ch\u00ednh l\u00e0 n\u00fat b\u1ea5m quy\u1ec1n l\u1ef1c quy\u1ebft \u0111\u1ecbnh c\u01a1 ch\u1ebf \"t\u1ef1 \u0111\u1ed9ng x\u00e1c nh\u1eadn\" hay \"t\u1ef1 ki\u1ec3m so\u00e1t\" ti\u1ebfn tr\u00ecnh...","contents":"Trong ng\u00e0nh c\u00f4ng nghi\u1ec7p x\u1eed l\u00fd s\u1ef1 ki\u1ec7n b\u1ea5t \u0111\u1ed3ng b\u1ed9 v\u1edbi Apache Kafka, c\u1ea5u h\u00ecnh l\u00e0 y\u1ebfu t\u1ed1 s\u1ed1ng c\u00f2n quy\u1ebft \u0111\u1ecbnh li\u1ec7u h\u1ec7 th\u1ed1ng c\u1ee7a b\u1ea1n c\u00f3 ch\u1ea1y m\u01b0\u1ee3t m\u00e0 hay s\u1ebd \u00e2m th\u1ea7m nu\u1ed1t ch\u1eedng d\u1eef li\u1ec7u c\u1ee7a ng\u01b0\u1eddi d\u00f9ng. D\u00f2ng c\u1ea5u h\u00ecnh nh\u1ecf g\u1ecdn:\n\n```php\n'enable.auto.commit' => env('AUTO_COMMIT', true),\n```\n\nTh\u01b0\u1eddng xu\u1ea5t hi\u1ec7n trong c\u00e1c file config Kafka c\u1ee7a Laravel (nh\u01b0 `config\/kafka.php`), \u0111\u00e2y ch\u00ednh l\u00e0 n\u00fat b\u1ea5m quy\u1ec1n l\u1ef1c quy\u1ebft \u0111\u1ecbnh c\u01a1 ch\u1ebf \"t\u1ef1 \u0111\u1ed9ng x\u00e1c nh\u1eadn\" hay \"t\u1ef1 ki\u1ec3m so\u00e1t\" ti\u1ebfn tr\u00ecnh \u0111\u1ecdc tin nh\u1eafn.\n\nD\u01b0\u1edbi \u0111\u00e2y l\u00e0 b\u00e0i vi\u1ebft m\u1ed5 x\u1ebb chi ti\u1ebft b\u1ea3n ch\u1ea5t v\u00e0 c\u1ea1m b\u1eaby \u0111\u1eb1ng sau d\u00f2ng c\u1ea5u h\u00ecnh n\u00e0y.\n\n---\n\n## 1. B\u1ea3n Ch\u1ea5t C\u1ee7a Offset V\u00e0 C\u01a1 Ch\u1ebf Commit L\u00e0 G\u00ec?\n\n\u0110\u1ec3 hi\u1ec3u `enable.auto.commit`, tr\u01b0\u1edbc h\u1ebft b\u1ea1n ph\u1ea3i hi\u1ec3u c\u00e1ch Kafka qu\u1ea3n l\u00fd ti\u1ebfn \u0111\u1ed9 \u0111\u1ecdc tin nh\u1eafn:\n\n* M\u1ed7i tin nh\u1eafn trong m\u1ed9t Partition c\u1ee7a Kafka \u0111\u1ec1u g\u1eafn li\u1ec1n v\u1edbi m\u1ed9t con s\u1ed1 th\u1ee9 t\u1ef1 g\u1ecdi l\u00e0 **Offset** (v\u00ed d\u1ee5: `0, 1, 2, 3...`).\n* **Commit** ch\u00ednh l\u00e0 h\u00e0nh \u0111\u1ed9ng m\u00e0 Consumer b\u00e1o cho Kafka Broker bi\u1ebft r\u1eb1ng: *\"Tao \u0111\u00e3 \u0111\u1ecdc v\u00e0 x\u1eed l\u00fd xong \u0111\u1ebfn c\u00e1i Offset s\u1ed1 X n\u00e0y r\u1ed3i nh\u00e9, l\u1ea7n sau \u0111\u1eebng g\u1eedi l\u1ea1i n\u1eefa\"*.\n\n---\n\n## 2. Hai Th\u00e1i C\u1ef1c: `true` (Auto) v\u00e0 `false` (Manual)\n\nD\u00f2ng c\u1ea5u h\u00ecnh tr\u00ean cho ph\u00e9p b\u1ea1n chuy\u1ec3n \u0111\u1ed5i gi\u1eefa hai tr\u01b0\u1eddng ph\u00e1i v\u1eadn h\u00e0nh ho\u00e0n to\u00e0n tr\u00e1i ng\u01b0\u1ee3c nhau:\n\n### A. Khi \u0111\u1ec3 `true` (M\u1eb7c \u0111\u1ecbnh - Auto Commit)\n\nKhi `enable.auto.commit` \u0111\u01b0\u1ee3c b\u1eadt l\u00e0 `true` (k\u1ebft h\u1ee3p v\u1edbi tham s\u1ed1 th\u1eddi gian `auto.commit.interval.ms`), Kafka Consumer s\u1ebd t\u1ef1 \u0111\u1ed9ng ng\u1ea7m \u0111\u1ecbnh g\u1eedi t\u00edn hi\u1ec7u x\u00e1c nh\u1eadn (commit) \u0111\u1ecbnh k\u1ef3 theo kho\u1ea3ng th\u1eddi gian (v\u00ed d\u1ee5 c\u1ee9 m\u1ed7i 5 gi\u00e2y m\u1ed9t l\u1ea7n) cho d\u00f9 code c\u1ee7a b\u1ea1n \u0111\u00e3 x\u1eed l\u00fd xong tin nh\u1eafn \u0111\u00f3 hay ch\u01b0a.\n\n* **\u01afu \u0111i\u1ec3m:** Ti\u1ec7n l\u1ee3i, c\u1ea5u h\u00ecnh nhanh g\u1ecdn, code kh\u00f4ng c\u1ea7n b\u1eadn t\u00e2m \u0111\u1ebfn vi\u1ec7c g\u1ecdi l\u1ec7nh l\u01b0u offset th\u1ee7 c\u00f4ng.\n* **\ud83d\udca5 C\u1ea1m b\u1eaby ch\u1ebft ng\u01b0\u1eddi (Data Loss \/ Ghost Processing):** Gi\u1ea3 s\u1eed Consumer v\u1eeba b\u1ed1c 100 tin nh\u1eafn t\u1eeb Kafka v\u1ec1 RAM. Ngay l\u1eadp t\u1ee9c, b\u1ed9 \u0111\u1ebfm th\u1eddi gian ch\u1ea1m m\u1ed1c 5 gi\u00e2y v\u00e0 Kafka t\u1ef1 \u0111\u1ed9ng th\u1ef1c hi\u1ec7n Auto-commit c\u00e1c Offset \u0111\u00f3. Nh\u01b0ng ng\u1eb7t m\u1ed9t n\u1ed7i, logic code b\u00ean trong \u0111ang x\u1eed l\u00fd \u0111\u1ebfn tin nh\u1eafn th\u1ee9 10 th\u00ec server b\u1ecb s\u1eadp ngu\u1ed3n (Crash)!\n * K\u1ebft qu\u1ea3: Kafka t\u01b0\u1edfng r\u1eb1ng to\u00e0n b\u1ed9 100 tin nh\u1eafn \u0111\u00e3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd xong xu\u00f4i, n\u00ean khi h\u1ec7 th\u1ed1ng kh\u1edfi \u0111\u1ed9ng l\u1ea1i, n\u00f3 b\u1ecf qua ho\u00e0n to\u00e0n 90 tin nh\u1eafn ch\u01b0a k\u1ecbp ch\u1ea1y. D\u1eef li\u1ec7u b\u1ed1c h\u01a1i trong im l\u1eb7ng!\n\n### B. Khi chuy\u1ec3n sang `false` (Manual Commit - Ki\u1ec3m so\u00e1t th\u1ee7 c\u00f4ng)\n\nKhi b\u1ea1n c\u1ea5u h\u00ecnh `'enable.auto.commit' => false`, quy\u1ec1n sinh s\u00e1t \u0111\u01b0\u1ee3c trao ho\u00e0n to\u00e0n l\u1ea1i cho l\u1eadp tr\u00ecnh vi\u00ean.\n\n* **C\u01a1 ch\u1ebf:** Consumer \u0111\u1ecdc tin nh\u1eafn $\\to$ Code ch\u1ea1y logic nghi\u1ec7p v\u1ee5 (l\u01b0u DB, g\u1ecdi API...) th\u00e0nh c\u00f4ng 100% $\\to$ Th\u1ee7 c\u00f4ng g\u1ecdi l\u1ec7nh `consumer->commit()`.\n* **\u01afu \u0111i\u1ec3m:** An to\u00e0n tuy\u1ec7t \u0111\u1ed1i. N\u1ebfu code b\u1ecb v\u0103ng l\u1ed7i \u1edf gi\u1eefa ch\u1eebng, l\u1ec7nh commit kh\u00f4ng \u0111\u01b0\u1ee3c g\u1ecdi, Kafka s\u1ebd hi\u1ec3u l\u00e0 tin nh\u1eafn ch\u01b0a \u0111\u01b0\u1ee3c x\u1eed l\u00fd v\u00e0 t\u1ef1 \u0111\u1ed9ng ph\u00e2n ph\u00e1t l\u1ea1i cho m\u1ed9t Worker kh\u00e1c v\u00e0o l\u1ea7n sau (\u0110\u1ea3m b\u1ea3o nguy\u00ean t\u1eafc *At-least-once delivery*).\n\n---\n\n## 3. \u00dd Ngh\u0129a C\u1ee7a Vi\u1ec7c \u0110\u01b0a V\u00e0o Bi\u1ebfn M\u00f4i Tr\u01b0\u1eddng (`env`)\n\nT\u1ea1i sao trong \u0111o\u1ea1n code m\u1eabu l\u1ea1i d\u00f9ng h\u00e0m `env('AUTO_COMMIT', true)` thay v\u00ec g\u00e1n c\u1ee9ng ch\u1eef `true` tr\u1ef1c ti\u1ebfp?