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Elixir & Phoenix: Scalable Backend Development · درس

استراتيجيات المصادقة والتفويض

أمّنوا نقاط نهاية API باستخدام أساليب مصادقة شائعة مثل JWT، ونفّذوا قواعد التفويض.

استراتيجيات المصادقة والتفويض درس مجاني في Elixir & Phoenix: Scalable Backend Development على CoddyKit. هذا هو الدرس 3 من أصل 4. يمكنك قراءة الدرس كاملاً أدناه مجاناً — ثم تمرن عليه مباشرة في المتصفح باستخدام محرر أكواد مدمج ومدرس ذكاء اصطناعي متاح 24/7. هذا الدرس جزء من مسار التعلم في Elixir & Phoenix: Scalable Backend Development، وتقدمك يتزامن عبر الويب وتطبيق CoddyKit. تتضمن دورة Elixir & Phoenix: Scalable Backend Development 4 دروس في المجموع.

بعض أجزاء هذا الدرس لم تُترجم بعد وتظهر باللغة الإنجليزية.

Securing Your API Endpoints

When building APIs with Phoenix, securing your endpoints is paramount. This ensures only authorized users can access specific resources and perform actions.

We'll explore two key aspects: Authentication (proving who you are) and Authorization (determining what you can do).

What is Authentication?

Authentication is the process of verifying a user's identity. It's how your API confirms that the person or application making a request is who they claim to be.

  • Common methods include username/password, API keys, or tokens.
  • Once authenticated, the user's identity is known to the system.

Token-Based Authentication

For APIs, sending username/password with every request is inefficient and insecure. Token-based authentication is a popular solution.

After initial login, the server issues a unique token. The client then sends this token with subsequent requests to prove its identity, without re-sending credentials.

JSON Web Tokens (JWT)

JSON Web Tokens (JWTs) are a common type of token. They are compact, URL-safe means of representing claims to be transferred between two parties.

A JWT is essentially a string with three parts, separated by dots:

  • Header: Describes the token type and signing algorithm.
  • Payload: Contains the 'claims' (user data, roles, expiration).
  • Signature: Verifies the token's integrity and authenticity.

JWT Header and Payload

Both the Header and Payload are JSON objects, Base64Url-encoded. This encoding makes them safe for URL transmission, but it's not encryption – anyone can read them.

Let's see how to encode a simple Header and Payload in Elixir:

alias Jason
alias Base

defmodule JWTExample do
  def encode_part(data) do
    data
    |> Jason.encode!()
    |> Base.url_encode64(padding: false)
  end

  def main do
    header = %{"alg" => "HS256", "typ" => "JWT"}
    payload = %{"user_id" => 123, "role" => "admin"}

    encoded_header = encode_part(header)
    encoded_payload = encode_part(payload)

    IO.puts "Encoded Header: " <> encoded_header
    IO.puts "Encoded Payload: " <> encoded_payload
  end
end

JWTExample.main()

JWT Signature Explained

The Signature is crucial for security. It's created by taking the encoded Header, the encoded Payload, a secret key, and the algorithm specified in the header, then cryptographically signing them.

This signature ensures the token hasn't been tampered with. If someone changes the header or payload, the signature verification will fail.

Creating & Verifying a JWT

Here's a full Elixir example demonstrating how to combine the parts to create a simple JWT and then verify its integrity. We'll use a secret key for signing.

Notice how `Base.url_decode64` and `:crypto.mac` are used to simulate JWT logic.

alias Jason
alias Base

defmodule JWTService do
  @secret_key "my_super_secret_key_123"

  def create_token(payload) do
    header = %{"alg" => "HS256", "typ" => "JWT"}

    encoded_header = encode_part(header)
    encoded_payload = encode_part(payload)

    signature = sign(encoded_header, encoded_payload)

    "#{encoded_header}.#{encoded_payload}.#{signature}"
  end

  def verify_token(token) do
    [encoded_header, encoded_payload, signature] = String.split(token, ".")
    expected_signature = sign(encoded_header, encoded_payload)

    if signature == expected_signature do
      decoded_payload = encoded_payload |> Base.url_decode64!() |> Jason.decode!()
      {:ok, decoded_payload}
    else
      {:error, "Invalid signature"}
    end
  end

  defp encode_part(data) do
    data
    |> Jason.encode!()
    |> Base.url_encode64(padding: false)
  end

  defp sign(encoded_header, encoded_payload) do
    data_to_sign = "#{encoded_header}.#{encoded_payload}"
    :crypto.mac(:hmac, :sha256, @secret_key, data_to_sign)
    |> Base.url_encode64(padding: false)
  end

  def main do
    payload = %{"user_id" => 456, "role" => "editor", "exp" => 1678886400}
    token = create_token(payload)
    IO.puts "Generated Token: " <> token

    case verify_token(token) do
      {:ok, data} -> IO.puts "Verified! Payload: " <> inspect(data)
      {:error, reason} -> IO.puts "Verification Failed: " <> reason
    end

