{"id":96402,"date":"2025-02-07T11:19:20","date_gmt":"2025-02-07T07:49:20","guid":{"rendered":"https:\/\/nabfollower.com\/blog\/how-to-prevent-double-spending-in-a-centralized-crypto-exchange-3384\/"},"modified":"2025-02-07T11:19:20","modified_gmt":"2025-02-07T07:49:20","slug":"how-to-prevent-double-spending-in-a-centralized-crypto-exchange-3384","status":"publish","type":"post","link":"https:\/\/nabfollower.com\/blog\/how-to-prevent-double-spending-in-a-centralized-crypto-exchange-3384\/","title":{"rendered":"\u0686\u06af\u0648\u0646\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646 \u0627\u0632 \u0647\u0632\u06cc\u0646\u0647 \u0647\u0627\u06cc \u0645\u0636\u0627\u0639\u0641 \u062f\u0631 \u0645\u0628\u0627\u062f\u0644\u0647 \u0631\u0645\u0632\u0646\u06af\u0627\u0631\u06cc \u0645\u062a\u0645\u0631\u06a9\u0632 \u062c\u0644\u0648\u06af\u06cc\u0631\u06cc \u06a9\u0631\u062f\u061f"},"content":{"rendered":"<div data-article-id=\"2263852\" id=\"article-body\">\n<p><strong>\u0645\u0634\u06a9\u0644<\/strong><br \/>\u0647\u0632\u06cc\u0646\u0647 \u0647\u0627\u06cc \u0645\u0636\u0627\u0639\u0641 \u0632\u0645\u0627\u0646\u06cc \u0627\u062a\u0641\u0627\u0642 \u0645\u06cc \u0627\u0641\u062a\u062f \u06a9\u0647 \u06cc\u06a9 \u0645\u0628\u0627\u062f\u0644\u0647 \u0628\u0647 \u06a9\u0627\u0631\u0628\u0631\u0627\u0646 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc \u062f\u0647\u062f \u0686\u0646\u062f\u06cc\u0646 \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u0628\u0631\u062f\u0627\u0634\u062a \u0631\u0627 \u0642\u0628\u0644 \u0627\u0632 \u0628\u0631\u0648\u0632\u0631\u0633\u0627\u0646\u06cc \u0645\u0627\u0646\u062f\u0647 \u0627\u0631\u0633\u0627\u0644 \u06a9\u0646\u0646\u062f. \u0628\u062f\u0648\u0646 \u0645\u0639\u0627\u0645\u0644\u0627\u062a \u0627\u062a\u0645\u06cc \u060c \u0645\u06cc \u062a\u0648\u0627\u0646 \u0648\u062c\u0648\u0647 \u0631\u0627 \u062f\u0633\u062a\u06a9\u0627\u0631\u06cc \u06a9\u0631\u062f.<\/p>\n<p><strong>\u0631\u0627\u0647 \u062d\u0644<\/strong><br \/>\u0627\u0632 \u0645\u0639\u0627\u0645\u0644\u0627\u062a \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 \u0628\u0627 \u062e\u0635\u0648\u0635\u06cc\u0627\u062a \u0627\u0633\u06cc\u062f \u062f\u0631 PostgreSQL \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f.<\/p>\n<p><strong>\u0627\u062c\u0631\u0627\u06cc \u0645\u062b\u0627\u0644 \u062f\u0631 Node.js \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 Sequelize orm-<\/strong><br \/><code>javascript<\/code><\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight plaintext\"><code>const { Sequelize, DataTypes } = require('sequelize');\nconst sequelize = new Sequelize('crypto_exchange', 'user', 'password', { dialect: 'postgres' });\n\nconst User = sequelize.define('User', {\n    balance: { type: DataTypes.FLOAT, allowNull: false }\n});\n\nconst withdrawFunds = async (userId, amount) =&gt; {\n    const transaction = await sequelize.transaction();\n    try {\n        const user = await User.findByPk(userId, { transaction });\n\n        if (user.balance &lt; amount) throw new Error(\"Insufficient funds\");\n\n        user.balance -= amount;\n        await user.save({ transaction });\n\n        await transaction.commit();\n        console.log(\"Withdrawal successful\");\n    } catch (error) {\n        await transaction.rollback();\n        console.error(\"Transaction failed:\", error.message);\n    }\n};\n\nwithdrawFunds(1, 100); \/\/ Example call\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0631\u0627 \u0648\u0627\u0631\u062f \u06a9\u0646\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0645\u0639\u0627\u0645\u0644\u0627\u062a \u0627\u0633\u06cc\u062f\u06cc \u062a\u0636\u0645\u06cc\u0646 \u0645\u06cc \u06a9\u0646\u062f \u06a9\u0647 \u0628\u0647 \u0631\u0648\u0632\u0631\u0633\u0627\u0646\u06cc \u0647\u0627\u06cc \u062a\u0639\u0627\u062f\u0644 \u0628\u0647 \u0635\u0648\u0631\u062a \u0627\u062a\u0645\u06cc \u0631\u062e \u0645\u06cc \u062f\u0647\u062f.