\n\n\u0110\u00e2y l\u00e0 t\u01b0 duy thi\u1ebft k\u1ebf c\u1ea5u h\u00ecnh linh ho\u1ea1t theo t\u1eebng m\u00f4i tr\u01b0\u1eddng (*Environment-based Configuration*):\n\n* **M\u00f4i tr\u01b0\u1eddng Local \/ Development:** \u0110\u1ec3 gi\u00e1 tr\u1ecb m\u1eb7c \u0111\u1ecbnh l\u00e0 `true`. L\u00fac n\u00e0y b\u1ea1n vi\u1ebft code nhanh, kh\u00f4ng c\u1ea7n b\u1eadn t\u00e2m \u0111\u1ebfn vi\u1ec7c qu\u1ea3n l\u00fd offset th\u1ee7 c\u00f4ng cho c\u00e1c b\u00e0i test nh\u1eb9 nh\u00e0ng.\n* **M\u00f4i tr\u01b0\u1eddng Production (H\u1ec7 th\u1ed1ng t\u00e0i ch\u00ednh, \u0111\u01a1n h\u00e0ng, thanh to\u00e1n):** B\u1ea1n ch\u1ee7 \u0111\u1ed9ng c\u1ea5u h\u00ecnh trong file `.env` th\u00e0nh `AUTO_COMMIT=false`, bu\u1ed9c h\u1ec7 th\u1ed1ng ph\u1ea3i b\u1eadt ch\u1ebf \u0111\u1ed9 Manual Commit \u0111\u1ec3 b\u1ea3o v\u1ec7 t\u1eebng \u0111\u1ed3ng d\u1eef li\u1ec7u c\u1ee7a kh\u00e1ch h\u00e0ng kh\u1ecfi m\u1ecdi s\u1ef1 c\u1ed1 s\u1eadp ngu\u1ed3n b\u1ea5t ng\u1edd.\n\n---\n\n## 4. B\u1ea3ng So S\u00e1nh Nhanh Cho K\u1ef9 S\u01b0\n\n| Ti\u00eau ch\u00ed | `AUTO_COMMIT = true` | `AUTO_COMMIT = false` |\n| :--- | :--- | :--- |\n| **M\u1ee9c \u0111\u1ed9 an to\u00e0n** | Th\u1ea5p (D\u1ec5 m\u1ea5t d\u1eef li\u1ec7u khi \u1ee9ng d\u1ee5ng crash). | **Cao tuy\u1ec7t \u0111\u1ed1i** (X\u1eed l\u00fd xong m\u1edbi x\u00e1c nh\u1eadn). |\n| **\u0110\u1ed9 ph\u1ee9c t\u1ea1p code** | \u0110\u01a1n gi\u1ea3n, kh\u00f4ng c\u1ea7n g\u1ecdi l\u1ec7nh commit th\u1ee7 c\u00f4ng. | Ph\u1ee9c t\u1ea1p h\u01a1n m\u1ed9t ch\u00fat (Ph\u1ea3i ch\u1ee7 \u0111\u1ed9ng g\u1ecdi l\u1ec7nh l\u01b0u offset). |\n| **Hi\u1ec7u n\u0103ng (Performance)** | Nh\u1ec9nh h\u01a1n m\u1ed9t ch\u00fat v\u00ec ch\u1ea1y ng\u1ea7m t\u1ef1 \u0111\u1ed9ng. | C\u1ea7n tinh ch\u1ec9nh th\u1eddi gian g\u1ecdi commit \u0111\u1ec3 t\u1ed1i \u01b0u I\/O. |\n| **Khuy\u00ean d\u00f9ng cho** | C\u00e1c h\u1ec7 th\u1ed1ng log l\u1eb7t v\u1eb7t, notification kh\u00f4ng quan tr\u1ecdng. | H\u1ec7 th\u1ed1ng c\u1ed1t l\u00f5i: Thanh to\u00e1n, \u0110\u01a1n h\u00e0ng, Kho v\u1eadn. |\n\n---\n\n## \ud83d\udca1 L\u1eddi K\u1ebft\n\nM\u1ed9t d\u00f2ng c\u1ea5u h\u00ecnh nh\u1ecf nh\u01b0 `'enable.auto.commit' => env('AUTO_COMMIT', true)` \u1ea9n ch\u1ee9a l\u1eb1n ranh gi\u1edbi gi\u1eefa s\u1ef1 ti\u1ec7n l\u1ee3i v\u00e0 t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u. Hi\u1ec3u r\u00f5 b\u1ea3n ch\u1ea5t c\u1ee7a n\u00f3 gi\u00fap b\u1ea1n ch\u1ee7 \u0111\u1ed9ng \u0111\u01b0a ra l\u1ef1a ch\u1ecdn ch\u00ednh x\u00e1c: Khi n\u00e0o n\u00ean \u0111\u00e1nh \u0111\u1ed5i s\u1ef1 an to\u00e0n l\u1ea5y t\u1ed1c \u0111\u1ed9, v\u00e0 khi n\u00e0o b\u1eaft bu\u1ed9c ph\u1ea3i si\u1ebft ch\u1eb7t k\u1ef7 lu\u1eadt x\u1eed l\u00fd tin nh\u1eafn trong h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n c\u1ee7a m\u00ecnh.","published_at":"2026-10-03T17:53:57.000000Z","scheduled_publish_at":null,"is_published":true,"is_shared":false,"updated_at":"2026-10-03T21:00:14.000000Z","edited_at":"2026-09-08T15:49:00.000000Z","translation_source":null,"trend_at":null,"promoted_at":null,"reading_time":5,"points":0,"views_count":7,"clips_count":0,"comments_count":0,"rated_value":null,"promoted":false,"trending":false,"is_draft":false,"is_public":true,"locale_code":"vi","is_video":false,"thumbnail_url":"https:\/\/images.viblo.asia\/263f0f96-a300-40a3-8a96-6b1d1724f819.png","user":{"data":{"id":182653,"url":"https:\/\/viblo.asia\/u\/hhoang","avatar":"7b8975e5-ecec-4eda-ba88-dd56fe2a29c0.jpg","name":"Huy Ho\u00e0ng","username":"hhoang","followers_count":182,"reputation":13592,"posts_count":1376,"banned_at":null,"level_partner":null,"following":false}},"tags":{"data":[{"slug":"apache-kafka","name":"apache kafka"}]},"commentators":{"data":[]}},{"id":106029,"title":"EzCode # B\u00e0i 21 \u2014 T\u00edch h\u1ee3p thanh to\u00e1n VNPay","slug":"R5JRQ3DD4Gv","url":"https:\/\/viblo.asia\/p\/ezcode-bai-21-tich-hop-thanh-toan-vnpay-R5JRQ3DD4Gv","user_id":184792,"moderation":null,"transliterated":"ezcode-bai-21-tich-hop-thanh-toan-vnpay","contents_short":"B\u00e0i 21 \u2014 T\u00edch h\u1ee3p thanh to\u00e1n VNPay\n\nH\u1ecdc xong b\u00e0i n\u00e0y b\u1ea1n s\u1ebd:\n- Hi\u1ec3u lu\u1ed3ng thanh to\u00e1n qua c\u1ed5ng trung gian v\u00e0 v\u00ec sao ph\u1ea3i c\u00f3 ch\u1eef k\u00fd\n- T\u1ea1o ch\u1eef k\u00fd HMAC-SHA512 v\u00e0 x\u00e1c th\u1ef1c callback t\u1eeb VNPay\n- Ho\u00e0n thi\u1ec7n ch\u1ee9c n\u0103ng mua kh\u00f3a h\u1ecdc v\u00e0 l\u1ecbch s\u1eed giao d\u1ecbch\nC\u1ea7n h\u1ecdc tr\u01b0\u1edbc: B\u00e0i 16, B\u00e0i 18\n\n1. V\u1ea5n \u0111\u1ec1 \u0111\u1eb7t ra\n\nH\u1ecdc vi\u00ean b\u1ea5m \"\u0110\u0103ng k\u00fd ngay\" tr\u00ean trang chi ti\u1ebft kh\u00f3a h\u1ecdc. Website ph\u1ea3i thu ti\u1ec1n r\u1ed3i m\u1edbi cho h\u1ecdc.\n\nNh\u01b0ng we...","contents":"# B\u00e0i 21 \u2014 T\u00edch h\u1ee3p thanh to\u00e1n VNPay\n\n> **H\u1ecdc xong b\u00e0i n\u00e0y b\u1ea1n s\u1ebd:**\n> - Hi\u1ec3u lu\u1ed3ng thanh to\u00e1n qua c\u1ed5ng trung gian v\u00e0 v\u00ec sao ph\u1ea3i c\u00f3 ch\u1eef k\u00fd\n> - T\u1ea1o ch\u1eef k\u00fd HMAC-SHA512 v\u00e0 x\u00e1c th\u1ef1c callback t\u1eeb VNPay\n> - Ho\u00e0n thi\u1ec7n ch\u1ee9c n\u0103ng mua kh\u00f3a h\u1ecdc v\u00e0 l\u1ecbch s\u1eed giao d\u1ecbch\n>\n> **C\u1ea7n h\u1ecdc tr\u01b0\u1edbc:** [B\u00e0i 16](bai-16-trang-ca-nhan-va-trang-vao-hoc.md), [B\u00e0i 18](bai-18-crud-khoa-hoc-va-upload-anh.md)\n\n---\n\n## 1. V\u1ea5n \u0111\u1ec1 \u0111\u1eb7t ra\n\nH\u1ecdc vi\u00ean b\u1ea5m \"\u0110\u0103ng k\u00fd ngay\" tr\u00ean trang chi ti\u1ebft kh\u00f3a h\u1ecdc. Website ph\u1ea3i thu ti\u1ec1n r\u1ed3i m\u1edbi cho h\u1ecdc.