    # Simulate tampering
    tampered_payload = %{"user_id" => 456, "role" => "admin", "exp" => 1678886400}
    tampered_token = create_token(tampered_payload)
    [h, _p, s] = String.split(tampered_token, ".")
    # Replace the payload but keep original signature
    tampered_token_str = "#{h}." <> (payload |> Jason.encode!() |> Base.url_encode64(padding: false)) <> ".#{s}"
    IO.puts "\nTampered Token: " <> tampered_token_str

    case verify_token(tampered_token_str) do
      {:ok, data} -> IO.puts "Verified (unexpectedly)! Payload: " <> inspect(data)
      {:error, reason} -> IO.puts "Tampering Detected: " <> reason
    end
  end
end

JWTService.main()

What is Authorization?

Once a user is authenticated (we know who they are), Authorization determines what actions they are allowed to perform and what resources they can access.

It's about permissions. For example, an 'admin' user might be able to delete posts, while a 'guest' user can only view them.

Role-Based Access Control (RBAC)

A common authorization strategy is Role-Based Access Control (RBAC).

  • Users are assigned one or more roles (e.g., 'admin', 'editor', 'viewer').
  • Each role has a predefined set of permissions (e.g., 'create_post', 'edit_own_post', 'delete_any_post').
  • When a request comes in, the system checks if the authenticated user's role has the necessary permission for the requested action.

Authorization with Phoenix Plugs

In Phoenix, Plugs are an excellent way to implement authorization logic. A Plug is a modular function that processes requests.

You can create a Plug that checks the user's role (often extracted from a JWT payload) before allowing access to a controller action or an entire scope of routes.

For example, a `RequireAdminPlug` would halt the request if the user's role isn't 'admin'.

JWT & Authz Check

Which of the following statements about JWTs and API security are TRUE?

Summary: Secure Your APIs

You've learned the fundamentals of securing API endpoints!

  • Authentication confirms identity, often using tokens like JWTs.
  • JWTs consist of an encoded Header, Payload, and a cryptographic Signature for integrity.
  • Authorization defines what an authenticated user can do, commonly managed with Role-Based Access Control (RBAC).
  • Phoenix Plugs are ideal for implementing authorization checks in your API routes.

Keep exploring security best practices to build robust and safe applications!

الأسئلة الشائعة

هل درس «استراتيجيات المصادقة والتفويض» مجاني؟

نعم — نص درس «استراتيجيات المصادقة والتفويض» كامل متاح مجاناً هنا على الويب. لتمرينه بشكل تفاعلي (محرر أكواد مدمج ومدرس ذكاء اصطناعي متاح 24/7) وفتح باقي دورة Elixir & Phoenix: Scalable Backend Development، انتقل إلى CoddyKit PRO. تتضمن دورة Elixir & Phoenix: Scalable Backend Development 4 دروس في المجموع.

ماذا ستتعلم في «استراتيجيات المصادقة والتفويض»؟

أمّنوا نقاط نهاية API باستخدام أساليب مصادقة شائعة مثل JWT، ونفّذوا قواعد التفويض. تتمرن على Elixir & Phoenix: Scalable Backend Development مع أكواد عملية تشغلها مباشرة في المتصفح، ومدرس ذكاء اصطناعي متاح 24/7 يجيب على أسئلتك أثناء عملك.

هل أحتاج إلى خبرة سابقة لأبدأ Elixir & Phoenix: Scalable Backend Development؟

لا تُشترط خبرة سابقة. Elixir & Phoenix: Scalable Backend Development على CoddyKit منظم للمبتدئين حتى المتقدمين، لذا يمكنك البدء من هنا أو من البداية والتقدم بسرعتك الخاصة. هذا هو الدرس 3 من أصل 4.

كم من الوقت يستغرق درس «استراتيجيات المصادقة والتفويض»؟

معظم دروس CoddyKit تستغرق حوالي 5–10 دقائق. كل منها موجز وتفاعلي، لذا تحرز تقدماً مستمراً وتستأنف من حيث توقفت عبر الويب والتطبيق.

هل يمكنني كتابة وتشغيل أكواد في درس Elixir & Phoenix: Scalable Backend Development هذا؟

نعم. كل درس في Elixir & Phoenix: Scalable Backend Development يتضمن محرر أكواد مدمج، لذا تكتب وتشغل أكواداً حقيقية مباشرة في متصفحك وتحصل على تعليقات فورية من الذكاء الاصطناعي — بدون إعداد محلي.

جميع الدروس في هذه الدورة

  1. مبادئ تصميم API وأفضل ممارساته
  2. تطبيق نقاط نهاية API وتسلسل البيانات
  3. استراتيجيات المصادقة والتفويض
  4. تقسيم الصفحات والتصفية وإصدار واجهات API
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