<\/p>\n<p>\u0633\u06cc\u0633\u062a\u0645 \u0639\u0627\u0645\u0644 \u0647\u0627\u06cc \u0627\u06cc\u0645\u0646 \u060c \u0645\u0642\u06cc\u0627\u0633 \u067e\u0630\u06cc\u0631 \u0648 \u063a\u0646\u06cc \u0627\u0632 \u0648\u06cc\u0698\u06af\u06cc \u0647\u0627\u06cc \u0645\u062a\u0646\u0627\u0633\u0628 \u0628\u0627 \u0646\u06cc\u0627\u0632\u0647\u0627\u06cc \u062a\u062c\u0627\u0631\u06cc \u062e\u0648\u062f \u0631\u0627 \u0628\u0633\u0627\u0632\u06cc\u062f. \u0627\u0632 \u0627\u062f\u063a\u0627\u0645 blockchain \u06af\u0631\u0641\u062a\u0647 \u062a\u0627 \u062a\u062c\u0627\u0631\u062a \u062f\u0631 \u0632\u0645\u0627\u0646 \u0648\u0627\u0642\u0639\u06cc \u060c \u0631\u0627\u0647 \u062d\u0644 \u0647\u0627\u06cc \u067e\u0627\u06cc\u0627\u0646 \u0628\u0647 \u067e\u0627\u06cc\u0627\u0646 \u0628\u0631\u0627\u06cc \u067e\u0631\u0648\u0698\u0647 \u062a\u0628\u0627\u062f\u0644 \u0631\u0645\u0632\u0646\u06af\u0627\u0631\u06cc \u062e\u0648\u062f \u0631\u0627 \u062f\u0631\u06cc\u0627\u0641\u062a \u06a9\u0646\u06cc\u062f. \u0628\u06cc\u0627\u06cc\u06cc\u062f \u0622\u06cc\u0646\u062f\u0647 \u062a\u062c\u0627\u0631\u062a \u062f\u06cc\u062c\u06cc\u062a\u0627\u0644 \u0631\u0627 \u0628\u0647 \u0647\u0645\u0631\u0627\u0647 \u062a\u0648\u0633\u0639\u0647 \u062a\u0628\u0627\u062f\u0644 \u0631\u0645\u0632\u0646\u06af\u0627\u0631\u06cc \u0645\u062a\u0645\u0631\u06a9\u0632 \u0627\u06cc\u062c\u0627\u062f \u06a9\u0646\u06cc\u0645.<\/p>\n<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u0645\u0634\u06a9\u0644\u0647\u0632\u06cc\u0646\u0647 \u0647\u0627\u06cc \u0645\u0636\u0627\u0639\u0641 \u0632\u0645\u0627\u0646\u06cc \u0627\u062a\u0641\u0627\u0642 \u0645\u06cc \u0627\u0641\u062a\u062f \u06a9\u0647 \u06cc\u06a9 \u0645\u0628\u0627\u062f\u0644\u0647 \u0628\u0647 \u06a9\u0627\u0631\u0628\u0631\u0627\u0646 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc \u062f\u0647\u062f \u0686\u0646\u062f\u06cc\u0646 \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u0628\u0631\u062f\u0627\u0634\u062a \u0631\u0627 \u0642\u0628\u0644 \u0627\u0632 \u0628\u0631\u0648\u0632\u0631\u0633\u0627\u0646\u06cc \u0645\u0627\u0646\u062f\u0647 \u0627\u0631\u0633\u0627\u0644 \u06a9\u0646\u0646\u062f. \u0628\u062f\u0648\u0646 \u0645\u0639\u0627\u0645\u0644\u0627\u062a \u0627\u062a\u0645\u06cc \u060c \u0645\u06cc \u062a\u0648\u0627\u0646 \u0648\u062c\u0648\u0647 \u0631\u0627 \u062f\u0633\u062a\u06a9\u0627\u0631\u06cc \u06a9\u0631\u062f. \u0631\u0627\u0647 \u062d\u0644\u0627\u0632 \u0645\u0639\u0627\u0645\u0644\u0627\u062a \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 \u0628\u0627 \u062e\u0635\u0648\u0635\u06cc\u0627\u062a \u0627\u0633\u06cc\u062f \u062f\u0631 PostgreSQL \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f. \u0627\u062c\u0631\u0627\u06cc \u0645\u062b\u0627\u0644 \u062f\u0631 Node.js \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 Sequelize &hellip;<\/p>\n","protected":false},"author":2,"featured_media":96403,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[339],"tags":[],"class_list":["post-96402","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dev"],"_links":{"self":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts\/96402","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/comments?post=96402"}],"version-history":[{"count":0,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts\/96402\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/media\/96403"}],"wp:attachment":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/media?parent=96402"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/categories?post=96402"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/tags?post=96402"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}