\n\nNh\u01b0ng website c\u1ee7a b\u1ea1n **kh\u00f4ng \u0111\u01b0\u1ee3c ph\u00e9p t\u1ef1 nh\u1eadn ti\u1ec1n**. Nh\u1eadn th\u1ebb ng\u00e2n h\u00e0ng \u0111\u00f2i ch\u1ee9ng ch\u1ec9 b\u1ea3o m\u1eadt, ki\u1ec3m \u0111\u1ecbnh, v\u00e0 tr\u00e1ch nhi\u1ec7m ph\u00e1p l\u00fd r\u1ea5t l\u1edbn. Kh\u00f4ng ai l\u00e0m m\u1ed9t m\u00ecnh.\n\nGi\u1ea3i ph\u00e1p l\u00e0 d\u00f9ng **c\u1ed5ng thanh to\u00e1n trung gian** nh\u01b0 VNPay: b\u1ea1n \u0111\u1ea9y ng\u01b0\u1eddi d\u00f9ng sang trang c\u1ee7a h\u1ecd, h\u1ecd x\u1eed l\u00fd ti\u1ec1n, r\u1ed3i b\u00e1o k\u1ebft qu\u1ea3 v\u1ec1.\n\n\u0110i\u1ec1u \u0111\u00f3 t\u1ea1o ra m\u1ed9t v\u1ea5n \u0111\u1ec1 m\u1edbi v\u00e0 r\u1ea5t th\u00fa v\u1ecb:\n\n> **VNPay b\u00e1o k\u1ebft qu\u1ea3 v\u1ec1 b\u1eb1ng c\u00e1ch g\u1ecdi l\u1ea1i m\u1ed9t \u0111\u1ecba ch\u1ec9 tr\u00ean website c\u1ee7a b\u1ea1n, k\u00e8m tham s\u1ed1 tr\u00ean URL. Nh\u01b0ng b\u1ea5t k\u1ef3 ai c\u0169ng g\u00f5 \u0111\u01b0\u1ee3c URL \u0111\u00f3.**\n\nK\u1ebb x\u1ea5u ch\u1ec9 c\u1ea7n g\u00f5 `?ctrl=payment&act=callback&vnp_ResponseCode=00&vnp_TxnRef=ORDER_123` l\u00e0 website t\u01b0\u1edfng h\u1ecd \u0111\u00e3 tr\u1ea3 ti\u1ec1n.\n\n**C\u00e1ch ch\u1ed1ng: ch\u1eef k\u00fd s\u1ed1.** B\u00e0i n\u00e0y d\u1ea1y b\u1ea1n c\u00e1ch n\u00f3 ho\u1ea1t \u0111\u1ed9ng.\n\n---\n\n## 2. Ki\u1ebfn th\u1ee9c m\u1edbi\n\n### 2.1. Lu\u1ed3ng thanh to\u00e1n b\u1ea3y b\u01b0\u1edbc\n\n1. **Ng\u01b0\u1eddi d\u00f9ng b\u1ea5m \"\u0110\u0103ng k\u00fd ngay\"** tr\u00ean trang chi ti\u1ebft kh\u00f3a h\u1ecdc.\n2. **Website t\u1ea1o m\u00e3 \u0111\u01a1n h\u00e0ng** v\u00e0 l\u01b0u m\u1ed9t d\u00f2ng v\u00e0o b\u1ea3ng `payments` v\u1edbi tr\u1ea1ng th\u00e1i `pending`.\n3. **Website d\u1ef1ng URL thanh to\u00e1n** ch\u1ee9a s\u1ed1 ti\u1ec1n, m\u00e3 \u0111\u01a1n, v\u00e0 **ch\u1eef k\u00fd** t\u00ednh t\u1eeb chu\u1ed7i b\u00ed m\u1eadt.\n4. **Chuy\u1ec3n h\u01b0\u1edbng ng\u01b0\u1eddi d\u00f9ng** sang trang VNPay.\n5. **Ng\u01b0\u1eddi d\u00f9ng tr\u1ea3 ti\u1ec1n** tr\u00ean trang VNPay. Website c\u1ee7a b\u1ea1n ho\u00e0n to\u00e0n kh\u00f4ng th\u1ea5y th\u00f4ng tin th\u1ebb.\n6. **VNPay g\u1ecdi l\u1ea1i `returnUrl`** k\u00e8m k\u1ebft qu\u1ea3 v\u00e0 m\u1ed9t ch\u1eef k\u00fd m\u1edbi.\n7. **Website x\u00e1c th\u1ef1c ch\u1eef k\u00fd.** \u0110\u00fang th\u00ec c\u1eadp nh\u1eadt `payments` th\u00e0nh `completed` v\u00e0 ghi m\u1ed9t d\u00f2ng v\u00e0o `enrollments` cho ng\u01b0\u1eddi d\u00f9ng \u0111\u01b0\u1ee3c h\u1ecdc.\n\nB\u01b0\u1edbc 3 v\u00e0 b\u01b0\u1edbc 7 l\u00e0 hai n\u1eeda c\u1ee7a c\u00f9ng m\u1ed9t c\u01a1 ch\u1ebf b\u1ea3o m\u1eadt.\n\n### 2.2. V\u00ec sao c\u1ea7n hai b\u1ea3ng `payments` v\u00e0 `enrollments`\n\nNh\u00ecn qua th\u00ec hai b\u1ea3ng n\u00e0y tr\u00f9ng l\u1eb7p \u2014 c\u1ea3 hai \u0111\u1ec1u ghi \"ai mua kh\u00f3a n\u00e0o\". Nh\u01b0ng ch\u00fang tr\u1ea3 l\u1eddi hai c\u00e2u h\u1ecfi kh\u00e1c nhau:\n\n| | `payments` | `enrollments` |\n|---|---|---|\n| Tr\u1ea3 l\u1eddi | \u0110\u00e3 c\u00f3 nh\u1eefng **giao d\u1ecbch** n\u00e0o | Ai \u0111\u01b0\u1ee3c **quy\u1ec1n h\u1ecdc** kh\u00f3a n\u00e0o |\n| Ghi khi n\u00e0o | Ngay khi b\u1eaft \u0111\u1ea7u thanh to\u00e1n | Ch\u1ec9 khi thanh to\u00e1n th\u00e0nh c\u00f4ng |\n| C\u00f3 tr\u1ea1ng th\u00e1i | `pending`, `completed`, `failed`, `cancelled` | Kh\u00f4ng |\n| M\u1ed9t ng\u01b0\u1eddi mua hai l\u1ea7n c\u00f9ng kh\u00f3a | Hai d\u00f2ng | Kh\u00f4ng th\u1ec3 \u2014 kh\u00f3a ch\u00ednh gh\u00e9p |\n\nM\u1ed9t giao d\u1ecbch th\u1ea5t b\u1ea1i \u0111\u1ec3 l\u1ea1i d\u00f2ng `payments` v\u1edbi `status = 'failed'` nh\u01b0ng **kh\u00f4ng** sinh d\u00f2ng `enrollments` n\u00e0o. Nh\u1edd v\u1eady b\u1ea1n v\u1eeba c\u00f3 l\u1ecbch s\u1eed \u0111\u1ea7y \u0111\u1ee7, v\u1eeba c\u00f3 danh s\u00e1ch quy\u1ec1n h\u1ecdc ch\u00ednh x\u00e1c.\n\n### 2.3. Ch\u1eef k\u00fd HMAC \u2014 c\u01a1 ch\u1ebf ch\u1ed1ng gi\u1ea3 m\u1ea1o\n\n**V\u1ea5n \u0111\u1ec1:** l\u00e0m sao bi\u1ebft d\u1eef li\u1ec7u tr\u00ean URL \u0111\u00fang l\u00e0 c\u1ee7a VNPay g\u1eedi, kh\u00f4ng ph\u1ea3i ai \u0111\u00f3 t\u1ef1 g\u00f5?\n\n**\u00dd t\u01b0\u1edfng:** hai b\u00ean c\u00f9ng bi\u1ebft m\u1ed9t **chu\u1ed7i b\u00ed m\u1eadt** m\u00e0 kh\u00f4ng ai kh\u00e1c bi\u1ebft. B\u00ean g\u1eedi d\u00f9ng n\u00f3 t\u00ednh ra m\u1ed9t m\u00e3 ki\u1ec3m tra t\u1eeb n\u1ed9i dung; b\u00ean nh\u1eadn t\u00ednh l\u1ea1i v\u00e0 so s\u00e1nh.\n\n```php\n$chuKy = hash_hmac('sha512', $chuoiDuLieu, $chuoiBiMat);\n```\n\nBa t\u00ednh ch\u1ea5t khi\u1ebfn n\u00f3 ho\u1ea1t \u0111\u1ed9ng:\n\n1. **\u0110\u1ed5i m\u1ed9t k\u00fd t\u1ef1 trong d\u1eef li\u1ec7u l\u00e0 ch\u1eef k\u00fd \u0111\u1ed5i ho\u00e0n to\u00e0n.** K\u1ebb x\u1ea5u kh\u00f4ng th\u1ec3 s\u1eeda s\u1ed1 ti\u1ec1n m\u00e0 gi\u1eef ch\u1eef k\u00fd c\u0169.\n2. **Kh\u00f4ng c\u00f3 chu\u1ed7i b\u00ed m\u1eadt th\u00ec kh\u00f4ng t\u00ednh \u0111\u01b0\u1ee3c ch\u1eef k\u00fd.** K\u1ebb x\u1ea5u bi\u1ebft c\u1ea3 thu\u1eadt to\u00e1n l\u1eabn d\u1eef li\u1ec7u v\u1eabn ch\u1ecbu.\n3. **Kh\u00f4ng th\u1ec3 suy ng\u01b0\u1ee3c ra chu\u1ed7i b\u00ed m\u1eadt** t\u1eeb ch\u1eef k\u00fd.\n\n`sha512` l\u00e0 thu\u1eadt to\u00e1n b\u0103m cho ra chu\u1ed7i 128 k\u00fd t\u1ef1 th\u1eadp l\u1ee5c ph\u00e2n.\n\n**Kh\u00e1c v\u1edbi `password_hash()` \u1edf B\u00e0i 14 th\u1ebf n\u00e0o?**\n\n| | `password_hash()` | `hash_hmac()` |\n|---|---|---|\n| M\u1ee5c \u0111\u00edch | L\u01b0u m\u1eadt kh\u1ea9u an to\u00e0n | X\u00e1c th\u1ef1c d\u1eef li\u1ec7u |\n| C\u00f3 mu\u1ed1i ng\u1eabu nhi\u00ean | C\u00f3 | Kh\u00f4ng |\n| C\u00f9ng \u0111\u1ea7u v\u00e0o cho c\u00f9ng \u0111\u1ea7u ra | Kh\u00f4ng | **C\u00f3** |\n| C\u1ea7n chu\u1ed7i b\u00ed m\u1eadt | Kh\u00f4ng | C\u00f3 |\n| T\u1ed1c \u0111\u1ed9 | **C\u1ed1 \u00fd ch\u1eadm** | Nhanh |\n\n\u0110i\u1ec3m th\u1ee9 ba l\u00e0 m\u1ea5u ch\u1ed1t: HMAC **ph\u1ea3i** cho c\u00f9ng k\u1ebft qu\u1ea3 v\u1edbi c\u00f9ng \u0111\u1ea7u v\u00e0o, n\u1ebfu kh\u00f4ng hai b\u00ean kh\u00f4ng so s\u00e1nh \u0111\u01b0\u1ee3c.\n\n### 2.4. `ksort()` \u2014 s\u1eafp x\u1ebfp \u0111\u1ec3 hai b\u00ean t\u00ednh gi\u1ed1ng nhau\n\n```php\nksort($inputData);\n```\n\n\u0110\u00e2y l\u00e0 chi ti\u1ebft d\u1ec5 b\u1ecf qua nh\u01b0ng b\u1eaft bu\u1ed9c.\n\nCh\u1eef k\u00fd \u0111\u01b0\u1ee3c t\u00ednh t\u1eeb m\u1ed9t **chu\u1ed7i** gh\u00e9p c\u00e1c tham s\u1ed1 l\u1ea1i. N\u1ebfu b\u1ea1n gh\u00e9p theo th\u1ee9 t\u1ef1 A, B, C m\u00e0 VNPay gh\u00e9p theo C, A, B, hai chu\u1ed7i kh\u00e1c nhau v\u00e0 hai ch\u1eef k\u00fd kh\u00e1c nhau \u2014 d\u00f9 d\u1eef li\u1ec7u gi\u1ed1ng h\u1ec7t.\n\n`ksort()` s\u1eafp x\u1ebfp m\u1ea3ng theo **kh\u00f3a** theo b\u1ea3ng ch\u1eef c\u00e1i. C\u1ea3 hai b\u00ean c\u00f9ng l\u00e0m v\u1eady th\u00ec lu\u00f4n ra c\u00f9ng m\u1ed9t th\u1ee9 t\u1ef1.\n\nK\u1ebft qu\u1ea3 sau `ksort`:\n\n```\nvnp_Amount, vnp_Command, vnp_CreateDate, vnp_CurrCode, vnp_IpAddr,\nvnp_Locale, vnp_OrderInfo, vnp_OrderType, vnp_ReturnUrl, vnp_TmnCode,\nvnp_TxnRef, vnp_Version\n```\n\n### 2.5. `urlencode()` \u2014 m\u00e3 h\u00f3a k\u00fd t\u1ef1 \u0111\u1eb7c bi\u1ec7t\n\n```php\n$hashdata .= urlencode($key) . \"=\" . urlencode($value);\n```\n\nT\u00ean kh\u00f3a h\u1ecdc c\u00f3 d\u1ea5u c\u00e1ch v\u00e0 d\u1ea5u ti\u1ebfng Vi\u1ec7t. URL kh\u00f4ng ch\u1ee9a \u0111\u01b0\u1ee3c nh\u1eefng k\u00fd t\u1ef1 \u0111\u00f3 tr\u1ef1c ti\u1ebfp.\n\n`urlencode()` \u0111\u1ed5i ch\u00fang th\u00e0nh m\u00e3 an to\u00e0n:\n\n| K\u00fd t\u1ef1 g\u1ed1c | Sau khi m\u00e3 h\u00f3a |\n|---|---|\n| d\u1ea5u c\u00e1ch | `+` |\n| `&` | `%26` |\n| `\u00f3` | `%C3%B3` |\n\nC\u1ea3 hai b\u00ean ph\u1ea3i m\u00e3 h\u00f3a gi\u1ed1ng nhau tr\u01b0\u1edbc khi t\u00ednh ch\u1eef k\u00fd, n\u1ebfu kh\u00f4ng k\u1ebft qu\u1ea3 l\u1ec7ch.\n\n### 2.6. Nh\u00e2n 100 s\u1ed1 ti\u1ec1n\n\n```php\n$vnp_Amount = $amount * 100;\n```\n\nVNPay t\u00ednh b\u1eb1ng **\u0111\u01a1n v\u1ecb nh\u1ecf nh\u1ea5t** c\u1ee7a ti\u1ec1n t\u1ec7. V\u1edbi \u0111\u1ed3ng Vi\u1ec7t Nam, quy \u01b0\u1edbc c\u1ee7a h\u1ecd l\u00e0 nh\u00e2n 100.\n\nKh\u00f3a h\u1ecdc 300.000\u0111 g\u1eedi \u0111i th\u00e0nh `30000000`.\n\n**Qu\u00ean nh\u00e2n 100 l\u00e0 kh\u00e1ch h\u00e0ng ch\u1ec9 tr\u1ea3 3.000\u0111.** \u0110\u00e2y l\u00e0 l\u1ed7i r\u1ea5t \u0111\u1eaft v\u00e0 r\u1ea5t hay g\u1eb7p khi t\u00edch h\u1ee3p c\u1ed5ng thanh to\u00e1n. Lu\u00f4n \u0111\u1ecdc k\u1ef9 t\u00e0i li\u1ec7u v\u1ec1 \u0111\u01a1n v\u1ecb ti\u1ec1n.\n\n### 2.7. B\u1ecf ch\u1eef k\u00fd ra tr\u01b0\u1edbc khi ki\u1ec3m tra l\u1ea1i\n\n```php\nif (isset($inputData['vnp_SecureHash'])) {\n $vnpSecureHash = $inputData['vnp_SecureHash'];\n unset($inputData['vnp_SecureHash']);\n}\n```\n\nKhi VNPay g\u1ecdi l\u1ea1i, URL ch\u1ee9a c\u1ea3 d\u1eef li\u1ec7u **l\u1eabn** ch\u1eef k\u00fd.\n\nMu\u1ed1n ki\u1ec3m tra, b\u1ea1n ph\u1ea3i t\u00ednh l\u1ea1i ch\u1eef k\u00fd t\u1eeb d\u1eef li\u1ec7u. Nh\u01b0ng n\u1ebfu \u0111\u1ec3 ch\u1eef k\u00fd c\u0169 n\u1eb1m trong m\u1ea3ng d\u1eef li\u1ec7u, b\u1ea1n s\u1ebd t\u00ednh ch\u1eef k\u00fd c\u1ee7a \"d\u1eef li\u1ec7u c\u1ed9ng ch\u1eef k\u00fd c\u0169\" \u2014 kh\u00f4ng bao gi\u1edd kh\u1edbp.\n\nV\u00ec v\u1eady ph\u1ea3i **c\u1eaft n\u00f3 ra, c\u1ea5t ri\u00eang, r\u1ed3i m\u1edbi t\u00ednh**.\n\n\u0110\u00e2y l\u00e0 m\u1eabu chung c\u1ee7a m\u1ecdi h\u1ec7 th\u1ed1ng ch\u1eef k\u00fd: **ch\u1eef k\u00fd kh\u00f4ng bao gi\u1edd l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a th\u1ee9 \u0111\u01b0\u1ee3c k\u00fd**.\n\n### 2.8. `vnp_ResponseCode`\n\nVNPay tr\u1ea3 v\u1ec1 m\u00e3 k\u1ebft qu\u1ea3. Ch\u1ec9 `\"00\"` l\u00e0 th\u00e0nh c\u00f4ng:\n\n| M\u00e3 | Ngh\u0129a |\n|---|---|\n| `00` | Th\u00e0nh c\u00f4ng |\n| `07` | Nghi ng\u1edd gian l\u1eadn |\n| `09` | Th\u1ebb ch\u01b0a \u0111\u0103ng k\u00fd d\u1ecbch v\u1ee5 |\n| `24` | Kh\u00e1ch h\u00e0ng h\u1ee7y giao d\u1ecbch |\n| `51` | Kh\u00f4ng \u0111\u1ee7 s\u1ed1 d\u01b0 |\n\n**Ch\u00fa \u00fd so s\u00e1nh b\u1eb1ng chu\u1ed7i `\"00\"` ch\u1ee9 kh\u00f4ng ph\u1ea3i s\u1ed1 `0`.** M\u00e3 `\"00\"` v\u00e0 `\"0\"` l\u00e0 hai chu\u1ed7i kh\u00e1c nhau, v\u00e0 m\u1ed9t s\u1ed1 m\u00e3 l\u1ed7i c\u00f3 s\u1ed1 0 \u0111\u1ee9ng \u0111\u1ea7u.\n\n### 2.9. Ki\u1ec3m tra quy\u1ec1n s\u1edf h\u1eefu \u0111\u01a1n h\u00e0ng\n\n```php\n$payment = $vnpayModel->getPaymentByOrderId($orderId);\nif (!$payment || $payment['user_id'] != $userId) {\n $_SESSION['error'] = \"Kh\u00f4ng c\u00f3 quy\u1ec1n h\u1ee7y thanh to\u00e1n n\u00e0y!\";\n ...\n}\n```\n\nC\u00f9ng nguy\u00ean t\u1eafc v\u1edbi B\u00e0i 18 m\u1ee5c 2.9: m\u00e3 \u0111\u01a1n h\u00e0ng n\u1eb1m tr\u00ean URL, n\u00ean ng\u01b0\u1eddi d\u00f9ng A ph\u1ea3i b\u1ecb ch\u1eb7n kh\u1ecfi vi\u1ec7c h\u1ee7y \u0111\u01a1n c\u1ee7a ng\u01b0\u1eddi d\u00f9ng B.\n\n---\n\n## 3. \u00c1p d\u1ee5ng v\u00e0o EzCode\n\nB\u00e0i n\u00e0y t\u1ea1o 4 file v\u00e0 s\u1eeda 2 file.\n\n### 3.1. Th\u00eam hai ph\u01b0\u01a1ng th\u1ee9c ghi danh v\u00e0o Model User\n\n> \ud83d\udcc1 `Models\/User.php` \u2014 **s\u1eeda**\n\n```php\n function checkEnrollment($user_id, $course_id)\n {\n $sql = \"SELECT * FROM enrollments WHERE user_id = ? AND course_id = ?\";\n $result = $this->db->queryOne($sql, $user_id, $course_id);\n return $result ? true : false;\n }\n\n function enrollCourse($user_id, $course_id, $price)\n {\n try {\n $sql = \"INSERT INTO enrollments (user_id, course_id, price, enrolled_at) VALUES (?, ?, ?, NOW())\";\n $result = $this->db->insert($sql, $user_id, $course_id, $price);\n return $result ? true : false;\n } catch (Exception $e) {\n return false;\n }\n }\n```\n\nModel `User` gi\u1edd \u0111\u00e3 ho\u00e0n ch\u1ec9nh v\u1edbi **10 ph\u01b0\u01a1ng th\u1ee9c**.\n\n**`checkEnrollment()`** d\u00f9ng `$result ? true : false` \u0111\u1ec3 \u0111\u1ed5i m\u1ea3ng ho\u1eb7c `false` th\u00e0nh \u0111\u00fang ki\u1ec3u lu\u1eadn l\u00fd. C\u00f3 th\u1ec3 vi\u1ebft g\u1ecdn `return (bool)$result;`, nh\u01b0ng c\u00e1ch n\u00e0y r\u00f5 ngh\u0129a h\u01a1n cho ng\u01b0\u1eddi m\u1edbi.\n\n**`enrollCourse()` kh\u00f4ng truy\u1ec1n c\u1ed9t `role`.** C\u00e2u `INSERT` ch\u1ec9 c\u00f3 4 c\u1ed9t, thi\u1ebfu `role`. Nh\u1edd c\u1ed9t \u0111\u00f3 c\u00f3 `DEFAULT 'student'` trong `ezcode.sql` (B\u00e0i 7) n\u00ean MySQL t\u1ef1 \u0111i\u1ec1n.\n\n\u0110i\u1ec1u n\u00e0y quan tr\u1ecdng v\u00ec m\u1ecdi truy v\u1ea5n th\u1ed1ng k\u00ea \u1edf B\u00e0i 19 v\u00e0 20 \u0111\u1ec1u l\u1ecdc `AND e.role = 'student'`. May m\u1eafn l\u00e0 gi\u00e1 tr\u1ecb m\u1eb7c \u0111\u1ecbnh kh\u1edbp.\n\n**Kh\u1ed1i `try\/catch` \u1edf \u0111\u00e2y kh\u00f4ng c\u00f3 t\u00e1c d\u1ee5ng.** `Database::insert()` \u0111\u00e3 t\u1ef1 b\u1eaft `PDOException` b\u00ean trong r\u1ed3i \u2014 n\u00f3 `echo` l\u1ed7i v\u00e0 tr\u1ea3 v\u1ec1 `null`. Ngo\u1ea1i l\u1ec7 kh\u00f4ng bao gi\u1edd tho\u00e1t ra t\u1edbi \u0111\u00e2y.\n\n\u0110\u00e2y l\u00e0 **ph\u00f2ng th\u1ee7 th\u1eeba** do kh\u00f4ng n\u1eafm r\u00f5 Model c\u1ee7a m\u00ecnh. Kh\u00f4ng h\u1ea1i g\u00ec, nh\u01b0ng t\u1ea1o c\u1ea3m gi\u00e1c an to\u00e0n gi\u1ea3.\n\n**`NOW()` c\u0169ng th\u1eeba** v\u00ec c\u1ed9t `enrolled_at` \u0111\u00e3 c\u00f3 `DEFAULT current_timestamp()`. L\u1ea1i m\u1ed9t s\u1ef1 tr\u00f9ng l\u1eb7p v\u00f4 h\u1ea1i.\n\n### 3.2. T\u1ea1o Model Enrollment\n\n> \ud83d\udcc1 `Models\/Enrollment.php` \u2014 **t\u1ea1o m\u1edbi**\n\n```php\ndb = new Database();\n }\n\n public function enroll($user_id, $course_id, $role = 'student', $price = 0)\n {\n $sql = \"INSERT INTO enrollments (`user_id`, `course_id`, `role`, `price`) VALUES (?, ?, ?, ?)\";\n return $this->db->insert($sql, $user_id, $course_id, $role, $price);\n }\n}\n```\n\n> \u26a0\ufe0f **L\u01b0u \u00fd:** File n\u00e0y l\u00e0 **code ch\u1ebft**.\n>\n> Class `Enrollment` \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a \u0111\u1ea7y \u0111\u1ee7, nh\u01b0ng **kh\u00f4ng m\u1ed9t file n\u00e0o trong project `include` hay kh\u1edfi t\u1ea1o n\u00f3**. B\u1ea1n c\u00f3 th\u1ec3 t\u1ef1 ki\u1ec3m ch\u1ee9ng b\u1eb1ng c\u00e1ch t\u00ecm chu\u1ed7i `new Enrollment` trong to\u00e0n b\u1ed9 project \u2014 kh\u00f4ng c\u00f3 k\u1ebft qu\u1ea3 n\u00e0o.\n>\n> Ch\u1ee9c n\u0103ng ghi danh th\u1eadt n\u1eb1m \u1edf `User::enrollCourse()` m\u00e0 b\u1ea1n v\u1eeba vi\u1ebft \u1edf m\u1ee5c 3.1.\n>\n> \u0110\u00e2y l\u00e0 **l\u1ed7i s\u1ed1 14** trong B\u00e0i 22.\n>\n> Tr\u1edb tr\u00eau l\u00e0 `Enrollment::enroll()` \u0111\u01b0\u1ee3c vi\u1ebft **t\u1ed1t h\u01a1n** `User::enrollCourse()`: n\u00f3 c\u00f3 tham s\u1ed1 `role`, d\u00f9ng d\u1ea5u backtick b\u1ecdc t\u00ean c\u1ed9t \u0111\u1ec3 tr\u00e1nh tr\u00f9ng t\u1eeb kh\u00f3a SQL, v\u00e0 kh\u00f4ng c\u00f3 kh\u1ed1i `try\/catch` th\u1eeba. Nh\u01b0ng n\u00f3 b\u1ecb b\u1ecf qu\u00ean.\n>\n> B\u1ea1n v\u1eabn t\u1ea1o file n\u00e0y \u0111\u1ec3 kh\u1edbp v\u1edbi repo.\n\n### 3.3. T\u1ea1o Model VNPay\n\n\u0110\u00e2y l\u00e0 file d\u00e0i nh\u1ea5t trong th\u01b0 m\u1ee5c `Models`.\n\n> \ud83d\udcc1 `Models\/VNPay.php` \u2014 **t\u1ea1o m\u1edbi**\n\n```php\ndb = new Database();\n }\n \n \/\/ T\u1ea1o URL thanh to\u00e1n VNPay\n public function createPaymentUrl($orderId, $amount, $orderInfo, $returnUrl) {\n $vnp_Url = \"https:\/\/sandbox.vnpayment.vn\/paymentv2\/vpcpay.html\";\n $vnp_Returnurl = $returnUrl;\n $vnp_TmnCode = \"2QXUI4J4\"; \/\/ M\u00e3 website t\u1ea1i VNPAY \n $vnp_HashSecret = \"KASJDKASJDKASJDKASJDKASJDKASJDKA\"; \/\/ Chu\u1ed7i b\u00ed m\u1eadt\n \n $vnp_TxnRef = $orderId; \/\/ M\u00e3 \u0111\u01a1n h\u00e0ng\n $vnp_OrderInfo = $orderInfo; \/\/ Th\u00f4ng tin \u0111\u01a1n h\u00e0ng\n $vnp_OrderType = \"billpayment\"; \/\/ Lo\u1ea1i h\u00e0ng h\u00f3a\n $vnp_Amount = $amount * 100; \/\/ S\u1ed1 ti\u1ec1n * 100\n $vnp_Locale = \"vn\"; \/\/ Ng\u00f4n ng\u1eef\n $vnp_IpAddr = $_SERVER['REMOTE_ADDR']; \/\/ IP kh\u00e1ch h\u00e0ng\n $vnp_CreateDate = date('YmdHis'); \/\/ Ng\u00e0y t\u1ea1o\n \n $inputData = array(\n \"vnp_Version\" => \"2.1.0\",\n \"vnp_TmnCode\" => $vnp_TmnCode,\n \"vnp_Amount\" => $vnp_Amount,\n \"vnp_Command\" => \"pay\",\n \"vnp_CreateDate\" => $vnp_CreateDate,\n \"vnp_CurrCode\" => \"VND\",\n \"vnp_IpAddr\" => $vnp_IpAddr,\n \"vnp_Locale\" => $vnp_Locale,\n \"vnp_OrderInfo\" => $vnp_OrderInfo,\n \"vnp_OrderType\" => $vnp_OrderType,\n \"vnp_ReturnUrl\" => $vnp_Returnurl,\n \"vnp_TxnRef\" => $vnp_TxnRef,\n );\n \n ksort($inputData);\n $query = \"\";\n $i = 0;\n $hashdata = \"\";\n foreach ($inputData as $key => $value) {\n if ($i == 1) {\n $hashdata .= '&' . urlencode($key) . \"=\" . urlencode($value);\n } else {\n $hashdata .= urlencode($key) . \"=\" . urlencode($value);\n $i = 1;\n }\n $query .= urlencode($key) . \"=\" . urlencode($value) . '&';\n }\n \n $vnp_Url = $vnp_Url . \"?\" . $query;\n if (isset($vnp_HashSecret)) {\n $vnpSecureHash = hash_hmac('sha512', $hashdata, $vnp_HashSecret);\n $vnp_Url .= 'vnp_SecureHash=' . $vnpSecureHash;\n }\n \n return $vnp_Url;\n }\n \n \/\/ X\u00e1c th\u1ef1c callback t\u1eeb VNPay\n public function verifyPayment($inputData) {\n $vnp_HashSecret = \"KASJDKASJDKASJDKASJDKASJDKASJDKA\";\n \n if (isset($inputData['vnp_SecureHash'])) {\n $vnpSecureHash = $inputData['vnp_SecureHash'];\n unset($inputData['vnp_SecureHash']);\n } else {\n $vnpSecureHash = '';\n }\n \n ksort($inputData);\n $i = 0;\n $hashData = \"\";\n foreach ($inputData as $key => $value) {\n if ($i == 1) {\n $hashData = $hashData . '&' . urlencode($key) . \"=\" . urlencode($value);\n } else {\n $hashData = urlencode($key) . \"=\" . urlencode($value);\n $i = 1;\n }\n }\n \n $secureHash = hash_hmac('sha512', $hashData, $vnp_HashSecret);\n return ($vnpSecureHash == $secureHash);\n }\n \n \/\/ L\u01b0u th\u00f4ng tin thanh to\u00e1n\n public function savePayment($orderId, $amount, $courseId, $userId, $status = 'pending') {\n $sql = \"INSERT INTO payments (order_id, amount, course_id, user_id, status, created_at) \n VALUES (?, ?, ?, ?, ?, NOW())\";\n return $this->db->insert($sql, $orderId, $amount, $courseId, $userId, $status);\n }\n \n \/\/ C\u1eadp nh\u1eadt tr\u1ea1ng th\u00e1i thanh to\u00e1n\n public function updatePaymentStatus($orderId, $status, $transactionId = null) {\n $sql = \"UPDATE payments SET status = ?, transaction_id = ?, updated_at = NOW() \n WHERE order_id = ?\";\n return $this->db->update($sql, $status, $transactionId, $orderId);\n }\n \n \/\/ L\u1ea5y th\u00f4ng tin thanh to\u00e1n\n public function getPaymentByOrderId($orderId) {\n $sql = \"SELECT * FROM payments WHERE order_id = ?\";\n return $this->db->queryOne($sql, $orderId);\n }\n \n \/\/ T\u1ea1o m\u00e3 \u0111\u01a1n h\u00e0ng\n public function generateOrderId() {\n return 'ORDER_' . date('YmdHis') . '_' . rand(1000, 9999);\n }\n \n \/\/ L\u1ea5y l\u1ecbch s\u1eed thanh to\u00e1n\n public function getPaymentHistory($userId) {\n $sql = \"SELECT p.*, c.title as course_title, c.image as course_image \n FROM payments p \n INNER JOIN courses c ON p.course_id = c.id \n WHERE p.user_id = ? \n ORDER BY p.created_at DESC\";\n \n return $this->db->query($sql, $userId);\n }\n}\n?>\n```\n\nTa \u0111\u1ecdc b\u1ea3y ph\u01b0\u01a1ng th\u1ee9c.\n\n**`generateOrderId()`** gh\u00e9p ba ph\u1ea7n: ti\u1ec1n t\u1ed1 `ORDER_`, th\u1eddi gian t\u1edbi gi\u00e2y, v\u00e0 b\u1ed1n s\u1ed1 ng\u1eabu nhi\u00ean. K\u1ebft qu\u1ea3 nh\u01b0 `ORDER_20250805080104_9029`.\n\nPh\u1ea7n ng\u1eabu nhi\u00ean c\u1ea7n thi\u1ebft v\u00ec hai ng\u01b0\u1eddi c\u00f3 th\u1ec3 b\u1ea5m mua trong c\u00f9ng m\u1ed9t gi\u00e2y. C\u1ed9t `order_id` c\u00f3 r\u00e0ng bu\u1ed9c `UNIQUE` n\u00ean tr\u00f9ng l\u00e0 ch\u00e8n th\u1ea5t b\u1ea1i.\n\n**`createPaymentUrl()`** d\u1ef1ng URL theo \u0111\u00fang n\u0103m b\u01b0\u1edbc \u1edf m\u1ee5c 2.4 t\u1edbi 2.6. V\u00f2ng l\u1eb7p x\u00e2y **hai** chu\u1ed7i song song:\n\n- `$hashdata` \u2014 chu\u1ed7i \u0111\u1ec3 t\u00ednh ch\u1eef k\u00fd, c\u00e1c c\u1eb7p n\u1ed1i b\u1eb1ng `&`\n- `$query` \u2014 chu\u1ed7i cho URL, m\u1ed7i c\u1eb7p k\u1ebft th\u00fac b\u1eb1ng `&`\n\nBi\u1ebfn `$i` l\u00e0 m\u1ed9t m\u1eb9o \u0111\u1ec3 bi\u1ebft \u0111\u00e2y c\u00f3 ph\u1ea3i c\u1eb7p \u0111\u1ea7u ti\u00ean kh\u00f4ng: c\u1eb7p \u0111\u1ea7u kh\u00f4ng c\u00f3 `&` ph\u00eda tr\u01b0\u1edbc, c\u00e1c c\u1eb7p sau th\u00ec c\u00f3.\n\nC\u00e1ch vi\u1ebft n\u00e0y kh\u00f3 \u0111\u1ecdc. D\u00f9ng `implode()` s\u1ebd g\u1ecdn h\u01a1n nhi\u1ec1u:\n\n```php\n$cacCap = [];\nforeach ($inputData as $key => $value) {\n $cacCap[] = urlencode($key) . \"=\" . urlencode($value);\n}\n$hashdata = implode('&', $cacCap);\n```\n\n**`verifyPayment()`** l\u00e0m ng\u01b0\u1ee3c l\u1ea1i: c\u1eaft ch\u1eef k\u00fd ra, t\u00ednh l\u1ea1i, so s\u00e1nh. \u0110\u00fang m\u1eabu \u1edf m\u1ee5c 2.7.\n\n**`savePayment()`, `updatePaymentStatus()`, `getPaymentByOrderId()`** l\u00e0 ba thao t\u00e1c CRUD th\u01b0\u1eddng tr\u00ean b\u1ea3ng `payments`.\n\n**`getPaymentHistory()`** d\u00f9ng `INNER JOIN` \u0111\u1ec3 l\u1ea5y k\u00e8m t\u00ean v\u00e0 \u1ea3nh kh\u00f3a h\u1ecdc.\n\n> \u26a0\ufe0f **L\u01b0u \u00fd \u2014 file n\u00e0y c\u00f3 hai v\u1ea5n \u0111\u1ec1 nghi\u00eam tr\u1ecdng.**\n>\n> **Th\u1ee9 nh\u1ea5t, kh\u00f3a b\u00ed m\u1eadt vi\u1ebft c\u1ee9ng trong m\u00e3 ngu\u1ed3n.**\n>\n> ```php\n> $vnp_TmnCode = \"2QXUI4J4\";\n> $vnp_HashSecret = \"KASJDKASJDKASJDKASJDKASJDKASJDKA\";\n> ```\n>\n> Hai gi\u00e1 tr\u1ecb n\u00e0y l\u00e0 **m\u00e3 m\u1eabu trong t\u00e0i li\u1ec7u VNPay**, kh\u00f4ng ph\u1ea3i m\u00e3 th\u1eadt c\u1ee7a m\u1ed9t website n\u00e0o. N\u00ean thanh to\u00e1n sandbox s\u1ebd b\u00e1o sai ch\u1eef k\u00fd \u2014 \u0111\u00f3 l\u00e0 h\u00e0nh vi \u0111\u00fang c\u1ee7a code, kh\u00f4ng ph\u1ea3i b\u1ea1n g\u00f5 sai.\n>\n> Nh\u01b0ng nghi\u00eam tr\u1ecdng h\u01a1n l\u00e0 **nguy\u00ean t\u1eafc**: kh\u00f3a b\u00ed m\u1eadt kh\u00f4ng bao gi\u1edd \u0111\u01b0\u1ee3c n\u1eb1m trong m\u00e3 ngu\u1ed3n. \u0110\u1ea9y code l\u00ean GitHub l\u00e0 c\u00f4ng khai kh\u00f3a cho c\u1ea3 th\u1ebf gi\u1edbi, v\u00e0 ai c\u00f3 kh\u00f3a th\u00ec t\u1ef1 t\u1ea1o \u0111\u01b0\u1ee3c giao d\u1ecbch gi\u1ea3.\n>\n> Chu\u1ed7i b\u00ed m\u1eadt c\u0169ng b\u1ecb **l\u1eb7p l\u1ea1i \u1edf hai ph\u01b0\u01a1ng th\u1ee9c**. \u0110\u1ed5i kh\u00f3a m\u00e0 qu\u00ean m\u1ed9t ch\u1ed7 l\u00e0 h\u1ec7 th\u1ed1ng h\u1ecfng.\n>\n> \u0110\u00e2y l\u00e0 **l\u1ed7i s\u1ed1 12** trong B\u00e0i 22.\n>\n> **Th\u1ee9 hai, file n\u00e0y d\u00f9ng `new Database()` nh\u01b0ng KH\u00d4NG `include_once \".\/Models\/Database.php\"`.**\n>\n> So s\u00e1nh v\u1edbi `Models\/Category.php` \u1edf B\u00e0i 6 hay `Models\/Courses.php` \u1edf B\u00e0i 10 \u2014 c\u1ea3 hai \u0111\u1ec1u c\u00f3 d\u00f2ng include \u1edf \u0111\u1ea7u. File n\u00e0y th\u00ec kh\u00f4ng.\n>\n> N\u00f3 ch\u1ea1y \u0111\u01b0\u1ee3c **ho\u00e0n to\u00e0n nh\u1edd may m\u1eafn**: `PaymentController` t\u00ecnh c\u1edd include `Models\/Courses.php` tr\u01b0\u1edbc, m\u00e0 file \u0111\u00f3 \u0111\u00e3 include `Database.php` r\u1ed3i.\n>\n> \u0110\u1ed5i th\u1ee9 t\u1ef1 hai d\u00f2ng include trong Controller l\u00e0 c\u1ea3 ch\u1ee9c n\u0103ng thanh to\u00e1n ch\u1ebft v\u1edbi l\u1ed7i `Class \"Database\" not found`.\n>\n> \u0110\u00e2y l\u00e0 **l\u1ed7i s\u1ed1 15** trong B\u00e0i 22 \u2014 m\u1ed9t **ph\u1ee5 thu\u1ed9c ng\u1ea7m**, lo\u1ea1i l\u1ed7i nguy hi\u1ec3m v\u00ec n\u00f3 \u1ea9n cho t\u1edbi khi ai \u0111\u00f3 v\u00f4 t\u00ecnh \u0111\u1ed9ng v\u00e0o.\n\n### 3.4. T\u1ea1o PaymentController\n\n> \ud83d\udcc1 `Controllers\/PaymentController.php` \u2014 **t\u1ea1o m\u1edbi**\n\n```php\ngetById($courseId);\n if (!$course) {\n $_SESSION['error'] = \"Kh\u00f3a h\u1ecdc kh\u00f4ng t\u1ed3n t\u1ea1i!\";\n header(\"Location: ?ctrl=course&act=list\");\n exit();\n }\n \n \/\/ Ki\u1ec3m tra \u0111\u00e3 \u0111\u0103ng k\u00fd ch\u01b0a\n $userId = $_SESSION['user_id'];\n $isEnrolled = $userModel->checkEnrollment($userId, $courseId);\n if ($isEnrolled) {\n $_SESSION['error'] = \"B\u1ea1n \u0111\u00e3 \u0111\u0103ng k\u00fd kh\u00f3a h\u1ecdc n\u00e0y r\u1ed3i!\";\n header(\"Location: ?ctrl=course&act=detail&id=$courseId\");\n exit();\n }\n \n \/\/ T\u1ea1o m\u00e3 \u0111\u01a1n h\u00e0ng\n $orderId = $vnpayModel->generateOrderId();\n $amount = $course['price'];\n $orderInfo = \"Thanh to\u00e1n kh\u00f3a h\u1ecdc: \" . $course['title'];\n $returnUrl = \"http:\/\/\" . $_SERVER['HTTP_HOST'] . \"\/EZCode_khoahoc\/?ctrl=payment&act=callback\";\n \n \/\/ L\u01b0u th\u00f4ng tin thanh to\u00e1n\n $vnpayModel->savePayment($orderId, $amount, $courseId, $userId);\n \n \/\/ T\u1ea1o URL thanh to\u00e1n\n $paymentUrl = $vnpayModel->createPaymentUrl($orderId, $amount, $orderInfo, $returnUrl);\n \n \/\/ Chuy\u1ec3n h\u01b0\u1edbng \u0111\u1ebfn trang thanh to\u00e1n\n header(\"Location: \" . $paymentUrl);\n exit();\n }\n \n \/\/ X\u1eed l\u00fd callback t\u1eeb VNPay\n public function callback() {\n include_once \".\/Models\/VNPay.php\";\n include_once \".\/Models\/User.php\";\n \n $vnpayModel = new VNPay();\n $userModel = new User();\n \n \/\/ L\u1ea5y d\u1eef li\u1ec7u t\u1eeb VNPay\n $inputData = $_GET;\n \n \/\/ X\u00e1c th\u1ef1c ch\u1eef k\u00fd\n if ($vnpayModel->verifyPayment($inputData)) {\n $orderId = $inputData['vnp_TxnRef'];\n $responseCode = $inputData['vnp_ResponseCode'];\n $transactionId = $inputData['vnp_TransactionNo'] ?? null;\n \n \/\/ L\u1ea5y th\u00f4ng tin thanh to\u00e1n\n $payment = $vnpayModel->getPaymentByOrderId($orderId);\n \n if ($payment) {\n if ($responseCode == \"00\") {\n \/\/ Thanh to\u00e1n th\u00e0nh c\u00f4ng\n $vnpayModel->updatePaymentStatus($orderId, 'completed', $transactionId);\n \n \/\/ \u0110\u0103ng k\u00fd kh\u00f3a h\u1ecdc cho user\n $userModel->enrollCourse($payment['user_id'], $payment['course_id'], $payment['amount']);\n \n $_SESSION['success'] = \"Thanh to\u00e1n th\u00e0nh c\u00f4ng! B\u1ea1n \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u0103ng k\u00fd kh\u00f3a h\u1ecdc.\";\n header(\"Location: ?ctrl=learn&act=detail&id=\" . $payment['course_id']);\n } else {\n \/\/ Thanh to\u00e1n th\u1ea5t b\u1ea1i\n $vnpayModel->updatePaymentStatus($orderId, 'failed', $transactionId);\n $_SESSION['error'] = \"Thanh to\u00e1n th\u1ea5t b\u1ea1i! Vui l\u00f2ng th\u1eed l\u1ea1i.\";\n header(\"Location: ?ctrl=course&act=list\");\n }\n } else {\n $_SESSION['error'] = \"Kh\u00f4ng t\u00ecm th\u1ea5y th\u00f4ng tin thanh to\u00e1n!\";\n header(\"Location: ?ctrl=course&act=list\");\n }\n } else {\n $_SESSION['error'] = \"Ch\u1eef k\u00fd kh\u00f4ng h\u1ee3p l\u1ec7!\";\n header(\"Location: ?ctrl=course&act=list\");\n }\n exit();\n }\n \n \/\/ Trang l\u1ecbch s\u1eed thanh to\u00e1n\n public function history() {\n include_once \".\/Models\/VNPay.php\";\n include_once \".\/Models\/Courses.php\";\n \n $vnpayModel = new VNPay();\n $coursesModel = new Courses();\n \n $userId = $_SESSION['user_id'];\n \n \/\/ L\u1ea5y l\u1ecbch s\u1eed thanh to\u00e1n\n $payments = $vnpayModel->getPaymentHistory($userId);\n \n include_once \".\/Views\/payment_history.php\";\n }\n \n \/\/ H\u1ee7y thanh to\u00e1n\n public function cancel($orderId) {\n include_once \".\/Models\/VNPay.php\";\n \n $vnpayModel = new VNPay();\n $userId = $_SESSION['user_id'];\n \n \/\/ Ki\u1ec3m tra quy\u1ec1n s\u1edf h\u1eefu\n $payment = $vnpayModel->getPaymentByOrderId($orderId);\n if (!$payment || $payment['user_id'] != $userId) {\n $_SESSION['error'] = \"Kh\u00f4ng c\u00f3 quy\u1ec1n h\u1ee7y thanh to\u00e1n n\u00e0y!\";\n header(\"Location: ?ctrl=payment&act=history\");\n exit();\n }\n \n \/\/ Ch\u1ec9 cho ph\u00e9p h\u1ee7y thanh to\u00e1n \u0111ang pending\n if ($payment['status'] == 'pending') {\n $vnpayModel->updatePaymentStatus($orderId, 'cancelled');\n $_SESSION['success'] = \"\u0110\u00e3 h\u1ee7y thanh to\u00e1n th\u00e0nh c\u00f4ng!\";\n } else {\n $_SESSION['error'] = \"Kh\u00f4ng th\u1ec3 h\u1ee7y thanh to\u00e1n n\u00e0y!\";\n }\n \n header(\"Location: ?ctrl=payment&act=history\");\n exit();\n }\n}\n?>\n```\n\n**Constructor ch\u1eb7n ng\u01b0\u1eddi ch\u01b0a \u0111\u0103ng nh\u1eadp** \u2014 c\u00f9ng k\u1ef9 thu\u1eadt v\u1edbi `TeacherController` \u1edf B\u00e0i 17, ch\u1ec9 kh\u00e1c l\u00e0 kh\u00f4ng ki\u1ec3m tra vai tr\u00f2.\n\n**`callback()` c\u00f3 ba t\u1ea7ng ki\u1ec3m tra l\u1ed3ng nhau**, v\u00e0 th\u1ee9 t\u1ef1 r\u1ea5t h\u1ee3p l\u00fd:\n\n1. Ch\u1eef k\u00fd h\u1ee3p l\u1ec7 kh\u00f4ng? \u2014 n\u1ebfu kh\u00f4ng th\u00ec d\u1eebng ngay\n2. \u0110\u01a1n h\u00e0ng c\u00f3 t\u1ed3n t\u1ea1i trong database kh\u00f4ng?\n3. M\u00e3 k\u1ebft qu\u1ea3 c\u00f3 ph\u1ea3i `\"00\"` kh\u00f4ng?\n\nBa t\u1ea7ng n\u00e0y ch\u1eb7n \u0111\u01b0\u1ee3c ba ki\u1ec3u t\u1ea5n c\u00f4ng kh\u00e1c nhau: gi\u1ea3 m\u1ea1o d\u1eef li\u1ec7u, b\u1ecba m\u00e3 \u0111\u01a1n h\u00e0ng, v\u00e0 gi\u1ea3 m\u1ea1o k\u1ebft qu\u1ea3 th\u00e0nh c\u00f4ng.\n\n**`create()` th\u1ea5y kh\u00f3a h\u1ecdc \u0111\u00e3 mua th\u00ec ch\u1eb7n** b\u1eb1ng `checkEnrollment()`. Ch\u00fa \u00fd `CourseController::register()` \u1edf m\u1ee5c 3.5 **c\u0169ng** ki\u1ec3m tra y h\u1ec7t. Tr\u00f9ng l\u1eb7p \u2014 nh\u01b0ng \u1edf \u0111\u00e2y l\u00e0 tr\u00f9ng l\u1eb7p **c\u00f3 \u00edch**, v\u00ec ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 g\u00f5 th\u1eb3ng `?ctrl=payment&act=create&id=1` b\u1ecf qua b\u01b0\u1edbc tr\u01b0\u1edbc.\n\n> \u26a0\ufe0f **L\u01b0u \u00fd:** D\u00f2ng d\u1ef1ng `$returnUrl` vi\u1ebft c\u1ee9ng \u0111o\u1ea1n \u0111\u01b0\u1eddng d\u1eabn:\n>\n> ```php\n> $returnUrl = \"http:\/\/\" . $_SERVER['HTTP_HOST'] . \"\/EZCode_khoahoc\/?ctrl=payment&act=callback\";\n> ```\n>\n> \u0110\u1eb7t project v\u00e0o th\u01b0 m\u1ee5c t\u00ean kh\u00e1c l\u00e0 VNPay g\u1ecdi l\u1ea1i sai \u0111\u1ecba ch\u1ec9 v\u00e0 giao d\u1ecbch treo v\u0129nh vi\u1ec5n \u1edf tr\u1ea1ng th\u00e1i `pending`.\n>\n> Ngo\u00e0i ra n\u00f3 d\u00f9ng `http:\/\/` vi\u1ebft c\u1ee9ng \u2014 website ch\u1ea1y HTTPS s\u1ebd b\u1ecb tr\u00ecnh duy\u1ec7t c\u1ea3nh b\u00e1o n\u1ed9i dung h\u1ed7n h\u1ee3p.\n>\n> \u0110\u00e2y c\u0169ng thu\u1ed9c **l\u1ed7i s\u1ed1 12** trong B\u00e0i 22.\n\n**M\u1ed9t \u0111i\u1ec3m nh\u1ecf:** `history()` t\u1ea1o object `$coursesModel` nh\u01b0ng **kh\u00f4ng d\u00f9ng t\u1edbi**. Code th\u1eeba \u2014 v\u00ec `getPaymentHistory()` \u0111\u00e3 t\u1ef1 `JOIN` l\u1ea5y t\u00ean kh\u00f3a h\u1ecdc r\u1ed3i.\n\n### 3.5. Th\u00eam register v\u00e0o CourseController\n\n> \ud83d\udcc1 `Controllers\/CourseController.php` \u2014 **s\u1eeda**\n\n```php\n public function register($id){\n \/\/ Ki\u1ec3m tra xem user \u0111\u00e3 \u0111\u0103ng nh\u1eadp ch\u01b0a\n if (!isset($_SESSION['user_id'])) {\n header(\"Location: ?ctrl=user&act=login\");\n exit();\n }\n \n $user_id = $_SESSION['user_id'];\n \n include_once \".\/Models\/Courses.php\"; \/\/ Include the Courses model\n include_once \".\/Models\/User.php\";\n \n $coursesModel = new Courses(); \/\/ Create an instance of the Courses model\n $userModel = new User();\n \n $course = $coursesModel->getById($id); \/\/ Fetch course details\n \n if (!$course) {\n $_SESSION['error'] = \"Kh\u00f3a h\u1ecdc kh\u00f4ng t\u1ed3n t\u1ea1i!\";\n header(\"Location: ?ctrl=course&act=list\");\n exit();\n }\n \n \/\/ Ki\u1ec3m tra \u0111\u00e3 \u0111\u0103ng k\u00fd ch\u01b0a\n $isEnrolled = $userModel->checkEnrollment($user_id, $id);\n if ($isEnrolled) {\n $_SESSION['error'] = \"B\u1ea1n \u0111\u00e3 \u0111\u0103ng k\u00fd kh\u00f3a h\u1ecdc n\u00e0y r\u1ed3i!\";\n header(\"Location: ?ctrl=course&act=detail&id=$id\");\n exit();\n }\n \n \/\/ Chuy\u1ec3n h\u01b0\u1edbng \u0111\u1ebfn thanh to\u00e1n\n header(\"Location: ?ctrl=payment&act=create&id=$id\");\n exit();\n }\n}\n```\n\nKh\u1ed1i n\u00e0y k\u1ebft th\u00fac b\u1eb1ng `}` \u0111\u00f3ng class \u2014 `CourseController` \u0111\u00e3 ho\u00e0n ch\u1ec9nh v\u1edbi 3 ph\u01b0\u01a1ng th\u1ee9c.\n\nPh\u01b0\u01a1ng th\u1ee9c n\u00e0y ch\u1ec9 **ki\u1ec3m tra r\u1ed3i chuy\u1ec3n ti\u1ebfp**, kh\u00f4ng t\u1ef1 l\u00e0m g\u00ec. N\u00f3 \u0111\u00f3ng vai m\u1ed9t tr\u1ea1m ki\u1ec3m so\u00e1t tr\u01b0\u1edbc khi v\u00e0o lu\u1ed3ng thanh to\u00e1n.\n\nCh\u00fa \u00fd d\u1ea5u ngo\u1eb7c nh\u1ecdn `{` n\u1eb1m **c\u00f9ng d\u00f2ng** v\u1edbi t\u00ean ph\u01b0\u01a1ng th\u1ee9c, kh\u00e1c v\u1edbi m\u1ecdi ph\u01b0\u01a1ng th\u1ee9c kh\u00e1c trong project. Chi ti\u1ebft nh\u1ecf cho th\u1ea5y \u0111o\u1ea1n n\u00e0y \u0111\u01b0\u1ee3c vi\u1ebft v\u00e0o l\u00fac kh\u00e1c.\n\n### 3.6. T\u1ea1o View l\u1ecbch s\u1eed thanh to\u00e1n\n\n> \ud83d\udcc1 `Views\/payment_history.php` \u2014 **t\u1ea1o m\u1edbi**\n\n```php\n\n\n
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